Posterior leukoencephalopathy syndrome

Posterior leukoencephalopathy syndrome is a newly recognised brain disorder that predominantly affects the cerebral white matter. Oedematous lesions p articularly involve the posterior parietal and occipital lobes, and may spr ead to basal ganglia, brain stem, and cerebellum. This rapidly evolving neu rological condition is clinically characterised by headache, nausea and vom iting, seizures, visual disturbances, altered sensorium, and occasionally f ocal neurological deficit. Posterior leukoencephalopathy syndrome is often associated with an abrupt increase in blood pressure and is usually seen in patients with eclampsia, renal disease, and hypertensive encephalopathy. I t is also seen in the patients treated with cytotoxic and immunosuppressive drugs such as cyclosporin, tacrolimus, and interferon alfa. The lesions of posterior leukoencephalopathy are best visualised with magnetic resonance (MR) imaging. T2 weighted MR images, at the height of symptoms, characteris tically show diffuse hyperintensity selectively involving the parieto-occip ital white matter. Occasionally the lesions also involve the grey matter. C omputed tomography can also be used satisfactorily to detect hypodense lesi ons of posterior leukoencephalopathy. Early recognition of this condition i s of paramount importance because prompt control of blood pressure or withd rawal of immunosuppressive agents will cause reversal of the syndrome. Dela y in the diagnosis and treatment can result in permanent damage to affected brain tissues.