Canines Flashcards
What canine endocrine disorder can cause a droopy or “tragic” facial expression?
Hypothyroidism
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?
Hypothyroidism
What is the classic age and breed of canines with Hypothyroidism?
Age: middle age
Breed: Mid to large breeds
What are common presenting signs for dogs with hypothyroidism?
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.
What is myxedema?
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.
How would you diagnose a dog with hypothyroidism? What would you expect to see?
- Measure serum total T4 (should be lowered)
- Measure free T4 (should be lowered)
- Measure TSH (should be increased)
- TSH stimulation test (rare)
- Thyroid imaging (reduced size, destruction, etc.)
- Routine labs such as CBC/CHEM (increased cholesterol, mild nonregenerative anemia)
How would you treat a canine with hypothyroidism?
Oral T4 (levothyroxine) or IV T4 if in myxedema coma
What other diseases lead to low total T4 in dogs?
euthyroid sick
How does congenital hypothyroidism present and how common is it?
presents with disproportionate dwarfism, etc. at birth.
it is rare
What is the prognosis for adult onset hypothyroidism?
good to excellent
What endocrine disease does this dog most likely to have?
PU/PD/Polyphagia, weight loss?
Diabetes Mellitus
What endocrine disease does this dog most likely to have?
PU/PD/Polyphagia, weight loss, vomiting, inappetence, lethargy?
Diabetes Mellitus with diabetic ketoacidosis (DKA) causing the vomiting, inappetence and lethargy.
What diagnostic tests would you run on a dog you suspect of having diabetes mellitus? What would you expect to see?
- Test serum fructosamine levels - will be elevated
- CBC/CHEM - hyperglycemia, +/- increased ALP/ALT (usually mild due to hepatic lipidosis)
- Urinalysis - glucosuria +/- low USG and ketonuria
Must have persistent hyperglycemia with glucosuria (having one without the other is NOT DM)
How would you treat a dog with diabetes mellitus?
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).
What dog breeds, ages and sex are predisposed to diabetes mellitus
Breed: australian terrier, standard/miniature schnauzer, samoyed, miniature/toy poodle
Age: middle aged to older. if juvenile <1yr
Sex: females > males
When would a fructosamine test be used in the diagnosis of a dog with diabetes mellitus and why?
if concerned hypoglycemia is stress induced.
Fructosamine estimates blood glucose over previous 2 weeks
What is another name for Hyperadrenocorticism?
Cushing’s disease
What are the 4 P’s of canine Hyperadrenocorticism/ cushings?
polyuria
polydipsia
polyphagia
panting
What canine endocrine disease are these signs most characteristic of?
PU/PD, polyphagia, panting, truncal alopecia, pot-bellied appearance, thick skin.
Hyperadrenocorticism (Cushings disease)
What are three types of Hyperadrenocorticism (Cushings disease)?
Iatrogenic
adrenal-dependent (ADH)
pituitary dependent (PDH)
What clinical signs are characteristic of Hyperadrenocorticism (Cushings disease)?
PU/PD, polyphagia, panting, truncal alopecia, pot-bellied appearance, thick skin.
What diagnostic tests can be used to diagnose canine Hyperadrenocorticism (Cushings disease)? What would you expect to see?
- CBC/CHEM:
Stress leukogram hypercholesterolemia, increased ALP (mild-marked)
increased ALT (mild)
Hyperglycemia (mild) - Urinalysis:
Dilute urine sp <1.020, Proteinuria, increased UPCr (urine creatinine) (mild to mod),
Can get bacterial UTI due to immunosuppression and diluted urine. - ACTH stimulation test - r/o iatrogenic
- Low dose dexamethasone suppression test (LDDST) - test for PDH
- Urine cortisol creatinine ratio (UCCr) - increased
- Endogenous ACTH - increased with PDH
- Adrenal ultrasound/xray - tumor
How would you treat pituitary dependent Hyperadrenocorticism (Cushings disease) in dogs?
trilostane, lysodren, or surgical hypophysectomy or bilateral adrenalectomy.
How would you treat adrenal dependent Hyperadrenocorticism (Cushings disease) in dogs?
trilostane, lysodren, or bilateral adrenalectomy
How can you differentiate between pituitary dependent and adrenal dependent Hyperadrenocorticism (Cushings disease) in dogs?
- Abdominal imaging - look for adrenal tumors
- Test Endogenous ACTH - will be increased for PDH but not for ADH
- 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
What is another name for Hypoadrenocorticism?
Addison’s disease
What is a classic presentation of Hypoadrenocorticism (Addison’s disease) in dogs?
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.
What physical exam findings might you see in a dog with Hypoadrenocorticism (Addison’s disease)?
Poor body condition Lethargy Weakness Dehydrated Bradycardia Weak pulses
What canine endocrine disease are these signs most characteristic of?
Anorexia, weakness, lethargy, weight loss, diarrhea, shaking or trembling, PU/PD.
Hypoadrenocorticism (Addison’s disease)
How would you diagnose a dog with suspected Hypoadrenocorticism (Addison’s disease)? What would you expect to see?
- 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
- Urinalysis: may have inappropriately concentrated urine due to renal medullary washout
- ACTH stimulation test - no response (cause of atrophied or destroyed adrenal tissue)
- Admonial imaging - atrophied or destroyed adrenal tissue
How would you treat a dog with Hypoadrenocorticism (Addison’s disease)?
Acute crisis: IV saline +/- dextrose, steroids for shock, long term mineralocorticoid replacement with desoxycorticosterone pivalate (DOCP) (mineralocorticoids)
