14- HYPERCALCEMIA

• Hypercalcemia

  Serum corrected calcium > 2.6
• Corrected calcium

  0.02 x (40 - albumin)
• Severity of hypercalcemia

  • Mild: up to 3
  • Moderate: 3-3.5
  • Severe: > 3.5
• Causes of hypercalcemia

  • Primary hyperparathyroidism (most common)
  • Vitamin D intoxication
  • PTH-related peptide
  • Sarcoidosis and granulomatous diseases (TB)
  • Malignancy: MM, squamous lung, prostate, breast, lymphoma
  • Metastasis to bone
  • Endocrine: Hyperthyroidism and Addison's
  • Drugs: thiazide, anti-acids, lithium, vit A & D supplements
  • Familial/genetics
• Presentation of hypercalcemia

  • Asymptomatic hypercalcemia on routine blood test
  • Acute severe hypercalcemia: confusion, stupor, LOC, lethargy, constipation, risk of cardiac arrest
  • Chronic slow manifestations: "Stones" (Nephrolithiasis, nephrocalcinosis, renal DI), "Bones" (Bone aches and pains, arthritis (ca pyrophosphate deposition), osteoporosis, osteitis fibrosa cystica ("brown tumors") à predisposes patient to pathologic fractures), "Groans" (Muscle pain & weakness, nausea & vomiting, constipation, peptic ulcer disease, pancreatitis), "Psychiatric overtones" (depression, fatigue, lethargy, anorexia, sleep disturbances, anxiety)
  • Cardiovascular manifestations: HTN, bradycardia
  • Corneal calcification
• Approach to hypercalcemia

  • History: symptoms, drug use (thiazide, vitamins), duration, family Hx
  • Examination: level of consciousness
  • Blood: Ca, PTH, vit D, phosphate, renal function, ACE level, PTH-related peptide (High PTH: 1° or 3° hyperparathyroidism (2° have low calcium), Low PTH: malignancy or other causes ex. Drugs)
  • Urinary Ca, urinary cAMP
  • ECG (SHORT QT, Prolonged QR, Wide ST, Bradycardia or arrhythmias)
  • Radiography: osteopenia (bone X-ray not good, DEXA better)
• Acute severe hypercalcemia treatment

  • Stop all medications that could cause high calcium
  • Saline rehydration is the mainstay of treatment: IV NS 4-6 L over 24 hours, 3-4 L for several days thereafter (caution in patients with cardiac or renal disease)
  • Loop diuretics (furosemide)
  • Calcitonin (nasal or SC): inhibits osteoclasts). Rapid onset (reduces Ca level within 24 hours) and wears off rapidly in 3 days
  • IV bisphosphonates (pamidronate, zoledronic acid) after rehydration, take several days to work but their effect lasts longer (mainstay of long-term Tx)
  • Steroids only used in certain cases: MM, lymphoma, sarcoidosis, vit D intoxication
  • Role of dialysis: when all measures have been done & pt. is still not improving, calcium not decreasing, or if pt. became drowsy or had LOC à urgent dialysis
  • If Ca > 3.5 or CNS (drowsy or LOC) or cardiac complication (arrythmias) à ICU