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Flashcards in 2013 questions Deck (113)
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1

This 25 year old Quarter Horse is presented for evaluation in July in the northern hemisphere. Which one of the following would be the most likely cause of this horse's abnormal hair shedding?

A-Pituiatary pars intermedia dysfunction

B-Diabetes mellitus

C-Equine metabolic syndrome

D-Infestation with Psoroptes equi

E- Adrenal dependent hyperadrenocorticism

A-Pituiary pars intermedia dysfunction

This horse has pituitary pars intermedia dysfunction.

This disorder is characterized by degeneration of dopamine producing neurons in the hypothalamus that normally exert an inhibitory action on the pituitary pars intermedia, resulting in functional adenomas in the pars intermedia that produce high levels of adrenocorticotropin hormone.

Clinical signs and laboratory findings include hypertrichosis, poor muscle tone, laminitis, hyperglycemia and insulin resistance, and increased susceptibility to infection.

2

This 3-year-old horse presents for evaluation of this dry, horny, wart-like mass on the distal forelimb. This horse also has smaller wart-like lesions on its muzzle. The other young horses in the herd have similar lesions.

Which one of the following is the most likely diagnosis?

A - Melanomatosis
B - Pediculosis
C - Papillomatosis
D - Trombiculosis
E - Dermatophilosis

C-Papillomatosis

These are warts, or papillomas, which is related to infection with equine papilloma virus.

Equine papillomatosis occurs most frequently in young horses and are most commonly found on the inner surfaces of the pinna, muzzle, distal limbs, and genitalia.

They are contagious, and since they usually resolve spontaneously, treatment is rarely pursued.

3

What is the diagnosis?


A - Ketosis
B - Nutritional Muscular Dystrophy
C - Metastatic Calcification
D - Vitamin E Deficiency
E - Vitamin C Deficiency

E-Vitamin C Deficiency

Think scurvy (vitamin C deficiency) when you see hemorrhages SQ in a guinea pig. Look for swollen joints (source of lameness) and a hx of lameness, anorexia, diarrhea, weakness. May be thin with a rough hair coat. See increased vulnerability to opportunistic infections, and sudden death. Follow this link to see the original Merck image of scurvy in a guinea pig

Rx with daily vitamin C 5-10 mg/kg, PO or IM, for 1-2 wk.

AVOID multivitamins! May cause toxicity for overdose of other vitamins. Need minimum 10 mg vitamin C/day (30 mg/day for pregnant sows) in diet.

Metastatic Calcification occurs mostly in MALES

Nutrional Muscular dystrophy and vitamin E deficiency are the same thing- can present like vitamin C deficiency but without diarrhea.

Ketosis is mostly a disease of fat or pregnant animals
 

4


During the fall, a 5 year-old standardbred mare from northern California is presented with a 5-day history of depression, partial anorexia and undulating fever between 102-106 F (38.9-41.1 C)..[N=99-101.3 F].

Physical exam reveals mucosal petechiae and icterus. The horse has edematous hindlimbs and appears reluctant to move.

Blood drawn for a complete blood count shows inclusion bodies in the neutrophils.

What is the diagnosis?

A - Equine infectious anemia (EIA)
B - Purpura hemorrhagica
C - Equine ehrlichiosis
D - Equine viral arteritis (EVA)
E - Equine Babesiosis

C-Equine ehrlichiosis

his is one of the 5 classic "anemia / edema " presentations of horses. (Remember "Big 3 are PEE" Purpura, EIA, EVA; 2 minors are Babesia, ehrlichia (now renamed Anaplasma).

Inclusion bodies in the neutrophils of a California horse with icterus and petechiae and an undulating fever says Equine granulocytic ehrlichiosis (EGE).

Originally classified as Ehrlichia equi, but is NOW called ANAPLASMA phagocytophila due to DNA sequencing studies. EGE is a seasonal necrotizing vasculitis (edema, icterus, petechiae) seen in N. California, suspected to be tick borne.

See dependent edema with Equine viral arteritis (EVA), but also should see respiratory presentation (conjunctivitis/pinkeye, rhinitis) +/- abortions.

Equine infectious anemia (EIA) is rarely seen today because of testing programs, but could present this way. Less likely because 92% cases seen around the Gulf of Mexico states (Texas to Florida), Mississippi river valley AND no inclusion bodies.

Purpura hemorrhagica is a type III Antigen/Antibody/Complement complex disease causing vascultis, petechia, purplish discoloration, usually afebrile, with Hx of recent Strangles (Strep equi equi) or bacterin vaccination.

Equine Babesiosis presents more as a hemolytic anemia: seen in the S. USA, endemic in Southern FLORIDA

5

Which organism determines the minimum temperature needed to pasteurize milk in the United States?

A - Brucella abortus
B - Mycobacterium bovis
C - Listeria monocytogenes
D - Coxiella burnetii
E - Escherichia coli
 

D-Coxiella burnetii

Temperature of pasteurization is set by the toughest, most heat-resistant organism, which is Coxiella burnetii, the cause of Q fever. If the temperature is high enough, for long enough to kill Coxiella, it will also kill the other organisms.

Historically, bovine TB, (Mycobacterium bovis) was the organism that prompted pasteurization ordinances.

Brucella and Listeria can also be transmitted in milk.

E. coli is typically a contaminant from unsanitary milking conditions.

Milk pasteurization standards in the United States are detailed in the Grade A Pasteurized Milk Ordinance. Basically, the higher the temp, the shorter the pasteurization time needed. ie: 90 C (194 F) for 0.5 seconds, or 100 C (212 F) for 0.01 seconds. (see item 16p)

6


Which pair of neonatal calf diarrheas both have public health/zoonotic significance?

A - Colibacillosis, Rotavirus
B - Salmonella, Coccidiosis
C - Cryptosporidiosis, Salmonella
D - Clostridium perfringens, Coronavirus
E - Colibacillosis, Ostertagiasis

C-Crytosporidiosis, Salmonella

Cryptosporidiosis is caused by a protozoa implicated in drinking water-associated outbreaks of diarrhea in humans; Salmonellae can infect humans from a number of different sources (turtles, chickens, eggs)

E. Coli can cause human disease, but Ostertagia and bovine rotavirus do not. (There IS a human version of rotavirus, however)

C. perfringens can be found in soil and in the normal gut flora and is not contagious.

7

This is a corneal abscess secondary to infectious keratoconjunctivitis (pinkeye).

What is the most commonly recognized organism that causes pinkeye in cows?

A - Neisseria spp.
B - Colesiota conjunctivae
C - Chlamydophila pecorum
D - Mycoplasma spp
E - Moraxella bovis

E- Moraxella bovis

In cattle, Moraxella bovis is the most commonly recognized cause of infectious keratoconjunctivitis, ("Pinkeye"); Other causes include Mycoplasma spp and Neisseria spp. The severity of infection with Moraxella bovis may increase with infection with IBR or other microbes. Chlamydophila pecorum is the most common cause of pinkeye in sheep.

8



Five calves are presented with an outbreak of profuse watery diarrhea, all less than 4 days old. The calves are dehydrated and weak.
The night before two other calves died. One had diarrhea, the other did not.
What is the clinical diagnosis?

A - Colibacillosis
B - Coccidiosis
C - Rotavirus
D - Neonatal Salmonella
E - Enterotoxemia

A-Colibacillosis

Colibacillosis is the most likely cause of watery diarrhea and sudden death in multiple calves less than 4 days old. Associated with failure of passive transfer (FPT) and septicemia.

Remember the AGE, SEVERITY and # AFFECTED when looking at calf diarrheas.

The EARLY diarrheas are due to:
Escherichia coli- less than 4 days old, multiple cases.
Rotavirus - 5d-2 wks old, self limiting, multiple calves.
Coronavirus, 4-30d, multiple calves
Enterotoxemia (Clostridium perfringens type C) 2 wks, healthiest, fastest growing calf, hemorrhagic diarrhea, sudden death!
Cryptosporidia, 1-4 wks, diarrhea, tenesmus, emaciation.

LATER diarrheas are:
Neonatal Salmonella-1-2 mos, fever and diarrhea, septicemia, sudden death.
Coccidiosis-older than 21 days and in ALL ages, bloody diarrhea, tenesmus.

9

What's wrong with this picture?

A - Left acetabular fracture
B - Sacrococcygeal dysgenesis
C - Megacolon
D - Pelvic fracture
E - Tail root avulsion

B-Sacrococcygeal dysgenesis

This is Sacrococcygeal dysgenesis, an inherited trait in Manx cats. Look for dysgenesis, agenesis of sacrum or other spinal column abnormalities.

May present asymptomatic or with palpable lumbosacral abnormalities and LMN hind limb signs. (Hopping or crouched gait). May see nonprogressive urinary or fecal incontinence, chronic constipation.

Sequelae include recurrent urinary tract infections, megacolon.

NO treatment.
 

10

A 3-year old Irish Setter presents with a history of lameness and swelling in the distal forelimb. A radiograph looks like the image below.

What is the presumptive diagnosis?

A - Osteosarcoma
B - Osteomyelitis
C - Panosteititis
D - Osteochondrosis
E - Hypertrophic osteodystrophy

A-osteosarcoma

This is a classic image of Osteosarcoma, a COMMON, aggressive bone tumor typically found in the appendicular skeleton, especially distal radius.

90% have microscopic metastases to lungs by time of Dx, (but less than 10% will have visible thoracic metastasis at time of diagnosis).

Usually, does not cross joint (unlike osteomyelitis, which usually DOES cross joint). Look for soft tissue swelling, periosteal proliferation, sunburst periosteal reaction (33%), possible pathologic fractures.

11


What are the two main causes of pregnancy toxemia in guinea pig sows?

A - Anemia and hyperkalemia
B - Ketosis and hypertension
C - Hypocalcemia and anemia
D - Hyperlipidemia and hyperglycemia
E - Hypocalcemia and thrombocytopenia
 

B-ketosis & hypertension

The two types of pregnancy toxemia in guinea pigs are-
1. Ketosis secondary to a negative energy balance and
2. Ischemia due to the uterine compression of the vascular supply of the uterus, GI tract, or kidneys resulting in hypertension.

Clinical signs of pregnancy ketosis are ketone breath, lethargy, incoordination, dyspnea, paralysis, and death. Treatment of pregnancy-related hypertension may require an emergency cesarean section.
 

12


Which of the following hays is highest in calcium?

A - Orchard grass hay
B - Barley hay
C - Oat hay
D - Alfalfa hay
E - Bermuda grass hay
 

D-Alfalfa Hay

Compared to other types of hays, alfalfa tends to be higher in calcium, protein, and energy.

13

An aged intact female potbellied pig presents for evaluation of abdominal distension. A large mass contiguous with the uterine wall is discovered with ultrasound exam of the abdomen.

Which of the following choices is the most likely cause of this finding?

A - Endometrial hyperplasia
B - Uterine leiomyoma
C - Uterine lymphosarcoma
D - Endometritis
E - Uterine adenocarcinoma

B- Uterine Leiomyoma

The most likely cause of a large uterine mass in an intact female potbellied pig is a uterine leiomyoma. These tumors do not typically metastasize so a cure may be achieved by surgical removal of the uterus.

Follow this link to see more on leiomyomas and other connective tissue tumors

14

A sandhill crane from a local zoo dies after a period of chronic weight loss and weakness. Nodular lesions are discovered in the liver and spleen.

Which one of the following choices is the most likely diagnosis?

A - Tuberculosis
B - Spirochetosis
C - Histomoniasis
D - Fowl cholera
E - Lymphoid leukosis

A-Tuberculosis

Tuberculosis due to Mycobacterium avium is the most common cause of these findings. M. avium is challenging to control in zoos and poultry flocks, because treatment may not be effective. A 3-month quarantine of all new additions to the aviary is strongly recommended.

Histomoniasis can produce caseous lesions similar to that of tuberculosis, but usually only involves the ceca and liver of galliform birds, especially turkeys and chickens. Histomoniasis is also known as blackhead.

15


A poultry operation has been having problems with sick birds and many have died over the past few months.

A few showed torticollis before death. Some of the currently ill fowl have swollen joints, wattles, and footpads.

One of the broilers with swollen wattles is sacrificed. There is caseous, suppurative material inside the wattle and necrotic lung lesions.

Which one of the following agents is likely involved?

A - Salmonella gallinarum
B - Paramyxovirus
C - Fowlpox
D - Pasteurella multocida
E - Marek's disease virus

 

D-Pasteurella multocida

Pasteurella multocida is the causative agent of Fowl Cholera. Older chickens are more vulnerable than are younger chickens.

The description above is of chronic fowl cholera. In acute fowl cholera, there are usually no clinical signs before a large number of birds die.

Classic lesions of Marek's diseaseare enlarged sciatic nerves and lymphoid tumors. It is a highly contagious disease, but may be subclinical in many cases.

16

This 25 year old Quarter Horse mare is presented for evaluation in July in the northern hemisphere. She is diagnosed with pituitary pars intermedia dysfunction.

Which one of the following medications would be most likely to be beneficial to this mare? 

A - Pentoxifylline
B - Isoxsuprine
C - Glucocorticoids
D - Pergolide
E - Methimazole

D-Pergolide

Pergolide is the treatment of choice for pituitary pars intermedia dysfunction (PPID).

PPID is characterized by degeneration of dopamine producing neurons in the hypothalamus that normally exert an inhibitory action on the pituitary pars intermedia, resulting in functional adenomas in the pars intermedia that produce high levels of adrenocorticotropin hormone.

Clinical signs and laboratory findings include hypertrichosis, poor muscle tone, laminitis, hyperglycemia and insulin resistance, and increased susceptibility to infection.

Diagnosis is commonly made by documenting increases in plasma adrenocorticotropin hormone levels in affected animals.

17

This 3 year old horse is presented for evaluation of these non-pruritic, non-painful face lesions. Most of the other young horses in the herd are also affected, and many of these horses also have lesions in the girth area.

Which one of the following diagnostic tests would be most likely to identify the cause of the lesions?

A - Fungal culture of hair and skin scales
B - Determination of serum antibody response to a regional panel of fungal pathogens
C - Biopsy
D - Testing for antinuclear antibodies in serum
E - Bacterial culture of hair and skin scales

Fungal culture of hair and skin scales.

This horse has dermatophytosis, or ringworm, typically caused by infection with Trichophyton equinum or Trichophyton metagrophytes.

Lesions can start as papular urticaria, but then progress to one or more, usually round, patches of alopecia, scaling, and crusting.

Culture confirms the diagnosis, and the recommended treatment is topical anti-fungal shampoos, although the disease is usually self-limiting.

The disease is highly contagious among susceptible animals and is also potentially zoonotic.

18

What is wrong with this picture? 

A - Posterior synechiae
B - Orbital cellulitis
C - Anterior lens luxation
D - Nuclear sclerosis
E - Cataract

This is Anterior lens luxation. Follow this link to see another lens displacement image- note the aphakic crescent to right side (area of pupil without lens)

Look for an opaque (cloudy, milky) lens behind pupil with cataracts. In contrast, Nuclear sclerosis looks like this.

Orbital cellulitis presents in large and hunting breeds of dogs with acute pain on opening mouth, eyelid swelling, unilateral prolapse of nictitating membrane, eye protrusion, conjunctivitis. Dog's face looks swollen with inflamed, red eyes , (aka: "Devil dog") 

19

An 8-year old German shepherd is presented with a 1-month history of cough, labored breathing and lethargy. He has fainted a few times after exertion.

Upon physical exam pallor and a slow capillary refill time is noted. The dog has jugular distension, diminished, quiet heart sounds, ascites and weak, variable femoral pulses.

T=102.0 F (38.9 C)..[N=99.5-102.5 F]
HR=140 bpm...........[N=80-120]
RR=24 brpm...........[N=15-34]

A thoracic radiograph reveals the following.

What is the clinical diagnosis?

A - Cor pulmonale
B - Peritoneopericardial hernia
C - Dilated cardiomyopathy
D - Congestive heart failure (left)
E - Pericardial effusion

This is the clinical picture of Pericardial effusion. Note the spherical "Balloon heart". Follow this link to see a DV view of Pericardial effusion. RX of choice is pericardiocentesis.

Ascites, distended jugulars suggests RIGHT congestive heart failure (CHF), more than left CHF (pulmonary edema, crackles, wheezes, cough).

Cor pulmonale is just another name for right CHF due to pulmonary hypertension.

Dilated cardiomyopathy (DCM) should be on your DDX. More likely to hear systolic murmur, arrhytmias, less likely to be muffled heart sounds. ECHOCARDIOGRAPHY resolves DDX between pericardial effusion, DCM and Peritoneopericardial hernia.

20

What kind of organism causes equine granulocytic ehrlichiosis?

A - Chlamydia
B - Spirochete
C - Protozoa
D - Anaplasma
E - Ehrlichia

D-anaplasma 

This is a tricky question to help you remember that two diseases FORMERLY classified as ehrlichia have now been re-classified. The causative organism of Equine granulocytic ehrlichiosis (EGE) was originally classified as Ehrlichia equi, but is now called ANAPLASMA phagocytophila due to DNA sequencing studies.

Do not confuse EGE, a necrotizing vasculitis in HORSE with BOVINE anaplasmosis, primarily an anemia, with icterus, fever.

Another name change occurred with the causative organism of Potomac Horse Fever (PHF), from Ehrlichia risticii to NEOrickettsia risticii. PHF presents as a febrile colitis/diarrhea, with laminitis 3-5 d after diarrhea in horses of all ages: A big rule out is salmonella (think septicemia/fever+ diarrhea).

21

Which one of the following disorders can develop secondary to Spirocerca lupi infection?

A - Mammary adenocarcinoma
B - Tracheal sarcoma
C - Hyperparathyroidism
D - Diverticulitis
E - Hypertrophic osteopathy

E - Hypertrophic osteopathy

Hypertrophic osteopathy can occur secondary to infection with the 'esophageal worm', Spirocerca lupi.

This parasite affects the esophagus, aorta, and thoracic vertebrae. Infection develops by ingestion of the intermediate host, the dung beetle, or other paratenic hosts such as birds, hedgehogs, lizards, mice, or rabbits.

Spirocercosis can also cause esophageal neoplasia or spondylitis of the thoracic vertebrae.

22

Which three nerve blocks will correctly isolate the majority of equine lamenesses?

A - Suspensory ligament infiltration, Coffin, Proximal metacarpal
B - Low 4-point, Fetlock, Peroneal
C - Heel, High 4-point, Proximal metacarpal
D - Palmar digital, Abaxial sesamoid, Low palmar
E - Median/Ulnar, Low volar, Navicular bursa

D - Palmar digital, Abaxial sesamoid, Low palmar

90% of all lameness is in the HOOF. That means the three LOWEST nerve block will help you isolate most lamenesses.

These 3 are:
1). HEEL block (also called palmar digital (PD), used to help Dx navicular syndrome )

2). PASTERN block (also known as the foot block, abaxial sesamoid nerve block (ASNB))- Can use to make a horse with acute laminitis comfortable)

3). FETLOCK block (Also called Low palmar, Volar or Low 4-point block).

If horse is still lame after these 3 blocks (heel, pastern, fetlock), continue up limb with metacarpal/high 4-point, then prox. metacarpal blocks next.

23

A guinea pig is presented for seizure-like activity. On closer observation the guinea pig is not having a seizure but is actually severely pruritic. It also has hyperkeratosis and generalized alopecia.

Which one of the following choices is the most likely diagnosis?

A - Follicular ovarian cysts
B - Trixacarus caviae
C - Klossiella cobayae
D - Copper deficiency
E - Scurvy

B - Trixacarus caviae

Trixacarus caviae causes the most severe dermatitis of all guinea pig ectoparasites. Ivermectin treatment is usually successful but is used off label.

Scurvy (hypovitaminosis C) can occur in guinea pigs as they rely on dietary intake of vitamin C.

Clinical signs include diarrhea, joint pain, alopecia, petechiae, weight loss, hypertriglyceridemia, hypercholesterolemia, and skeletal muscle hemorrhage.

24


A 9-year old neutered male cat is presented, he is an indoor/outdoor cat who has recently been losing weight. He doesn't run around like he used to and wheezes now when he does move around. His owner relates that he hasn't had much of an appetite the last few weeks and is vomiting every day or so lately.

On physical exam it is noted that the cat is thin, with mild dehydration and somewhat dark mucous membranes but a normal capillary refill time. On auscultation inspiratory wheezes and somewhat irregular, muffled heart sounds are heard.

T=103.1 F (39.5 C).....[N=100-103.1 F]
HR=124 bpm..............[N=100-140]
RR=30 brpm..............[N=16-40]

A lateral chest radiograph looks like the image below.

What is likely to have caused this illness?


A - Feline mediastinal lymphosarcoma
B - Lung lobe torsion
C - Pleural effusion
D - Hit by a car
E - Hypertrophic cardiomyopathy

D- Hit by a car

This is a diaphragmatic hernia (see loops of bowel with gas density overlapping lung fields).

Almost always secondary to trauma, esp. in pets HIT BY CARS. May present acutely after accident (shock, pale, tachypnea, tachycardia, dyspnea), or may show up with NO Hx of trauma and nonspecific GI, respiratory signs. May hear gut sounds in chest, muffled heart sounds. Can be congenital (think Weimaraner, Cocker), asymptomatic and go undiagnosed until middle age!!

In cattle, associated with traumatic reticuloperitonitis (Hardware Disease).

Look for FLOATING LUNGS with pleural effusion.

With Hypertrophic cardiomyopathy (HCM) may have more severe cardiac sign, may see classic "Valentine" heart on DV rads.

Lung tumors, like Feline mediastinal lymphosarcoma may obscure what should be dark, air-filled lung fields, but you still will not see loops of bowel in there. Follow this link to see a primary lung tumor. Note the contrast with multiple metastatic tumors in the lung.

25

Which reportable condition can affect cattle, but mainly causes disease in sheep?

A - Vesicular stomatitis
B - Anthrax
C - Malignant Catarrhal fever
D - Rinderpest
E - Bluetongue

E-bluetongue

Bluetongue is almost exclusively a sheep disease, (but cattle and deer can get it).

Rinderpest mainly affects cattle and is reported to be eliminated as of October 2010 by the the United Nation's Global Rinderpest Eradication Program. Because it is a classic severe and reportable vesicular disease, vets will likely need to keep rinderpest on their mental DDX list for years to come.

Pseudorabies is basically a pig pathogen. Can affect cows, but horses (and humans) are resistant

Vesicular Stomatitis (VS) can occur in horses, pigs, cows. Remember the big 8 vesicular diseases: BVD, IBR, BPS, MCF, Bluetongue, VS, FMD, Rinderpest)

26

How long is a practice required to maintain client medical records?

A - Decades
B - Years
C - Months
D - Never
E - Weeks

B-years

The exact amount of time you must preserve medical records varies by state and provincial law, but it is measured in YEARS, usually 4-6 years or so.

The number of years is typically based on the statue of limitations in your state or province for bringing certain claims against veterinarians.

In the state of Michigan for example, claims include general professional malpractice (2 years), negligence (3 years), property damage (3 years) and breach of contract (6 years).

See the AVMA's Principles of Veterinary Medical Ethics (2008 revision), form the last word on vet ethics. Section VIII covers medical records handling.

27

A 3-year old Quarter horse/Appaloosa cross mare is presented on emergency because she collapsed in the last 30 minutes.

The mare is recumbent and weak, with respiratory stridor, muscle fasiculations, sweating, prolapse of the third eyelid and her lips pulled back spasmodically, like a grin.

T=100.2 F (37.9 C)..[N=99-101.3 F]
HR=24 bpm.............[N=28-40]
RR=16 brpm............[N=10-14]

The horse is hydrated and has had no recent history of colic. During the examination, she improves markedly and within 60 minutes stands and appears almost normal again with no treatment.

What is the clinical diagnosis?

A - Hyperkalemic periodic paralysis
B - Myasthenia gravis
C - Epilepsy
D - Equine degenerative myelopathy
E - Grass staggers

A - Hyperkalemic periodic paralysis

This is likely to be Hyperkalemic periodic paralysis (HyPP), an autosomal dominant trait found in ~ 4% of Quarter horses.

Heterozygotes often have periodic episodes 15-90 min: prolapse 3rd eyelid, muscle fasiculations, collapse. 25% cases traced back to one stallion named "Impressive".

Onset of signs unpredictable, and many triggers: diets high in POTASSIUM (>1.1%, ie: alfalfa hay, molasses, electrolyte supplements, kelp-based supplements). Fasting, anesthesia, heavy sedation, trailer rides, and stress can precipitate clinical signs.

Grass staggers think "goose-stepping" (overstepping) from ergot on grass. EDM think ataxia in foals 6-8 mos. Epilepsy poorly documented in horses. Myasth. Gravis basically a dog disease.

28


A 3-month old calf is presented for necropsy. The calf collapsed and suddenly died this morning after she escaped and was chased around the back pasture for 45 minutes by her owner.

Among other things, endocardial plaques in the left ventricle of this calf's heart are discovered.

What advice should be given the farmer?

A - Search the calf barn for sources of lead
B - Check the mother for bovine leukosis by AGID
C - Take all the calves off ionophore-containing feed
D - Treat the other calves with vitamin E/Selenium
E - Start the other calves on Ceftiofur (Naxcel ®)

D - Treat the other calves with vitamin E/Selenium

Treat the other calves with vitamin E/Selenium. Think of white muscle disease when you see SUDDEN DEATH and endocardial PLAQUES in a young calf, lamb or kid with a history of recent VIGOROUS EXERCISE. Follow this link to a Merck image of pale ventricular myocardium.

Typically seen in young, fast-growing animals (ie: calves 2 weeks-6 mos) Clinical signs may include dyspnea (due to myocardial disease), stiff gait, arched back, weakness, recumbent but BAR (bright, alert, responsive).

Sudden death may resemble enterotoxemia, should see acute bloody diarrhea, convulsions, opisthotonos in first days of life with enterotoxemia.

29

A cow is presented on emergency with urea/non-protein nitrogen toxicity.

What is the treatment of choice?

A - IV Fluids with MgSO4, Na thiosulfate PO
B - Atropine, Protopam chloride IV q 4-6 hours
C - Rumenotomy
D - Relieve bloat, drench with 2-8 liters sodium bicarbonate
E - Rumenal infusion 2-8 liters vinegar,3-10 gallons cold water

E - Rumenal infusion 2-8 liters vinegar,3-10 gallons cold water

Treat Urea/non-protein nitrogen (NPN) toxicity with a rumenal infusion 2-8 liters 5% acetic acid (vinegar) and 3-10 gallons of cold water. The vinegar decreases rumenal pH which slows absorption of un-ionized ammonia. Repeat Q 6 hours up to 48 hours. Best results if animal is still ambulatory.

It is often impossible to treat these cases before they die because of rapid progression to death. If possible, Rx with IV fluids. If necessary, relieve bloat.

Urea/NPN toxicity is related to ammoniated feed toxicity which causes so-called "Bovine bonkers". Manage ammoniated feed toxicity by removing the ammoniated feed and treating severe cases with anticonvulsants like diazepam, pentobarbital.

30

A bovine diet that is low in thiamine or high in sulfur can cause ____________.

A - Parturient paresis
B - Polioencephalomalacia
C - Downer cows
D - Pseudorabies
E - Pregnancy toxemia
 

B - Polioencephalomalacia

The two most common causes of polioencephalomalacia (PEM) are low thiamine (due to thiaminase activity from plants like bracken fern or low thiamine diets) and high sulfur in the diet (which can come from a high molasses-urea diet, corn or sugar cane byproducts, water, or other plants, including alfalfa, Canada thistle (Cirsium arvense), kochia, (Kocchia scoparia), and lambsquarter (Chenopodium spp).

31


A 2-year old heifer is presented who died the night before.

She was stunted compared to her herdmates, and had a 3-week history of poor appetite, unthriftiness, diarrhea.

Necropsy reveals that the abomasum is edematous and covered in small umbilicated nodules 1-2 mm in diameter (cobblestone or "Moroccan leather" appearance).

Several other younger cows in this Spring-calving herd look unthrifty and have diarrhea too.

What is the plan of action?

A - Deworm cows post-calving, calves by midsummer, all stock in fall
B - Treat affected heifers with Ivermectin, repeat in 6 months
C - Treat affected heifers with Albendazole
D - Treat herd with Amprolium, repeat q 5 weeks
E - Cull the sick cows, Keep horses off same pasture 3 months

A - Deworm cows post-calving, calves by midsummer, all stock in fall

Treatment includes deworming cows post-calving, calves by midsummer, all stock in fall. An abomasum with a cobblestone or "Moroccan leather" appearance is pathognomonic for Ostertagia, one of the three stomach worms of cattle. Follow this link to see a Merck image of Ostertagia in an abomasum. These worms remain dormant in the gastric glands of the abomasum, emerging in the spring.

Rx is based on regular deworming of whole herd (2-4 times/year). Ivermectin or high dose Albendazole/Fenbendazole, given repeatedly can help treat the dormant ("hypobiotic") Ostertagia in the gastric glands.

Amprolium is your treatment of choices for calves and cows with Coccidiosis.

Refs: Pasquini's Guide to Bovine Clinics, 4th ed. pp. 21, 55 and the Merck Veterinary Manual online edition.

32


Pyrrolizidine alkaloid toxicity is caused by chronic ingestion of which one of the following plants?

A - Lupinus spp (lupine)
B - Astragalus spp (locoweed)
C - Nerium spp (oleander)
D - Senecio spp (ragwort)
E - Persea spp (avocado)
 

D - Senecio spp (ragwort)

Common plants containing pyrrolizidine alkaloids (PA) are: Senecio vulgaris, S. jacobea, Amsinckia intermedius, Heliotropium europaeum, Crotolaria spectabilis.

Although generally not palatable, livestock will eat these plants when baled in hay or on pasture when forage is scarce. Chronic ingestion allows accumulation of toxic levels of PA, resulting in hepatic fibrosis.

Poisoning is most common in horses and cattle, sheep and goats are more resistant to toxic effects.

Persea spp (avocado leaves) contain persin. Signs of toxicity are: noninfectious mastitis, abrupt cessation of milkflow, heart failure.

Nerium spp (oleander) contain cardiac glycosides. Signs of toxicity are: sudden death, weakness, diarrhea, cardiac arrhythmias.

Lupinus spp (lupine) contain alkaloids. Signs of toxicity are: birth defects (ingestion at 40-70 days in cattle), abortion, tremors, incoordination, head pressing, seizures.

Astragalus and Oxytropis spp (locoweed) contain alkaloids (swainsonine). Signs of toxicity are: excitability, incoordination, difficulty eating, exaggerated mouth movements, depression.

Follow this link to a Merck table with images of Poisonous RANGE plants. Follow this link to a Merck table with images of Poisonous HOUSE plants

Refs: Knight and Walter's A Guide to Plant Poisoning, 1st ed, pp. 144-6, 155-9, Pasquini's Guide to Bovine Clinics 4th ed., p. 233, Forero, Livestock-Poison Plants of CA, U of CA, Davis, ANR, pp. 7, 23, and the Merck Veterinary Manual online edition.

33

Which one of the following choices includes the cardinal sign of trigeminal neuritis?

A - Paralyzed eyelid, ear or lip on one or both sides of the face
B - Dysphagia, dysphonia and stridor
C - Masseter muscle pain associated with chewing
D - Circling and head tilt toward side of lesion, no other signs
E - Inability to close the mouth
 

E - Inability to close the mouth

Idiopathic trigeminal neuritis, cranial nerve 5, (CN 5) is characterized by acute onset of flaccid jaw paralysis. Affected animals cannot close their mouth and have difficulty eating and drinking. Seen occasionally in dogs, rare in cats. Cause is unknown.

Idiopathic facial nerve paralysis, cranial nerve 7, (CN 7) results in the inability to move the eyelid, lip, or ear and dryness of the eyes and mouth.

Masticatory myositis is characterized by pain on opening the mouth and swelling of the muscles of mastication (acute) or atrophy of the temporalis and masseter muscles with the inability to open the mouth due to fibrosis (chronic).

Dysphagia, dyphonia, and stridor are most often associated with dysfunction of the vagus nerve, cranial nerve 10 (CN 10).

Circling and head tilt toward the side of the lesion with no other signs is a common presentation of vestibulocochlear nerve, cranial nerve 8 (CN 8) lesions. Concurrent CN 7 paralysis and Horner's syndrome (ptosis, miosis, enophthalmis) may be present with middle- and inner-ear infections.

Refs: Chrisman's Neurology for the Small Animal Practitioner, 2003 p.159, Cote's Clin Vet Advisor-Dog and Cat 1st ed., pp. 374-5, 687, 1105-6, Pasquini's Guide to Small Animal Clinics 3rd ed., p. 562-3, 590, and the Merck Veterinary Manual online edition.

34

An adopted adult cat from a shelter with an unknown vaccination history tests positive for feline leukemia virus (FeLV) infection by IFA.

What should the owner be told?

A - Need a Western blot test to confirm diagnosis
B - Strong chance of lifelong FeLV infection
C - Need an ELISA test in 12 weeks to confirm diagnosis
D - Possible transient FeLV infection
E - Cat may be vaccinated for FeLV

B - Strong chance of lifelong FeLV infection

97% of cats positive for feline leukemia virus (FeLV) by IFA remain persistently infected and viremic for life.

The FeLV ELISA is more seNsitive than the IFA (fewer false Negs, so trust a NEG test more), so it is a better general screening test with which to start. Click here for a diagram.

The FeLV IFA is more sPecific than the ELISA, (fewer false Pos, so trust a POS test more) so it is a better confirmatory test for any cats with a positive FeLV ELISA. Click here for a diagram.

THREE things to remember about FeLV and vaccinations:
1. FeLV ELISA and IFA tests measure ANTIGEN, not antibody, so FeLV vaccination does NOT interfere with testing.
2.Vaccinate FeLV-positive cats yearly against respiratory, enteric viruses with inactivated vaccines.
3. FeLV vaccination for FeLV-negative cats has been associated with sarcomas. Vaccinate LOW on the LEFT hind.

Refs: Blackwell's 5-Min. Vet Consult Canine-Feline, 4th ed. pp. 490-1, Cote, Clin Vet Advisor-Dog and Cat, 1st ed. pp. 380-2 and the Merck Veterinary Manual online edition.

35

How long after the first rabies vaccination is a dog, cat or ferret considered to be immunized and protected against rabies?

A - Same day
B - After 7 days
C - After 24 hours
D - After 14 days
E - After 28 days

E. after 28 days

After 28 days. According to the Compendium for Rabies Control, a peak rabies virus antibody titer is reached 28 days after initial vaccination and immediately after booster vaccination.

Here are some thoughts on rabies:
When in doubt, it is never wrong to check with your local health department.

Basically all potential rabies exposures boil down to 2 questions:
1. Who is involved?
Animal-Animal exposure (less alarm bells)
Animal bites/exposes human (more alarm bells)

2. Was animal vaccinated/up to date on vaccination?
Up to date on vaccs (less alarm bells, shorter observation)
Vaccinated, but not up to date (Handle on case-by-case basis)
Un-vaccinated pet (more alarm bells, euthanize or long observation period)
Wild animal, esp. bats, raccoon, skunk (euthanize, send head to state lab)

When dealing with rabies questions, ask yourself if this seems like a HIGH-risk exposure (ie: wild raccoon bites a child)
or a LOWER risk exposure (ie: Up-to-date vaccinated dog messes with woodchuck but no bite wounds on dog).

For high risk lean towards euthanasia/testing or long quarantine. For low risk lean towards short observation period (10 days) and a rabies booster.

Refs: The SINGLE BEST REF on rabies is the Compendium for Rabies Prevention and Control, 2011; Nov 4, 2011 / 60(RR06);1-14.

For info on post-exposure prophylaxis for people see: Human Rabies Prevention-US, 2008 ACIP Reccs: May 23, 2008 / 57(RR03);1-26,28 and, as always, the Merck Veterinary Manual online edition.

36

A poultry operation has been having problems with sick birds and many have died over the past few months.

A few showed torticollis before death. Some of the currently ill fowl have swollen joints, wattles, and footpads.

One of the broilers with swollen wattles is sacrificed. There is caseous, suppurative material inside the wattle and necrotic lung lesions.

Which one of the following agents is likely involved?

A - Salmonella gallinarum
B - Paramyxovirus
C - Fowlpox
D - Pasteurella multocida
E - Marek's disease virus

D - Pasteurella multocida

Pasteurella multocida is the causative agent of Fowl Cholera. Older chickens are more vulnerable than are younger chickens.

The description above is of chronic fowl cholera. In acute fowl cholera, there are usually no clinical signs before a large number of birds die.

Classic lesions of Marek's diseaseare enlarged sciatic nerves and lymphoid tumors. It is a highly contagious disease, but may be subclinical in many cases.

Refs:The Merck Veterinary Manual online edition. Image courtesy, The Poultry Site.

37

A nine-year-old Irish setter presents for vomiting. The owner states that the dog does not really retch, but just spits up food soon after eating. The dog is normal otherwise. Thoracic radiographs are taken.

Based on the lateral radiograph below, which one of the following choices would be useful to determine a definitive diagnosis for this case?

A - Test for acetylcholine receptor antibodies
B - Cardiac echocardiography and doppler flow
C - Endrophonium challenge test
D - Pass a stomach tube and prep for emergency laparotomy
E - Ultrasonography of abdomen

Test for acetylcholine receptor antibodies, to ruleout myasthenia gravis, which is a frequent finding in older dogs with acquired megaesophagus, outlined in the image below.
 

Edrophonium (Tensilon) can be given as a clinical test for myasthenia gravis. However, since this dog is not weak it would not be useful.

Megaesophagus can be idiopathic or secondary to several disorders. Other causes include megaesophagus are heavy metal toxicity, polymyositis, lupus, and possibly hypothyroidism.

Refs: Cote, Clin Vet Advisor 2nd ed. pp. 709-11, Merck Vet Manual 10th ed. online, Dilation of the Esophagus in Small Animals, Image courtesy, Dr Kalumet and Wikimedia Commons.

38

A farmer has a few 8-12 week old pigs with weight loss, diarrhea, and a few with expiratory dyspnea.

Several pigs with similar symptoms have died recently. Mucous membranes are pale, and inguinal lymph nodes are enlarged.

Which one of the following viruses is the most likely causative agent?

A - Parvovirus
B - Manangle virus
C - Circovirus
D - Herpesvirus
E - Paramyxovirus

Circovirus, a nonenveloped DNA virus was first described in Canada in 1991 and causes Postweaning multisystemic wasting syndrome (PMWS).

The virus is also associated with porcine dermatitis and nephropathy syndrome caused by necrotizing vasculitis, which is more prominent in the skin, renal pelvis, mesentery, and spleen.

Refs: Handbook of Pig Medicine, Jackson & Cockcroft, pp. 188-190, Merck Vet Manual 10th ed. online, Images courtesy, The Pig Site.

39

A group of chickens presents with facial edema, green diarrhea, neurologic signs (ataxia, paralysis, torticollis) and respiratory distress. Morbidity and mortality are high.

Necropsy of a few birds shows edema and hemorrhage in the proventriculus and conjunctiva. Clinical signs and lesions are shown in the images below.

Preliminary results of virus isolation shows positive hemagglutination. Which one of the following choices is the most likely diagnosis?

A - Newcastle disease
B - Aflacatoxicosis
C - Avian pneumovirus
D - Infectious bronchitis
E - Fowl cholera

A-Newcastle disease

The symptoms above are compatible with the viscerotropic velogenic strain of Newcastle Disease.

Hemorrhage and edema in the proventriculus is a very common post mortem finding. Also, multifocal necrosis and hemorrhage of the intestinal mucosa at lymphoid foci (eg cecal tonsils) is almost pathognomomic.

Infectious bronchitis predominantly has respiratory symptoms and is negative onhemagglutination.

Refs: Cornell University College of Veterinary Medicine Atlas of Avian Diseases Newcastle Disease and the Merck Vet Manual 10th ed. online. Images courtesy Cornell University College of Veterinary Medicine Atlas of Avian Diseases.

40

A farm has ducklings that are weak, ataxic, or paralyzed with limbs spread out to the sides.

Necropsy shows white streaking in the musculature in many of the ducklings and a hemorrhagic cerebellum in one. Images are shown below.

Which one of the following choices is the most likely diagnosis?

A - Avian encephalomyelitis
B - Fusarium toxicosis
C - White Castle disease
D - Vitamin E deficiency
E - X-linked muscular dystrophy

D-vitamin E deficiency

Vitamin E deficiency causes 3 syndromes in birds: 1) encephalomalacia, 2) exudative diathesis, and 3) muscular dystrophy.

With exudative diathesis to occur, the diet is deficient in both vitamin E and selenium. With muscular dystrophy, the diet is deficient in both vitamin E and sulfur amino acids.

Avian encephalomyelitis has no gross necropsy lesions. It is caused by a picornavirus that is shed primarily in the feces.

Refs: Vitamin E and Selenium Deficiency, Cornell University College of Veterinary Medicine Atlas of Avian Diseases and the Merck Vet Manual 10th ed. online. Images courtesy Cornell University College of Veterinary Medicine Atlas of Avian Diseases.

41

A 7-year old male German shepherd presents with a history of weakness in the hind limbs, urinary incontinence and recent obsessive chewing around his tail area. Dorsiflexion of the tail over the back and extension of the hind limbs elicits a painful response.

There is moderate hindlimb ataxia. He does not withdraw each hind leg when a toe is pinched, but bears weight on the hindlimbs. Patellar reflexes are normal.

What is the clinical diagnosis?

A - Wobbler syndrome
B - Cauda equina syndrome
C - Hip dysplasia
D - Diskospondylitis
E - Radiculoneuritis

B- cauda equina syndrome

This is a common presentation of Cauda equina syndrome. Look for PAIN in the lumbosacral area (elicited by tail raise, hindlimb extension), LMN hindlimbs, especially Sciatic nerve damage at L7-S1 (lack withdrawal), +/- urinary/fecal incontinence, +/- SELF-MUTILATION of tail, perineum, pelvic limb.

Lesion due to compression of cauda equina at L7-S1 (lumbosacral stenosis). Can be congenital (abn development dorsal arch L7-S1, small dogs, Border Collies) or acquired (degenerative changes, big dogs, especially German Shepard, Rottweiler, Boxer).

Wobbler syndrome is a cervical spinal cord disease (also called cervical vertebral instability/ caudal cervical spondylomyelopathy). In adult form it is an intervertebral disc disease, usually seen at C5-C6 or C6-C7 in Dobies> 5 yrs, Great Danes> 2 years.

Diskospondylitis is a good second choice on your DDX of a large middle aged dog presenting with lumbosacral pain. Due to bacterial/fungal infection of intervertebral disk and adjacent vertebral bodies. Look for systemic signs like fever (1/3 of patients), weight loss, anorexia. Follow this link to see a Merck image of diskospondylitis.

Refs: De Lahunta, Vet Neuroanatomy and Clin Neurology, 2nd ed. p. 74, Pasquini's, Tschauner's Guide to Small Animal Clinics, vol 1, 2nd ed. pp. 529, 533, and the Merck Veterinary Manual online edition.

42

Which one of the following organisms causes "chronic respiratory disease" in chickens and "infectious sinusitis" in turkeys?

A - Pasteurella multocida
B - Ornithobacterium rhinotracheale
C - Chlamydophila psittaci
D - Avibacterium gallinarum
E - Mycoplasma gallisepticum

E- Mycoplasma gallisepticum

Mycoplasma gallisepticum causes these diseases. It is the most pathogenic avian mycoplasma.

Morbidity is high and mortality low in chickens. Symptoms include respiratory distress, sneezing, nasal discharge, and frothiness about the eyes.

Refs: Mycoplasma gallisepticum, Cornell University College of Veterinary Medicine Atlas of Avian Diseases and the Merck Vet Manual 10th edition online. Image courtesy Cornell University College of Veterinary Medicine Atlas of Avian Diseases.

43

A chicken farm has some chickens with para- or monoparesis for several weeks.

On close examination of the affected chickens, the irises are light colored and the pupils are misshapen.

Necropsy of one of the affected birds shows diffuse thickening of the lumbar plexus on one side.

Some of the birds have recovered without intervention. Which one of the following choices is the most likely diagnosis?

A - Marek's disease
B - Infectious laryngotracheitis
C - Chlamydiosis
D - Infectious encephalomyelitis
E - Newcastle disease
 

A- Marek's Disease

Marek's disease usually causes a lymphoproliferative syndrome. Infiltrates develop in peripheral nerves, irises, feather follicles, and other organs.

It can also be subclinical and still cause decreased growth rates and a drop in egg production. Vaccination has a greater than 90% efficacy.

Newcastle disease can cause neurologic symptoms, but usually they are in conjunction with, or following, respiratory symptoms.

Refs:Marek's Disease Cornell University College of Veterinary Medicine Atlas of Avian Diseases, and the Merck Vet Manual 10th ed. online. Images courtesy Cornell University College of Veterinary Medicine Atlas of Avian Diseases.

44

Which one of the following organisms causes infectious coryza in chickens?

A - Ornithobacterium rhinotracheale
B - Pasteurella multocida
C - Chlamydophila psittaci
D - Avibacterium gallinarum
E - Mycoplasma gallisepticum 

D- Avibacterium gallinarum

Avibacterium gallinarum. Infectious Coryza causes acute respiratory disease and primarily affects chickens. The severe form is most often seen in young adults.

Clinical signs include nasal discharge, sneezing, swelling of the infraorbital sinuses, facial edema with eyelids so swollen they cannot open, swollen wattles, and conjunctivitis.

Refs: Cornell University College of Veterinary Medicine Atlas of Avian Diseases Infectious Coryza, and the Merck Vet Manual 10th ed. online. Image courtesy Cornell University College of Veterinary Medicine Atlas of Avian Diseases.

45

A chicken farm has nearly all of its chickens sick with coughing, dyspnea, gasping, nasal discharge, conjunctivitis, blood-stained beaks, and hemorrhagic mucoid expectorations.

Mortality is about 15%. Necropsy shows most of the lesions in the trachea with mucus accumulation, diphtheritic mucoid or hemorrhagic casts, and necrosis.

Which one of the following choices is the most likely diagnosis?


A - Fowl cholera
B - Infectious laryngotracheitis
C - Fowl pox
D - Infectious bronchitis
E - Ornithobacterium rhinotracheale

B-infectious laryngotracheitis

The hemorrhagic expectorations are highly suspicious of Infectious Laryngotracheitis.

This disease is highly contagious and recovered birds become carriers and are the most important vector. During an outbreak, adults should be immediately vaccinated.

Infectious bronchitis lesions are generally not hemorrhagic and mortality is not as high.

Refs: Cornell University College of Veterinary Medicine Atlas of Avian Diseases Infectious Laryngotracheitis; Merck Vet Manual 10th ed. online. Images courtesy, Cornell University College of Veterinary Medicine.

 

46

A chicken farm has a large number of sick chickens. Clinical signs are coughing, sneezing, and dyspnea.

There is a decrease in egg production and the eggs are misshapen and thin-shelled. Necropsy of several chickens shows edema of the trachea, bronchi, and sinuses in most birds, but no hemorrhages.

Preliminary virus isolation testing shows a negative hemagglutination reaction with chicken RBCs.

Which one of the following choices is the most likely diagnosis?

A - Chlamydophila psittaci
B - Avian influenza
C - Ornithobacterium rhinotracheale
D - Infectious bronchitis
E - Newcastle disease

D-infectious bronchitis

Think 3 Rs with Infectious bronchitis: respiratory, renal, reproductive.

Nephropathogenic strains of infectious bronchitis virus (IBV) cause diarrhea and possibly fatal secondary urolithiasis.

Newcastle disease and avian influenza have positive hemagglutination reactions with chicken RBCs.

Refs: Cornell University College of Veterinary Medicine Atlas of Avian Diseases Infectious Bronchitis and the Merck Vet Manual 10th ed. online. Images courtesy Cornell University College of Veterinary Medicine Atlas of Avian Diseases.

47

Which one of the following choices is the organism that causes fowl cholera?

A - Ornithobacterium rhinotracheale
B - Avibacterium gallinarum
C - Pasteurella multocida
D - Mycoplasma gallisepticum
E - Chlamydophila psittaci

C-Pasteurella multocida

Fowl Cholera is a highly contagious disease caused by P multocida. Acutely, there may be fever, ruffled feathers, anorexia, and cyanosis of the comb and wattles.

The chronic form of Fowl Cholera is characterized by localized infections of the wattles, sinuses, foot pads, sternal bursa and joints.

Refs: Cornell University College of Veterinary Medicine Atlas of Avian Diseases, and the Merck Vet Manual 10th ed. online; Image courtesy Cornell University College of Veterinary Medicine Atlas of Avian Diseases.

48

Which one of the following choices is the best treatment for infection with Chlamydophila psittaci?

A - Doxycycline
B - Enrofloxacin
C - Ceftazidime
D - Ciprofloxacin
E - Amikacin

A-Doxycycline

Doxycycline.

Chlamydophila psittaci causes clinical disease in hundreds of bird species. Clinical signs vary from asymptomatic to diarrhea and respiratory symptoms.

Chlamydiosis is a REPORTABLE disease and poses a significant public health concern for humans.

Refs: Merck Vet Manual 10th ed. online; Image courtesy Atlas of Avian Diseases, Cornell University College of Veterinary Medicine.

49

A group of chickens presents with scabby, proliferative, and ulcerative lesions on the comb, wattles, eyelids, feet, and legs. Mortality is low.

Which one of the following choices is the most likely diagnosis? 

A - Fowl cholera
B - Avian pox
C - Infectious coryza
D - Fowl plague
E - Marek's disease

B Avian Pox

Avian pox, also known as Fowlpox. This disease is not contagious to humans.

There are two forms of the disease - 1) cutaneous or dry pox has low mortality, with proliferative lesions on comb, wattles, etc, and 2) diphtheritic or wet pox that causes yellow canker lesions on mucous membranes, tongue, esophagus, or trachea.

Fowl cholera causes swellings and abscesses in the comb and wattles, but also affects the respiratory tract. The mortality can be high.

Refs: Cornell University College of Veterinary Medicine Atlas of Avian Diseases, Avian Pox, and the Merck Vet Manual 10th ed. online; Image courtesy of Cornell University College of Veterinary Medicine Atlas of Avian Diseases.

50

A chicken farm has had several ill and dead birds over the past week.

Examination of the sick chickens shows severe depression, ecchymoses and edema of the comb and wattles, green diarrhea, and some are unable to walk with absent perching reflexes.

Which one of the following choices is the most likely diagnosis?

A - Avian encephalomyelitis
B - Mycoplasma gallisepticum
C - Avian influenza
D - Infectious bronchitis
E - Infectious coryza

C-Avian Influenza

Avian Influenza, also called fowl plague, is the most likely diagnosis. This virus can either be of low pathogenicity (most common) or highly pathogenic.

Viruses of low pathogenicity typically cause subclinical or mild respiratory disease. The case above is due to a highly pathogenic strain of avian influenza.

Infectious bronchitis is characterized by respiratory symptoms and is a differential for infection with an avian influenza strain of low pathogenicity.

Refs: Cornell University College of Veterinary Medicine Atlas of Avian Diseases: Avian Influenza and the Merck Vet Manual 10th ed. online; Image courtesy Cornell University College of Veterinary Medicine Atlas of Avian Diseases.

51

Which one of the following diseases causes hock sitting, ataxia, and paralysis in chicks 1-2 weeks of age and blue opacity of the lens in those that survive the acute phase of the disease? The disease can affect chickens, pheasants, quail, and turkeys.

A - Infectious laryngotracheitis
B - Avian encephalomyelitis
C - Fowl cholera
D - Mycoplasma gallisepticum
E - Avian metapneumonia 

B. Avian Encephalomyelitis

Avian Encephalomyelitis, also called epidemic tremor, is the most likely diagnosis. This disease has about 60% morbidity and 25% mortality.

Other differentials would include vitamin E deficiency, thiamine deficiency, Newcastle disease, and Marek's disease, however, these do not typically cause cataracts.

M gallisepticum typically causes a chronic respiratory disease in chickens and infectious sinusitis in turkeys.

Refs: Cornell University College of Veterinary Medicine Atlas of Avian Diseases: Avian Encephalomyelitis and the Merck Vet Manual 10th ed. online; Images courtesy Cornell University College of Veterinary Medicine Atlas of Avian Diseases.

52

A 4-year-old stallion presents with urine scald, fecal retention and a right head tilt. Rectal examination reveals atonia of the anus and rectum, however, no fracture is palpated.

Which one of the following tests is most indicated?

A - Search the pasture for yellow star thistle
B - Immunoblot against DNA fragments from P tenuis
C - Cervicothoracic spinal radiography
D - Tibial muscle and nerve biopsies
E - Antibodies against P2-myelin protein

E-Antibodies against P2-myelin protein

Antibodies against P2-myelin protein. Horses with polyneuritis equi have circulating antibodies against P2-myelin protein. Other diseases to rule out in this case would be equine herpesvirus-1 and equine protozoal encephalomyelitis.

Refs: Mayhew, Large Animal Neurology, 2nd ed. pp. 274-276, 255-257, 260-267 and the Merck Veterinary Manual online edition.

53

A 15 year old cat is presented with a 3 week progression of wandering in circles to the left, standing in corners, and dull mentation.

Conscious proprioceptive deficits (knuckling) can be elicited in the right thoracic and right pelvic limbs.

There is a decreased menace response on the right, but pupillary light reflexes are normal in both eyes. The examination is otherwise normal. A brain tumor is suspected.

Where is the most likely location of the lesion?

A - Cerebellum
B - Left cerebrum
C - Right cerebrum
D - Right brainstem
E - Left brainstem

B-left cerebrum

Left cerebrum.
Remember that conscious proprioception and visual perception are affected by lesions in the contralateral cerebral hemisphere.

Circling direction is generally toward the side of the lesion.

Refs: Curtis Dewey, A Practical Guide to Canine and Feline Neurology, 2nd ed. pp. 17-22 and the Merck Veterinary Manual online edition.

54

A 4-year-old Rat Terrier is presented with a 3 day history of progressive stumbling and falling.

Physical exam reveals a right head tilt, left sided hypermetria, generalized ataxia and vertical nystagmus.

Which one of the following choices is at the top of the differential list?

A - Fibrocartilagenous embolism
B - Ascending and descending myelomalacia
C - Central pontine myelinolysis
D - Amyotrophic lateralizing sclerosis
E - Granulomatous meningoencephalitis

E-Granulomatous meningoencephalitis

Granulomatous meningoencephalitis.
The lesion in this case localizes to the left cerebellum causing the left hypermetria and a right paradoxical head tilt.

Granulomatous meningoencephalitis often affects this area.

Another top differential would be a cerebellar neoplasm.

Refs: De Lahunta, Vet Neuroanatomy and Clin Neurology, 3rd ed. p. 333 and the Merck Veterinary Manual online edition.

55

The 12-year-old spayed female cat shown below is presented with a history of weakness for the past 2 days. She has neck ventroflexion and a stiff, stilted gait.

Which one of the following is in the top of the differential list?

A - Hyperkalemic periodic paralysis
B - Caudal occipital malformation
C - Hypokalemic myopathy
D - Cervical vertebral malformation
E - Bilateral otitis media/interna

Hypokalemic myopathy.
The posture is classic for hypokalemia and other neuromyopathies (e.g., myasthenia gravis, organophosphate intoxication) in cats.

Hyperkalemic periodic paralysis has not been reported in cats.

Refs: Dewey, A Practical Guide to Canine and Feline Neurology, 2 nd ed. pp. 497-500 and the Merck Veterinary Manual online edition. Image courtesy of Dr. Shirley Scott.

56

This radiographic image shows osteoarthritis of the lower hock joints of a horse.

What is the common name for this problem?

A - Bone spavin
B - Ringbone
C - Splints
D - Tarsal hydrarthrosis

E - Osselets 

A-Bone spavin

This is bone spavin, the number one hock problem (tarsus) in horses, an osteoarthritis of the lower hock joints, usually affecting the distal intertarsal and tarsometatarsal articulations. Etiology not clear (several theories)-seen most in Standardbreds, Quarter Horses. If horse is lame, tends to drag toe.

Tarsal hydrarthrosis (bog spavin) is a chronic synovitis of the tibiotarsal joint- look for swelling and distention of the joint capsule.
Follow this link to see a photo of bog spavin (lateral swelling, left tarsus).

Refs: Pasquini & Spurgeon's Anatomy Dom An 11th ed. pp. 100-1, 645b and the Merck Veterinary Manual online edition.

57

A 5 year old female spayed Cocker Spaniel is presented with a strange expression. Her right ear and lip appear to droop. There is ptosis O.D. (right eye) and the dog is drooling on the exam table.

What anatomic structure is damaged?

A - Left side medulla, motor tract
B - Trigeminal nerve
C - Left side inner ear
D - Right side inner ear
E - Facial nerve

E-Facial nerve 

Think of facial nerve paralysis (CN 7) with a unilaterally droopy face.

Remember the facial nerve is motor to the muscles of facial expression (explaining the right side drooped ear, lip and eyelid) and innervates the lacrimal and salivary glands. Loss of innervations can lead to a dry eye, and possibly to exposure keratitis if animal losses ability to close eyelid from damage to facial nerve innervation of the orbicularis oculi muscle.

Idiopathic in 75% of canine cases (25% of cats). Can also see these signs with middle ear damage (from otitis media), from facial nerve trauma (ear surgery in dogs, or pressure from halter buckles in anesthetized horse), or neoplasia. Follow this link to see a horse with facial nerve damage: note the nose pulled to horse's left. (means facial nerve damaged on right).

Think more of a dropped jaw with trigeminal nerve neuropathy (CN 5-dogs, horses).

Refs: Pasquini & Spurgeon's Anatomy Dom An 11th ed. pp., 552-4, 579 , Pasquini's, Tschauner's Guide to Sm An Clin, vol 1, 2nd ed. p. 563 and the Merck Vet Manual online edition.

58

An three year old white rat is presented with yellowing fur and a brownish, granular sebaceous secretion at the base of affected hair shafts.

What should the owner be told?

A - Probable ringworm, resolves spontaneously with sunlight exposure
B - Normal age-related change
C - Common manifestation of chorioptic mange
D - Staph dermatitis, responsive to antiseptic shampoo
E - Moisture-related dermatitis, cage needs more frequent cleaning

 

B-normal age-related change

These are normal age related changes. Rats normally live two to three years, though some may live to five years of age.

With age, the hair coat of white rats normally develop yellowing fur. They may also show a brownish, granular sebaceous secretion at the base of affected hair shafts which an owner may mistake for a skin parasite.

Refs: Quesenberry and Carpenter, Clin Med and Surg of Ferrets, Rabbits and Rodents, 3rd ed. p. 342.

59

What are ongoing losses in fluid therapy?

A - Fluids given minus extracellular volume estimate
B - The tears I shed when I can't make sense of fluid calculations
C - Urine output
D - Vomit and diarrhea
E - Percent dehydration multiplied by body weight
 

D-Vomit and diarrhea 

Ongoing losses are typically vomiting, diarrhea or other losses into a third compartment (pleura, abdomen etc). These are sometimes called "contemporary" losses. A classic example of a disease with significant ongoing losses is a puppy with parvovirus who has both diarrhea and vomiting.

Sensible losses are easily measured, like the fluids the animal loses by urination.

Insensible losses are the fluids an animal loses that are hard to measure, through breathing and via the skin. In humans and animals that sweat (like horses) sweating is part of insensible losses.

Remember that all three types of loss must be accounted for (or at least estimated) when calculating fluids needed to rehydrate a dehydrated animal.

Refs: Cote, Clin Vet Advisor-Dog and Cat, 2nd ed. pp. 287-9, McCurnin and Bassert, Clin Textbook for Vet Technicians, 7th ed. pp. 683-4 and the Merck Veterinary Manual online edition.

60

What is the proper name for this parasite of pigs?


A - Dioctophyma renale
B - Stephanurus dentatus
C - Capillaria plica
D - Gnathostoma spinigerum
E - Trichinella spiralis

B-Stephanurus dentatus

This is Stephanurus dentatus, the swine kidney worm.

Found worldwide, particularly in tropical and subtropical areas. Seen in the U.S. as a parasite of pigs raised outside in the southeastern and southcentral states.

Click here to see these large worms (2-4.5 cm long) encysted in pairs along the ureters from the kidney to the bladder (courtesy of the UPenn CAL site).

Refs: The Merck Veterinary Manual online edition.

61

What is a dysmature foal?

A - Born pre-term, but with paradoxically normal respiratory function
B - Born to mare that ate endophyte-infested fescue
C - Born post-term, normal axial skeletal size but emaciated
D - Born post-term but small
E - Born pre-term with ciliary dyskinesia

D-born post-term but small

Dysmature foals are born post-term but small. Also called "small for gestational age", these foals are thought to have suffered placental insufficiency in-utero.

A postmature foal is a post-term foal that with normal axial skeletal size but is thin to emaciated. Most commonly born to mares ingesting endophyte-infested fescue.

Gestation length in mares ranges from 310 days to more than 370 days.

Refs:Pasquini's Guide to Eq Clin, 3rd ed. pp. 121 and the Merck Veterinary Manual online edition.

62

What condition would be expected to have a positive Ortolani sign?

A - Cranial cruciate rupture
B - Osteochondrosis dissecans (shoulder)
C - Hip dysplasia
D - Coxofemoral luxation
E - Panosteitis

C-hip dysplasia

A positive Ortolani sign indicates joint laxity, typically associated with hip dysplasia. A click/pop heard or felt by one hand pressed over coxofemoal joint while other hand presses upward and abducts knee. Think LARGE, hindlimb-LAME dogs, especially German shepherds.

Follow these links to see radiographs of: early hip dysplasia,(no DJD yet), severe hip dysplasia (Note flattened, angular femoral head, poor congruence (parallel line) with acetabulum) and in contrast normal canine hips with deeply seated femoral heads and good congruence with acetabulae.

Do a "Thumb test" for coxofemoral luxation (dislocated hip)- place thumb in the groove between greater trochanter & ischial tuberosity, externally rotate femur: thumb is pushed OUT of groove with normal hip, but stays in groove with luxated hip or fractured femoral head.

A positive drawer sign indicates cranial cruciate rupture.

Panosteitis characterized by long bone pain on palpation and Hx of a shifting leg lameness in young, large dogs.

Refs: Pasquini's, Tschauner's Guide to Sm An Clin, vol 1, 2nd ed. pp. 638-40; Blackwell's 5-Min. Vet Consult Canine-Feline, 4th ed. pp. 624-5 and the Merck Veterinary Manual online edition.
 

63

Which nerve block predicts how a horse with caudal heel pain (also called navicular disease) may respond to digital neurectomy?

A - Heel block
B - Local infiltration of suspensory ligament
C - Pastern block
D - Fetlock block
E - High 4-point block

A-heel block

A heel block (also called the palmar digital block) will anesthetize the bulbs of the heel, mimicking the effect of a palmar digital neurectomy, the last-ditch treatment to lengthen the athletic life of a horse with caudal heel pain (navicular disease).

Remember that neurectomy will eliminate pain, but not disease- you do it when there has been no improvement from medical Rx after 6-12 weeks.

Follow this link to see a radiograph of navicular disease.

Refs: Pasquini, Jahn and Bahr, Guide to Eq Clin: LAMENESS vol. II, pp. 62-4 and X8 and the Merck Veterinary Manual online edition.

64

A 10-year old male intact Doberman mix dog is presented with one testicle that is grossly enlarged and nonpainful and the other atrophied. What condition(s) are expected to be seen in association with this presentation?

A - Increased aggression, territoriality
B - Feminization syndrome
C - Benign prostatic hypertrophy, constipation
D - Penile hypertrophy, hirsutism
E - Hypothyroidism
 

B-Feminization syndrome

Feminization syndrome.
Nonpainful unilateral testicular swelling in an old dog should make you think of neoplasia, especially an estrogen-secreting sertoli cell tumor, which can cause feminization syndrome. See gynecomastia, penile atrophy, pendulous prepuce, attraction of other males, blood dyscrasias, +/-bone marrow depression (via high estrogen), bilateral alopecia.

Remember that cryptorchidism increases risk of sertoli cell tumor: About 25-29% of sertolis develop feminization syndrome and ~ 70% of intra-abdominal testicular tumors, regardless of type, cause feminization syndrome.

May see prostate hypertrophy with sertoli, but it is due to squamous metaplasia, not the classic (and common) benign prostatic hypertrophy (BPH). Hypothyroidism and BPH are common older dog conditions, but not associated with unilateral testicular hypertrophy.

Remember that sex hormones are also secreted by the zona reticularis of adrenal cortex and can see feminization or virilism with excess secretion.

Refs: Pasquini's, Tschauner's Guide to Sm An Clin, vol 1, 2nd ed. p. 458, Blackwell's 5-Minute Vet Consult Canine Feline, 4th ed. pp. 318, 1242-3 and the Merck Veterinary Manual online edition.

65

Failure to control mild endemic respiratory disease in swine caused by Mycoplasma hyopneumoniae predisposes pigs to complications.

Exudative bronchopneumonia and polyarthritis are most commonly seen in herds infected with both Mycoplasma hyopneumoniae and which other organism?

A - Hemophilus parasuis
B - Fusobacterium necrophorum
C - Swine influenza virus
D - Bordetella bronchiseptica
E - Pasteurella multocida

E-Pasteurella multocida

Pasteurella multocida infection in conjunction with Mycoplasma hyopneumoniae causes exudative bronchopneumonia, polyarthritis, and chronic lung lesions. Mycoplasma hyopneumoniae, (also called "Enzootic pneumonia") is a common, smoldering low-level illness. Stressors (parasites, other infections, even weather) can result in severe pneumonia.

Best managed by decreasing stressors with improved ventilation and decreased overcrowding. In endemic herds, ABX for sick individuals (ie: lincomycin, tylosin, tiamulin, or a tetracycline) helps control illness, most likely by preventing secondary bacterial infection (like Pasteurella).

Bacterin vaccines give good protection, decrease signs (coughing). Pre-farrowing vaccination of sows decreases colonization in suckling piglets.

Ref: The Merck Veterinary Manual online edition.

66

A 2 day old pup has a GGT level of 500 times the adult upper reference range. Which one of the following choices is the most likely interpretation?

A - Caused by traumatic placental detachment
B - Due to colostrum absorption
C - Associated with bone development
D - Suggestive of a congenital a liver shunt
E - Associated with neonatal cholestasis

B-Due to colostrum absoprtion

Very high GGT levels are seen with colostrum absorption

In newborn pups, lambs, and calves, an increase in GGT up to 1000 times is normal when they receive high levels of colostrum from the dam.

High levels of GGT are produced in the mammary epithelium during lactation. When evaluating bloodwork, reference ranges specific for the age of the patient should be utilized.

Refs: Latimer, Mahaffey, Prasse, Duncan and Prasse's: Veterinary Laboratory Medicine 4th ed. pp. 193-214 and the Merck Veterinary Manual online edition.

67

A 2 year old Angus cow presents with weakness of the hind limbs and a staggering gait. On physical exam, the heart rate and respiratory rate are slow and irregular, and the pupils are dilated. The cow's breath and urine smell like the odor of mouse urine.

Suddenly the cow's pulse becomes rapid and thready, she collapses, and dies of apparent respiratory failure.

Which one of the following plants is most likely to have caused this spectrum of clinical signs?

A - Veratrum spp (False hellebore, Skunk cabbage)
B - Pinus ponderosa (Western yellow pine)
C - Tetradymia spp (Horsebrush)
D - Conium maculatum (Poison hemlock)
E - Centaurea spp (Knapweed, Yellow star thistle)

D-Conium maculatum (Poison Hemlock)

Poisoning with Conium maculatum (Poison hemlock) is responsible for the death of this cow.

At least 8 toxic piperidine alkaloids have been isolated from poison hemlock . Coniine is found in seeds and the mature plants; g-coniceine is found in young growing plants.

Poison hemlock is toxic to all livestock and humans. Signs of toxicity develop 1-2 hours after ingestion and are usually fatal.

Signs include nervousness, trembling, weakness especially of the hind limbs, weak pulse, irregular heart rate, recumbency, coma and death. A mousy odor exuding from the urine and breath is pathognomonic.

Ingestion of poison hemlock during gestation causes arthrogryposis and other congenital defects in cattle, goats, and pigs.

Click here to see an image of Conium maculatum (Poison hemlock).

Click Here to see a Merck table of Poisonous Range Plants of Temperate North America.

Refs: Forero, Livestock-Poison Plants of CA, U of CA, Davis, ANR, p. 39, Knight and Walter's A Guide to Plant Poisoning of Animals in NA, pp. 38-40, 282, and the Merck Veterinary Manual online edition.

68

A 7 day old Tb filly is anesthetized with isoflurane in oxygen for a cerebrospinal fluid tap when an irregular heart beat is heard on the doppler. The heart rate is approximately 90 beats per minute. A recording of the electrocardiogram is printed as shown in the image below.

Which one of the following choices correctly identifies this arrhythmia?

 

A - Atrial flutter
B - Paroxysmal ventricular tachycardia
C - Ventricular escape beats
D - Premature atrial contractions
E - Premature ventricular contractions

E-Premature ventricular contractions

Three premature ventricular contractions are present on this ECG strip.

Usual characteristics of PVCs - No p wave present that is associated with the QRS wave, the QRS is wider than normal and bizarre in shape compared to normal, often the QRS is oriented opposite to that of the sinus beats.

The orientation of the QRS is the same (both negative) in both the normal and ectopic beats in this case. Don't be fooled by the presence of the small waveform just before the PVC, these are the T waves from the prior beat.

Cardiac arrhythmias that occur under anesthesia can be caused by hypercarbia, hypoxemia, hypotension, hypothermia, anesthetic drugs, sympathetic stimulation, electrolyte disturbances, and myocardial disease.

This foal had just been induced with isoflurane, was likely hypoventilating, and a little deeper than necessary. The isoflurane was decreased, she was put on a ventilator - the PVCs disappeared and did not return.

Refs: Muir and Hubbell's Equine Anesthesia, 2nd ed. pp. 85-88, Grimm, Tranquilli, and Lamont's Essentials of Anes and Analgesia in SA, 2nd ed. p. 230. ECG image courtesy of Dr JG Adams.

69

The following lesion is typically found on the ventral midline of which species?


A - Sheep and goats
B - Cattle
C - Camelids
D - Pigs
E - Horses

B-cattle

Cattle. This is a circumscribed dermatitis along the ventral midline of a cow with cutaneous stephanofilariasis, caused by Stephanofilaria stilesi a filarial parasite of cattle.

Cutaneous stephanofilariasis has been reported throughout the North AMerica but is more common in the western and southwestern U.S.

The intermediate host is the horn fly, Haematobia irritans which ingests filarial larvae when it feeds on skin lesions.

Refs:Pasquini's Guide to Bovine Clinics, 4th ed. p.180 and the Merck Veterinary Manual online edition.

70

A herd of ewes has had an abortion storm in which 80% of animals are affected, all stages of gestation are affected, and lambs that are born are very weak. On the placentas, cotyledons have white foci of necrosis.

Which one of the following choices is the primary differential diagnosis?

A - Brucella
B - Histophilus ovis
C - Toxoplasma gondii
D - Chlamydiosis
E - Listeria monocytogenes

C-Toxoplasma gondii

T. gondii infection can cause severe abortion storms in sheep.

Clinical signs pathognomonic of T. gondii are bright to dark red cotyledons with white foci of necrosis; the intercotyledonary areas of placenta are normal.

With Brucella and Histophilus ovis the abortion rate is much lower. Abortion caused by Listeria spp is associated with the feeding of silage.

Refs: Youngquist and Threlfall, Current Therapy in Large Animal Theriogenology 2nd ed. pp. 667-80, Pugh and Baird's Sheep and Goat Medicine 2nd ed. pp. 220-1 and the Merck Veterinary Manual online edition.

71

A mare presents with a history of herding and mounting other mares in a broodmare group. During the physical exam, the mare is very unruly and tries to bite and kick.

After sedation, rectal palpation findings reveal a walnut sized, smooth left ovary and a softball sized right ovary. No ovulation fossa is palpable on the right ovary.

Which one of the following choices is the most likely diagnosis for the right ovary?

A - Cystic ovary
B - Granulosa cell tumor
C - Anovulatory follicle
D - Hematoma
E - Transitional status
 

B-Granulosa cell tumor

Granulosa cell tumors (GCTs) secrete reproductive hormones such as testosterone, inhibin, and estrogen. Testosterone causes the mare to show stallion-like behavior, while estrogen causes persistent estrus

Approximately 50-90% of mares with GCTs have elevated testosterone and over 85% of mares with GCTs have high inhibin.

With GCTs the contralateral ovary tends to stop producing follicles and resembles an ovary during anestrus.

Click here to see GCT from a mare.

Refs: Youngquist and Threlfall, Current Therapy in Large Animal Theriogenology 2nd ed. pp. 144-152, Pasquini's Guide to Equine Clinics, 3rd ed. p. 188 and the Merck Veterinary Manual online edition.

72

You are presented a healthy 10 yr old maiden mare for breeding evaluation in January. On rectal palpation, both ovaries have multiple, small (less than 15 mm) follicles and no corpus lutea. The uterus is flaccid with no edema.

Which one of the following choices is the most likely explanation of the findings in this mare?

A - The mare is in diestrus
B - The mare is too old and now is infertile
C - Early pregnancy
D - Seasonal anestrus
E - Estrus has just passed

D-Seasonal anestrus

Anestrus

Mares are seasonal breeders and enter anestrus in the short day months, late fall and winter. In anestrus the ovaries are inactive with small follicles and no corpus lutea.

During estrus, the uterus softens and multiple follicles form on the ovaries. During pregnancy the uterus has good tone.

Refs: Youngquist and Threlfall, Current Therapy in Large Animal Theriogenology 2nd ed. pp. 144-152, Pasquini's Guide to Equine Clinics, 3rd ed. pp. 160-1 and the Merck Veterinary Manual online edition.

73

A herd of 12 multiparous broodmares housed on a 25 acre pasture in the southeastern United States are having reproductive problems.

Of the three mares that have foaled so far this year, none have produced milk. Another mare is now 12 months in foal and has no udder development.

Which one of the following choices is the most likely diagnosis?

A - Malnutrition
B - Fescue toxicity
C - Retained placentas
D - Placentitis
E - Mastitis

B-Fescue toxicity

Fescue toxicity.

Ingestion of fescue grass contaminated with the endophyte fungus Acremonium coenophialum causes agalactia, thickened placentas, and prolonged pregnancy in mares by suppressing prolactin release. Toxicity is most significant in the last 90 days of gestation

Mares should be removed from fescue pastures (and not fed fescue hay) for the last 90 days of gestation to reduce the incidence of fescue-associated problems. Treatment with domperidone can help affected mares produce milk.

Mares with malnutrition are more likely to abort than carry a pregnancy over term.

Refs: Youngquist and Threlfall, Current Therapy in Large Animal Theriogenology 2nd ed. pp. 131-4, Pasquini's Guide to Equine Clinics, 3rd ed. pp. 218, 241 and the Merck Veterinary Manual online edition.

74

What recommendation should be given to the owner of a mare that has had Caslick's vulvoplasty surgery?

A - Mare has a higher than normal risk for metritis
B - Mare should not be bred by a stallion
C - Mare will need an episiotomy before foaling
D - Mare has a decreased risk for perineal laceration
E - Mare should not be bred

D-mare will need an episiotomy before foaling

The mare will need an episiotomy (a surgically planned incision on the perineum and the posterior vaginal wall) prior to foaling.

Sometimes an episiotomy may be needed prior to breeding by stallion if the remaining vulvar cleft is too small to permit intromission.

A Caslick's operation (vulvoplasty, a superficial form of the episioplasty) is used to treat pneumovagina in horses to prevent genital infections and infertility.

Refs: McKinnon and Voss, Equine Reproduction, 1st ed. pp. 418-20, Pasquini's Guide to Equine Clinics, 3 rd ed. p. 177 and the Merck Veterinary Manual online edition.

75

What is the neuroanatomic cause of extensor rigidity in the forelimbs of a cat with Schiff-Sherrington syndrome?

A - Brachial plexus trauma
B - Polyradiculoneurtitis of peripheral nerve sheaths at cervical intumescence
C - Subdural white matter compression at C6-T3
D - Damage to thoracic spinocerebellar tracts in superficial white matter
E - Interruption of inhibitory neuron input from lumbar spinal cord

E-Interruption of inhibitory neuron input from lumbar spinal cord

With severe trauma between T2-T13, inhibitory pathways (esp. around L2-L4) are interrupted and cervical intumescence neurons (C6-T2) are "released", causing extensor hypertonia in the forelimbs.

Think of Schiff-Sherrington syndrome when you see a combination of forelimb extensor rigidity and hind limb flaccid paralysis, in an animal that has just had major spinal trauma, like being hit by a car.

Refs: de Lahunta and Glass, Vet Neuroanatomy & Clin Neurology, 3rd ed. p. 248-50, Pasquini's, Tschauner's Guide to Small Animal Clinics, vol 1, 2nd ed. p. 529 and the Merck Veterinary Manual online edition.

76

A 5 year old quarterhorse is presented with a depigmented hyperkeratotic plaques localized to the concave aspect of both ears.

What message should be communicated to the owner?

A - Typically secondary to underlying immunosuppression
B - Surgical removal is curative
C - Need to check the pasture for photosensitizing plants
D - Lesions usually persist for life
E - Do not breed this horse

D-Lesions usually persist for life

Equine aural plaques (papillary acanthoma, ear papilloma) typically persist for life.

Equine aural plaques are caused by a papillomavirus and thought to be transmitted through mechanical transmission by biting Black flies (Simulium spp.)

There is no specific treatment. Prevention includes application of fly repellent and stabling the horse during the Black fly's feeding times (dusk and dawn).

Refs: Pasquini's Guide to Eq Clin, 3rd ed. pp. 292 and the Merck Vet Manual online.

77

This calf was aborted at 7.5 months pregnancy in early fall. The dam was a primiparous beef animal housed on pasture in Northern California.

Necropsy revealed multiple petechial hemorrhages on the palate and scleral mucus membranes of the fetus, and marked lymphadenopathy. The calf was not decomposed; the cow retained the placenta.

Which one of the following choices is the most likely diagnosis of the abortion in this case?

A - Foothill abortion agent
B - Leptospira pomona
C - Pine needles
D - Brucella abortus
E - Neospora caninun
 

A-Foothill abortion agent

This is a typical case of foothill abortion, also called Epizootic Bovine Abortion. The condition is common in the coastal and Sierra Nevada foothills, and throughout much of the western United States. It is the most common cause of abortion in California beef cattle.

The etiologic agent has not been identified with certainty. Research suggests that it is a delta protobacteria with DNA homology to bacteria of the vibrio genus. Pregnant cattle exposed to thymic tissues from aborted fetuses can be protected from abortion by feeding tetracycline through the early stages of pregnancy.

The agent is transmitted by the soft shelled Pajahuello tick (Ornithodorus coriaceus). The disease occurs predominantly in heifers. Infection develops during the first trimester of pregnancy while abortions occur later around the 5th to 9th month.

Exposed cattle develop immunity, but it is not known how long protection lasts. However, abortion does not often recur in these animals. The presence of petechial hemorrhages and lymphadenopathy in a late-term aborted fetus is suggestive of foothill abortion.

Neospora is another common abortifacient of beef cattle, but does not produce lymhadenopathy or petechiae in the fetus. Leptospirosis, brucellosis, and pine needles also do not produce the same pathologic lesions as the foothill agent.

Ref: Pasquini's Guide to Bovine Clinics 4th ed., p. 123, Divers and Peek, Rebhun's Diseases of Dairy Cattle, 2nd ed., pp. 430 -1,
Image courtesy Dr. Lisle George copyright 2012 and the Merck Veterinary Manual online edition.

78

A registered Hereford cow on pasture gave birth to this calf with a very short, curly, frosted-looking pale coat and normal-appearing skin. By two weeks of age, some of the hair is falling out. Which one of the following choices is the most likely explanation for its' appearance?

A - Normal appearance until 21 days of age
B - Baldy calf syndrome
C - Zinc deficiency
D - Ichthyosis
E - Congenital hypotrichosis

E-Congenital hypotrichosis

This calf has congenital hypotrichosis of Herefords, an autosomal recessive genetic problem.

Hereditary hypotrichosis can be differentiated from the other disease choices because the dermis of the calf is normal in appearance.

Baldy calf disease is an inherited problem of Holsteins. The calves may lose hair, have thickened skin and metabolic illnesses.

Refs: Smith, Large Animal Internal Medicine, 3rd ed., p. 1849 and the Merck Veterinary Manual online edition, Images courtesy Dr. Lisle George copyright 20112.

79

Which one of the following ectoparasites normally spends its entire life cycle on the chicken, causing feather damage, anemia and irritation?

A - Northern fowl mite
B - Red chicken mite
C - Trombicula alfreddugesi
D - Dermanyssus gallinae
E - Neocnemidocoptes gallinae
 

A-northern fowl mite

The Northern fowl mite (Ornithonyssus sylviarum) is the only poultry mite that normally spends its entire life cycle on the host. O. sylviarum is the most important parasite of caged layers and breeding chickens in the U.S..

Click here to see northern fowl mites on a hen.

MOST chicken mites are nocturnal feeders that are only on the birds at night. They hide during the day away from the chicken, under manure and in crevices of the chicken house, where they lay eggs.

Click here to see a photo of Dermanyssus gallinae.

Click here to see a chicken with D. gallinae mites

Ref: The Merck Veterinary Manual online edition.

80

The menace response is used to test which cranial nerves?

A - V and VIII
B - II and VII
C - IX and X
D - I and VIII
E - V and VII

B- II and VII

The menace response is used to test visual input (cranial nerve II – optic) and blink response (cranial nerve VII – facial). Take care not to induce air movement which would elicit a tactile response (cranial nerve V – trigeminal) instead of visual.

There are many mnemonics to help memorize the cranial nerves. Click here for mnemonics courtesy of Neuromonkey.

Refs: Curtis Dewey, A Practical Guide to Canine and Feline Neurology, 2nd ed. pp. 57,63 and the Merck Veterinary Manual online edition. 

81

Several rabbits in a commercial meat operation have developed genital scabs, perineal ulcerations a crusty exudate around the nose and eyes. Microhemaglutination tests are positive for treponematosis.

Which one of the following steps is most effective to treat this problem?

A - Isolate affected animals, Lincomycin in water 2-3 weeks
B - Amprolium-medicated feed for whole herd, 2 weeks; Increase ventilation
C - Clindamycin PO for exposed rabbits, 8 days; Cull affected animals
D - Amipcillin PO for affected rabbits, 10-14 days
E - Penicillin IM for all rabbits, 5-7 days

E- Penicillin IM for all rabbits, 5-7 days

Treat ALL rabbits with parenteral (IM) penicillin when there is an outbreak of Treponema cuniculi (tremponematosis). Tetracycline or chloramphenicol are also effective

AVOID oral antibiotics in rabbits, which can upset normal gram-positive gut flora.

Particularly avoid lincosamide antibiotics like Clindamycin and Lincomycin, which target gram-postive bacteria and are specifically contraindicated in rabbits and rodents

Refs: Quesenberry and Carpenter, Clin Med and Surg of Ferrets, Rabbits and Rodents, 3rd ed. pp. 235-6, Plumb's Vet Drug Handbook, 7th ed. pp. 309-13,1056-1059 and the Merck Veterinary Manual online edition.

82

A stray dog is presented after being hit by a car.

The dog has hypotonic forelimbs and spastic paresis in the hinds. All four limbs have proprioceptive deficits and sensation loss-signs are worse in the forelimbs.

Where is the lesion?

A - Cranial cervical: C1-C5
B - Thoracolumbar T3-L3
C - Cervicothoracic: C6-T2
D - Cannot say without cutaneous trunci reflex results
E - Lumbosacral L4-S3

C- Cerviothoracic: C6-T2

Cervicothoracic: C6-T2. Weak, hypotonic (Lower motor neuron-LMN) forelimbs and spastic paresis (Upper motor neuron-UMN) hindlimbs are signs of a cervicothoracic (C6-T2) lesion. May see worse signs in fores then hinds.

NOTE: This is the OPPOSITE presentation as Schiff-Sherrington syndrome ie: severe spinal cord trauma T3-L3, with thoracic limb extensor rigidity (UMN) and hind limb flaccid paralysis (LMN). Lesion is caudal to T2, typically see animal soon (hours) after a bad trauma, like hit by car.

Can localize T3-L3 lesion by checking cutaneous trunci reflex -The lesion is usually 1-2 vertebrae cranial to the line of analgesia (where dog does not feel pinching skin).

With C1-C5 would expect UMN signs in all 4 limbs, usually worse in hinds.

With a T3-L3, would see UMN hind limb signs and normal forelimbs.

Refs: De Lahunta, Vet Neuroanatomy & Clin Neurology, 2nd ed. pp. 180-190, Pasquini's, Tschauner's Guide to Small Animal Clinics, vol 1, 2nd ed. pp. 529, 542, and the Merck Veterinary Manual online edition.

83

What nerve(s) need to be blocked in order to dehorn cattle?

A - Auriculopalpebral and Infraorbital
B - Cornual
C - Auriculopalpebral
D - Cornual and Infratrochlear
E - Infratrochlear

B- Cornual

Typically a cornual nerve block (branch of the trigeminal- midway between eye and base of horn, just below temporal line) will anesthetize most cows for dehorning. If that is not enough, do a ring block around the base of the horn.

In contrast, for goats you need to block BOTH the cornual nerve (caudal ridge, root of zygomatic arch of frontal bone) and infratrochlear nerve (dorsomedial to eye, close to edge of bony orbit) before dehorning. This is because the goat horns lie more rostral on the skull and closer to the bony orbits than the horns of a cow.

Refs: Pasquini and Spurgeon's Anatomy Dom An 11th ed. p. 545 and the Wikimedia Commons image library.

84

A 4 year-old quarterhorse in California is presented with fever, lethargy, ataxia, icterus, petechiation, and limb edema.

A complete blood count shows characteristic neutrophil inclusion bodies suggesting equine granulocytic ehrlichiosis.
 

Which one of the following choices is the most appropriate treatment?

A - Streptomycin
B - Oxytetracycline
C - Penicillin
D - Euthanize. There is no effective treatment
E - Chloramphenicol

B Oxytetracycline

Oxytetracycline is an extremely effective treatment for Equine granulocytic ehrlichiosis (Anaplasma phagocytophilum), most commonly seen in California in the United States. Dexamethsone may help horses with severe ataxia and edema (20 mg, sid for 2-3 days).

Penicillin, chloramphenicol, and streptomycin are not effective.

Refs: Smith, Large Animal Internal Medicine, 3rd ed. pp. 1073-4 and the Merck Veterinary Manual online edition.

85

Which one of the following conditions occurs in the Fall in temperate climates, among cattle moved from poor pasture to lush pasture?

A - Acute bovine pulmonary emphysema and edema
B - Rumenal hyperkeratosis
C - Verminous bronchitis (Husk)
D - Vagal indigestion
E - Hypocalcemic paresis

A- Acute bovine pulmonary emphysema and edema

Acute bovine pulmonary emphysema and edema(ABPEE) is associated with Fall onset, occurring 5-10 days after changing cattle from poorer to better, often lush, pasture.

Toxicity occurs because rumen micro-organisms convert L-tryptophan in lush pasture grasses to pneumotoxic 3-methylindole, which damages respiratory epithelial cells.

Refs: Pasquini, Guide to Bovine Clinics 4th ed. p. 67 and the Merck Veterinary Manual online edition.

86

An adult horse with clinical signs of voluminous gastric reflux, depression, colic, and fever is most likely suffering from which one of the following choices?

A - Proliferative enteropathy
B - Proximal enteritis
C - Cantharidin toxicity
D - Ulcerative duodenitis
E - Right dorsal colitis

B- Proximal enteritis

Proximal enteritis, or duodenitis-proximal jejunitis, is a clinical syndrome characterized by large volumes of gastric reflux resulting from excessive fluid and electrolyte secretion into the small intestine and small intestinal inflammation and edema.

Laminitis is an important potential sequela. The cause is unknown but several bacteria and toxins including Clostridium difficile, Clostridium perfringens, Salmonella, and fumonosin B1 mycotoxins have been implicated.

Ulcerative duodenitis is a disorder of foals resulting in fever, colic, diarrhea, and delayed gastric emptying. Lawsonia intracellularis causes proliferative enteropathy in foals and weanlings, a disease characterized by hypoproteinemia, diarrhea, chronic ill thrift, and ventral edema.

Right dorsal colitis is typically a result of non-steroidal anti-inflammatory drug toxicity and results in hypoproteinemia and colic.

Cantharidin toxicity (blister beetles, Epicauta spp.) causes a wide range of clinical signs predominated by profuse diarrhea, stranguria and pollakiuria, and colic.

Refs: Smith, Large Animal Internal Medicine, 4th ed., pp. 725-28 and the Merck Veterinary Manual online edition.

87

A dog that was treated for vomiting with metoclopramide is now displaying involuntary muscle spasms and inappropriate aggression.

Which one of the following choices is most appropriate to help reverse the adverse effects?

A - Diphenhydramine hydrochloride
B - Acepromazine
C - Telazol (tiletamine-diazepam combination)
D - Yohimbine
E - Ketamine

A- Diphenhydramine hydrocloride

Diphenhydramine hydrochloride. Metoclopramide crosses the blood-brain barrier, where dopamine antagonism at the medullary chemoreceptor trigger zone (CTZ) causes an antiemetic effect.

This dopamine antagonism can also cause adverse extrapyramidal signs, like involuntary muscle spasms, motor restlessness and inappropriate aggression. If recognized in time, extrapyramidal signs can be reversed by restoring the dopamine:acetylcholine balance with the anticholinergic action of an antihistamine like diphenhydramine hydrochloride.

The pyramidal and extrapyramidal systems are a complex series of upper motor neurons (UMN) that connect the cerebral cortex to distant body parts and influence muscular tone and control.

The pyramidal system controls skilled muscle movement.
The extrapyramidal system helps support the body against gravity (posture) and recruits spinal reflexes to initiate voluntary movement.

Refs: De Lahunta, Vet Neuroanat & Clin Neuro, 3rd ed. pp. 192, 195-200, Plumb's Vet Drug Handbook, 7th ed. pp. 909-2 and the Merck Veterinary Manual online.

88

A dozen young chickens at a broiler-raising facility are found dead on their backs and sides with no premonitory signs.

Necropsy of a dead bird shows good body condition and no particular pathology. What is the most likely clinical diagnosis?

A - Dissecting aneurysm
B - Newcastle disease
C - Flip over disease
D - Highly pathogenic avian influenza
E - Ascites syndrome

C-Flip over disease

This is the clinical picture of flip-over disease, a production-related disease associated with intensive husbandry. The cause is not known but thought to be related to high carbohydrate intake. Ventricular fibrillation may be the cause of sudden death, and a lack of gross pathology is common.

Because broilers affected with flip over disease frequently die on their backs, differential diagnosis includes ascites syndrome (waterbelly). Sick birds with ascites syndrome typically show clinical signs like cyanosis, panting and abdomens distended by fluid. Essentially a form of right ventricular heart failure secondary to pulmonary hypertension or more rarely, hepatic failure.

Dissecting aneurysm is another cause of sudden death, but animals display severe hemorrhage on necropsy. Click here to see a necropsied chicken with frank abdominal hemorrhage and a ruptured aorta

Ref: The Merck Veterinary Manual online edition.

89

An immunochromatographic test kit for detection of fecal canine parvoviruses (CPV) antigen is being tested in a local cat shelter where as many as 10% of the cats there may have panleukopenia secondary to infection with the canine parvovirus.

Here are simulated test results, compared to a gold standard test for CPV.

.....................CPV pos.......CPV neg.............Total

Test kit positive..........128..............734...........862

Test kit negative..........63............1575...........1638

Total.........................191............2309...........2500

What is the sensitivity of this test kit?

A - 734/862
B - 1575/2309
C - 128/734
D - 128/191
E - 1575/1638

D- 128/191

Sensitivity=128/191 (67%) a/(a+c)
This is a classic example of a 2x2 table in epidemiology, used to compare a new test (the immunochromatographic test kit) to a gold standard test (the CPV test). Draw a 2x2 table, and label the boxes a,b,c,d. Sensitivity = a/(a+c). Click here to see a Basic 2X2 table.

Feline panleukopenia virus(FPV) is closely related to type 2 canine parvoviruses(CPV-2, CPV-2a, CPV-2b). CPV-2a and CPV-2b have been shown to cause a panleukopenia-like illness in domestic cats. Click here for a PDF summary on Canine and Feline Parvovirus in Animal Shelters (may take a half minute to load) by Dr. Cynda Crawford, Maddie's Shelter Medicine Program, Univ. Florida College Vet Med.

Refs: Decaro et al, Characterisation of canine parvovirus strains isolated from cats with feline panleukopenia, Res Vet Sci. 2010 Mar 22, Hennekens and Buring, Epidemiology in Medicine 5th ed. pp. 332-39

90

Which one of the following choices would be the best method for controlling anaplasmosis in adult cattle in the United States?

A - Long-acting oxytetracycline for entire herd
B - Imidocarb prophylaxis
C - Serotest and cull affected cows
D - Vaccination with a modified live vaccine
E - Spray pastures with carbaryl insecticide

A-Long acting oxytetracycline for entire herd

Long-acting oxytetracycline for entire herd. Anaplasmosis is transmitted through tick vectors. Theoretically, tick control should eliminate the agent. Unfortunately, there is no effective method for controlling ticks on a range pasture.

Affected cattle are long term carriers, so effective control must be based upon minimizing the number of inapparently infected cattle within the herd. This is best accomplished with 2 to 4 weekly injections of long-acting oxytetracycline.

Imidocarb has been used for treating carrier cows in some countries, but the drug is not currently approved for use in the United States in cattle.

Modified live vaccines exist, but have variable efficacy, availability and adverse effects.

Refs: Smith's Large An Med 3rd ed. pp. 1049-55, Pasquini's Guide to Bov Clin, 4th ed. p. 92 and Merck Veterinary Manual online edition.

91

In September, a 5-year-old Quarterhorse mare is presented with a 5-day history of left head tilt, facial paralysis, depression, and stumbling. The horse is ataxic and knuckles on both forelegs, worse on the left. There is muscle atrophy of the left pectorals and right hindquarters and strips of localized spontaneous sweating over the left trunk.

The horse is immunoblot test-positive for Sarcocystis neurona.

What prognosis is given to the owner if she elects to treat the horse?

A - Prognosis is grave
B - At least 60% of treated horses improve
C - 50% of treated horses recover completely
D - Prognosis is good if treated with doxycycline
E - Only 25% of treated horses improve

B- At least 60% of treated horses improve

The prognosis is guarded to fair for treatment of Equine protozoal myeloencephalitis (EPM). Less than 25% recover completely, but at least 60% of treated horses improve.

Horses that remain positive by immunoblot testing commonly relapse, but horses who become negative by immunoblot testing rarely relapse.

Refs: Plumb's Vet Drug Handbook, 7th ed. pp. 1190-2, 1271-6, Pasquini's Guide to Eq Clin, 3rd ed. pp. 250, 266-7, and the Merck Veterinary Manual online edition.

92

A 3-year old male neutered Labrador retriever from the Ohio river valley basin is presented with chronic large bowel diarrhea and signs of respiratory disease (cough, fever).

A lymph node smear shows round to ovoid (1-4 micrometers) encapsulated structures inside macrophages and giant cells. The organisms have thin cell walls, with thin clear zone between cell wall and cytoplasm.

Click here to see image

What is the diagnosis?

A - Aspergillosis
B - Coccidioidomycosis
C - Histoplasmosis
D - Cryptococcosis
E - Blastomycosis

C- Histoplasmosis

Think of Histoplasmosis in a dog with these findings (possible respiratory and diarrheal fungal disease, with tiny organisms in macrophages). Histoplasmosis is seen in the river valleys of the central United States, associated with bird and bat droppings in soil.

The big DDX is blastomycosis, also seen in the same area, with a respiratory presentation. Histo is more a chronic diarrheal and respiratory disease in dogs and a respiratory disease in cats. Note that histoplasma organisms are much smaller (1-4 micrometer for histo vs. 8-25 micrometers for blasto), and UNLIKE blasto, histoplasma organisms are difficult to detect with routine H&E stain. Use PAS, Gomoris methenamine silver or Gridley's fungal stains to see yeast forms in macrophages and giant cells (round to ovoid structures(1-4 micrometers), thin cell wall, thin, clear zone between cell wall and cytoplasm.

Coccidioidomycosis is seen in the arid and semiarid Southwestern U.S., Mexico and Central America. Organisms vary in size (20-80 micrometers to 200 micrometers) spherules with a double-contoured wall. Mature spherules (sporangia) contain tiny endospores (sporangiospores) 2-5 micrometers in diameter. THINK DUSTY DESERT. Spores are carried on dust and inhaled. Epidemics may occur after dust storms or excavation.

Because it is ubiquitous, positive culture results for aspergillus should be supported by demonstration of narrow, hyaline, septate, branching hyphae. Usually a nasal presentation in dogs.

Think of Cryptococcus in cats with a granulomatous rhinitis and sinusitis. This nasal cavity disease in cats sometimes causes a swollen "roman nose" appearance. Seen in other species as well (cows, dogs) but with varying presentations.

Refs: Pasquini's, Tschauner's Guide to Sm An Clin, vol 1, 2nd ed. pp. 702-5 and the Merck Veterinary Manual online edition.

93

Which parasite can cause cutaneous larva migrans in people?

A - Spirocerca sp.
B - Gasterophilus spp
C - Habronema spp
D - Ancylostoma spp
E - Trichuris spp

D- Ancylostoma spp

Hookworms (Ancylostoma spp) may cause cutaneous larva migrans in people. Note that Roundworms (Toxocara spp, Toxasacaris spp) are also zoonotic, causing visceral and ocular larva migrans in people.

In dogs, Whipworms, Trichuris spp are associated with a hypoadrenocorticism-like syndrome (hyponatremia, hyperkalemia, azotemia, metabolic acidosis). Whipworm infection has been suggested as one cause of cecocolic intussusception.

Habronema spp in horses can cause tumorlike stomach nodules and sometimes cutaneous lesions.

Refs: Cote', Clin Vet Advisor-Dog and Cat, 1st ed. pp. 529-30, 979-80, 1165-6 and the Merck Vet Manual online edition

94

A 3 year old male cat is positive for feline leukemia virus (FeLV) by both ELISA and IFA tests.

A complete blood count (CBC) shows
PCV=19%.................[N=24-45%] with polychromasia, reticulocytosis, anisocytosis
WBC=3,600...............[N=3800-19,500] with neutropenia, lymphopenia
Thrombocytes=300,000/microliter..[N=300,000-700,000]

In addition to feline leukemia, what other infection is suspected in this cat?

A - Cytauxzoon variabilis
B - Toxoplasma gondii
C - Mycoplasma haemofelis
D - Hemobartonella bigemina
E - Chlamydophila felis

C. Mycoplasma haemofelis

When you see regenerative anemia (polychromasia, reticulocytosis, anisocytosis) in a FeLV-positive cat, suspect coinfection with Mycoplasma haemofelis (or Mycoplasma haemominutum). Typically, the anemia of feline leukemia virus (FeLV) alone is NON-regenerative.

Mycoplasma haemofelis (formerly called Hemobartonella felis) causes feline infectious anemia, and is treated with tetracyclines.

Click here to see regenerative anemia on a blood smear.

In the SE USA, Cytauxzoon felis must be differentiated from Mycoplasma felis in cats with regenerative anemias.

Think of Toxoplasma gondii (with neurologic and ocular manifestations) more in association with feline immunodeficiency virus (FIV).

Refs: Blackwell's 5-Min. Vet Consult Canine-Feline, 4th ed. pp. 490-1, Cote, Clin Vet Advisor-Dog and Cat, 1st ed. pp. 380-2, Wikimedia Commons and the Merck Veterinary Manual online edition.

95

A 6 year old female spayed cocker spaniel is presented with a 2 day history of lethargy. Upon physical exam mucosal petechiae and ecchymoses and an ocular hemorrhage O.D. is noted

A coagulation profile shows the following:
Thrombocytes= 49,720..[N=200,000-900,000]
Buccal mucosal bleeding time (BMBT), increased
Activated partial thromboplastin time (aPTT), normal
Prothrombin time (PT), normal
Thrombin time (TT), normal

What is the diagnosis?

A - Hepatic insufficiency
B - Anticoagulant rodenticide toxicity
C - Disseminated intravascular coagulation (DIC)
D - Von Willebrand's disease
E - Idiopathic thrombocytopenia
 

E- idiopathic thrombocytopenia

The history, plus a lab pattern of low platelets, increased bleeding time and normal aPTT, PT and TT tests suggests thrombocytopenia. Idiopathic thrombocytopenia (often immune-mediated) is the most common cause of spontaneous bleeding in dogs. Twice as common in females; cockers, poodles and old English sheepdogs are predilected, but can occur in any breed.

Of the common causes of coagulation disorders, only disseminated intravascular coagulation (DIC) also presents with thrombocytopenia.

Follow this link to see a table of the four most important coagulation disorder patterns

Refs: Blackwell's 5-Min. Vet Consult Canine-Feline, 4th ed. pp.1335-7, Pasquini's, Tschauner's Guide to Sm An Clin, vol 1, 2nd ed. pp. 290-3 and the Merck Veterinary Manual online edition.

96

An 8-year old neutered male golden retriever is presented with a 2 month history of nonspecific lethargy and weight loss.

T=99.8 F (37.7 C)..[N=99.5-102.5 F]
RR=24 brpm.......[N= 15-34]
HR=64 bpm........[N= 80-120]

On physical exam, there is normal hydration and mild ascites.

Complete Blood Count
PCV=45%....[N= 37-55%], RBC=6.5 x 1012 g/L...[N=5.2-8.5 x 1012]
Normocytic, normochromic
WBC=12,350...[N=5400-15300],
Neuts=63%...[N=60-70%],Lymphs=24%...[N=12-30%],
Monos=5%.....[N=3-10%], Eos=8%...[N=2-10%]

Blood Chemistry
Na=148 mEq/L...[N=146-156], Cl=118 mEq/L...[N=109-122],
K=6.0 mEq/L...[N=3.8 -5.6]

LDH=200 u/L...[N=24-219], ALT=36 u/L....[N=8.2-57]
AST=14 u/L.....[N= 13-15], GGT=4.4 u/L...[N= 1.0-9.7]
Alk Phos=101 u/L...[N=1-114]
Glucose=120 mg/dL...[N= 79-126], Cholesterol=200 mg/dL..[N= 116-300]
BUN=29 mg/dL...[N=7.0-26], ..........Creatinine=1.6 mg/dL....[N=0.5-1.6]

Bilirubin (total)=0.4 mg/dL...[N=0.0-0.4 ]
Total protein=4.6 g/dL...[N=5.5-7.5],
(globulin=3.0 g/dL...[N=2.1-3.7 ], albumin=1.6 mg/dL...[N=2.6-4.0])

Urinalysis
USpG=1.031...[N=1.016-1.060], no WBC or RBC,protein +++

Which diagnosis is on top of the differential diagnosis list?

A - Diabetes insipidus
B - Glomerulonephritis
C - Hypoadrenocorticism
D - Renal disease
E - Pyelonephritis

B- Glomerulonephritis

Glomerulonephritis is a top rule out here for a middle-aged dog with low albumin, ascites and proteinuria without evidence of urinary infection (no RBC or WBC in urine sediment).

This is a type III immune reaction in which antigen-antibody complexes deposited on glomeruli or capillary walls of glomeruli, stimulate complement and cause damage via a neutrophilic inflammatory response.

Another big rule out for a canine protein-losing nephropathy is renal amyloidosis. Renal biopsy is the best way to distinguish between glomerulonephritis and amyloidosis

Refs: Blackwell's 5-Min. Vet Consult Canine-Feline, 4th ed. pp. 548-9, Pasquini's, Tschauner's Guide to Sm An Clin, vol 1, 2nd ed. pp. 360-1 and the Merck Veterinary Manual online edition.

97

This 3 year old Charolais bull weighing 2100 lbs was found at pasture walking in circles. He has been fed silage enriched with 5% dried chicken litter in addition to the winter pasture. 

T = 104.6°F (40.3°C)..[N=101.5-103.5 F]
Pulse rate = 46 beats per minute....[N=55-80bpm]
Resp. rate = 21 per minute....[N=10-30 brpm]

He is depressed, anorectic and drooling, with a head tilt to right. The right ear and eyelid both droop. The bull is ataxic with predominantly right sided proprioceptive deficits.

A sample of cerebrospinal fluid (CSF) taken at the lumbosacral space has normal color, no turbidity but has an increased mononuclear cell count and an elevated protein concentration.

Which one of the following choices is the most likely diagnosis?

A - Otitis media/interna
B - Nervous coccidiosis
C - Rabies
D - Thromboembolic meningoencephalitis
E - Listeriosis

E- Listeriosis

Listeriosis is most likely in this bull. Infection with Listeria monocytogenes usually presents with MULTIFOCAL brainstem signs as seen by dysfunction of multiple cranial nerves, most often V, VII-X, and XII.

Circling is thought to be more than just CN VIII damage because of the intensity associated - affected animals will sometimes continuously circle till they collapse. This suggests that other areas of the brain such as the basal ganglia and the descending reticular formation are also affected.

Thromboembolic meningoencephalitis (TEME) causes brainstem and cerebellar signs but the CSF would be neutrophilic and xanthochromic. The xanthrochromia is due to vasculitis/thrombosis in the CNS. TEME is more common in feedlot calves; respiratory disease, septicemia, and joint disease may also be seen.

Animals with otitis media/interna are alert and responsive, and have signs of vestibular dysfunction, but are not paretic.

The bull could have rabies, but the multifocal nature of this bull's problem and the localization of lesions to the brainstem favor a diagnosis of listeriosis.

Patients with nervous coccidiosis are usually centrally blind, and have cerebral rather than brainstem signs. It is most often seen in calves soon after the development of diarrhea.

Refs: Pasquini's Guide to Bovine Clinics 4th ed., p 141-4, 150, Divers and Peek, Rebhun's Diseases of Dairy Cattle, pp. 512-8, 520, 530, 551-3, and the Merck Veterinary Manual online edition. Image courtesy Dr. Lisle George copyright 2012

98

This 11-year-old spayed female cat is presented with generalized weakness and unable to lift her head.

The owners have noticed her at the water bowl more often and she seems to be urinating more in the last month.

Which blood chemistry test would be most likely to diagnose cause of her weakness?

A - Bicarbonate
B - Calcium
C - Sodium
D - Chloride
E - Potassium

E-Potassium

Potassium. This is a classic presentation of a cat with hypokalemic myopathy which is often due to potassium loss from renal disease.

Other causes of generalized weakness and neck ventroflexion include polymyositis, organophosphate toxicity, myasthenia gravis.

Refs: Curtis Dewey, A Practical Guide to Canine and Feline Neurology, 2nd ed. pp. 458-9 and the Merck Veterinary Manual online edition. Image courtesy Dr. Shirley Scott.

99

A 7-year old male German shepherd presents with a history of weakness in the hind limbs, urinary incontinence and recent obsessive chewing around his tail area. Dorsiflexion of the tail over the back and extension of the hind limbs elicits a painful response.

There is moderate hindlimb ataxia. He does not withdraw each hind leg when a toe is pinched, but bears weight on the hindlimbs. Patellar reflexes are normal.

What is the clinical diagnosis?

A - Hip dysplasia
B - Wobbler syndrome
C - Radiculoneuritis
D - Cauda equina syndrome
E - Diskospondylitis

D- Cauda equina syndrome

This is a common presentation of Cauda equina syndrome. Look for PAIN in the lumbosacral area (elicited by tail raise, hindlimb extension), LMN hindlimbs, especially Sciatic nerve damage at L7-S1 (lack withdrawal), +/- urinary/fecal incontinence, +/- SELF-MUTILATION of tail, perineum, pelvic limb.

Lesion due to compression of cauda equina at L7-S1 (lumbosacral stenosis). Can be congenital (abn development dorsal arch L7-S1, small dogs, Border Collies) or acquired (degenerative changes, big dogs, especially German Shepard, Rottweiler, Boxer).

Wobbler syndrome is a cervical spinal cord disease (also called cervical vertebral instability/ caudal cervical spondylomyelopathy). In adult form it is an intervertebral disc disease, usually seen at C5-C6 or C6-C7 in Dobies> 5 yrs, Great Danes> 2 years.

Diskospondylitis is a good second choice on your DDX of a large middle aged dog presenting with lumbosacral pain. Due to bacterial/fungal infection of intervertebral disk and adjacent vertebral bodies. Look for systemic signs like fever (1/3 of patients), weight loss, anorexia. Follow this link to see a Merck image of diskospondylitis.

Refs: De Lahunta, Vet Neuroanatomy and Clin Neurology, 2nd ed. p. 74, Pasquini's, Tschauner's Guide to Small Animal Clinics, vol 1, 2nd ed. pp. 529, 533, and the Merck Veterinary Manual online edition.

100

A 12-year old male neutered cat weighing 14 pounds is presented with a 2-month history of PU/PD, increased appetite, lameness, weight gain, exercise intolerance and dyspnea.

Physical exam shows a systolic heart murmur with a gallop rhythm, a lateral chest radiograph shows pulmonary effusion and a large heart.

T=102.0 F..[N=100-103.1F]
HR=110 bpm.......[N=130-140]
RR=24 brpm........[N=16-40]

A CBC shows

PCV=48 %.............[N=24-45%], WBC=14,850..[N=3800-19,500]
Neuts=88%............[N=35-75% ], Lymphs=4%..[N=20-55%]
Monos=7%.............[N=1-4%], Eos=1%..[N=2-12%]
Basos=rare............[N=rare]

Blood chemistry reveals the following
NA=150................[N=151-161], K=5.1..[N=3.5-5.1]
LDH=200...............[N=35-225], ALT=108..[N=8.3-53]
Total protein=10.1..[N=5.7-8.0], Glucose=350..[N=63-132]
Alk Phos=200.........[N=3-65], Cholesterol=250..[N=95-130]
BUN=47 mg/dL.......[N=10-30], Creatinine=3.4 mg/dL..[N=0.8-2.0 ]
Bilirubin (total)=0.3.[N=0.0-0.2]

Urinalysis
U Sp. G= 1.018........[N=1.020-1.040]
Glucose +++, WBC ++, RBCs +, protein +++

Which one of the following choices is the most likely diagnosis?

A - Acromegaly
B - Hyperadrenocorticism
C - Diabetes insipidus complicated by cardiomyopathy
D - Hyperthyroidism complicated by renal disease
E - Pancreatic exocrine insufficiency 

A-Acromegaly

his complicated mix of diabetes mellitus , renal disease and heart failure/cardiomyopathy in an OLDER MALE cat suggests feline acromegaly.

First presenting sign may be PU/PD, polyphagia of diabetes. WEIGHT GAIN in an unregulated diabetic cat STRONGLY SUGGESTS acromegaly, (but they may LOSE weight at first).

Follow this link to see pulmonary edema and a large heart.

May see prognathism (long mandible), lameness (esp. cats), marked vertebral spondylosis, thickened skin, large head, wide interdental spaces and a Stress leukogram (High neuts, low lymphs/Eos)

Refs: Blackwell's 5-Minute Vet Consult Canine Feline, 5th ed. p. 17, Tschauner/Pasquini's Guide to Sm An Clinics, 3rd ed. p. 683 and the Merck Veterinary Manual online edition.

101

The sheep seen in the images below presents with listlessness, reluctance to move, and a crusty muzzle. On examination, there is a wide reddened area just proximal to the coronary bands.

Which one of the following choices is the most likely diagnosis?

A - Sheeppox
B - Fuzzy wool disease
C - Caprine arthritis/encephalitis
D - Vesicular stomatitis
E - Bluetongue

E-Bluetongue

Bluetongue is an infectious, noncontagious viral disease of ruminants. Some affected sheep will have swollen, cyanotic tongues. It is transmitted via bites from the vector - Culicoides spp biting midges.

Sheeppox can cause crusty, scabby lesions on the nose, but not lameness or the changes at the coronary band.

Refs: Merck Vet Manual 10th ed. online. Images courtesy Dr Jerry J Callis, Dr Brian WJ Mahy and the CDC.

102

A zebra recently imported from Zimbabwe to a London zoo died after a being ill for about 2 weeks. He was febrile and very depressed, with dyspnea and respiratory distress in the last 24 hours.

Other signs included hyperemia of the conjunctiva and edema all over the head and neck, especially the eyelids and the supraorbital fossae. Necropsy reveals a clear pericardial effusion, froth in the upper airways, and heavy distended lungs.

Which one of the following choices is the most likely diagnosis?

A - Equine viral arteritis
B - Equine influenza
C - African Horse Sickness
D - Piroplasmosis


E - Equine infectious anemia 

C-African Horse Sickness

African Horse Sickness (AHS) presents with fever, respiratory signs, and edema. Those with respiratory signs die within about a week; death occurs after 1-2 weeks in the "cardiac" form of the disease.

Caused by an orbivirus, AHS is transmitted via bites of infected Culicoides spp. most often during warm, humid, seasons.

AHS is very lethal, especially in naive populations where mortality approaches 90%. No specific treatment is effective, but attenuated-live virus vaccines are available that are protective.

Edema is a prominent clinical sign, especially of the head and neck. Pulmonary edema and hydropericardium are a common necropsy findings.

The disease is endemic in southern Egypt and occurs sporadically in many parts of Africa. AHS has never occurred in the United States and is a REPORTABLE disease.

Other differentials include anaplasmosis, piroplasmosis, equine viral arteritis, and Equine infectious anemia

Refs: Blackwell's 5 Minute Consult: Equine 2nd ed., p. 41, and the Merck Vet Manual 10th edition online, Image courtesy, Dr Jerry J Callis, Dr Brian WJ Mahy and the CDC.

103

A fourteen-year-old cat presents with a protruded nictitating membrane and miotic pupil on the right. There is an absent right palpebral reflex and a right head tilt. The physical, ophthalmologic, and neurological exams are normal.

Where is the lesion?

A - Right brachial plexus
B - Left cavernous sinus
C - Right medulla oblongata
D - Left brachial plexus
E - Right middle/inner ear

E-Right middle/inner ear

A lesion of the right middle/inner ear could cause ipsilateral Horner's syndrome (miosis, ptosis, enophthalmos), facial nerve paralysis, and vestibulopathy.

Otitis Media and Interna is the most common cause of disease in this area, but neoplasia can also occur in the middle/inner ear.

A brachial plexus avulsion can also cause an ipsilateral Horner's syndrome, but not facial nerve paralysis or vestibulopathy.

Refs: Cote, Clin Vet Advisor 2nd ed. pp. 543-5 and the Merck Veterinary Manual online edition. Image courtesy, Nottingham Vet School.

104

What are potential complications to surgical thyroidectomy in a hyperthyroid cat?

A - Laryngeal paralysis
B - May miss ectopic thyroid tissue
C - Horner's syndrome
D - All of these
E - Hypocalcemia

D- All of these

A unilateral thyroidectomy could allow for recurrent Hyperthyroidism, by way of hyperplasia or adenoma, of the contralateral thyroid gland.

The cat should be treated medically for several weeks before surgery.

Refs: Cote, Clin Vet Advisor 2nd ed. pp 562-5 and the Merck Veterinary Manual online edition. Image courtesy, Nottingham Vet School

105

A 12-year-old neutered male mixed-breed cat presents with weight loss, polyphagia, polydipsia, polyuria, and unkempt haircoat. The cat is thin and has tachycardia.

Which one of the following tests is most likely to confirm the presumptive diagnosis?

A - Urinalysis
B - Abdominal ultrasonography
C - Serum T4
D - Fecal examination
E - Abdominal radiographs

C-Serum T4. The signalment and clinical signs are highly compatible with hyperthyroidism.

Canned food diet, ectoparasiticide exposure, and mixed breed origin are probable risk factors for Hyperthyroidism.

The three treatment options are antithyroid medication, radioactive iodine therapy, and surgical thyroidectomy.

Refs: Cote, Clin Vet Advisor 2nd ed. pp. 562-5 and the Merck Veterinary Manual online edition. Image courtesy, Nottingham Vet School.

106

The following cytology is from a bronchoalveolar lavage in a dog.

Which one of the following choices is the most likely diagnosis?

A - Fungal bronchopneumonia
B - Bacterial contamination
C - Eosinophilic pneumonitis
D - Bacterial bronchopneumonia
E - Actinomyces pneumonia 

B-Bacterial contamination

Simonsiella are bacteria that normally inhabit the pharynx and have a large, ladder-like appearance. Their presence indicates contamination from the oropharynx.

Bacteria, if present within neutrophils or macrophages, would be a significant finding.

Refs: Cote, Clin Vet Advisor 2nd ed. pp 160-2 and the Merck Veterinary Manual online edition. Image courtesy, Nottingham Vet School.

107

A five-year-old mixed breed presents with acute swelling of the left pinna that is determined to be an aural hematoma.

Which one of the following choices is the best treatment?

A - Pinnectomy
B - None of these
C - Incisional drainage
D - Bulla osteotomy
E - Fine-needle aspiration

C-Incisional drainage

This is an aural hematoma, a commonly seen condition in practice. Following incisional drainage, mattress sutures are applied to prevent deformation and the ear is bandaged to the head.

It is important to determine the underlying cause of aural hematomas with a thorough aural exam, cytology, thyroid profile, food trial, or allergy skin testing.

Refs: Cote, Clin Vet Advisor 2nd ed. pp. 120-2 and the Merck Veterinary Manual online edition. Image courtesy, Nottingham Vet School.

108

A fourteen-year-old neutered male Lab presents with a sudden onset of a left head tilt and horizontal nystagmus with the fast phase to the right.

He is barely ambulatory with ataxia but has normal conscious proprioception and normal stride length. The rest of his physical and neurologic exam is normal.

Which one of the following choices is the most likely location of the lesion? 

A - Left peripheral vestibular
B - Right cerebrum
C - Left cerebrum
D - Right brainstem
E - Right rostral cerebellar peduncle

A-Left peripheral vestibular

Peripheral vestibular disease in a geriatric dog has a high likelihood of being idiopathic geriatric vestibular syndrome – a self-limiting syndrome.

Otitis Media and Interna or hypothyroidism would be other possibilities.

Refs: Cote, Clin Vet Advisor 2nd ed. pp. 1170-1 and the Merck Veterinary Manual online edition. Image courtesy, Nottingham Vet School.

109

A five-year-old Boxer dog presents for routine vaccinations. The owner points out a small, smooth mass on the right ear.

Fine needle aspiration cytology is shown below. Which one of the following choices is the most likely diagnosis? 

A - Pyogranulomatous inflammation
B - Bacterial inflammation
C - Transmissible venereal tumor
D - Lymphoma
E - Mast cell tumor

E-Mast cell tumor

This cytology slide shows mast cells full of purple histamine granules, suggesting a mast cell tumor. Follow this link to see another slide of mast cell cytology.

Grossly, appearances are highly variable and mast cell tumors can be mistaken for skin tags or lipomas.

Skin and subcutaneous masses should always be examined cytologically. These tumors can range from low grade to highly aggressive with local recurrence or lymph node metastasis.

Transmissible venereal tumors are often papillary or nodular in appearance. Cytologically they are a round cell tumor with large, central nucleoli.

Refs: Cote, Clin Vet Advisor 2nd ed. pp 701-3 and the Merck Veterinary Manual online edition. Images courtesy, Nottingham Veterinary School and Wikimedia commons.

110

A twelve-year-old female spayed miniature schnauzer presents with a history of seizure-like episodes.

Physical exam reveals an irregular heart beat. CBC and panel are unremarkable except for a mild triglyceridemia. ECG is shown below.

Which one of the following choices is the most likely diagnosis?

A - Sick sinus syndrome
B - First degree AV block
C - Ventricular tachycardia
D - Atrial fibrillation
E - All of these

A-Sick sinus syndrome.

The "seizure-like" episodes, after questioning the owner further, were actually syncopal episodes. Syncope lacks muscle activity and post-ictal behavior.

Older female Miniature Schnauzers tend to be overrepresented with sick sinus syndrome.

The ECG here shows sinus arrest with bradycardia and tachycardia.

First degree AV block is characterized by an increased PR interval.

Second degree AV block consists of occasional P waves not followed by QRS complexes.

Refs: Cote, Clin Vet Advisor 2nd ed. pp.1022-4 and the Merck Veterinary Manual online edition. Image courtesy, Nottingham Vet School.

111

Which one of the following choices is the most likely finding consistent with myocardial hypoxia in the ECG below? 

A - Increased T amplitude
B - Alternating bradycardia and tachycardia
C - Variable complex intervals
D - ST segment depression
E - Narrow QRS complex

D-ST segment depression or elevation is consistent with myocardial hypoxia.

Tall T waves are commonly normal in cats and dogs, however, if the onset of tall waves is noted during ECG monitoring over time it could indicate hypoxia or movement artifact.

Alternating bradycardia and tachycardia is seen with sick sinus syndrome (SSS). In SSS, the sinoatrial node is unable to generate an impulse. Older female miniature schnauzers are predisposed. Look for signs of fainting, weakness, confusion. Rx is a pacemaker.

Refs: Cote, Clin Vet Advisor 2nd ed. web only and the Merck Veterinary Manual online edition. Image courtesy, Nottingham Vet School.

112

A 12-year-old male Labrador retriever is presented with a one-year history of cough and stridor.

Which one of the following choices can be ascertained from the thoracic radiographs? 

A - Emphysema
B - Megaesophagus
C - Cranial mediastinal mass
D - Hypoinflation of lungs
E - Severe heartworm disease

D- Hypoinflation of lungs.

Within the thorax, there is poor inflation with the diaphragm remaining in a relatively vertical position and contacting the entire caudal border of the heart. There is increased opacity throughout the lungs, with a bronchointerstitial pattern.

The cranial mediastinum is uniformly widened on the d/v projections with no evidence of a mass on the lateral projection. The heart and vessels appear normal.

The pulmonary changes are probably due to hypoinflation secondary to upper airway obstruction, however, additional airway or parenchymal disease cannot be ruled out. In this case, the dog had bilateral laryngeal paralysis.

Emphysema can be either alveolar or interstitial. Pekingese can have congenital lobar emphysema due to poor development of bronchiolar cartilage resulting in air trapping during expiration.

Refs: Thrall, Textbook of Veterinary Diagnostic Radiology 6th ed. pp. 608-31 and the Merck Veterinary Manual online edition., Radiographic interpretation and images courtesy, Dr A. Zwingenberger and Veterinary Radiology.

113

A 3-year-old neutered male Lhasa Apso was presented with a one month duration of left pelvic limb lameness and depression.

Based on the radiographs, where is the problem located? 

A - Right Sacrum
B - L6-7
C - Left ilium
D - Left stifle
E - Right femoral head

C-Left ilium

There is a mixed lytic and productive bone lesion on the wing of the left ilium, extending to the cranial acetabulum. The femoral head is not involved.

The lesion is seen best on the v/d projection.The differentials would include neoplasia or osteomyelitis.

The diagnosis in this case is osteomyelitis secondary to coccidiomycosis.

Refs: Cote Clin Vet Advisor 2nd ed. pp. 800-1 and the Merck Veterinary Manual online edition. Images courtesy, Dr A Zwingenberger and Veterinary Radiology.