Canines

Question 1

What canine endocrine disorder can cause a droopy or “tragic” facial expression?

Answer 1

Hypothyroidism

Question 2

Case: Middle-aged to mid-to-large breed dog with dullness, weight gain, lethargy, hypothermia, dry coat, bilaterally symmetric nonpruritic alopecia with rat tail; rare - myxedema with “tragic” facial expression or stupor; signs can be vague and variable.

What Endocrine disorder is this characteristic of?

Answer 2

Hypothyroidism

Question 3

What is the classic age and breed of canines with Hypothyroidism?

Answer 3

Age: middle age
Breed: Mid to large breeds

Question 4

What are common presenting signs for dogs with hypothyroidism?

Answer 4

dullness, weight gain, lethargy, hypothermia, dry coat, bilaterally symmetric nonpruritic alopecia with rat tail.

Rare signs: myxedema with “tragic” or droopy facial expression or stupor.

Question 5

What is myxedema?

Answer 5

swelling of the skin and underlying tissues giving a waxy consistency, typical of patients with underactive thyroid glands.

the more general condition associated with hypothyroidism, including weight gain, mental dullness, and sensitivity to cold.

Question 6

How would you diagnose a dog with hypothyroidism? What would you expect to see?

Answer 6

1. Measure serum total T4 (should be lowered)
2. Measure free T4 (should be lowered)
3. Measure TSH (should be increased)
4. TSH stimulation test (rare)
5. Thyroid imaging (reduced size, destruction, etc.)
6. Routine labs such as CBC/CHEM (increased cholesterol, mild nonregenerative anemia)

Question 7

How would you treat a canine with hypothyroidism?

Answer 7

Oral T4 (levothyroxine) or IV T4 if in myxedema coma

Question 8

What other diseases lead to low total T4 in dogs?

Answer 8

euthyroid sick

Question 9

How does congenital hypothyroidism present and how common is it?

Answer 9

presents with disproportionate dwarfism, etc. at birth.

it is rare

Question 10

What is the prognosis for adult onset hypothyroidism?

Answer 10

good to excellent

Question 11

What endocrine disease does this dog most likely to have?

PU/PD/Polyphagia, weight loss?

Answer 11

Diabetes Mellitus

Question 12

What endocrine disease does this dog most likely to have?

PU/PD/Polyphagia, weight loss, vomiting, inappetence, lethargy?

Answer 12

Diabetes Mellitus with diabetic ketoacidosis (DKA) causing the vomiting, inappetence and lethargy.

Question 13

What diagnostic tests would you run on a dog you suspect of having diabetes mellitus? What would you expect to see?

Answer 13

1. Test serum fructosamine levels - will be elevated
2. CBC/CHEM - hyperglycemia, +/- increased ALP/ALT (usually mild due to hepatic lipidosis)
3. Urinalysis - glucosuria +/- low USG and ketonuria

Must have persistent hyperglycemia with glucosuria (having one without the other is NOT DM)

Question 14

How would you treat a dog with diabetes mellitus?

Answer 14

At home - long acting insulin, dietary changes; if ketoacidosis - regular insulin and IV fluid therapy with electrolytes in hospital.

Diet: complex carbs and higher in fiber (slower transit time and more steady absorption). Hills W/D, purina OM.
Feeding Schedule: fed same time each day (twice). Feed ~30min before insulin administration (ensure ate, if didn’t eat 1/2 insulin dose).

Question 15

What dog breeds, ages and sex are predisposed to diabetes mellitus

Answer 15

Breed: australian terrier, standard/miniature schnauzer, samoyed, miniature/toy poodle
Age: middle aged to older. if juvenile <1yr
Sex: females > males

Question 16

When would a fructosamine test be used in the diagnosis of a dog with diabetes mellitus and why?

Answer 16

if concerned hypoglycemia is stress induced.

Fructosamine estimates blood glucose over previous 2 weeks

Question 17

What is another name for Hyperadrenocorticism?

Answer 17

Cushing’s disease

Question 18

What are the 4 P’s of canine Hyperadrenocorticism/ cushings?

Answer 18

polyuria
polydipsia
polyphagia
panting

Question 19

What canine endocrine disease are these signs most characteristic of?

PU/PD, polyphagia, panting, truncal alopecia, pot-bellied appearance, thick skin.

Answer 19

Hyperadrenocorticism (Cushings disease)

Question 20

What are three types of Hyperadrenocorticism (Cushings disease)?

Answer 20

Iatrogenic
adrenal-dependent (ADH)
pituitary dependent (PDH)

Question 21

What clinical signs are characteristic of Hyperadrenocorticism (Cushings disease)?

Answer 21

PU/PD, polyphagia, panting, truncal alopecia, pot-bellied appearance, thick skin.

Question 22

What diagnostic tests can be used to diagnose canine Hyperadrenocorticism (Cushings disease)? What would you expect to see?

Answer 22

1. CBC/CHEM:
   Stress leukogram hypercholesterolemia, increased ALP (mild-marked)
   increased ALT (mild)
   Hyperglycemia (mild)
2. Urinalysis:
   Dilute urine sp <1.020, Proteinuria, increased UPCr (urine creatinine) (mild to mod),
   Can get bacterial UTI due to immunosuppression and diluted urine.
3. ACTH stimulation test - r/o iatrogenic
4. Low dose dexamethasone suppression test (LDDST) - test for PDH
5. Urine cortisol creatinine ratio (UCCr) - increased
6. Endogenous ACTH - increased with PDH
7. Adrenal ultrasound/xray - tumor

Question 23

How would you treat pituitary dependent Hyperadrenocorticism (Cushings disease) in dogs?

Answer 23

trilostane, lysodren, or surgical hypophysectomy or bilateral adrenalectomy.

Question 24

How would you treat adrenal dependent Hyperadrenocorticism (Cushings disease) in dogs?

Answer 24

trilostane, lysodren, or bilateral adrenalectomy

Question 25

How can you differentiate between pituitary dependent and adrenal dependent Hyperadrenocorticism (Cushings disease) in dogs?

Answer 25

1. Abdominal imaging - look for adrenal tumors
2. Test Endogenous ACTH - will be increased for PDH but not for ADH
3. High Dose Dexamethasone Suppression Test (HDDST) - cortisol levels still suppressed at 4/8hr sample = PDH, can never confirm PDH cause there are some PDH cases that will not suppress

Question 26

What is another name for Hypoadrenocorticism?

Answer 26

Addison’s disease

Question 27

What is a classic presentation of Hypoadrenocorticism (Addison’s disease) in dogs?

Answer 27

Age: Young adult
Sex: Female
Breeds: standard poodle, nova scotia duck tolling retrievers, portugese water dogs, bearded collie. WHWT. Wheaton terriers… but also any dogs.
Signs: loss of condition (anorexia, weakness/lethargy), recurrent gastroenteritis (weight loss, diarrhea), shaking/trembling, PU/PD, poor response to stress, acute circulatory collapse, and renal failure when “early” signs go unnoticed.

Question 28

What physical exam findings might you see in a dog with Hypoadrenocorticism (Addison’s disease)?

Answer 28

Poor body condition
Lethargy
Weakness
Dehydrated
Bradycardia
Weak pulses

Question 29

What canine endocrine disease are these signs most characteristic of?

Anorexia, weakness, lethargy, weight loss, diarrhea, shaking or trembling, PU/PD.

Answer 29

Hypoadrenocorticism (Addison’s disease)

Question 30

How would you diagnose a dog with suspected Hypoadrenocorticism (Addison’s disease)? What would you expect to see?

Answer 30

1. CBC/CHEM: Stress leukogram (lack of one could indicate animal is very ill), nonregenerative normocytic or normochromic anemia, Azotemia (increased BUN), hyperkalemia, hyponatremia, hyperphosphatemia, increased liver enzymes
2. Urinalysis: may have inappropriately concentrated urine due to renal medullary washout
3. ACTH stimulation test - no response (cause of atrophied or destroyed adrenal tissue)
4. Admonial imaging - atrophied or destroyed adrenal tissue

Question 31

How would you treat a dog with Hypoadrenocorticism (Addison’s disease)?

Answer 31

Acute crisis: IV saline +/- dextrose, steroids for shock, long term mineralocorticoid replacement with desoxycorticosterone pivalate (DOCP) (mineralocorticoids)