Images in paediatrics: subcutaneous fat necrosis causing radial nerve palsy.

1 of 2 DESCRIPTION A baby boy was born at term by forceps extraction following uneventful pregnancy. The baby did not require resuscitation at birth. On routine postnatal check, it was noticed that the baby had left-sided wrist drop ( fi gure 1 ). An area of palpable subcutaneous nodules with some erythema was identifi ed over the lower part of left arm ( fi gure 2 ). It was thought to be subcutaneous fat necrosis which had most likely caused radial nerve palsy. There were no associated signs suggested for brachial plexus injury. There was good fl exion at the elbow and normal movements at shoulder. There was no evidence of fracture in the upper limb on x-ray. He received physiotherapy in the form of splinting and passive movements to prevent secondary contractures. After 4 weeks, he started showing some minimal extension of the fi ngers. The skin over the area of fat necrosis was desquamated. At his 10 week follow-up, his left arm seemed completely recovered. He had full range of movements. There is limited literature available relating radial nerve palsy secondary to subcutaneous fat necrosis. It is thought to be due to intrauterine pressure effect and almost universally there is a good recovery. 1 The actual incidence of radial nerve injury may be greater as a few cases are misinterpreted as mild Klumpke’s palsies. 2 Postnatal subcutaneous fat necrosis is found to be possible side effect of whole body cooling in cases of birth asphyxia. 3 Images in...