Pamidronate as first-line treatment of hypercalcemia in neonatal subcutaneous fat necrosis: A case series

Use of Calcitonin for Hypercalcemia in a Premature Neonate With Congenital Mesoblastic Nephroma

We report on a premature neonate (31 4/7 weeks' gestation) who presented with hypercalcemia secondary to congenital mesoblastic nephroma (CMN), the most common type of renal tumor in neonates. Typical presentation includes a palpable abdominal mass or swelling and may include abdominal pain, hematuria, fever, or hypertension. A less common complication of CMN is hypercalcemia of malignancy. Although the primary management strategy for hypercalcemia of malignancy is to treat the underlying disease, there are several agents that can be used as well for acute hypercalcemia including fluids, loop diuretics, corticosteroids, bisphosphonates, and calcitonin. However, there is minimal evidence to guide efficacious and safe treatment selection and dosing as hypercalcemia is a rare complication of this tumor type. This case adds to the current body of literature as only the second case of parathyroid hormone-related peptide-mediated hypercalcemia in a preterm neonate treated with calcitonin and is the first to specify a successful dose escalation strategy of calcitonin for this indication.

Genetic causes of neonatal and infantile hypercalcaemia

The causes of hypercalcaemia in the neonate and infant are varied, and often distinct from those in older children and adults. Hypercalcaemia presents clinically with a range of symptoms including failure to thrive, poor feeding, constipation, polyuria, irritability, lethargy, seizures and hypotonia. When hypercalcaemia is suspected, an accurate diagnosis will require an evaluation of potential causes (e.g. family history) and assessment for physical features (such as dysmorphology, or subcutaneous fat deposits), as well as biochemical measurements, including total and ionised serum calcium, serum phosphate, creatinine and albumin, intact parathyroid hormone (PTH), vitamin D metabolites and urinary calcium, phosphate and creatinine. The causes of neonatal hypercalcaemia can be classified into high or low PTH disorders. Disorders associated with high serum PTH include neonatal severe hyperparathyroidism, familial hypocalciuric hypercalcaemia and Jansen's metaphyseal chondrodysplasia. Conditions associated with low serum PTH include idiopathic infantile hypercalcaemia, Williams-Beuren syndrome and inborn errors of metabolism, including hypophosphatasia. Maternal hypocalcaemia and dietary factors and several rare endocrine disorders can also influence neonatal serum calcium levels. This review will focus on the common causes of hypercalcaemia in neonates and young infants, considering maternal, dietary, and genetic causes of calcium dysregulation. The clinical presentation and treatment of patients with these disorders will be discussed.

Subcutaneous Fat Necrosis and Hypercalcemia with Nephrocalcinosis in Infancy: Case Report and Review of the Literature

Subcutaneous fat necrosis is an uncommon benign panniculitis affecting more commonly full-term newborns. It has been associated with birth asphyxia and meconium aspiration, as well as therapeutic hypothermia. Although the prognosis is generally favorable, complications such as hypercalcemia, thrombocytopenia, hypoglycemia and hypertriglyceridemia may complicate its course. The most serious complication is hypercalcemia that may reach life threatening levels and can be associated with nephrocalcinosis. We thereby describe a case of subcutaneous fat necrosis after therapeutic hypothermia, which presented with late-onset refractory severe hypercalcemia and persistent nephrocalcinosis during the follow up of the patient. Due to the risk of the development of chronic kidney disease, we highlight the importance of careful monitoring of hypercalcemia and review the literature of subcutaneous fat necrosis related to nephrocalcinosis.