Biotin-responsive basal ganglia disease revisited: clinical, radiologic, and genetic findings.

OBJECTIVE: To investigate the clinical, genetic, and neuroradiologic data of biotin-responsive basal ganglia disease (BBGD) and clarify the disease spectrum. METHODS: We first investigated all patients attending our Division of Pediatric Neurology with a genetically proven diagnosis of BBGD between 2009 and 2011. All patients underwent a detailed medical history and clinical examination, extensive laboratory investigations including genetic tests, and brain MRI. Finally, we conducted a systematic review of the literature. RESULTS: We enrolled 10 patients meeting the diagnostic criteria for BBGD, and analyzed the data on 14 patients from 4 previous reports. The BBGD occurred predominantly in preschool/school-aged patients in the Saudi population, but it was also observed in other ethnic groups. The typical clinical picture consisted of recurrent subacute encephalopathy leading to coma, seizures, and extrapyramidal manifestations. The brain MRI typically showed symmetric and bilateral lesions in the caudate nucleus and putamen, infra- and supratentorial brain cortex, and in the brainstem. Vasogenic edema characterized the acute crises as demonstrated by diffusion-weighted imaging/apparent diffusion coefficient MRI. Atrophy and gliosis in the affected regions were observed in patients with chronic disease. Early treatment with a combination of biotin and thiamine resulted in clinical and neuroradiologic improvement. Death and neurologic sequelae including dystonia, mental retardation, and epilepsy were observed in those who were not treated or were treated late. CONCLUSION: BBGD is an underdiagnosed pan-ethnic treatable condition. Clinicians caring for patients with unexplained encephalopathy and neuroimaging showing vasogenic edema in the bilateral putamen and caudate nuclei, infra- and supratentorial cortex, and brainstem should consider this disorder early in the hospital course because a therapeutic trial with biotin and thiamine can be lifesaving.

Acute necrotizing encephalopathy associated with enterovirus infection.

Acute necrotizing encephalopathy is a rare, clinically distinct entity of acute encephalopathy triggered by acute febrile diseases, mostly viral infections. It is postulated to arise from uncontrolled cytokine release during a febrile illness, and is most often seen in East Asia. We describe a rare Saudi patient of acute necrotizing encephalopathy attributable to enterovirus in a 4 years and 6 months old girl. A work-up revealed elevations in serum and cerebrospinal fluid interleukin-6 and tumor necrosis factor-α. The outcome on intravenous pulse methylprednisolone was good. This case is the first, to the best of our knowledge, of acute necrotizing encephalopathy reported from Saudi Arabia with a good outcome despite severe magnetic resonance imaging findings and delay in the steroid treatment.