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

Background: Subcutaneous fat necrosis (SCFN) can be complicated by severe hypercalcemia, which is frequently asymptomatic. Nephrocalcinosis is associated with hypercalcemia and, in other clinical settings, has been linked to furosemide and glucocorticoid use. First-line bisphosphonate therapy treating hypercalcemia in neonatal SCFN is not well described.

Objectives: To describe the biochemical changes and risk of nephrocalcinosis in infants with hypercalcemia, secondary to neonatal SCFN, treated with initial pamidronate.

Methods: A retrospective chart review of five infants treated with initial pamidronate and without furosemide or glucocorticoids. Data were collected on the following: timing of presentation, therapeutic response, and presence of nephrocalcinosis.

Results: Hypercalcemia resolved after 2.8±1.7 days; this is compared to 7.6±2.8 days from previously reported cases utilising alternative therapies (P=0.012). There were no episodes of rebound hypercalcemia or hypocalcemia. Nephrocalcinosis was present in four of five cases. When including published cases, age at diagnosis was associated with presenting serum calcium (P=0.003) and nephrocalcinosis was associated with higher serum calcium (P=0.014) and time from SCFN to hypercalcemia diagnosis (P=0.002).

Conclusions: This retrospective case series demonstrates that first-line pamidronate treatment was effective and safe in the resolution of hypercalcemia. Nephrocalcinosis was observed, despite the avoidance of furosemide and glucocorticoid therapy, and associated with greater disease severity and duration of hypercalcemia.