Hypercalcemic States

Key Features

Essentials of Diagnosis

• Abdominal pain, polyuria, polydipsia, hypertension, nephrocalcinosis, failure to thrive, renal stones, intractable peptic ulcer, constipation, uremia, and pancreatitis

• Bone pain or pathologic fractures, subperiosteal bone resorption, renal parenchymal calcification or stones, and osteitis fibrosa cystica

• Impaired concentration, altered mental status, mood swings, and coma

General Considerations

• Hypercalcemia is defined as a serum calcium level > 11 mg/dL

• Severe hypercalcemia is a level > 13.5 mg/dL

• More than 80% of hypercalcemic children or adolescents have either hyperparathyroidism or a malignant tumor

• Hyperparathyroidism is rare in childhood and may be primary or secondary

  • Most common cause of primary hyperparathyroidism is parathyroid adenoma

  • Most common cause of secondary hyperparathyroidism is chronic kidney disease with impaired phosphate excretion

Clinical Findings

Symptoms and Signs

• Due to hypercalcemia

  • Manifestations include hypotonicity and muscle weakness; apathy, mood swings, and bizarre behavior; nausea, vomiting, abdominal pain, constipation, and weight loss; hyperextensibility of joints; and hypertension, cardiac irregularities, bradycardia, and shortening of the QT interval

  • Coma occurs rarely

  • Calcium deposits occur in the cornea or conjunctiva (band keratopathy) and are detected by slit-lamp examination

• Due to increased calcium and phosphate excretion

  • Loss of renal concentrating ability causes polyuria, polydipsia, and calcium phosphate deposition in renal parenchyma or as urinary calculi with progressive renal damage

• Due to changes in the skeleton

  • Initial findings include bone pain, osteitis fibrosa cystica, subperiosteal bone absorption in the distal clavicles and phalanges, absence of lamina dura around the teeth, spontaneous fractures, and moth-eaten appearance of the skull on radiographs

  • Later, there is generalized demineralization with high risk of subperiosteal cortical bone

Diagnosis

• Bone changes may be subtle in children

• Technetium sestamibi scintigraphy is preferred over conventional procedures (ultrasound, computed tomography, and MRI) for localizing parathyroid tumors

Treatment

• Initial management is vigorous hydration with normal saline and forced calcium diuresis with a loop diuretic such as furosemide (1 mg/kg given every 6 hours)

• If response is inadequate, glucocorticoids or calcitonin may be used

• Bisphosphonates are being used more often in refractory pediatric hypercalcemia

• Resection of parathyroid adenoma or subtotal removal of hyperplastic parathyroid glands is the preferred treatment

• Treatment of secondary hyperparathyroidism from chronic kidney disease is primarily directed at controlling serum phosphorus levels with phosphate binders

• Pharmacologic doses of calcitriol are used to suppress PTH secretion

• Long-term therapy for hypercalcemia of malignancy is the treatment of the underlying disorder

• There is also an increasing role for bisphosphonates in treatment of chronic hypercalcemia

Outcome

Prognosis

• Excellent after resection of a single adenoma

• Usually good following subtotal parathyroidectomy for diffuse hyperplasia or removal of multiple adenomas; depends on correction of the underlying defect

• In patients with multiple sites of parathyroid ...