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1

Which of the following clinical signs is not consistent with discoid lupus erythematosis in dogs?

a. Alopecia and crusting the muzzle, lips, and periorbitally

b. Depigmentation of the nasal planum

c. Loss of "cobblestone" appearance of the nasal planum

d. Hyperpigmentation of ventral abdomen

d. Hyperpigmentation of ventral abdomen

Clinical signs consistent with DLE include depigmentation, erythema, scaling, and loss of the "cobblestone" appearance of the nasal planum. Alopecia, crusting, scaling, and ulcerations can also be seen on the face, muzzle, lips, pinnae, and periorbitally

2

You are presented with a bitch that whelped her first litter 2 weeks ago. Two of the pups have died and the remaining 2 have neurological signs, suckle poorly, and cry constantly. Which of the following choices is the primary differential diagnosis?

a. Canine herpes virus

b. Canine parvovirus

c. Neonatal septicemia

d. Transplacental roundworm infection

e. Congenital disease

a. Canine herpes virus

Canine herpes virus (CHV) rarely causes disease other than mild respiratory signs in adult dogs. However, naive newborn pups have high morbidity and mortality if infected at less than 3 weeks of age. Naive bitches should be exposed to CHV prior to breeding or the bitch and pups quarantined for 3 weeks before and after whelping. Canine parvovirus in neonates can cause vomiting, diarrhea, or acute death due to cardiovascular failure in pups 3-8 weeks old

3

A 2-year old male neutered cat presents to you depressed, hypersalivating, and ataxic with muscle tremors. The owner reports that a pyrethrin-based spot-on formulation for flea control belonging to their Golden Retriever was accidentally applied on the cat earlier today. Which of the following drugs will you use to treat the cat's clinical signs?

a. Methocarbamol

b. Amoxicillin

c. Acepromazine

d. Atropine

e. 2-PAM

a. Methocarbamol

Pyrethrins alter the activity of the sodium ion channels of nerves, which prolongs the period of sodium conductance. This increases the length of depolarization resulting in repetitive nerve firing. Cats are particularly sensitive to pyrethrin-containing products and can develop clinical signs within hours after administration. Affected animals should be bathed to remove remaining product. Minor clinical signs such as hypersalivation and ear twitching are usually self-limiting and do not require treatment. Control of marked tremors or seizures can be achieved with methocarbamol (Robaxin).

4

A 7-year old female spayed Standard Poodle presents with weakness and lethargy. A chemistry panel shows a Na+ = 130 mEq/L (142-152 mEq/L), K+ = 6.5 mEq/L (3.9-5.1 mEq/L), BUN 55 mg/dl (8-28 mg/dl), creatinine 1.9 mg/dl (0.5-1.7 mg/dl). The test to run for a definitive diagnosis would be which of the following?

a. Electrocardiogram

b. Thoracic radiographs

c. ACTH stimulation test

d. Bile acids test

c. ACTH stimulation test

The chemistry profile above is highly suggestive of hypoadrenocorticism. An ACTH stimulation test would give a definitive diagnosis for Addison's disease if the plasma cortisol concentration is low after ACTH administration. A bile acids test is not indicated since liver function is not in question. Thoracic radiographs may show microcardia, hypoperfused lungs, and rarely megaesophagus. ECG abnormalities would be consistent with hyperkalemia, which includes wide, flat, or absent P waves, widened QRS complexes, tall spiking T waves, and bradycardia.

5

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

a. Facial nerve

b. Left side inner ear
c. Trigeminal nerve

d. Right side inner ear

e. Left side medulla, motor intact

a. 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 dropped 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 trigenimal nerve neuropathy (CN 5-dogs, horses).

6

You are called out on a house-call to see the 3-year-old male Labrador Retriever shown in the photo below. He presents for bilateral periocular edema (see photo) and facial pruritus. This has been a recurrent problem for the last 4 months. The owners reported the dog would be normal for several days, and then acutely develop the periocular swelling and itching. These episodes always happened while the dog was inside the house.

The previous episodes would last for several hours, and then the edema would resolve en route to the veterinary clinic. After each episode, the dog had some residual periocular or facial pruritus for 1-2 days.

You perform conjunctival swabs and aspirates of the edematous area which reveal large numbers of eosinophils.

What is the most likely underlying cause of the dogs signs?

a. Bacterial infection

b. Parasitism

c. Hypersensitivity

d. Autoimmune disorder

e. Neoplasia

c. Hypersensitivity

Edema as you see here is a common clinical sign of a type I hypersensitivity reaction or allergy. The intermittent nature of the episodes suggests some type of allergic reaction, most likely infrequent contact with a potent allergen to which the dog has become sensitized. An underlying allergic etiology is further supported by the presence of eosinophils.

Identifying the underlying allergy in cases like this one can be challenging, and a thorough history and investigation of the dog's environment is warranted.

The other answer choices presented are less consistent with the recurrent and sudden clinical signs that are repeatedly observed.

7

A 12-year-old mixed breed female spayed dog presents with a several-month history of lethargy, hair loss, and greasy skin. The patient's face, feet, and tail are not clinically affected and she is mildly pruritic. This photomicrograph shows the results of impression cytology obtained from the patient. What is the most likely name of the organism pictured?

a. Staphylococcus pseudointermedius (Staphylococcus intermedius)

b. Malassezia globosa

c. Malassezia pachydermatis

d. Staphylococcus hyicus

a. Staphylococcus pseudointermedius (Staphylococcus intermedius)

Intracytoplasmic cocci from a dog's skin are most likely Staphylococcus pseudintermedius (formerly called Staphylococcus intermedius), which is the species host-adapted to canines. Staphylococcus hyicus is host-adapted to pigs, so is less likely to be isolated from a dog. Malassezia (yeast) organisms are much larger than cocci and are not observed within the cytoplasm of neutrophils.

8

A 3-year old West Highland White Terrier presents for flea allergic dermatitis. The owner is concerned because she is on an appropriate adulticide and insect growth regulator, but live fleas are still being found on the patient. Additionally, the dog also has moderate signs of flea allergy dermatitis; papular/pustular dermatitis in the lumbosacral region. Why might the treatment be failing?

a. Owner is not applying the product properly and not treating the environment

b. Owner is not treating the environment

c. Owner is not applying the product properly

d. Owner is not applying the product properly and is not treating other pets in the household

e. Owner is not applying the product properly, owner is not treating the environment, and other pets in the household are not on flea control

f. Other pets in the household are not on flea control

e. Owner is not applying the product properly, owner is not treating the environment, and other pets in the household are not on flea control

This question is a review of the most common reasons for failure of a flea product to work. Education is extremely important when starting flea treatment. Always question how the owner applies the product, whether the environment is being treated, and make sure all pets in the household are undergoing treatment. One is often surprised how many owners apply topical products just to the hair of their animals. Many owners (and veterinarians) blame lack of response to resistance against flea adulticides; however, it is much more likely (in the majority of cases) that it is due to one of these 3 listed reasons.

9

A four-year old Labrador Retriever presents with an aural hematoma of the right ear. Given the cytological findings from an ear swab as seen in this image, which one of the following ear cleaning combinations will you not send home with your patient?

a. Mometasone, gentamicin, clotrimazole

b. Thiabendazole, neomycin, and dexamethasone

c. Gentamicin, betamethasone valerate, and clotrimazole

d. Neomycin, bacitracin, and polymyxin B

d. Neomycin, bacitracin, and polymyxin B

This patient has a high number of malassezia yeast visualized on cytology. This organism can be responsible for perpetuating otitis externa. It is not unusual to see yeast in the ear canal of a dog; however, yeast numbers of greater than 5 per high powered field can be considered abnormal.

Other clinical signs of otitis externa may include ear pain, pruritis, aural discharge, bad odor, and neurologic signs.

Effective treatments for uncomplicated otitis externa typically contain an antifungal, antibiotic, and an anti-inflammatory. Since this dog primarily has a yeast infection it is imperative that the ear medication prescribed has an anti-fungal. The answer choices provided are commonly known as triple antibiotic ointment (neomycin, bacitracin, and polymyxin B), Tresaderm (thiabendazole, neomycin, and dexamethasone), Mometamax (mometasone, gentamicin, clotrimazole), and Otomax (gentamicin, betamethasone valerate, and clotrimazole). Note that the triple antibiotic ointment does not contain an anti-fungal.

Additionally, the ears should be cleaned before applying the ear medication. Many ear cleaners contain antifungals too (Triz Ultra + Ketoconazole), which may enhance treatment response.

10

Demodicosis often coincides with bacterial infections. On a recheck examination of an 8-month old pit bull with demodicosis you find swelling and furunculosis over the lateral thighs that is draining serosanguinous fluid. Cytology of the fluid reveals 4+ cocci, and you diagnose a deep bacterial pyoderma. You culture the lesion and start Clindamycin based on the culture results. The dog returns in four weeks for another recheck examination. No bacteria are found on cytology, and clinically the dog looks excellent. You repeat a skin scrape and find Demodex mites. You inform the owner to continue Ivermectin. What should you do regarding continuation of antibiotics?

a. Continue the antibiotics for another 2 weeks

b. Discontinue the antibiotics, since cytology was negative and the clinical signs have resolved

c. Continue the antibiotics until the demodex has resolved

d. Perform another culture and if positive keep treating; if negative discontinue antibiotics

a. Continue the antibiotics for another 2 weeks

Deep pyodermas involve tissues deeper than the epidermis including the dermis and even subcutis. Most often deep infections have resulted from an uncontrolled superficial infection. Deep lesions usually heal on the surface before the deeper infection is resolved; making clinical cure difficult to assess. Therefore, antibiotic treatment should be continued for 7-21 days after the tissues return to normal. In general, deep infections can require 6-8 weeks of antibiotic treatment and even 12 weeks for severe cases. Superficial infections require 3-4 weeks of antibiotic therapy or one week past clinical resolution.
Culture results will often be positive in normal dogs since normal dogs will have bacteria on their skin surface and in hair follicles. It is better to manage based on clinical signs. Cytology can miss deeper infections and it is better to extend antibiotic treatment even if cytology is negative.
It is not necessary to continue the antibiotics until resolution of demodicosis. Keep in mind that many Demodex patients will require several months of treatment. It is better to prevent recurrence of bacterial infections with topical therapy such as benzoyl peroxide shampoos.

11

Microsporum canis, Trichophyton mentagrophytes, and Microsporum gypseum are the three most common dermatophytes affecting dogs and cats. It is important to obtain fungal cultures and determine the species since the above species have different sources of infection. Knowing the source of the infection is critical to determining an appropriate treatment plan. Please match the following dermatophyte species with its primary source of infection.

a. Microsporum canis (dogs); Microsporum gypseum (plants), Trichophyton mentagrophytes (rodents)

b. Microsporum canis (cats); Microsporum gypseum (soil), Trichophyton mentagrophytes (soil)

c. Microsporum canis (cats); Microsporum gypseum (rodents), Trichophyton mentagrophytes (dogs)

d. Microsporum canis (dogs); Microsporum gypseum (soil), Trichophyton mentagrophytes (cats)

e. Microsporum canis (cats), Microsporum gypseum (soil), Trichophyton mentagrophytes (rodents)

e. Microsporum canis (cats), Microsporum gypseum (soil), Trichophyton mentagrophytes (rodents)

Microsporum gypseum is geophilic (meaning that it loves to grow in soil). This species often affects dogs that like to dig. Trichophyton mentagrophytes is zoophilic and usually rodents serve as the host; dogs such as hunting dogs or roaming cats are most commonly affected. Microsporum canis is most commonly contracted from cats. It is extremely important to know which species of dermatophyte is causing the infection in order to prevent re-exposure. For example, in dogs with Microsporum gypseum, preventing them digging in the yard is going to be an important part of the treatment plan.

12

A 5-year old male neutered German Shepherd presents with a history of nasal dermatitis. Previous treatment with a 2-week course of antibiotics and prednisone resulted in partial improvement of the lesions followed by recurrence. On physical examination, you see the lesions on the nasal planum and oral mucosa shown in the images.

You perform a biopsy, and histopathology shows clefts characterized by residual basal keratinocytes remaining attached to the basement membrane zone and having a "tombstone" appearance. The intact primary bullae are non-inflammatory, but there is mononuclear inflammation of the superficial dermis. IgG and complement deposition between keratinocytes at all levels of the epidermis is present. The histologic diagnosis is pemphigus vulgaris. Which of the following is appropriate information to give the client regarding the treatment AND prognosis for this condition?

a. Treatment with fluconazole and/or clotrimazole is recommended and the long-term prognosis is good for most dogs

b. 0.1-0.5 mg/kg of prednisolone twice daily with possible addition of azathioprine is recommended and the long-term prognosis is good for most dogs

c.  Treatment with 0.1-0.5 mg/kg of prednisolone twice daily with the possible addition of topical tacrolimus is recommended and the long-term prognosis is good for most dogs

d. 2-4 mg/kg of prednisolone twice daily with possible addition of azathioprine is recommended but the long-term prognosis is poor

e. 2-4 mg/kg of prednisolone and concurrent treatment with retinoids is recommended but the long-term prognosis is poor

d. 2-4 mg/kg of prednisolone twice daily with possible addition of azathioprine is recommended but the long-term prognosis is poor

Pemphigus vulgaris is an autoimmune disorder causing vesicles, ulceration, and crusting. It can affect the whole body, but it especially affects the mucocutaneous junctions and oral mucosa. The onset of the disease can be sudden (acute) or gradual over many weeks (chronic).

The disorder is caused by an IgG autoantibody that binds to intracellular adhesion molecules (desmoglein) causing a loss of cohesion between keratinocytes resulting in acantholysis, vesicle formation, and eventually ulceration.

The treatment is immunosuppressive therapy with corticosteroids and frequently additional immunomodulatory or immunosuppressive drugs such as azathioprine, cyclophosphamide, chlorambucil, or others. Unfortunately, long-term therapy is generally required and these treatments cause serious side-effects long-term. Prognosis is poor and euthanasia is often performed.

13

A 5-month-old pit bull puppy presents for a small area of hair loss. The lesion is well-demarcated, and the dog is not pruritic. Upon examination, you notice mild crusting around the lesion. You perform skin cytology and no bacteria or yeast is observed. Skin scrape reveals a few cigar-shaped mites. What is your next step?

a. Initiate therapy with Ivermectin

b. Initiate therapy with Amitraz dips

c. Benign neglect and monitor the lesions

d. Initiate therapy with Lyme sulfur dips

c. Benign neglect and monitor the lesions

Localized, juvenile onset demodicosis usually resolves without treatment as the immune system develops. Because this patient only has a small area of alopecia and few mites, starting therapy with Ivermectin and Amitraz dips is pre-mature. Both these therapies have marked side effects. Ivermectin causes neurological signs, and Amitraz can cause allergic reactions, hypothermia, bradycardia, and hyperglycemia (especially in small puppies). Lyme sulfur dips are not effective against follicular Demodex mites (as found in dogs). Demodex gatoi is found in cats and is a superficial mite that can be treated with Lyme sulfur.

14

A 2-year-old neutered male greyhound presents for crusting along his ear pinnae and elbows. The owner also explains that the dog is intensely pruritic. The dog mainly lives indoors but is also let outside into the backyard. The owner lives on a large rural property that is heavily wooded. You perform cytology, which returns negative for bacteria and yeast. You are highly suspicious of Sarcoptes. Which of the following would be most useful to help in your diagnosis of Sarcoptic mange?

a. Pinnal-pedal reflex, clinical signs, superficial skin scrape

b. Deep skin scrape, pinnal-pedal reflex, clinical signs

c. Clinical signs, superficial skin scrape, trichogram

d. Histopathology, deep skin scrape, trichogram

e. Superficial skin scrape, histopathology, trichogram

a. Pinnal-pedal reflex, clinical signs, superficial skin scrape

A superficial skin scrape is most useful. A deep skin scrape is used for Demodex mites, which reside in the hair follicles. Superficial skin scraping is indicated for Sarcoptic mange, since this mite lives in the stratum corneum. Pinnal-pedal reflex can be positive in 70% of Sarcoptic mange infestation but can also be positive in any dog with pruritus. Clinical signs are helpful because Sarcoptes typically infects the non-haired portions of the skin such as the ear pinnae, elbows, hocks, and ventral abdomen. If the mite is not found on skin scraping and you have clinical signs indicative of Sarcoptes then a therapeutic trial is warranted. Keep in mind that in most cases you will not be able to find the mite.

A trichogram would not be indicated. This method can be used to diagnose dermatophytosis and sometimes Demodex. Histopathology will reveal a perivascular dermatitis that is non-specific. Rarely are the mites found on histopathology.

15

A 5 year old, male neutered, West Highland White Terrier presents for the skin lesions seen in the picture below. He has a history of lethargy and poor appetite. The lesions partially responded to antibiotics initially, but then began to progress again. You take a biopsy of the skin which shows cutaneous blastomycosis. What is the next most important diagnostic test?

a. Blastomyces antibody titer

b. Abdominal radiographs

c. Thoracic radiographs

d. Deep skin scraping

d. Blastomyces antigen test

c. Thoracic radiographs

Blastomycosis is caused by a dimorphic fungus and generally occurs in the Missouri, Mississippi, Tennessee, and Ohio river valleys. Pulmonary involvement occurs in the majority of cases, so thoracic radiographs are an important step to staging the patient. Other organs that can be affected include the lymph nodes, eyes, bones, central nervous system, and urinary tract.

Abdominal radiographs are not very sensitive to detect involvement with internal organs. Abdominal ultrasound, if available, would be preferred over abdominal radiographs.

Antibody tests are neither sensitive nor specific and are not very useful once a diagnosis is already made.

16

What breed of dog develops a dermatosis that seems to be related to a relative Zinc deficiency?

a. Siberian Husky

b. Bull dog

c. Cocker Spaniels

d. Shetland Sheepdog

a. Siberian Husky

This syndrome has also been seen in Alaskan Malamutes. They develop a crusting skin disease referred to as Zinc Responsive Dermatosis, where there is scaling, crusting, and alopecic dermatitis most frequently around the eyes, ears, prepuce, scrotum and vulva.

Absolute dietary deficiency of Zinc is rare. Zinc responsive dermatosis is related to defective intestinal absorption of Zinc. Oral Zinc supplementation can bring rapid resolution in most patients.

17

A 5-year old West Highland White Terrier presents for seborrhea oleosa and pruritus. You perform skin scrapes and a cytology and diagnose Malassezia dermatitis. Which of the following is the best treatment option?

a. Ketoconazole

b. Cephalexin

c. Griseofulvin

d. Carprofen

e. Prednisone

 

a. Ketoconazole

This medication, along with other -azoles (fluconazole, itraconzole), are commonly prescribed treatments for Malassezia. Terbinafine is another antifungal medication that is becoming more popular for the treatment of Malassezia and dermatophytosis. Although, Griseofulvin is an antifungal it is not effective against Malassezia. Prednisone and carprofen may help with inflammation, but not clear the infection.

18

A 2-year old female spayed Dachshund presents for further evaluation as a result of a mass on the pinna noted by the owner. On physical exam, the only abnormality noted was this mass. Cytology is consistent with a histiocytoma. Which of the following is the most reasonable treatment option?

a. Chemotherapy using lomustine

b. Radiation therapy

c. Benign Neglect

d. Cryotherapy

e. Radical surgical excision

c. Benign Neglect

Histiocytomas are typically benign and will often present as a small, raised mass that may or may not be ulcerated. Fortunately, these masses usually regress on their own, and surgical or medical intervention is typically not necessary.

19

A 5-year old female Golden Retriever presents for lethargy, dark runny stool, and dehydration. Bloodwork from yesterday showed markedly elevated plasma endogenous ACTH levels, K+ = 6.2 (3.9-5.1 mEq/L), Na+ = 135 (142-152 mEq/L), BUN = 62 mg/dl (8-28 mg/dl). Long-term maintenance therapy for this patient should most likely include:

a. Supplementation with physiologic doses of prednisone

b. IV fluids and daily doses of IV dexamethasone sodium phosphate

c. Mineralcorticoid, glucocorticoid, and NaCl supplementation

d. Mineralcorticoid supplementation alone

 

c. Mineralcorticoid, glucocorticoid, and NaCl supplementation

This dog has hypoadrenocorticism which is usually a deficiency in both glucocorticoids and mineralocorticoids. Elevated endogenous plasma ACTH concentrations with hypoadrenocorticism means the disease is due to primary adrenocortical insufficiency and failure to produce both types of corticosteroids (as opposed to secondary adrenocortical insufficiency, when the pituitary does not produce sufficient ACTH). Maintenance treatment of this disease includes supplementation with mineralocorticoids (e.g. Fludrocortisone acetate), glucocorticoids (e.g. Prednisone), and sodium chloride in the diet. IV fluids and dexamethasone sodium phosphate is used in an acute crisis.

20

Which is not a consequence of insulin deficiency in diabetes mellitus in a dog?

a. Weight gain leading to obesity

b. Increased mobilization of fat

c. Increased hepatic gluconeogenesis

d. Impaired energy utilization

e. Hepatic lipidosis and ketosis

a. Weight gain leading to obesity

Insulin deficiency causes weight loss, not weight gain. An insulin-deficient dog is essentially starving the cells of its body. Its energy utilization is impaired because it can't import glucose into its cells. In response to the decreased energy in the body's cells, the liver upregulates gluconeogenesis and glycogenolysis, exacerbating the hyperglycemia. The mobilization of fat is increased to supply the body with an alternative energy source. As adipocytes are broken down, the resulting free fatty acids are imported to the liver where they are converted to energy, triglycerides (which are stored in the liver causing hepatic lipidosis), and ketones (causing ketosis).

21

Which of the following is true of canine hypothyroidism?

a. It more commonly occurs in older, large breed dogs

b. It causes a voracious appetitie leading to weight gain

c. It causes thinning and increased fragility of skin

d. It can cause calcinosis cutis

a. It more commonly occurs in older, large breed dogs

Canine hypothyroidism can cause many skin changes including hyperpigmentation, alopecia, pyoderma, and seborrhea, but thinning and increased fragility of the skin does not occur. This is more consistent with hyperadrenocorticism, or Cushing's disease. Calcinosis cutis is also a clinical sign of Cushing's disease. Weight gain does occur with hypothyroidism due to a slower metabolism. Affected animals usually do not have a voracious appetite.

22

A 7-year old female Standard Poodle presents to you for acute onset of vomiting and weakness after the owners returned from vacation. On physical exam, you estimate that the dog is 7% dehydrated, has a respiratory rate of 36 breaths per minute, heart rate of 44 beats per minute and temperature of 99 degrees F. You quickly attach ECG leads and expect to see which of the following abnormalities?

a. Ventricular tachycardia

b. Tall, narrow QRS complexes

c. No P waves

d. Inverted T waves

c. No P waves

Based on the history and the physical exam findings of dehydration and bradycardia, you should be concerned about hypoadrenocorticism. Hypoadrenocorticism patients are typically hyperkalemic. ECG abnormalities with hyperkalemia include wide, flat, or absent P waves, widened QRS complexes, tall spiking T waves, and bradycardia.

23

A 7-year old female spayed Golden Retriever that you suspect has Addison's disease has bloody diarrhea, inappetance, and is dehydrated. What should be your next step?

a. Give IV dexamethasone and subcutaneous fluids

b. Start aggressive IV fluid therapy and run chemistry panel

c. Give Lysodren

d. Run a chemistry panel and perform an abdominal ultrasound

b. Start aggressive IV fluid therapy and run chemistry panel

Addisonian patients often present in hypovolemic shock, so the first step to treating this dog is to restore vascular volume with IV fluids and to run a chemistry panel to check the extent of electrolyte abnormalities (hyponatremia, hyperkalemia, and elevated BUN). IV dexamethasone would not take precedence over restoring vascular volume, and subcutaneous fluid treatment is not aggressive enough for treatment of hypovolemia. Abdominal ultrasound would not be a priority in this case but could eventually be helpful in ruling in/out other differentials.

Lysodren is used for treating hyperadrenocorticism. One possible complication of Lysodren treatment is to make a dog Addisonian, which often causes the animal to present with the signs described as in the question.

24

A dog presents to you with suspected hyperadrenocorticism. You would like to try to diagnose and differentiate between pituitary dependent and adrenal dependent hyperadrenocorticism with one test. Which of the following tests for hyperadrenocorticism is primarily a screening test, but can also be a differentiating test?

a. ACTH stimulation test

b. High dose dexamethasone supression test

c. Endogenous ACTH level

d. Low dose dexamethasone suppression test

e. Urine cortisol:creatinine ratio

d. Low dose dexamethasone suppression test

The 8-hour post-dexamethasone sample is used to determine if the pet has hyperadrenocorticism. If the 8-hour sample is above 1.4 ug/dL, the test is diagnostic for hyperadrenocorticism (either pituitary dependent or adrenal dependent). If the 4-hour sample is below 1.4 ug/dL or less than half of the baseline value, it is diagnostic for pituitary dependent hyperadrenocorticism.

The urine cortisol:creatinine ratio is a screening test to rule out hyperadrenocorticism, if it is normal. The endogenous ACTH level and high dose dexamethasone suppression tests are differentiating tests only. An ACTH stimulation test is a screening test but cannot differentiate pituitary versus adrenal dependent hyperadrenocorticism.

25

A 5-year old male mixed breed dog presents with polyuria, polydipsia, polyphagia, and weight loss. The most likely diagnosis is ______.

a. Exocrine pancreatic insufficiency

b. Diabetes mellitus

c. Hyperadrenocorticism

d. Hypothyroidism

b. Diabetes mellitus

Diabetes mellitus is the most likely diagnosis of those listed above. The 4 classic signs of DM are PU, PD, PP, and weight loss.

EPI patients have PP and weight loss but are not PU and PD. Hyperadrenocorticism patients have PU, PD, and PP, but do not lose weight. None of the clinical signs described are consistent with hypothyroidism in a dog.

26

Which is not a consequence of insulin deficiency in diabetes mellitus in a dog?

a. Weight gain leading to obesity

b. Impaired energy utilization

c. Hepatic lipidosis and ketosis

d. Increased hepatic gluconeogenesis

e. Increased mobilization of fat

a. Weight gain leading to obesity

Insulin deficiency causes weight loss, not weight gain. An insulin-deficient dog is essentially starving the cells of its body. Its energy utilization is impaired because it can't import glucose into its cells. In response to the decreased energy in the body's cells, the liver upregulates gluconeogenesis and glycogenolysis, exacerbating the hyperglycemia. The mobilization of fat is increased to supply the body with an alternative energy source. As adipocytes are broken down, the resulting free fatty acids are imported to the liver where they are converted to energy, triglycerides (which are stored in the liver causing hepatic lipidosis), and ketones (causing ketosis).

27

What is the primary goal in the initial treatment of diabetic ketoacidotic dogs?

a. Lowering the elevated blood glucose

b. Controlling obesity or concurrent disorders causing insulin resistance

c. Correction of acidosis, electrolyte abnormalities, and hyperosmolality

d. Getting the animal to eat

c. Correction of acidosis, electrolyte abnormalities, and hyperosmola

Initial treatment of DKA patients is aimed at correcting acidosis by administering bicarbonate (if the total bicarbonate is markedly low), correcting electrolyte abnormalities with IV fluids, potassium and phosphorus supplementation, and correction of hyperosmolality. Regulating blood glucose, getting the animal to eat, controlling obesity and concurrent disease should be addressed after immediate life-threatening issues are resolved.

28

A 7-year old, male, castrated shepherd mix presents for polyuria and polydipsia. The physical exam reveals a body condition score of 4/9 and 5% dehydration. The urine specific gravity is 1.006. The urinalysis, chemistry panel, and CBC are otherwise unremarkable. Which of the following is the most likely diagnosis?

a. Central diabetes insipidus

b. Fanconi syndrome

c. Chronic renal failure

d. Diabetes mellitus

 

a. Central diabetes insipidus

Diabetes mellitus is ruled out with a normal blood glucose on the chemistry panel and lack of glucose in the urine on the urinalysis. Chronic renal failure is ruled out because there is no azotemia on the chemistry panel. Fanconi syndrome usually occurs in Basenjis and is ruled out because there is no glucose in the urine.

29

A 9-year old male, neutered German Shepherd dog is presented to your clinic for evaluation of tenesmus, tail chasing, and hematochezia. Malodorous mucopurulent discharge is noted near his anus. On examination, you find multiple ulcerations around his perineum. Rectal examination reveals reduced anal tone and mucosal thickening. What are your treatment recommendations for this dog?

a. Initiate therapy with metronidazole

b. Initiate chemotherapy with the alkylating agent, melphalan, as this is the treatment of choice for anal sac adenocarcinoma

c. Initiate therapy with cyclosporine

d. Initiate broad-spectrum antibiotics to treat for an infected anal gland abscess

e. Surgically correct with a 360-degree anoplasty

c. Initiate therapy with cyclosporine

The signalment, history and clinical signs are most consistent with a perianal fistula. Although the pathogenesis is not fully understood, this disease is thought to be primarily immune-mediated. The treatment of choice for perianal fistula is medical management with cyclosporine, as resolution is achieved in greater than 65% of dogs. Surgical correction may lead to fecal incontinence or stricture formation, however surgery for removal of the anal sacs in combination with cyclosporine has recently shown promise.

If this was an anal gland abscess, lancing the abscess and drain placement with systemic antimicrobial therapy would be indicated. If you suspected this to be a cancerous process, a minimum database including CBC, chemistry, thoracic radiographs and abdominal ultrasound are recommended for disease staging. The treatment of choice for anal sac adenocarcinoma is surgical resection, followed by adjunct therapy.

30

Which of these is an adrenergic vasopressor in dogs?

a. Glycopyrrolate

b. Dopamine

c. Atropine

d. Hydralazine

b. Dopamine

Adrenergic vasopressors are frequently used to treat hypotension during anesthesia. Drugs in this category are dopamine, dobutamine, ephedrine, phenylephrine, and norepinephrine. Atropine and glycopyrrolate are anticholinergic drugs. Hydralazine is a vasodilator used to treat hypertension.