ANZCVS 2016

Question 1

1. a) Describe how you would perform a neurologic examination of the peripheral nervous system in a dog presented for evaluation of gait disturbance. • musculoskeletal palpation

Answer 1

• Musculoskeletal palpation: Assessed via concomitant palpation of contralateral muscles to judge symmetry and tone as well as to locate areas of atrophy. This is best done with the examiner positioned above the patient. Palpation of joints and long bones is also recommended to rule out non-neurologic disease. A “normal” patient will have symmetrical muscles with normal tone and no evidence of atrophy.

Question 2

1. a) Describe how you would perform a neurologic examination of the peripheral nervous system in a dog presented for evaluation of gait disturbance. You do not need to refer to cranial nerve evaluation or mentation in your answer. - Gait and posture

Answer 2

• Analysis of gait: Performed with sufficient time, on a non-slippery surface ad with the help with an assistant. Gait must be visually evaluated for:

• Paresis (weakness = motor system dysfunction): Described in terms of ambulatory or non-ambulatory. Weak patients with some preserved voluntary movement are said to be “-paretic”, while patients unable to voluntarily move the limb/limbs are said to be “-plegic”. These suffixes are combined with a prefix to denote limb involvement (i.e. Mono, Hemi, Para or Tetra). A “normal” patient must be able to stand and ambulate without noticeable weakness.
• Ataxia (incoordination = dysfunction of the sensory system): Described as proprioceptive (scuffing, dragging feet), vestibular (unable to walk in a straight line) or cerebellar (dysmetria). A “normal” patient must be able to ambulate in a traight line with good coordination, without dragging feet or executing exaggerated limb mo tions.
• Lameness: associated with pain, such as secondary to route signature. A “normal” patient must be able to ambulate without lameness. • Posture: Observation of head and body position. A “normal” patient must be able to evenly balance on all four feet and should not display abnormal head position.
• Head tilt implies vestibular dysfunction
• Head turn implies forebrain dysfunction
• Arched back suggests neck or back pain
• Root signature suggests nerve root compression, typically in the thoracic limbs.
• Schiff-Sherington suggests severe spinal lesion between T2-L4
• Decerebellate rigidity implies rostral cerebellar lesion (extended thoracic limbs, flexed pelvic limbs)
• Decerebrate rigidity implies rostral brainstem lesion (rigid extension of all four limbs)
• Cervical flexion – possibly secondary to hypokalemia, thiamine deficiency (cats), hyperthyroidism (cats), CKD (dog/cat), Myasthenia Gravis (cats)

Question 3

1. a) Describe how you would perform a neurologic examination of the peripheral nervous system in a dog presented for evaluation of gait disturbance. You do not need to refer to cranial nerve evaluation or mentation in your answer.
   - Postural reactions

Answer 3

• Postural Reactions: Assessed via manual tests such as General Proprioception, Placing, Hopping, Wheelbarrow, Extensor Postural Thrust and Hemistand

• General Proprioception: with the patient in standing position, turn each paw gently onto the dorsum and place on the ground or exam table. A “normal” patient must quickly correct the paw to a normal standing position.

- Placing: Usually performed in cats and small dogs. Divided into tactile and visual placing. For tactile placing, pick the patient up and cover the eyes. Bring the patient to the edge of the table and watch for placing the limbs onto the table surface. For visual placing keep the eyes uncovered. A “normal” patient quickly and precisely places the foot onto the table surface.

- Hopping: Most reliable postural reaction. Stand over patient and lift the entire body so that only one limb touches the ground. Move the patient laterally on the down limb. A “normal” patient moves laterally quickly and smoothly without tripping or falling.

- Wheelbarrow: Lift the rear limbs off the ground and move the patient forward. A “normal” patient makes coordinated steps with the thoracic limbs

- Extensor Postural Thrust: Hold the patient off the ground, lower the rear limbs and move the patient forward. A “normal” patient immediately makes coordinated steps backwards when the pelvic limbs touch the ground.

- Hemistand/Hemiwalk: Stand on one side of the patient and lift the thoracic and pelvic limb on one side (Hemistand), then gently push the patient away from you (hemiwalk). A “normal” patient is able to stand on two limbs and make coordinated lateral steps.

Question 4

1. a) Describe how you would perform a neurologic examination of the peripheral nervous system in a dog presented for evaluation of gait disturbance.

Spinal Reflexes

Answer 4

• Spinal Reflexes: Graded on a scale of 0-4

0 = absent

1 = decreased

2 = normal

3 = exaggerated

4 = clonic

• Patellar Reflex: Assesses the femoral nerve (L4-L6); The patient is placed in lateral recumbency. The limb is held “off” the ground with the stifle slightly flexed. The patellar ligament is stroked with a reflex hammer. A “normal” patient with demonstrate a rapid extension of the stifle. The interpretation of “decreased” or “exaggerated” response is made based on comparison to the contralateral limb and clinical experience.
• Cranial tibial reflex: Assesses the peroneal branch of the Sciatic nerve (L6-S1). With the patient in lateral recumbency, strike the belly of the cranial tibial muscle with a reflex hammer. A “normal” patient with demonstrate a quick flexion of the hock.
• Gastrocnemius Reflex: Assesses the tibial branch of the sciatic nerve (L6-S1) – least reliable “reflex” of the pelvic limbs. With the patient in lateral recumbency, strike the calcaneal tendon immediately above the insertion on the calcaneus. A “normal” patient will present a sudden contraction of the gastrocnemius muscle with a reflection up the caudal thigh muscles.
• Extensor Carpi Radialis Reflex: Assesses the radial nerve (C8-T1). With the patient in lateral recumbency and carpus slightly flexed, strike the extensor carpi radialis belly on the cranial aspect of the proximal forearm. A “normal” patient with present sudden extension of the carpus.
• Biceps Reflex: Assesses the musculocutaneous nerve (C6-C8). With the patient in lateral recumbency and limb slightly pulled caudally, place the thumb over the tendon of insertion of the biceps onto the radius and gently tap it with the reflex hammer. A “normal” patient will present a sudden contraction of the biceps with flexion of the elbow.
• Triceps reflex: Also assesses the radial nerve (C8-T1). With the patient in lateral recumbency and elbow slightly flexed to add tension to the triceps tendon, strike the tendon just above the insertion onto the olecranon. A “normal” patient will present triceps contraction with extension of the elbow.
• Withdrawal reflexes: Very reliable reflex on all four limbs. Does not equate intact nociception. Withdrawal involves a local spinal reflex, while nociception involves conscious recognition and behavioral response. On pelvic limbs primarily assesses sciatic (L6-S1) but also femoral nerve (L4-L6). With the patient in lateral recumbency, pinch the toes and watch for withdrawal of the limb. A “normal” patient will flex all major peripheral joints (hip, stifle, hock for rear limb and shoulder, elbow and carpus for thoracic limb).

Question 5

1. a) Describe how you would perform a neurologic examination of the peripheral nervous system in a dog presented for evaluation of gait disturbance.

Nociception

Answer 5

• Nociception: Only necessary in paralyzed patients. With the patient in lateral recumbency, start with fingertips on the interdigital skin before moving on to the toes. Firmly pinch the toes, and only use hemostats if no response is obtained. A “normal” patient will demonstrate a behavioral or physiologic response to the stimulus, such as crying, whimpering, trying to bite, mydriasis or increased respiratory rate.

Question 6

1. a) Describe how you would perform a neurologic examination of the peripheral nervous system in a dog presented for evaluation of gait disturbance.
   b) Describe with the aid of a diagram the reflex arc for the patella reflex and the normal response.

Answer 6

Question 7

a) Describe how you would perform a neurologic examination of the peripheral nervous system in a dog presented for evaluation of gait disturbance.

Explain the difference between a withdrawal reflex and a nociceptive response and how you would interpret them.

Answer 7

The withdrawal reflex involves only a reflex arch between sensory and motor nerves of the tested limb, without central (cortical) involvement. Nociception requires cortical processing of the nociceptive stimulus and creation of a behavioral response. Upon pinching a digit the patient may withdraw the limb via flexion of all three main peripheral joints (withdrawal reflex). This reflex can only be considered a response if the patient displays behavioral or physiologic signs such as crying, whining, trying to bite, myosis or increased respiratory rate.

Question 8

a) List the four (4) most likely differential diagnoses for a male dog with haematuria and non-productive stranguria.

Answer 8

Benign Prostatic Hyperplasia

Prostatitis

Cystic Calculi

Urinary Tract Infection

Question 9

b) List the abnormalities likely to be seen on serum biochemistry in a patient with non-productive stranguria which has persisted for more than 24 hours.

Answer 9

Hyperkalemia

Azotemia

Hyperlactemia (Metabolic acidosis)

Hyperphosphatemia

Question 10

Patient with non-productive stranguria which has persisted for more than 24 hours.

c) State the clinical cardiac abnormalities which may be seen in this patient.
d) Describe the underlying cause of these cardiac abnormalities.

Answer 10

Bradycardia (due to hyperkalemia), tall T waves, prolonged PR interval, wide QRS complexes, decreased to absent P waves. Ventricular flutter, fibrillation and asystole can occur with severe hyperkalemia.

Hyperkalemia suppresses cardiac depolarization, leading to bradycardia and EKG abnormalities.

Question 11

e) List the two (2) most likely components of a urolith in a dog and the expected urine pH characteristics for each.

Answer 11

• Magnesium-Ammonium-Phosphate (Struvite): pH >6.5-7.0
• Calcium Oxalate: pH <6.0

Question 12

f) Describe the layered structure of the bladder wall and identify which layer(s) contributes most to the strength of surgical closure.

Answer 12

The urinary bladder wall is composed of 4 layers: Serosa, muscularis (Detrusor muscle), submucosa and mucosa. The submucosa provides the majority of the structural resistance to suture pull-through and must therefore be included in the sutured closure.

Question 13

g) Name the anatomical landmarks which define the trigone.

Answer 13

• Urethral orifice (Apex)
• Ureteral openings (line connecting both forms the base of the trigone)

Question 14

h) State why the lateral ligaments of the bladder should be identified and avoided during surgery.

Answer 14

They cross at nearly right angles to the ureters. Identification prevents inadvertent trauma to the ureters.

Question 15

i) Describe an appropriate closure method for the bladder. Include in your answer the time taken for mucosal defects to heal and for full tissue strength to be regained in the bladder after cystotomy incision.

Answer 15

Closure can be performed as a simple-continuous layer including submucosa, muscularis and serosal layers. The mucosa can be sutured separately, also as simple-continuous, if hemorrhage is expected (this is typically not necessary). Mucosal defects heal in 5 days. Full tissue strength is regained in 14 to 21 days.

Question 16

j) List five (5) risk factors for recurrence of calcium oxalate uroliths. In what percentage of cases would calcium oxalate urolithiasis be expected to recur following surgical removal?

Answer 16

Risk factor for recurrence include:

Hypercalcemia

Acidic urine (pH <6.5)

Hyperadrenocorticism

Primary Hyperparathyroidism

Presence of liver disease

Obesity

Carbohydrate-rich diet

Up to 50% of CaOx urolyths are expected to recur in dogs within 3 years.

Question 17

k) Discuss the management strategies available to reduce recurrence of calcium oxalate uroliths.

Answer 17

• Dietary therapy: Alkalinizing diets with higher moisture content
• Increasing water consumption
• Potassium Citrate supplementation: forms a soluble salt with calcium, preventing CaOx crystal formation. Helps alkalinize the urine. Goal pH 7-7.5
• Thiazide diuretics: Enhances tubular reabsorption of calcium and promote diuresis.
• Vitamin B6: increases metabolism of glyoxylate to glycine
• Correction of underlining condition that may cause hypercalcemia (i.e. hyperparathyroidism).
• Glucocorticoids
• Bisphosphonates

Question 18

1. The principles of surgery as described by Halstead are as relevant today as they were over 100 years ago. List the six (6) surgical principals attributed to Halstead and describe how they can be applied in surgery.

Answer 18

• Gentle Tissue Handling
• Meticulous Hemostasis
• Preservation of blood supply
• Aseptic Technique
• Obliteration of dead space
• Accurate tissue apposition
• Tension-free closure

Question 19

a) Define the term osteochondrosis and osteochondritis dissecans (OCD), and describe the processes that lead to the development of OCD in dogs. You may wish to use a diagram.

Answer 19

• Osteochondrosis: Failure of osteochondral ossification
• Osteochondritis Dissecans: The development of a cartilage flap secondary to osteochondrosis, leading to exposure of the subchondral bone.

The exact etiology of osteochondrosis is not entirely understood. It has been suggested that local conformation forces and microtrauma lead to focal necrosis of the epiphyseal cartilage canals. This results in cartilage infarction (necrosis). Infarcted cartilage does not undergo endochondral ossification, but rather proliferates resulting in areas of thickened cartilage. This eventually leads to a metabolically deprived state, resulting in local chondrocyte death and matrix degeneration. The necrotic area is gradually replaced by fibrous tissue which ultimately undergo intramembranous ossification. The overlying cartilage eventually fissures due to local forces, becoming an OCD lesion.

Question 20

b) List five (5) proposed aetiologic mechanisms for OCD in dogs.

Answer 20

• Joint morphology and Limb Conformation (i.e. hyperextension of the tarsocrural joint, elbow incongruity)
• Rapid Growth (increased incidence in giant breeds)
• Overfeeding energy (may result in elevated levels of GH, T3, T4 and Insulin, stimulating chondrocyte differentiation and proliferation)
• Diets high in Calcium and Vit D (only demonstrated in Great Danes)
• Microtrauma (may increase the incidence and severity of microscopic osteochondral lesions. Only demonstrated in humans and pigs)

Question 21

c) List all the joints that can be affected by OCD in dogs and the specific site within the joint that the OCD lesion is most commonly found.

Answer 21

• Shoulder – Caudal humeral head
• Elbow - medial humeral condyle
• Stifle – Lateral condyle
• Tarsus – medial or lateral trochlear ridges

Question 22

A 10-year-old male neutered German shepherd dog is presented to your clinic in a collapsed state. The owners reported that he has been lethargic but had eaten a meal a few hours prior to presentation. At presentation the dog is recumbent, depressed and has a large, distended abdomen. His mucous membranes are pale, capillary refill time (CRT) delayed, and his peripheral pulses are weak. He is tachycardic and tachypneic.

a) What is your initial assessment of this patient, include a problem list and a list of differential diagnoses.

Answer 22

Assessment: Shock, most likely obstructive but also possibly cardiogenic or hypovolemic

Problem list:

• Abdominal distension: possible causes include hollow viscera distension (GDV, mesenteric torsion), peritoneal effusion (blood, chyle, transudate or exudate), abdominal tumors or pneumoperitoneum.
• Pale mucous membranes: consistent with vasoconstriction (sympathetic activation) or anemia (blood loss)
• Prolonged CRT: consistent with vasoconstriction or low cardiac output. Causes may include decreased cardiac preload due to vascular obstruction, severe blood loss or volume shift, leading to decreased cardiac output and impaired perfusion.
• Weak peripheral pulses: consistent with hypotension or severe vasoconstriction. Possible causes may include decreased cardiac output, severe blood loss or vascular obstruction.
• Tachycardia: consistent with increased sympathetic or decreased parasympathetic tone. Causes may include blood loss, hypoxemia, pain, fever, electrolyte imbalances, thyroid dysfunction, etc..
• Tachypnea: consistent with sepsis, acidosis, pain, pulmonary disease, pleural disease, diaphragmatic compression, etc…

Question 23

A 10-year-old male neutered German shepherd dog is presented to your clinic in a collapsed state. The owners reported that he has been lethargic but had eaten a meal a few hours prior to presentation. At presentation the dog is recumbent, depressed and has a large, distended abdomen. His mucous membranes are pale, capillary refill time (CRT) delayed, and his peripheral pulses are weak. He is tachycardic and tachypneic.

b) Describe (in point form) your immediate approach to emergency stabilization and immediate diagnostic evaluation of this patient and justify your answer.

Answer 23

• Oxygen support via face mask: This patient presents signs of shock, which invariably involves some degree of hypoxemia and acidosis (respiratory or metabolic).
• IV fluid therapy (large bore catheter): The presence of weak pulses and tachycardia indicate poor perfusion. Even if the cause is not hypovolemia, temporary volume expansion with isotonic crystalloids and/or colloids/hypertonic saline is nearly always recommended in a hypotensive patient in order to improve organ perfusion until the cause of shock can be determined.
• Application of a tight abdominal bandage: potentially useful if abdominal hemorrhage is suspected of confirmed via abdominocentesis. Only to be used short term while the patient is being stabilized. Will not arrest arterial of hepatic hemorrhage.
• Assessment of peripheral blood pressure: Used to guide IV fluid and vasopressant therapy, as well as to evaluate response to treatment.
• Vasopressor therapy: Often necessary after volume expansion to maintain normotension.
• Continuous ECG: Performed during initial stabilization and throughout surgical and post-operative care to detect arrhythmias that may interfere with cardiac output. Institute therapy as needed.
• Thoracic and abdominal radiography: Utilized to investigate the cause of shock and to rule out concomitant thoracic disease such as aspiration pneumonia.
• Antibiotic therapy: Only justified if aspiration pneumonia or significant GI bacterial translocation are suspected.
• Point-of-care blood tests: Including CBC, Biochemistry, Blood gasses and Lactate if available. Performed concomitantly with initial stabilization measures. Used to evaluate the degree of metabolic acidosis, anemia, electrolyte imbalances, hypoglycemia and hemoconcentration. Lactate levels may have prognostic value.
• Focused Assessment with Sonography in Trauma: Utilized to screen for abdominal effusion and masses.
• Abdominocentesis: Performed to collect abdominal fluid for point-of-care analysis (if present based on FAST U/S)
• Gastric decompression (in case of GDV): Only attempted once the cardiovascular stabilization has begun. Ideally accomplished via orogastric tube after administration of opioid analgesia, rapid-induction general anesthesia and endotracheal intubation. Rapidly improves cardiovascular function but may also cause further cardiovascular insult due to reperfusion injury. If an orogastric tube cannot be passed, a large-bore over-the-needle catheter can be introduced into the area of greatest tympani on the right or left dorsolateral abdomen after hair clipping and aseptic prep.

Question 24

A 10-year-old male neutered German shepherd dog is presented to your clinic in a collapsed state. The owners reported that he has been lethargic but had eaten a meal a few hours prior to presentation. At presentation the dog is recumbent, depressed and has a large, distended abdomen. His mucous membranes are pale, capillary refill time (CRT) delayed, and his peripheral pulses are weak. He is tachycardic and tachypneic.

c) On abdominal ultrasound examination you discover a peritoneal effusion – discuss how you would investigate and determine the nature of this effusion.

Include in your answer the following information:

• Describe and appropriate technique to collect or sample the fluid.
• List the types of effusion that may accumulate in a body cavity and identify the clinical pathology features of each. Give an example of a typical cause for each of these fluid types.
• List and briefly describe further diagnostic tests which can be performed to determine the nature/origin of the peritoneal fluid.

Answer 24

Abdominocentesis: A 18 or 20-gauge, 1.5-inch plastic over-the-needle catheter with added side holes is introduced into the abdominal cavity at the most gravity-dependent region. This is typically performed on the right side of the abdomen with the patient in left lateral recumbence to avoid puncturing the spleen. Fluid is allowed to drip into a sterile collection tube, including clot tube and EDTA. If fluid is not obtained a 3ml syringe can be attached. Samples are also obtained for aerobic and anaerobic bacterial cultures. Four to six smears are made for cytology.

Types of Abdominal Effusion:

• Pure Transudates (TP < 25 g/l; Cell count <1000/L; primarily Monocytes): Typically, a result of increased hydrostatic pressure such as secondary to right-sided cardiac disease, cirrhotic hepatic disease or neoplasia. Pure transudates quickly irritate the peritoneum, inciting an inflammatory response that converts the fluid into modified transudate (causes therefore overlap).
• Modified Transudates (TP <35 g/l; cell count <5000/L; increased number of non-degenerative neutrophils). Typically, a result of increased hydrostatic pressure such as secondary to right-sided cardiac disease, Left-sided CHF (cats), decreased oncotic pressure (hypoalbuminemia), cirrhotic hepatic disease and lymphatic obstruction (Diaphragmatic hernia and neoplasia).
• Exudates (TP >35 g/l; cell count >5000/l; mononuclear cells and neutrophils. Lactate often >200 IU/L).
  
  • Septic: High nucleated cell count, degenerative neutrophils, intracellular bacteria. Caused by septic peritonitis (i.e. perforated hollow viscera, penetrating trauma, infectious diseases, etc…)
  • Non-septic: Non-degenerative neutrophils, NO bacteria. Possible causes include neoplasia, hernias, liver-lobe torsion, pancreatitis and resolving septic exudates.
• Chyle ( TP 20-60 g/l; cell count 400 to 10.000/l; predominantly small lymphocytes. High triglyceride concentration (higher than serum) and low cholesterol (lower than serum). Cholesterol/triglyceride ration <1. Causes may include trauma, neoplasia, cardiomyopathy, idiopathic or diaphragmatic hernia.
• Urine (turbid, blood-tinged fluid with higher creatinine concentration than that of blood): typically, a result of trauma, urinary tract obstruction and neoplasia are also possible.
• Bile (golden brown to green fluid, high number of neutrophils and macrophages containing yellow-green to green-blue cytoplasmatic pigment). Typically a result of trauma, cholelithiasis and necrotizing cholelithiasis.
• _Hemorrhage (_gross appearance and cell distribution of blood, but non-clotting. Also does not contain platelets). Possible causes include trauma, coagulopathy, neoplasia and vascular injury (such as tearing of short gastric vessels during GDV).

Question 25

A 10-year-old male neutered German shepherd dog is presented to your clinic in a collapsed state. The owners reported that he has been lethargic but had eaten a meal a few hours prior to presentation. At presentation the dog is recumbent, depressed and has a large, distended abdomen. His mucous membranes are pale, capillary refill time (CRT) delayed, and his peripheral pulses are weak. He is tachycardic and tachypneic.

d) You determine that there is hemoabdomen resulting from a ruptured splenic mass.

Describe in point form your approach to the further management of this patient up until the time of surgery. Include any preoperative investigations and assessments. Briefly summarize any discussion you would have with the owner prior to surgery regarding the possible disease process and complications of surgery – include the most likely differential diagnosis based on presentation and signalment.

Answer 25

Management until surgery:

• Blood transfusion if PCV <20% or hemoglobin less than 5-7 g/dL (necessary is roughly 44% of cases)
• Coagulation profile to rule out DIC. Administer Fresh Frozen Plasma, unfractionated heparin or heparin-activated plasma if suspected.
• Continuous crystalloid or ideally colloid/hypertonic saline IVF therapy to support normotension. Add adrenergic drugs (dopamine, norepinephrine CRI if necessary).
• Continuous ECG monitoring for early detection of arrhythmias. Initiate therapy (lidocaine IV bolus and/or CRI) if indicated.
• Abdominal fluid collection + analysis and FAST abdominal scan included with initial assessment, but can be repeated to judge progression of hemorrhage / response to therapy.
• Heat support due to shock (warm blankets, warm air blanket)

Discussion with owner:

The most likely differential diagnosis is hemoabdomen secondary to a ruptured splenic hemangiosarcoma. The client must to advised that (Wendelberg, JAVMA, 2014):

• 90% of patients presented for hemoabdomen the spleen is the source of hemorrhage;
• 60% of splenic tumors are malignant
• 40% of splenic tumors are hemangiosarcomas
• 8 % of patient will die during or shortly after surgery. Common causes of death include thrombotic, coagulation syndromes or hemorrhage from metastatic sites.
• Risk factors for death included declining PCV, cardiac ventricular arrhythmias and thrombocytopenia. PCV<30% and intraoperative arrhythmias double the odds of death.

Question 26

A 10-year-old male neutered German shepherd dog is presented to your clinic in a collapsed state. The owners reported that he has been lethargic but had eaten a meal a few hours prior to presentation. At presentation the dog is recumbent, depressed and has a large, distended abdomen. His mucous membranes are pale, capillary refill time (CRT) delayed, and his peripheral pulses are weak. He is tachycardic and tachypneic.

e) What vascular anatomy must be preserved when performing suture ligation of the major splenic vessels during a splenectomy?

Answer 26

The ligation of the splenic artery must be performed distal to the branch that supplies the left limb of the pancreas.

Question 27

A 10-year-old male neutered German shepherd dog is presented to your clinic in a collapsed state. The owners reported that he has been lethargic but had eaten a meal a few hours prior to presentation. At presentation the dog is recumbent, depressed and has a large, distended abdomen. His mucous membranes are pale, capillary refill time (CRT) delayed, and his peripheral pulses are weak. He is tachycardic and tachypneic.

f) Based on a post-surgical histologic diagnosis of splenic hemangiosarcoma what prognosis you would give the owner for this dog following surgery alone or surgery with further treatment. Answer in brief point form.

Answer 27

The overall prognosis highly depends on clinical stage (Wendelburg, JAVMA 2015). Dogs with stage II (ruptured splenic mass) have a worse prognosis that that of patients with Stage I. Patients with Stage III (hemorrhage from metastatic disease) have the poorest prognosis.

• Prognosis for surgery alone:
• Stage I: 5.5 months, with 1- and 2-year survival rates of 35 and 11% respectively
• Stage III: 0.9 months, with 1-year survival rate of 0%
• Prognosis for surgery + chemotherapy: 4 ½ months (conventional + metronomic protocols). Effects more pronounced during the early portion of the follow-up period.

Question 28

2. You are presented with a 10-month-old spayed female Labrador retriever dog with a 4-month history of an intermittent bilateral forelimb lameness. Physical examination reveals bilateral elbow pain.
   a) List the four (4) conditions/components that make up canine elbow dysplasia.

Answer 28

UAP, FCP, RUI (incongruity), OCD

Question 29

2. You are presented with a 10-month-old spayed female Labrador retriever dog with a 4-month history of an intermittent bilateral forelimb lameness. Physical examination reveals bilateral elbow pain.
   b) Which components of elbow dysplasia would be most likely to be present in this patient based on the breed?

Answer 29

MCD (FCP)

Question 30

2. You are presented with a 10-month-old spayed female Labrador retriever dog with a 4-month history of an intermittent bilateral forelimb lameness. Physical examination reveals bilateral elbow pain.
   c) List four (4) diagnostic modalities reported to be of use in diagnosing canine elbow dysplasia.

Answer 30

Radiography, CT, Arthroscopy, MRI

Question 31

2. You are presented with a 10-month-old spayed female Labrador retriever dog with a 4-month history of an intermittent bilateral forelimb lameness. Physical examination reveals bilateral elbow pain.
   d) Which modality or combination of modalities is considered the most sensitive and specific for the diagnosis of canine coronoid process disease?

Answer 31

CT and Arthroscopy

Question 32

2. You are presented with a 10-month-old spayed female Labrador retriever dog with a 4-month history of an intermittent bilateral forelimb lameness. Physical examination reveals bilateral elbow pain.
   e) Outline two (2) relevant treatment options for canine coronoid process disease. Include in your answer the reasoning/justification for each treatment and the expected outcome in the short and long term for each treatment.

Answer 32

• Arthroscopic removal of FCP fragment: quickly improved patient comfort and may minimize the development of “kissing lesions” on the trochlea. Does not affect the development of OA over time.
• Release of the biceps insertion on the ulna: May decrease transarticular forces between the trochlea and the medial coronoid process. May aid in the healing of microcracks and reduce the risk of MCD, but still unproven to affect the progression of OA.

Question 33

2. You are presented with a 10-month-old spayed female Labrador retriever dog with a 4-month history of an intermittent bilateral forelimb lameness. Physical examination reveals bilateral elbow pain.
   f) Name the separate ossification center of the proximal ulna at the level of the elbow joint that fails to fuse in some dogs and identify the age by which fusion normally occurs.

Answer 33

Anconeal process ossification center arises at 11-12 weeks of age and is expected to fuse at 4-5 months

Question 34

2. You are presented with a 10-month-old spayed female Labrador retriever dog with a 4-month history of an intermittent bilateral forelimb lameness. Physical examination reveals bilateral elbow pain.
   g) Discuss the condition known as incomplete ossification of the humeral condyle (IOHC).

Answer 34

IOHC is a failure of union between the lateral and medial halves of the humeral condyle. Normal ossification begins at 2 weeks and is complete between 8 and 12 weeks. The origin of this disorder is unknown, but it appears to be related to elbow incongruence. Spaniels are overrepresented, suggesting a genetic cause. Over 90% of patients will be bilaterally affected. Medial coronoid abnormalities are also frequently present. Typical presentation includes weight-bearing lameness, particularly after exercise. Patients can also present for non-weight-bearing lameness due to condylar fracture. Diagnosis is usually obtained on a well-positioned craniocaudal radiographic view of the elbow, and both elbows should always be radiographed. Surgical treatment is recommended even for non-fractured cases to decrease the chance of fracture. Intercondylar lag screw fixation is most commonly performed.

Question 35

3. Brachycephalic dogs often present with exercise intolerance and upper respiratory noise.
   a) List the primary anatomic abnormalities that can be seen in brachycephalic dogs.

Answer 35

• Stenotic nostrils
• Elongated soft palate
• Hypoplastic trachea
• Everted laryngeal saccules

Question 36

3. Brachycephalic dogs often present with exercise intolerance and upper respiratory noise.

b) Discuss how anatomical abnormalities lead to brachycephalic obstructive airway syndrome (BAOS). Include in your answer a discussion of altered alveolar function.

Answer 36

BAOS is caused by the combined effect of anatomical abnormalities which lead to increased resistance to air passage during breathing. In normal dogs, resistance to air flow through the nasal cavity accounts for roughly 80% total resistance. Stenotic nostrils restrict nasal air flow and increase the necessary negative pressure during inspiration, causing surrounding tissues to collapse. An elongated soft palate is pulled caudally during inspiration, obstructing the dorsal aspect of the glottis and sometimes getting pulled between the corniculate processes of the arytenoid cartilages. This intermittent obstruction further increases respiratory effort and causes turbulent airflow. Turbulence traumatizes local tissues, causing inflammation and edema. During expiration the tip of the epiglottis may be blown into the nasopharynx. The elongated soft palate can also interfere with the normal occlusion of the airways during deglutition, predisposing patients to aspiration pneumonia. Hypoplastic trachea is congenital stenosis characterized by apposed or overlapping tracheal rings, as well as a narrow dorsal tracheal membrane. Tracheal hypoplasia is associated with continuous respiratory distress, coughing and tracheitis. Eversion of the laryngeal saccules is considered the first stage of laryngeal collapse, and results from the constantly elevated negative inspiratory pressures within the upper respiratory system.

Negative pressure causes the saccules to evert, and air turbulence causes trauma and inflammation leading to edema, partially obstructing the ventral aspect of the glottis. The increase in air flow resistance also leads to increased pulmonary pressure due to hypoxic vasoconstriction. The imbalance between vasoconstricting and vasodilating endothelial agents stimulates the expression of proliferative substances like thromboxane A2 and endothelin-1, l, leading to pulmonary hypertension and altered alveolar function, further contributing to systemic hypoxia.

Question 37

3. Brachycephalic dogs often present with exercise intolerance and upper respiratory noise.
   c) Describe or draw the three (3) stages of laryngeal collapse and their appearance during laryngoscopy.

Answer 37

Stage 1: Everted Laryngeal Saccules

Stage 2: Medial displacement of the cuneiform processes of the aryepiglottic folds

Stage 3: Collapse of the corniculate processes of the arytenoid cartilages

Question 38

d) The following questions all relate to your management of a 10-month-old female French bulldog that presents with respiratory distress, cyanosis and hyperthermia (rectal temperature 41.5°C). During the examination she regurgitates.
* Describe how you would initially assess and stabilize this patient.

Answer 38

• Stabilization: Immediately provide O2 via face mask (if tolerated) or O2 cage and light sedation with low-dose acepromazine (0.01 to 0.05 mg/kg IM – may take 15-30 min to work) or butorphanol (0.1 to 0.5 mg/kg IM or IV) to reduce patient distress. Provide active cooling via ice packs and air flow (fan) to address hyperthermia and prevent further panting. Keep patient in a cool and quiet environment. If respiratory arrest appears imminent, rapid-induction with propofol (1 mg/kg IV PRN) of alfaxalone (2-3 mg/kg IV PRN) followed by endotracheal intubation or tracheostomy should be considered. Glucocorticoids (Dexamethasone SP 0.1 mg/kg IM, IV or SQ) can be considered to reduce airway inflammation, but repeated doses should be avoided due to risk of GI ulceration.
• Diagnostics: Assess SpO2 to determine current O2 saturation. Blood gas analysis to assess the degree of respiratory dysfunction/hypoxemia. Ideally performed on arterial sample. Thoracic radiography (once deemed safe based on patient status and level of distress) to assess for pulmonary edema, bronchopneumonia, tracheal collapse and mainstem bronchial collapse. Further diagnostics may include CT and laryngeal exam under anesthesia.

Question 39

The following questions all relate to your management of a 10-month-old female French bulldog that presents with respiratory distress, cyanosis and hyperthermia (rectal temperature 41.5°C). During the examination she regurgitates.

• List three (3) classes of drugs you would consider using to manage this patient’s gastrointestinal signs and state why it is required. Provide one (1) specific example from each drug class.

Answer 39

• Proton-pump blockers (Omeprazole) – shown to be more effective than H2-blockers at increasing gastric pH, therefore potentially more useful at preventing esophagitis.
• Prokinetic agents (Metoclopramide or Cisapride) – increase gastric emptying and GES tone. Cisapride has been shown to be more effective than metoclopramide.
• Antiemetics (maropitant) – highly effective and safe centrally-acting antiemetic. Does not directly alter the incidence of regurgitation but reduces the chance of vomiting.

Question 40

The following questions all relate to your management of a 10-month-old female French bulldog that presents with respiratory distress, cyanosis and hyperthermia (rectal temperature 41.5°C). During the examination she regurgitates.

• What are the most common complications of surgery for uncomplicated BOAS (2 marks)? Given the hyperthermia present on initial presentation list four (4) systemic sequalae could occur in this patient

Answer 40

• Complications of BOAS surgery: Minimal for nasoplasty alone, perhaps suture dehiscence and local discoloration. Respiratory distress may after staphylectomy may occur due to edema or if the procedue fails to remove enough soft palate. Transient intra-op hemorrhage is common with laser-assisted turbinectomy, and the aberrant turbinate can regrow within 6 months. Acute respiratory distress and death can occur due to high anesthetic risk of these patients.

Question 41

a) Briefly describe each of the factors that are considered to predispose to canine cruciate ligament disease.

Answer 41

• Breed: Breed-variations of the material properties of the CrCL have been identified. In one study between Rottweiller and Racing Grayhounds, Rottweiler CrCL’s required half the load per unit of body weight to rupture.
• Tibial Plateau Angle: the degree of caudal angulation of the tibial plateau affects the tendency of the stifle towards caudal femoral subluxation during weightbearing. This tendency is primarily opposed by the CrCL, thus a steep angle may increase the degree of stress on the ligament and predispose it to failure.
• Age: The material properties of the CrCL decrease with time (modulus of elasticity, maximum stress, strain energy). These effects are more pronounced in dogs weighing less than 15Lb, and are consistent with the observation that CrCLR occurs at a younger ate in larger dogs.
• Obesity/Poor physical condition: The CrCL is rich in mechanoceptors an proprioceptors. Joint loading increases the strain on the CrCL, leading to contraction of the caudal thigh muscles and relaxation of the quadriceps group, which is protective of the CrCL. Obesity/poor physical condition may mitigate these protective mechanisms, resulting in repetitive strain injury to the CrCL.

Question 42

e) Name the two (2) most common types of meniscal injuries associated with canine cruciate disease and discuss why, in terms of the anatomy and function of the canine stifle joint, these are the most common.

Answer 42

The mechanism of meniscal injury appears to be directly related to the abnormal motion of the CrCL -deficient stifle. The medial meniscus is firmly attached to the tibia by the cranial and caudal meniscotibial ligaments. This prevents the medial meniscus from “sliding” with the femoral and tibial condyles during the caudal femoral subluxation observed in a CrCL-deficient stifle. Once the CrCL is torn and medial meniscus assumes an important stabilizer role (wedge effect). The caudal horn remains “trapped” between the condyles of the femur/tibia and is constantly subjected to shear stress applied against the longitudinal and radial fibers, typically leading to longitudinal tears. The same forces will eventually propagate the tear through the radial- and along the longitudinal fibers, leading the a “bucket handle” tear.