(See also general discussion of hypercalcemia Hypercalcemia Hypercalcemia is a total serum calcium concentration > 10.4 mg/dL (> 2.60 mmol/L) or ionized serum calcium > 5.2 mg/dL (> 1.30 mmol/L). Principal causes include hyperparathyroidism, vitamin... read more .)
Etiology of Neonatal Hypercalcemia
The most common cause of neonatal hypercalcemia is
Iatrogenic causes usually involve excess calcium or vitamin D, or phosphate deprivation, which can result from prolonged feeding with incorrectly prepared formula.
Other causes of neonatal hypercalcemia include
Subcutaneous fat necrosis
Abnormal renal function
Maternal hypoparathyroidism or maternal hypocalcemia may cause secondary fetal hyperparathyroidism, with changes in fetal mineralization (eg, osteopenia).
Subcutaneous fat necrosis may occur after major trauma and causes hypercalcemia that usually resolves spontaneously.
Neonatal hyperparathyroidism is very rare.
Williams syndrome's key features include supravalvular aortic stenosis Aortic Stenosis Aortic stenosis (AS) is narrowing of the aortic valve, obstructing blood flow from the left ventricle to the ascending aorta during systole. Causes include a congenital bicuspid valve, idiopathic... read more , pulmonary valvular or peripheral pulmonary artery stenosis, atrial septal defect Atrial Septal Defect (ASD) An atrial septal defect (ASD) is an opening in the interatrial septum, causing a left-to-right shunt and volume overload of the right atrium and right ventricle. Children are rarely symptomatic... read more and/or ventricular septal defect Ventricular Septal Defect (VSD) A ventricular septal defect (VSD) is an opening in the interventricular septum, causing a shunt between ventricles. Large defects result in a significant left-to-right shunt and cause dyspnea... read more , renal artery stenosis Renal Artery Stenosis and Occlusion Renal artery stenosis is a decrease in blood flow through one or both of the main renal arteries or their branches. Renal artery occlusion is a complete blockage of blood flow through one or... read more , aortic anomalies, elfin facies, and hypercalcemia of unknown pathophysiology; infants may also be small for gestational age Small-for-Gestational-Age (SGA) Infant Infants whose weight is the 10th percentile for gestational age are classified as small for gestational age. Complications include perinatal asphyxia, meconium aspiration, polycythemia, and... read more , and hypercalcemia can be noted early in infancy, usually resolving by age 12 months.
Idiopathic neonatal hypercalcemia is a diagnosis of exclusion and is difficult to differentiate from Williams syndrome and often requires genetic testing.
Symptoms and Signs of Neonatal Hypercalcemia
Symptoms and signs of neonatal hypercalcemia may be noted when total serum calcium is > 12 mg/dL (> 3 mmol/L). These signs can include anorexia, gastroesophageal reflux, nausea, vomiting, lethargy or seizures or generalized irritability, and hypertension. Other symptoms and signs include constipation, abdominal pain, dehydration, feeding intolerance, and failure to thrive. Some neonates have weakness. With subcutaneous fat necrosis, firm purple nodules may be observed on trunk, buttocks, or legs.
Diagnosis of Neonatal Hypercalcemia
Total or ionized serum calcium level
Diagnosis of neonatal hypercalcemia is made by measuring the total or ionized serum calcium level.
Treatment of Neonatal Hypercalcemia
IV normal saline plus furosemide
Sometimes corticosteroids, calcitonin, and bisphosphonates
Marked elevation of serum calcium may be treated with normal saline 20 mL/kg IV plus furosemide 2 mg/kg IV and, when persistent, with corticosteroids and calcitonin. Bisphosphonates are also increasingly used in this context (eg, etidronate by mouth or pamidronate IV). Treatment of subcutaneous fat necrosis is with a low-calcium formula; fluids, furosemide, calcitonin, and corticosteroids are used as indicated by the degree of hypercalcemia.
Fetal hypercalcemia caused by maternal hypoparathyroidism can be treated expectantly, because it usually resolves spontaneously within a few weeks.
Treatment of chronic conditions includes a low-calcium, low-vitamin D formula.