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 indicative of other diseases, 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.
Hypercalcemia per se can result in fatigue, depression, confusion, anorexia, nausea, vomiting, constipation, pancreatitis or increased urination "Bones, stones, groans, and psychic moans" is a saying which will help you remember the signs and symptoms of hypercalcemia; if it is chronic it can result in urinary calculi (renal stones or bladder stones). Abnormal heart rhythms can result, and EKG findings of a short QT interval and a widened T wave suggest hypercalcemia.
Symptoms are more common at high calcium blood values (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 (C75.0)
multiple endocrine neoplasia (MEN)
familial isolated hyperparathyroidism (Online 'Mendelian Inheritance in Man' (OMIM) 146200)
hydration is needed because many patients are dehydrated due to vomiting or renal defects in concentrating urine.
increased salt intake also can increase body fluid volume as well as increasing urine sodium excretion, which further increases urinary calcium excretion (In other words, calcium and sodium (salt) are handled in a similar way by the kidney. Anything that causes increased sodium (salt) excretion by the kidney will, en passant, cause increased calcium excretion by the kidney)
after rehydration, a loop diuretic such as furosemide can be given to permit continued large volume intravenous salt and water replacement while minimizing the risk of blood volume overload and thence pulmonary edema. In addition, loop diuretics tend to depress renal calcium reabsorption thereby helping to lower blood calcium levels
can usually decrease serum calcium by 1-3 mg/dL within 24 h
caution must be taken to prevent potassium or magnesium depletion
Additional therapy: bisphosphonates and calcitonin
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
all patients with cancer-associated hypercalcemia should receive treatment with bisphosphonates since the 'first line' therapy (above) cannot be continued indefinitely nor is it without risk. Further, even if the 'first line' therapy has been effective, it is a virtual certainty that the hypercalcemia will recur in the patient with hypercalcemia of malignancy. Use of bisphoponates in such circumstances, then, becomes both therapeutic and preventative
patients in renal failure and hypercalcemia should have a risk-benefit analysis before being given bisphosphonates, since they are relatively contraindicated in renal failure.
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
Helps prevent recurrence of hypercalcemia
Dose is 4 Units per kg via subcutaneous or intramuscular route every 12 hours, usually not continued indefinitely
gallium nitrate inhibits bone resorption 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
