Is Therapeutic Hypothermia Real Cause of Subcutaneous Fat Necrosis in Newborns?

Abstract

Sir,We read with great interest the article by Sivanandanet al. [1], who reported subcutaneous fat necrosis (SFN)in a newborn suffering from perinatal asphyxia who wastreated with total body cooling. In their report [1], it issuggested that therapeutic body cooling increases the riskof SFN and renal complications. Recently, we reported acase of SFN, which was complicated by hypercalcemia,due to perinatal hypoxic injury [2]. Unlike case of Siva-nandan et al. [1], our patient did not undergo hypothermiatherapy. Hence, we would like to make some comments ontheir report.Firstly, the authors have reported that as if SFN is mainlycaused by therapeutic hypothermia in newborns. It should beemphasized that neonatal SFN is primarily caused by someperinatal conditions such as birth asphyxia, cord accidents,meconium aspiration [1, 2], but therapeutic hypothermia mayfacilitate this process [3]. Therefore, in the reported case, itseems likely that SFN has been caused by perinatal asphyxiasecondary to abruptio placenta. Hence, title of the article“Subcutaneous fat necrosis as a complication of therapeutichypothermia in a term neonate” is not consistent with thereported case.Secondly, therapeutic hypothermia may cause renal dam-age [4]. However, hypoxic-ischemic injury itself is the maincause of renal injury in these cases.Thirdly, in the present case, the skin lesions have beenreported only in areas where the skin was in contact with thecooling blanket [1]. Actually, in SFN, erythematous nodulesand plaques are mainly located over bony prominences suchas the back, thighs, arms and buttocks [2, 5]. Therefore, it iscontroversial whether total body cooling treatment is themajor risk factor of SFN in the reported case.In conclusion, SFN of the newborn is a disorder of theadipose tissue, mostly affecting full-term or post-terminfants who experience perinatal distress. Nevertheless,though perinatal hypoxic-ischemic event is the real causeof SFN, hypothermia may facilitate its occurrence. In addi-tion, the patients with SFN should be closely monitored fordeveloping other problems like renal complications relatedto hypoxic-ischemic injury.References