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12 Cards in this Set
- Front
- Back
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Explain normal Ca++ metabolism:
GI absorption: serum: reservoir: primary regulator PTH secretion is stimulated when Ca++ < ____: How does PTH increase serum Ca? |
GI absorption - 200 mg/day
serum - 50% free, 45% protein bound, 5% complexed reservoir - bones primary regulator - PTH <7.5 mg/dl kidney reabsorption, active vit-D in kidney, bone resorption |
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Effect of serum albumin, tourniquet, pH, and serum P on Ca++:
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albumin - decrease of 1g/dl --> serum Ca++ decrease 0.8 mg/dl
tourniquet - transudation of plasma water elevates total serum Ca pH --> changes in pH --> changes Ca-protein binding (0.1 pH --> 0.12 mg/dl Ca) serum P - increased serum P --> lowers ionized Ca, then total serum Ca as CaPO4 deposited in bone |
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Major causes in differential of hypocalcemia:
S/S of hypocalcemia: |
decreased PTH
PTH resistance (pseudohypoPTH) decreased vit D increased deposition pancreatitis increased bone mineralization carpopedal spasm, paresthesia, muscle cramps, tetany, psychosis, prolonged QT, cardiac changes |
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Signs of hypocalcemia:
What is pseudohypoPTH: |
Chvostek's sign, Trousseau's sign, hyperreflexia, dry skin, brittle hair, transverse ridging of nails, dental enamel hypoplasia
hormone resistant hypoPTH, short stature, round face, short neck, brachydactyly, retarded |
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first step in hypocalcemia dx:
How to R/O pseudo-hypoCa, acute respiratory alkalosis: Next step in eval: |
check serum ionized Ca
check serum albumin, pH check serum PTH if low - +hypoPTH (duh) if high - check serum P; low P = vit D deficiency, pancreatitis, bone mets disease |
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When do you see high serum P?
Tx of hypocalcemia: Acute symptomatic hypocalcemia requires: |
rhabdomyolysis, CRF, pseudohypoPTH
correction of disease Ca++ supplementation - IV, PO vit D supplementation immediate 10-15 mEq Ca++ IV |
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Who usually gets primary hyperPTH?
75% are due to what: Explain high PTH effect on serum Ca: Most common presentation: |
post-menopausal women
single adenomas increased bone resorption, GI absorption, increased vit D stimulation asymtomatic hypercalcemia |
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PTH, pancreas, pituitary, AD:
PTH, medullary thyroid, pheo, AD: Effect of sarcoid, histoplasmosis: ARF and hypercalcemia: |
MEN 1
MEN 2a increased active vit D polyuric recovery phase --> elevated PTH, active vit D, dissolution of ectopic CaPO4 deposits |
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Meds that can cause hypercalcemia:
Malignancies and hypercalcemia: |
vit D intox - dialysis patients, women being tx'ed for OP
Milk-alkali - ingestion of large amounts of Ca, alkali products TZ diuretics most common - secondary to osteolytic lesions - breast ca, MM lymphomas - too much active vit D squamous, renal, bladder, ovarian - PTHrP type proteins |
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defect in familial benign hypocalciuric hypercalcemia:
When should it be suspected? Clinical features of hyperPTH: features of sarcoid: |
mutation in PTH calcium receptors
urinary Ca/creatinine ratio <0.01 nephrolithiasis, hyperchloremic acidosis, hyperP, pseudogout, osteitis fibrosa cystica hilar adenopathy, rash, lymphadenopathy, EKC conduction abnormalities |
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Features of malignancies and hyperCa:
thyrotoxicosis: Tx of acute hypercalcemia: |
serum Ca > 15, anorexia, weight loss
hyperreflexia, systolic HTN fluids, induce calciuria - saline diuresis anti-resorptive therapy: 1st line - pamidronate disodium IV adjunct - calcitonin 2nd line - etidronate, gallium nitrate |
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Drug more potent than pamidronate, rapid onset, relapse time twice as long:
Indications for surgery in primary hyperPTH: |
zoldronic acid
serum Ca >11.5 nephrolithiasis compromised renal fxn hypercalciuria OP age <50 |
