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29 Cards in this Set
- Front
- Back
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Normal total calcium concentration in serum is?
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8.5 to 10.5 mg/dL
or 2.0 to 2.5 mM |
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At pH 7.4, 1 g/dL of albumin binds how much calcium?
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0.8 mg/dL
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How much calcium exists in ionized form in serum usually?
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50% (1-1.25 mM)
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To maintain calcium balance, how much calcium must the kidneys excrete daily?
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150-200 mg
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What is the agonist for calcium sensing receptor?
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Ionized calcium
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What is the most common cause of hypercalcemia in adults?
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Malignancies
Primary hyperparathyroidism: single adenoma in most cases (MEN-I and MEN-II), renal insufficiency, and prolonged immobolization. |
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What are systemic mediators for hypercalcemia in malignancy?
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PTHrP, 1,25-(OH)2-VitD3, ectopic PTH
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What are local mediators for hypercalcemia?
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Osteoclastic activating factors (IL-1, IL-6, lymphotoxin), TNF-beta, TGF-alpha
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How will iPTH be affected depending on the cause of hypercalcemia?
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iPTH will be high in hyperparathyroidism and low in malignancies.
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How will phosphate be affected depending on the cause of hypercalcemia?
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Phosphate will be low in hyperparathyroidism and high in hypervitaminosis D.
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How are 1,25-(OH)2-VitD3 levels affected by the causes of hypercalcemia?
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1,25-(OH)2-VitD3 will be increased in sarcoidosis and granulomatous diseases.
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How are 25-(OH)2-VitD3 levels affected by the causes of hypercalcemia?
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25-(OH)2-VitD3 will be increased in hypervitaminosis D.
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What will the Ca levels from a 24 hour urine Ca excretion test look for malignancy, hyperparathyroidism, and familial hypocalciuric hypercalcemia?
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Highest in malignancy, high in hyperparathyroidism, and normal to low in familial hypocalciuric hypercalcemia.
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What are the treatments for hypercalcemia?
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Discontinue Ca supplements and vitamin D; volume expansion with saline; loop diuretics (after saline); bisphosphonates (inhibit osteoclast activity; take 48 hours to work); dialysis in patients with renal failure; calcitonin (works quick in first 48 hours, use with bisphosphonates).
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Why should IV phosphate be avoided in patients with hypercalcemia?
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Can cause metastatic calcification.
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What are some of the causes of hypoparathyroidism causing hypocalcemia?
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Infiltrative diseases (amyloid, Wilson's disease, and hemachromatosis), surgical ablation, hypomagnesemia, and polyglandular autoimmune syndrome type 1
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What drugs can cause hypocalcemia?
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Bisphosphonates, loop diuretics, amphotericin B, aminoglycosides, cis-platinum, phenobarbital, and phenytoin
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What are the CV signs of hypocalcemia?
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Prolonged QT interval, arrhythmias, hypotension, and heart block
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What are the skin signs of hypocalcemia?
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Dry skin, coarse hair, brittle nails, eczema, psoriasis, candidiasis (HAM syndrome)
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How does hypocalcemia affect the eyes?
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It can give a patient cataracts.
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What are the neuromuscular manifestations of hypocalcemia?
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Excitability, paresthesias (numbness and tingling in fingers, toes, and circumoral regions), carpopedal spasm, laryngeal stridor, tetany, Chvostek's sign, and Trousseau's sign.
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Long standing hypocalcemia can cause papilledema and basal ganglia calcifications, which can cause symptoms mimicing what disease?
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Parkinson's disease
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What are the CV manifestations of hypercalcemia?
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Hypertension, arrhythmias, heart block, shortened QT
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What are the GI symptoms of hypercalcemia?
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Anorexia, nausea, vomiting, pancreatitis, peptic ulcer disease, Zollinger-Ellison syndrome
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What are the neuromuscular symptoms of hypercalcemia?
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Hyporeflexia, myalgia, and arthraliga
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What are the genitourinary symptoms of hypercalcemia?
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Polyuria, nephrocalcinosis, nephrolithiasis, acute renal failure
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What is the treatment for acute hypocalcemia?
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10-20 mL of Ca gluconate in 50-100 mL of D5W IV over 10 minutes. Needs cardiac monitoring.
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What is the treatment for intermediate hypocalcemia?
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Ca gluconate (10-15 mg/kg) over 6-8 hours.
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What is the treatment for chronic hypocalcemia?
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Ca supplements, thiazide diuretics, and rocaltrol
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