Endocrine3- Ca Disorders of Horses
Card Set Information
Endocrine3- Ca Disorders of Horses
Secondary hypoparathyroidism in horses is secondary to... (2)
sepsis (critically ill patients), hypomagnesemia
Secondary hyperparathyroidism in horses is secondary to... (2)
renal failure, nutritional
What are the hallmarks of hypoparathyroidism in horses? (3)
low calcium, low PTH, increased phosphorous
Clinical signs of hypoparthyroidism in horses. (6)
muscle fasciculations, seizures, ataxia, arrhythmias, ileus, colic [ALL SIGNS OF HYPOCALCEMIA IN GENERAL]
In horses, primary hypoparathyroidism is __________.
Ca2+ blocks _______ from getting into the cells; therefore, blocking __________.
Clinical signs of hypocalcemia are related to _______________, thus increased ___________.
increased Na+ entering cells; depolarization
Striated muscle contraction depends on...
how much Ca2+ is inside the cells.
Smooth muscle contraction depends on...
how much Ca2+ is outside the cells (extracellular).
Synchronous diaphragmatic flutter in horses is caused by...
hypocalcemia (hypoparathyroidism) and often with concurrent low Mg2+
Synchronous diaphragmatic flutter occurs because the ________ nerve is in a low ______ environment and is easier to _________.
phrenic; Ca2+; depolarize (every time the heart contracts, the depolarization spreads from the SA node to the phrenic nerve)
RFM occurs with _________ because the uterus is a _________, which requires _______ to contract.
hypocalcemia; smooth muscle; Ca2+
Why do sick horses develop hypocalcemia?
inflammatory cytokines impair the function of the parathyroid gland--> low PTH
Binding of Ca2+ to albumin is ____-dependent.
With acidosis, Ca2+ is not _________ in as high proportions as normal; therefore, metabolic acidosis may lead to __________ on bloodwork.
bound to albumin; hyperCa2+
Metabolic aklalosis is associated with _________ because...
hypocalcemia; increased binding of Ca2+ and Mg2+ to albumin, decreasing their free plasma concs.
Prolonged exercises causes _________ [acid-bse status].
Why do horses under severe exercise develop alkalosis?
hyperventilation--> respiratory alkalosis; chloride loss in sweat--> replace with bicarb
In acute renal injury/tubular necrosis, there is decreased renal __________; thus, increasing urinary __________ and contributing to the development of _________.
Ca2+ reabsorption; excretion; hypocalcemia
In duodenitis-proximal jejunitis (DPJ), horses develop _________ because...
hypocalcemia; horse is refluxing stomach contents, losing Cl---> replaced with bicarb--> alkalosis--> hypocalcemia
Thyroid gland pathologies in horses are usually __________.
aesthetic (don't cause clinical disease)
Clinical signs of hyperCa2+ in horses. (6)
depend on primary problem: neurologic, muscular, GI, depression, decreased GI motility, PU/PD
How does hyperCa2+ causes PU/PD?
Ca2+ decreases affect of ADH, decreases H2O reabsorption--> diuresis
Common cause of secondary hypercalcemia in horses.
Cause of primary hyperparathyroidism in horses.
function chief cell adenoma--> autonomous secretion of PTH
Lab findings associated with primary hyperparathyroidism in horses. (3)
hyperCa2+, hypophosphatemia, high PTH
Secondary hyperparathyroidism in horses due to renal disease is accompanied by... (2)
hyperphosphatemia, hypovitaminosis D.
Secondary hyperparathyroidism in horses due to nutrition is caused by... (2)
excess phosphate/oxalates in diet, low Ca2+ diet
Clinically, what do you see with nutritional secondary hyperparathyroidism in horses? (3)
osteodystrophia fibrosa, osteitis fibrosa, equine osteoporosis
Hypocalcemia and/or hyperphosphatemia induce parathyroid _________ and ____________.
hyperplasia; increased PTH secretion
Excess of phosphates/oxalates in the diet bind ________, causing an increase in __(3)__.
Ca2+; PTH, bone resorption, and bone loss
Vit D increased ____________ and __________ of __(2)__.
intestinal absorption; renal reabsorption; Ca2+ and Ph
Vit D increases _______ formation.
Vit D inhibits _________; therefore, low vit D leads to ___________.
PTH secretion; hyperparathyroidism
Hypervitaminosis D in horses is usually caused by... (2)
iatrogenic, toxic plants
Clinical signs of hypervitaminosis D in horses. (3)
weight loss, soft tissue mineralization, organ failure
Lab findings in horses with hypervitaminosis D. (4)
increased Ca2+, increased Ph, low PTH,+/- evidence of organ failure
Treatment and prognosis for horses with hypervitaminosis D. (2)
palliative, cortisol [
Hypercalcemia of malignancy in horses is seen with... (4)
lymphosarcoma, SCC, ameloblastoma, multiple myeloma
Lab findings in horses with hypercalcemia of malignancy. (4)
hypercalcemia, hypoposphatemia, high PTHrP, low PTH
Hypercalcemia of malignancy is often accompanied by _________ on radiograph.
Treatment and prognosis for hypercalcemia of malignancy in horses. (3)
palliative, chemotherapy, sx [PROGNOSIS IS
Why do horses with CKD, unlike other species, develop hypercalcemia?
calcium retention due to high GI absorption and renal excretion of Ca2+ (renal excretion reduced in CKD, obvi)