Acute leukoencephalopathies: Differential diagnosis and investigation

BACKGROUND- Acute and subacute leukoencephalopathies of the CNS result in neurological deficits that are attributable to dysfunction of the white- matter tracts or that involve primarily white matter on magnetic resonance neuroimaging. The differential diagnosis is broad. REVIEW SUMMARY - We review the differential diagnosis and clinical approach to acute leukoencephalopathies based on the setting in which they occur and their clinical and radiological features. We discuss specific features that should lead one to search for a cause other than an idiopathic inflammatory demyelinating disease of the CNS. We examine the spectrum of the inflammatory demyelinating diseases of the CNS and how clinical, imaging, and pathological studies can be used to differentiate among these entities. CONCLUSIONS - Evaluation of the leukoencephalopathies requires a broad knowledge of the differential diagnosis and spectrum of the idiopathic inflammatory demyelinating diseases. Brain biopsy, when supported by experienced neuropathological interpretation, can often assist in the diagnostic process.