‘Destructive encephalopathy in incontinentia pigmenti'

SIR–Destructive encephalopathy is a rare complication of incontinentia pigmenti in infants, characterized by haemorrhagic necrosis of the brain.1, 2 The pathogenesis is not fully understood but, as with the other neurological symptoms associated with incontinentia pigmenti, a vascular aetiology is suspected.3, 4 We present a neonate with haemorrhagic necrosis secondary to incontinentia pigmenti whose magnetic resonance angiogram (MRA) supported a vascular origin for her symptoms. Written patient consent was obtained from parents for publication of the report and images. A female infant was born at term by normal vaginal delivery to a Caucasian English mother and Gambian father. She developed a pigmented rash on day 2 of life and was unrousable the following morning. On admission to hospital she was hypothermic (34.8°C), with a central capillary refill time of 3 seconds. She was encephalopathic, hypotonic, with no suck or gag reflexes, and had clonus in both ankles. There was no other significant finding She subsequently developed right-sided clonic seizures, successfully treated with phenobarbital. Basic investigations were normal, including blood and cerebrospinal fluid cultures. On day 3 her rash was darker and vesicular. Incontinentia pigmenti was diagnosed, and genetic testing subsequently confirmed she had the common deletion in the NEMO gene. Magnetic resonance imaging of her brain on day 6 showed 'blooming', indicative of petechial haemorrhage within areas of infarction (Fig. 1). The features were consistent with haemorrhagic necrosis secondary to incontinentia pigmenti. MRA demonstrated small, attenuated arteries involving the middle and posterior cerebral artery branches (Fig. 2). Following the onset of her encephalopathy, she made no forward progress and developed West syndrome with intractable seizures. She died aged 11 months. Axial T2 fast spin echo (left) and axial field echo T2* showing scattered areas of abnormal signal in basal ganglia and the white matter representing 'blooming', indicative of petechial haemorrhage within areas of infarction. Towne's projection of a time of flight magnetic resonance angiogram displaying attenuation of the cerebral arteries, particularly on the left. Acute encephalopathy with haemorrhagic necrosis is a rare complication of incontinentia pigmenti in infants.1, 2 The pathogenesis is not fully understood. Light and electron microscopy of the brain parenchyma are normal in children with this condition, with some eosinophils and macrophages being present but no firm evidence of inflammation.2 MRA findings in an infant with this condition have only been reported once before, demonstrating small intracerebral vessels with poor filling of the distal middle and posterior cerebral artery branches.1 Our abnormal MRA findings confirm these findings, supporting a vascular origin for neurological symptoms in incontinentia pigmenti. We wish to thank Dr Peter Baxter for his help and support in preparing this manuscript. Dr Hart's post is funded by a grant from the Jessop Baby Fund.