Reversible posterior leukoencephalopathy syndrome

Posterior reversible encephalopathy syndrome (PRES) is a syndrome characterized by headache, confusion, seizures and visual loss. It may occur due to a number of causes, predominantly malignant hypertension, eclampsia and some medical treatments. On magnetic resonance imaging (MRI) of the brain, areas of edema (swelling) are seen. The symptoms tend to resolve after a period of time, although visual changes sometimes remain. It was first described in 1996. Posterior reversible encephalopathy syndrome (PRES) is a syndrome characterized by headache, confusion, seizures and visual loss. It may occur due to a number of causes, predominantly malignant hypertension, eclampsia and some medical treatments. On magnetic resonance imaging (MRI) of the brain, areas of edema (swelling) are seen. The symptoms tend to resolve after a period of time, although visual changes sometimes remain. It was first described in 1996. Typical symptoms of PRES, listed according to prevalence, include: altered mental status (encephalopathy), seizure, and headache. Less commonly there may be visual disturbances, focal neurologic signs, and status epilepticus. Several factors appear to play a role in the pathogenesis of PRES, including medications that suppress the function of the immune system (immunosuppressive e.g. cyclosporine, Tacrolimus), kidney failure, eclampsia, severe high blood pressure, systemic lupus erythematosus, and postpartum hemorrhage. The diagnosis is typically made clinically and supported with magnetic resonance imaging of the brain often revealing hyperintensities on T2-weighed imaging. Three patterns have been described: superior frontal sulcus, dominant parieto-occipital, and holohemispheric watershed. The treatment of PRES is dependent on its cause. Anti-epileptic medication may also be appropriate. Many cases resolve within 1–2 weeks of controlling blood pressure and eliminating the inciting factor. However some cases may persist with permanent neurologic impairment in the form of visual changes and seizures among others. Though uncommon, death may occur with progressive swelling of the brain (cerebral edema), compression of the brainstem, increased intracranial pressure, or a bleed in the brain (intracerebral hemorrhage). PRES may recur in about 5-10% of cases; this occurs more commonly in cases precipitated by hypertension as opposed to other factors (medications, etc.). The number of cases of PRES that occur each year is not known. It may be somewhat more common in females.