Canine Top Endocrine Diseases

Question 1

what is the classic case presentation of hypothyroidism?

Answer 1

middle aged dog with insidious signs - weight gain, lethargy, exercise intolerance, hypothermia, bilaterally symmetric non-pruritic alopecia with a rat tail & dry coat, rare myxedema with a tragic facial expression

Question 2

what is the etiology of hypothyroidism?

Answer 2

lymphocytic thyroiditis or thyroid atrophy

Question 3

what initial screening is done when diagnosing hypothyroidism?

Answer 3

cbc - mild normocytic normochromic non-regenrative anemia chem - possible hypercholesteremia, hypertriglyceridemia serum T4 - low, either true or euthyroid sick syndrome

Question 4

after initial screening, what diagnostics are done for hypothyroidism?

Answer 4

serum free T4 - if low, true hypothyroidism, if normal, euthyroid sick syndrome TSH - if high, true hypothyroidism, if normal/low, euthyroid sick syndrome

Question 5

how is hypothyroidism treated? what monitoring is done upon the start of treatment?

Answer 5

oral synthetic T4 (levothyroxine) - gi absorption is poor, given ever 12-24 hours for life, will see slow improvement over weeks to months for monitoring - post-pill T4 4-6 weeks after starting treatment & then every 3-6 months

Question 6

what is iatrogenic thyrotoxicosis?

Answer 6

pu/pd/pp, hyperactivity, & tachycardia - reevaluate treatment

Question 7

what is the prognosis of hypothyroidism?

Answer 7

excellent

Question 8

T/F: euthyroid sick syndrome can complicate the diagnosis of hypothyroidism

Answer 8

TRUE

Question 9

what is seen at birth in a dog with congenital hypothyroidism?

Answer 9

disproportionate dwarfism

Question 10

what treatment is done for a dog with hypothyroidism that is in a myxedema coma?

Answer 10

T4 must be given IV

Question 11

what is the classic case presentation of a dog with diabetes mellitus?

Answer 11

middle aged dog that is pu/pd/pp, weight loss, cataracts (blindness)

Question 12

what is the etiology of diabetes mellitus?

Answer 12

immune mediated destruction of the pancreatic islet cells (less common - severe pancreatitis)

Question 13

what are predisposing factors for dogs with diabetes mellitus?

Answer 13

obesity, hyperadrenocorticism, steroid administration, & pregnancy

Question 14

what clinical signs are seen in a dog with DKA?

Answer 14

vomiting, inappetance, lethargy, & dehydration

Question 15

what initial screening is done for diagnosing diabetes mellitus?

Answer 15

CBC, chem - persistent hyperglycemia, increased ALP, hypercholesterolemia, & pre-renal azotemia if DKA - decompensation of DM set off by concurrent diseases (infection, pancreatitis)

Question 16

after initial testing, what diagnostics are done for diabetes mellitus?

Answer 16

serum fructosamine - gives bg over 1-3 weeks

Question 17

what treatment is done for stable diabetic dogs?

Answer 17

long acting SQ insulin ever 12 hours, diabetic specific diet at home monitoring - at home bg checks, fructosamine, bg curves, & clinical parameters

Question 18

what treatment is done for a dog in DKA?

Answer 18

IV fluids, regular insulin CRI, & treatment of concurrent disease

Question 19

what are some common complications associated with diabetes mellitus?

Answer 19

secondary infections - cystitis, dermatitis, cataracts (affect 80% dogs in first year of diagnosis)

Question 20

what is the prognosis for a dog with diabetes mellitus?

Answer 20

good if the owner is able to provide care

Question 21

what is the classic case presentation of a cushing’s dog?

Answer 21

middle aged dog - pu/pd/pp/panting, pot belly appearance, truncal alopecia, hepatomegaly, & muscle weakness

Question 22

what are the etiologies of cushing’s disease?

Answer 22

pituitary microadenoma (PDH), adrenal tumors, or iatrogenic - PDH most common, adrenal tumors more likely if > 20 kg

Question 23

what initial screening is done when working up a suspected cushing’s dog?

Answer 23

CBC - stress leukogram, mature neutrophilia, monocytosis, lymphopenia, eosinopenia, & thrombocytosis chem - ALP elevation, hypercholesterolemia urinalysis - isosthenuria +/- proteinuria

Question 24

after initial screening, what diagnostics are done for a possible cushing’s dog?

Answer 24

ACTH stim - only for iatrogenic LDDST, urine cortisol:creatinine, & always treat non-adrenal illnesses before pursuing diagnostics/treatment

Question 25

what differentiating test for PDH vs AT done is done after the diagnosis of hyperadrenocorticism?

Answer 25

abdominal ultrasound, HDDST, endogenous ACTH

Question 26

what treatment is used for cushing’s dogs due to PDH?

Answer 26

trilostane - others include mitotane & rare surgery

Question 27

what treatment is used for cushing’s dogs due to an adrenal tumor?

Answer 27

surgical adrenalectomy is the treatment of choice due to the likelihood of malignancy (carcinoma) meds - trilostane/mitotane

Question 28

what monitoring is recommended for cushing’s dogs?

Answer 28

clinical signs & ACTH stim test

Question 29

what is the prognosis for cushing’s dogs from PDH? what about AT?

Answer 29

PDH - good if medically managed AT - fair to poor (can invade caudal vena cava & met)

Question 30

what are common sequelae seen with cushing’s dogs?

Answer 30

secondary infections, hypertension, & proteinuria

Question 31

T/F: stress can cause false positive test results for ACTH stimulation & LDDST for suspect cushing’s dogs

Answer 31

TRUE

Question 32

what is the classic case presentation of an addison’s dog?

Answer 32

young to middle aged usually female dog - poodles & purebreds - waxing/waning signs that worsen with stress, vague gi signs, weight loss - can progress to addisonian crisis (bradycardia, hypotension, vomiting, diarrhea, lethargy)

Question 33

what is the etiology of addison’s disease?

Answer 33

immune-mediated destruction of the adrenal cortex, iatrogenic from long term steroid use that isn’t tapered, or with mitotane/trilostane therapy

Question 34

what are the two forms of addison’s disease? how are they different?

Answer 34

typical - glucocorticoid & mineralocorticoid deficiency atypical - just glucocorticoid deficiency

Question 35

what is the only definitive test for addison’s disease? what other diagnostics are done alongside it?

Answer 35

definitive - ACTH stim others - cbc, chem, baseline cortisol, & UA

Question 36

what is seen on cbc, chem, & urinalysis in a suspect addison’s dog?

Answer 36

CBC - lack of a stress leukogram in a sick dog, eosinophilia, lymphocytosis, normocytic normochromic non-regenerative anemia typical chem - decreased Na:K ratio <27, hyponatremia, hyperkalemia, hypoglycemia, metabolic acidosis, hypercalcemia, hypoalbuminemia atypical chem - all changes except for electrolyte derangements UA - isosthenuria

Question 37

what treatment is used for an addisonian crisis?

Answer 37

isotonic iv fluid resuscitation, treat life threatening hyperkalemia, dex SP IV until diagnoss is confirmed before starting mineralocorticoids

Question 38

what is the long term treatment used for addison’s patients?

Answer 38

physiologic steroids, DOCP injections

Question 39

for addison’s patients on DOCP, what needs to be monitored?

Answer 39

monitor lytes on days 14 & 25 to determine dosage/dosing interval

Question 40

what is the prognosis for addison’s disease?

Answer 40

excellent with treatment