Hypercalcaemia

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}} Hypercalcaemia (or Hypercalcemia) is an elevated calcium level in the blood. (Normal range: 9-10.5 mg/dL or 2.2-2.6 mmol/L). It can be an asymptomatic laboratory finding, but because an elevated calcium level is often a clue to other serious disease, a diagnosis should be undertaken if it persists. It can be due to excessive skeletal calcium release, increased intestinal calcium absorption, or decreased renal calcium excretion.

Contents 1 Signs and symptoms 2 Causes 3 Treatments 3.1 first line therapy 3.2 second line therapy 3.3 other therapies 4 See also 5 External links

Signs and symptoms

Hypercalcemia per se can result in fatigue, depression, confusion, anorexia, nausea, vomiting, constipation, or increased urination; if it is chronic it can result in urinary calculi (renal stones or bladder stones). Abnormal heart rhythms can result, and an EKG finding of a short QT interval suggests hypercalcemia.

Symptoms are more common at high calcium levels (12.0 mg/dL or 3 mmol/l). Severe hypercalcemia (above 15-16 mg/dL or 3.75-4 mmol/l) is considered a medical emergency: at these levels, coma and cardiac arrest can result.

Causes

• hyperparathyroidism and malignancy account for ~90% of cases
• abnormal parathyroid gland function
  • primary hyperparathyroidism
    • solitary parathyroid adenoma
    • primary parathyroid hyperplasia
    • parathyroid carcinoma (Template:ICD10)
    • multiple endocrine neoplasia (MEN)
    • familial isolated hyperparathyroidism (OMIM 146200)
  • lithium use
  • familial hypocalciuric hypercalcemia/familial benign hypercalcaemia (OMIM 145980, OMIM 145981, OMIM 600740)
• malignancy
  • solid tumor with metastasis (e.g. breast cancer)
  • solid tumor with humoral mediation of hypercalcemia (e.g. lung or kidney cancer)
  • hematologic malignancy (multiple myeloma, lymphoma, leukemia)
• vitamin-D metabolic disorders
  • hypervitaminosis D (vitamin D intoxication)
  • elevated 1,25(OH)₂D levels (e.g. sarcoidosis and other granulomatous diseases)
  • idiopathic hypercalcemia of infancy (OMIM 143880)
  • rebound hypercalcemia after rhabdomyolysis
• disorders related to high bone-turnover rates
  • hyperthyroidism
  • prolonged immobilization
  • thiazide use
  • vitamin A intoxication
• renal failure
  • severe secondary hyperparathyroidism
  • aluminum intoxication
  • milk-alkali syndrome

Treatments

The goal of therapy is to treat the hypercalcemia first and subsequently effort is directed to treat the underlying cause.

first line therapy

• hydration, increasing salt intake, and forced diuresis
  • hydration is needed because many patients are dehydrated due to vomiting or renal defects in concentrating urine. Increasing body fluid level can increase urine calcium excretion.
  • increased salt intake also can increase body fluid volume as well as increasing urine sodium excretion, which further increases urinary calcium excretion
  • after rehydration, saline or a loop diuretic can be given to force diuresis and depress renal calcium reabsorption
  • can usually decrease serum calcium by 1-3 mg/dL within 24 h
  • caution must be taken to prevent potassium or magnesium depletion

second line therapy

• bisphosphonates are pyrophosphate analogues with high affinity for bone, especially areas of high bone-turnover.
  • they are taken up by osteoclasts and inhibit osteoclastic bone resorption
  • current available drugs include (in order to potency): (1st gen) etidronate, (2nd gen) tiludronate, IV pamidronate, alendronate, risedronate, and (3rd gen) zolendronate
• calcitonin blocks bone resorption and also increases urinary calcium excretion by inhibiting renal calcium reabsorption
  • usually used in life-threatening hypercalcemia along with rehydration, diuresis, and bisphosphonates

other therapies

• rarely used, or used in special circumstances
  • plicamycin inhibits bone resorption (rarely used)
  • gallium nitrate inhibits bone resprotion and changes structure of bone crystals (rarely used)
  • glucocorticoids increase urinary calcium excretion and decrease intestinal calcium absorption
    • no effect in calcium level in normal or 1' hyperparathyroidism
    • effective in hypercalcemia due to osteolytic malignancies (multiple myeloma, leukemia, Hodgkin's lymphoma, carcinoma of the breast) due to antitumor properties
    • also effective in hypervitaminosis D and sarcoidosis
  • dialysis usually used in severe hypercalcemia complicated by renal failure. Supplemental phosphate should be monitored and added if necessary
  • phosphate therapy can correct the hypophosphatemia in the face of hypercalcemia and lower serum calcium

See also

• Calcium metabolism
• Hypocalcaemia
• Electrolyte disturbance
• Disorders of calcium metabolism
• ATC code V03#V03AG Drugs for treatment of hypercalcemia

External links

• Template:MedlinePlus
• Template:EMedicine
• Template:DiseasesDBfr:Calcémie