The cause of Rasmussen's encephalitis remained a big medical mystery for several years. Early research seemed to indicate viral causes, but no organism was consistently found in the brains of afflicted patients. In the early 1990s, a breakthrough in research was achieved - Rasmussen's encephalitis was found to be an autoimmune disease, a disorder in which the body is attacked by its own immune system.
Also known as Chronic Focal Encephalitis (CFE), Rasmussen's encephalitis is a rare, progressive neurological disorder affecting a single cerebral hemisphere and usually occurring in children under the age of ten.
The sudden onset of epileptic seizures in childhood and the progressive worsening of such seizures often lead to a diagnosis of Rasmussen's encephalitis. Other diagnostic signs include gradual mental deterioration as well as the onset of hemiparesis and other one-sided symptoms.
Rasmussen's encephalitis first manifests in childhood with the onset of epileptic seizures. Later, symptoms progress to one-sided paralysis of the body (hemiparesis), blindness of one eye (hemianopsia), inflammation of the brain (encephalitis), dementia, and ultimately, mental deterioration.
Surgical intervention is often required to disconnect or remove the affected cerebral hemisphere. This procedure is known as hemispherectomy. Initially, anti-epileptic drugs may be prescribed, but pharmaceutical treatment is rarely effective in controlling the seizures. Alternative forms of treatment include the removal and reinfusion of blood plasma (a process known as plasmapheresis), administering immunoglobulin intravenously, imposing a ketogenic diet (high fat, low carbohydrate), and administering steroids.