Nejm 1992;326:1196

Cause/Epidem/Pathophys:

• Hyperparathyroidism (Hyperparathyroidism) via renal calcitriol (activated vit D) production (Ann IM 1994;121:633, 709)
• Cancers, esp lung, breast, and hepatoma (Nejm 1992;327:1663), by:
1. PTH-like protein secretions, with T-cell leukemias/lymphomas (Nejm 1990;322:1106; Ann IM 1989;111:484)
2. Secretion of other bone-resorbing substances
3. Tumor conversion of 25-OH vit D to 1,25-OH vit D (calcitriol)
4. Local osteolytic mets
• Sarcoid, Hodgkin's lymphoma, non-Hodgkin's lymphoma, cat scratch disease (Jama 1998;279:532), and tbc, via extrarenal calcitriol (activated vit D) production in granulomas (Ann IM 1994;121:633, 709)
• Vit D intoxication (Nejm 1992;326:1173) including the milk-alkali syndrome (Ann IM 1982;97:242)
• Immobilization
• Thyrotoxicosis
• Thiazides rarely (Nejm 1971;284:828)
• Vit A intoxication (Ann IM 1974;80:44)
• Disseminated coccidiomycosis (Nejm 1977;297:431)
• Benign familial hypocalciuric hypercalcemia (autosomal dominant) (Ann IM 1985;102:511)
• Adrenal insufficiency

Sx:Fatigue, weakness, sleepiness, nausea/anorexia, constipation, polyuria/dypsia, and volume depletion

Si:Confusion, delirium, drowsiness, coma

Pancreatitis, increased risk of digoxin toxicity

Lab:

Chem:Calcium elevated (Calcium Level, Corrections in Serum for corrections for low proteins) 10.5 mg %; sx usually between 11-12 mg %, really toxic over 14 mg %

Noninv:EKG, Short QT interval w normal T wave, segment from QRS to beginning of T shortened

Rx:

Acute rx for Ca⁺⁺ >13 mg %, to decrease within hours:

• Normal saline 2.5-4 L/24 h iv to assure intravascular volume adequately replaced (CVP or Swann monitoring), avoid furosemide (Nejm 1984;310:1718) initially, but often needed after volume replaced to prevent volume overload and accelerate renal calcium clearance
• Pamidronate (Aredia) 60-90 mg iv over 24 h (Med Let 1992;34:1), or 4-8 mg/h

Chronic rx, work over 1-5 d, worth doing even with metastatic cancer since diminishes sx and allows hospital discharge (Ann IM 1990;112:499):

• Biphosphonates, eg, pamidronate (Aredia) 60-90 mg iv infusion over 8-24 h (Med Let 1992;34:1) or 1200 mg po qd × 5 d
• Steroids (Ann IM 1980;93:269, 449) primarily for sarcoid pts, eg, prednisone 20 mg po tid
• Calcitonin 4 U/kg q 6 h sc or im, relatively weak agent alone
• Indomethacin (rarely helpful if due to cancer)
• Gallium nitrate iv infusion, experimental (Med Let 1991;33:41; Ann IM 1988;108:669) 200 mg/m² in 1 L continuous infusion qd × 5 d