9/7 - Additional Endocrinopathies

Insulinoma

What endocrine condition/tumor occurs in dogs, cats, and especially ferrets, usually in older animals? Standard poodles, boxers, and terriers are more susceptible. Signs include weakness, good appetite, and seizures due to low glucose and elevated epinephrine. Diagnostics include CBC/Chem, fasting hypoglycemia, severely low glucose (measured with concurrent BG of under 40), and lack of ketones. Do thoracic radiographs to evaluate metastasis to the liver, and abdominal ultrasound although masses are usually small and not visible. Treatment is either surgical (liver biopsy, excision, risks of: pancreatitis, DM, cerebral laminar necrosis), or medical (prednisone, diazoxide, streptozotocin, diet management (multiple small meals)). Prognosis is guarded-poor due to metastasis before diagnosis, and treatment is usually palliative.

Hypoglycemia

Cancer cachexia, sepsis, liver disease, insulinoma, hepatoma, drugs, small breed puppies, and pregnancy with malnutrition can all cause/have what blood sugar condition?

Gastrinoma

What endocrine tumor/condition is also called Zollinger-Ellison syndrome and affects older dogs? Signs include vomiting, hematemesis, diarrhea, melena, anorexia, and weight loss. It is diagnosed by elevated serum gastrin levels and abdominal ultrasound. Treatment is with proton pump inhibitors, sucralfate, and surgery to remove the tumor, do partial gastrectomy if needed, and endoscopy to evaluate ulcer severity. It involves overproduction of gastrin and HCl in the stomach.

Hyperparathyroidism

What endocrine condition involves calcium homeostasis, with the hormones: parathormone (made by PTH gland Chief cells and stimulated by low Ca), calcitonin (made by C cells in thyroid and lowers Ca), and vitamin D (cholecalciferol)? It comes in the primary, secondary, and tertiary types. Signs include: PU/PD, lethargy, incontinence, weakness, exercise intolerance, anorexia, muscle wasting, vomiting, constipation, or no signs at all. Urinary tract disease and Ca urolithiasis can also occur. Diagnosis is via elevated PTH with elevated Ca or normal PTH, and ionized Ca must be evaluated. Radiographs can show osteopenia and urolithiasis, and ultrasound of the neck can show enlarged affected glands and atrophied normal glands. Treatment is with surgical excision, medical management with bisphosphonates/calcimimetics, and post-op management to correct the hypocalcemia which will occur, giving IV calcium gluconate if needed.

Parathormone

What hormone is made by chief cells in the PTH gland and is stimulated in response to low Ca?

Calcitonin

What hormone is made by C cells in the thyroid and serves to lower Ca?

Primary

Which type of hyperparathyroidism is usually due to a benign adenoma, rarely has hyperplasia, and is similar to HHM/pseudohyperparathyroidism? It has high Ca and PTH.

Secondary

Which type of hyperparathyroidism is due to nutritional, renal, or intestinal causes? It has PTH and low Ca.

Tertiary

Which type of hyperparathyroidism is due to receptor abnormalities?

Hypercalcemia

What blood ion condition involves these differentials: granulomatous disease, osteopathy, spurious changes, hyperparathyroidism, hypervitaminosis D, addison’s disease, renal disease, neoplasia (lymphoma), idiopathic causes, and increased temperature in cats?

Hypoparathyroidism

What hormone condition will have low Ca and PTH? It can occur due to immune-mediated destruction of parathyroid glands, such as in lymphocytic parathyroiditis, and can occur in any age but usually around 5 years. There is no obvious breed or sex predilection but small breeds may get it more often. Signs include hypocalcemia signs, such as: muscle fasciculation, cramps, seizures, itchiness, pawing at face, cataracts, and diaphragm contractions concurrent with heartbeat. Diagnosis is with decreased total and ionized Ca, increased P, and decreased iPTH. Treatment is via IV Ca for emergency stabilization, oral calcitriol, and oral Ca supplements if needed.

Ionized

Should ionized or free Ca be measured when testing for hyperparathyroidism?

Calcitriol

Therapy with what hormone/drug, the active form of vitamin D, should be given on the day of or a day before surgery for a hyperparathyroidism tumor? It can take 3-4 days to work and should be slowly decreased until the animal can maintain normal Ca. You should aim to get Ca to the low end of the normal range. Oral calcium supplementation with calcium carbonate can also be given and then tapered during this post-op period.

Renal

Which type of secondary hyperparathyroidism occurs due to chronic kidney disease, when low calcium triggers PTH, leading to demineralized bone? Treatment is by treating the CKD, ensuring normal Ca/P production, and calcitriol therapy if P becomes less than 6.

Nutritional

Which type of secondary hyperparathyroidism can be intestinal or dietary?

Intestinal

Which type of nutritional secondary hyperparathyroidism occurs due to intestinal malabsorption, and is accompanied by diarrhea? You should correct the primary disease and give calcitriol.

Dietary

Which type of nutritional secondary hyperparathyroidism occurs due to inappropriate Ca/P ratio in food, leading to low Ca and vitamin D, lameness, loose teeth, swollen maxilla, and pathologic fractures?

Insipidus

Which type of diabetes is usually a nephrogenic condition, involving decreased in ADH/VP, can be congenital or acquired, and usually occurs either less than 2 years old or over 6 years old, in cases where it is secondary to a pituitary tumor? Another type can occur due to decrease in receptors, which is congenital but rare. Signs include PU/PD, incontinence due to large amount of urine, and possible neurological signs. A database will show: polycythemia, azotemia, hypernatremia, USG of 1.001-1.012, and CT/MRI can also be done. Water intake is usually over 100 ml/kg/day. Other PU/PD diseases must be ruled out first, including CDI, NDI, and psychogenic polydipsia as the final three rule-outs. After contacting an internist, the DDAVP and water deprivation tests may be done.

DDAVP

What test (abbreviated) is done to test for diabetes insipidus, and involves measuring water intake for 2-3 days, catching urine at the same time every day, and treating with this drug/hormone (desmopressin) for 5-7 days to look for a response? Monitoring should be done on days 5-7. Decrease in water intake and 50% increase in USG are consistent with PP or CDI, while moderate response is consistent with partial central DI, and no response at all is consistent with nephrogenic DI. It can be given as nasal drops and is similar in structure to ADH/VP but more antidiuretic.

Water Deprivation

What test done to test for PP or DI can be fatal to the animal, and should never be done to a dehydrated dog? All other causes of PU/PD should first be ruled out. The protocol involves slowly decreasing available water over 3 days, doing it in hospital, getting weights/USG/creatinine/PE every hour, and doing it until the animal is 5% dehydrated and has a USG over 1.030. If the urine is concentrated, then PP is occurring. DDAVP test can also be done alongside this.

Nephrogenic

Which type of Diabetes Insipidus is either primary or secondary? Primary is rare, occurring due to thiazide diuretics (inhibits Na resorption in the loop, increasing Na and H2O absorption in the proximal tubule) and/or low salt diet, and treatment may only decrease water intake to only 2X that of normal, and can be handled by owners or treated. Secondary must be treated and is due to problems in the renal system.

SIADH

What condition (abbreviated) involves inappropriate ADH release, as well as severe hyponatremia, plasma hypo-osmolality, water intoxication, and natriuresis and high urine osmolality? Signs include vomiting, agitation, seizures, and normal renal, hepatic, adrenal, and thyroid function. It can occur due to drugs, encephalitis, neoplasia, or intrathoracic masses causing decreased preload. Treatment is with treating the primary disease, restricting water, and furosemide.

Growth

What hormone is both catabolic and anabolic, acting as an insulin antagonist and working like IGF-1 in the liver? It simulates protein synthesis and growth production. Deficiency can be congenital (retained Rathke’s pouch) or due to dwarfism: primarily in German shepherds and some cats, no sex predilection, signs appear at 2-3 months, decreased basal IGF-1, thyroid testing is required, and an open epiphysis can occur in older dogs. Treatment for deficiency is with hGH, and prognosis is 3-4 years, as the cyst will still grow.