RESUMO
Isovaleric acidemia (IVA) is an inborn error of branched chain amino acid metabolism that may manifest as acute neonatal metabolic acidosis or as chronic intermittent form with developmental delay or recurrent episodes of acute metabolic acidosis. Early diagnosis is the key to prevent morbidity and mortality. Brain imaging abnormalities are rarely described in IVA. We report a case of chronic intermittent IVA with acute presentation in a 4-month-old infant who presented with acute metabolic acidosis. Brain magnetic resonance imaging (MRI) revealed symmetric signal intensity changes in bilateral lentiform nuclei with an unreported T1-weighted (T1W) symmetric hyperintense ring-like appearance in bilateral putamen.
RESUMO
BACKGROUND: Thiamine deficiency in infants is still encountered in developing countries. It may present with acute neurological manifestations of infantile encephalitic beriberi. OBJECTIVE: To review brain MRI findings in infantile encephalitic beriberi from a single institution. MATERIALS AND METHODS: A retrospective review of MRI scans in 22 infants with acute-onset beriberi encephalopathy was carried out. RESULTS: Hyperintense lesions on T2-weighted images were seen symmetrically in the putamen in all patients, in the caudate nuclei in 16/22 (73%), the thalami in 7/22 (32%) and the globi pallidi in 3/22 (14%) of the infants. Altered signal intensity lesions in the cerebral cortex were seen in 7/22 (32%). The mammillary bodies were seen in one infant and the periaqueductal gray matter in two. There was restricted diffusion in 14/22 (64%), and 6/8 children with no evidence of restriction had been imaged ≥10 days after presentation. MR spectroscopy showed increased lactate peak in 6/8 infants (75%). CONCLUSION: Recognition of symmetrical T2-W hyperintense lesions in the basal ganglia with restricted diffusion and prominent lactate peak may allow early diagnosis of encephalitic beriberi in at-risk infants.
