Leigh syndrome: serial MR imaging and clinical follow-up.

BACKGROUND AND PURPOSE Subacute necrotizing encephalomyelopathy, or Leigh syndrome (LS), is a progressive neurodegenerative disorder characterized by symmetrical spongiform lesions in the brain with onset usually in infancy or early childhood. Little is known of the developing process of the brain lesions in LS that are particularly relevant to the occurrence of fatal respiratory failure. Our purpose was to determine whether fatal respiratory failure can be predicted before death on the basis of clinical characteristics or findings on longitudinal MR images of the brain. METHODS Clinical records and serial MR studies of eight patients with LS aged 3 months to 12 years who met the diagnostic criteria for LS were reviewed retrospectively, with special reference to a correlation between loss of respiratory control and MR abnormalities. Both T1- and T2-weighted images were obtained at the onset of disease or when clinical symptoms worsened. RESULTS Serial MR images were divided into three groups on the basis of the following findings: 1) symmetrical basal ganglia lesions before brain stem involvement (n = 4); 2) initial involvement of the brain stem (n = 2); and 3) cerebral white matter lesions followed by brain stem lesions (n = 2). Lesions of the lower brain stem were always present when patients had near fatal respiratory failure. However, upper brain stem lesions were transient and were found in parallel to reversible respiratory disorder. Fatal respiratory failure was unpredictable from clinical or neuroradiologic findings. CONCLUSION Brain stem lesions are associated with the loss of respiratory control in patients with LS, but the time at which fatal respiratory failure will occur is unpredictable.