Lecture 4 1/31/25 Flashcards
(39 cards)
What is the mechanism of hypervitaminosis D?
increased intestinal absorption of Ca2+ and phosphrous
What are the causes of hypervitaminosis D?
*intoxication
–vit. D rodenticide
–topical anti-psoriasis cream
*excessive supplementation
–calcitriol
–dietary
What are the clinical features of hypervitaminosis D?
-can have a rapid increase in Ca
-acute PUPD
-acute renal failure
-tissue mineralization
-vomiting/anorexia/lethargy
-arrhythmias, seizures, death
What are the clin path features of hypervitaminosis D?
-tCa increases
-iCa increases
-phosphorus increases
-PTH of 0
-PTH-rp of 0
What is the mechanism of granulomatous disease?
-stimulated macrophages produce calcitriol
-leads to increased Ca2+ and P
What are the potential causes of granulomatous disease?
-infections
-sterile panniculitis
-granulomatous inflammation
Why are the clinical signs in granulomatous disease contributed to the disease and its cause rather than the hypercalcemia?
typically only see mild increases in Ca with granulomatous disease; not enough to see clinical signs
What are the characteristics of idiopathic hypercalcemia?
-most common cause of increased Ca in cats
-typically occurs in middle-aged cats, but can occur at any age
-mild to moderate increase in Ca
-must rule out other causes, especially lymphoma
What are the clinical signs of idiopathic hypercalcemia?
-may be asymptomatic
-hyporexia and weight loss
-vomiting
-constipation
-stones
What are the treatment options for cats with idiopathic hypercalcemia?
-diet change; increase fiber, decrease Ca (first rec)
-prednisolone
-PO bisphosponates
What are the characteristics of hypercalcemia associated with Addison’s disease?
-usually mild increased tCa
-possible normal iCa
-clinical signs NOT due to increased Ca
-mechanism unknown; theories include decreased renal Ca excretion, hemoconcentration, and increased protein binding of Ca
What are the non-pathologic mechanisms of hypercalcemia?
-young, growing animals; correlates to bone growth
-post-prandial
-spurious; due to hemolysis or lipemia
What are the effects of hypocalcemia on the neurons?
-Na+ channels are more likely to open
-neuron is easier to depolarize; threshold is lower
-neuron is more excitable; spontaneous muscle contractions more likely
What causes clinical manifestations of hypocalcemia?
excitability of neuronal and muscular tissues
What are the clinical manifestations of hypocalcemia?
-muscle tremors
-facial rubbing
-restlessness
-seizures
-hyporexia and weight loss
What is the approach to hypocalcemia?
-confirm hypocalcemia with an iCa measurement
-history
-clinical signs
-minimum database
-PTH measurement
-vit. D measurement
What are the steps of emergency treatment for hypocalcemia?
-10% calcium gluconate IV
-ECG monitoring
-benzodiazepines if seizures occur
What is the maintenance treatment for primary hypoparathyroidism?
calcitriol +/- calcium carbonate that is titrated to maintain iCa within the reference interval
Which diseases cause hypocalcemia?
-primary hypoparathyroidism
-eclampsia
-ethylene glycol toxicity
-acute pancreatitis
-renal failure
-severe gut disease
What are the mechanisms for hypocalcemia?
-decreased PTH
-decreased calcitriol/vit. D
-increased Ca utilization
-increased Ca consumption
What are the characteristics of hypoparathyroidism?
-decreased secretion of PTH
-can be primary or secondary/iatrogenic
What are the characteristics of primary hypoparathyroidism?
-destruction or atrophy of parathyroid glands
-usually immune-mediated
-clin path shows low PTH, tCa and iCa
-phosphorus is normal to increased on clin path
Which animals are most likely to develop primary hypoparathyroidism?
-young, female dogs
-poodles, mini schnauzers, german shepherds, and golden retrievers
What are the main clinical signs of hypoparathyroidism?
-seizures/tetany
-intense rubbing/pawing at face
-intense biting/licking at paws
-signs that worsen with excitement, exercise, and/or petting
