Posterior leucoencephalopathy syndrome

Overview
Posterior leukoencephalopathy syndrome is a newly recognized neurologic disorder that affects the cerebral white matter.

Pathophysiology
The syndrome consists of edematous lesions that involve the posterior parietal and occipital lobes, and may spread to basal ganglia, brain stem, and cerebellum.

Diagnosis
Signs and symptoms of the syndrome evolve rapidly.

Symptoms
Headache, nausea and vomiting, seizures, visual disturbances, altered sensorium, and occasionally focal neurological deficit.

Signs
Abrupt onset of hypertension is usually seen in patients with eclampsia, renal disease, and hypertensive encephalopathy. It is also seen in the patients treated with cytotoxic and immunosuppressive drugs such as cyclosporin, tacrolimus, and alpha interferon.

MRI
The lesions of posterior leukoencephalopathy are best visualised with magnetic resonance (MR) imaging. T2 weighted MR images, at the height of symptoms, characteristically show diffuse hyperintensity selectively involving the parieto-occipital white matter. Occasionally the lesions also involve the grey matter.

CT
Computed tomography can also be used satisfactorily to detect hypodense lesions of posterior leukoencephalopathy.

Treatment
Early recognition of this condition is important because prompt control of blood pressure or withdrawal of immunosuppressive agents may reverse the syndrome. Delay in the diagnosis and treatment can result in permanent damage to affected brain tissues.