Subcutaneous fat necrosis in newborn—an unusual case and review of literature

Abstract

Subcutaneous fat necrosis (SCFN) of the newborn is an uncommon, self-limiting panniculitis mostly occurring within the first few weeks after birth. SCFN has been described mostly in term or post-term newborn infants in literature. We report a preterm infant developing extensive subcutaneous fat necrosis within the first week of life after significant perinatal hypoxic injury. The infant was conservatively managed for subcutaneous fat necrosis but developed hypercalcaemia and required prolonged medical treatment. Hypercalcaemia is a rare but serious complication of subcutaneous fat necrosis and needs prolonged follow-up. The etiopathogenesis of both subcutaneous fat necrosis in newborn and the resultant hypercalcaemia are poorly understood. Conclusion: Significant subcutaneous fat necrosis can develop in both preterm and term infants, and preterm infants also develop significant complications including hypercalcaemia.Keywords Subcutaneous fat necrosis of newborn . Hypercalcaemia . Perinatal hypoxia . Hypoglycaemia Case reportA male preterm infant weighing 2,300 g was born after a crash Caesarean section at a gestational age of 33+6 weeks. His mother presented with a foetal heart of 30/min and a history of reduced foetal movements for 24 h. The infant was born in poor condition (blue, floppy with no respiratory effort) and no heart rate was noted at birth. The infant needed full cardiopulmonary resuscitation till 4 min of age. First heart rate was detected at 2 min of age, and first gasping effort was noted at 9 min of age, The infant needed continued ventilatory support in view of poor respiratory effort. Apgar scores were 1 at 1 min and 5 at 5 min. Cord blood gases reflected severe combined respiratory and metabolic acidosis. He was ventilated for the first 24 h of life.He suffered from severe hypoxic ischaemic encephalopathy, and abnormal movements of both the upper extremities were noted from 11 h of age. In view of his prematurity, therapeutic hypothermia was not considered appropriate. He was treated with phenobarbitone for the first 6 days of life. He developed abnormal liver and renal functions and also developed severe hypoglycaemia requiring high concentration of dextrose infusion (25% dextrose) to maintain normoglycaemia (total fluid intake was restricted initially in view of severe hypoxic ischaemic encephalopathy (HIE)). Generalised hypertonia was noted very early in life. He developed large bilateral intraventricular haemorrhages which subsequently resulted in bilateral posthaemorrhagic hydrocephalus.He developed an erythematous rash over the dorsum of the chest, abdomen, and right arm which felt warm in comparison to the rest of the body on the third day of life. This developed into a sclerematous appearance by day 5. A punch biopsy of skin confirmed subcutaneous fat necrosis

Necrosis grasa subcutánea con hipercalcemia persistente en un neonato tratado con hipotermia terapéutica. Reporte de un caso

“…5,6 Se han sugerido factores genéticos predisponentes relacionados con dislipemia y trombofilia familiar. [7][8][9] Nuestro paciente presentaba varios factores de riesgo para NGS perinatales: hipoxia perinatal, tratamiento con hipotermia, trombocitopenia e hipoglucemia.…”

“…En la hipodermis, existe necrosis; los adipocitos contienen hendiduras en forma de agujas d i s p u e s t a s r a d i a l m e n t e , q u e s o n á c i d o s grasos cristalizados junto con células gigantes multinucleadas y formación de granulomas. 1,3,7 El diagnóstico diferencial debe realizarse, sobre todo, con esclerema neonatorum y paniculitis por frío.…”

“…Ambas, en muchos casos, preceden a la NGS, lo que hace pensar que son probablemente secundarias a la hipotermia. 7 La complicación más importante por su potencial gravedad es la hipercalcemia, presente en el 30%-69% de los casos, con mortalidad en torno al 15%. 8,11 Comienza entre las 2 y las 16 semanas, cuando la NGS empieza a mejorar.…”

“…13 La fisiopatología de la hipercalcemia se atribuye a una sobreproducción de 1,25-OH vitamina D extrarrenal aberrante, independiente de la paratohormona. La producción extrarrenal de 1,25-OH vitamina D está inducida por los macrófagos de granulomas inflamatorios localizados en las lesiones cutáneas, 7 y se observa, en estudios histológicos, un aumento de la expresión de alfa-1-hidroxilasa en el infiltrado inflamatorio de estas lesiones. 3,14 Esta enzima, habitualmente, se encuentra a nivel renal y metaboliza el precursor 25-OH vitamina D a 1,25-OH vitamina D en un proceso regulado por la paratohormona.…”

“…Los granulomas y la necrosis de adipocitos podrían liberar calcio. 7 Habitualmente, el nivel de paratohormona es normal.…”