Bickerstaff brainstem encephalitis

Bickerstaff Brainstem Encephalitis (BBE) is a rare inflammatory disorder of the central nervous system, primarily affecting the brainstem and occasionally extending to the cerebellum and cerebrum. It is characterized by acute onset of diplopia (double vision), ataxia (lack of muscle coordination), and areflexia (absence of neurologic reflexes), closely resembling Guillain-Barré syndrome (GBS), with which it shares several immunological features. The condition is named after Edwin Bickerstaff, a British neurologist who first described the syndrome in 1951.

Symptoms and Signs

BBE presents with a distinctive clinical triad:

• Diplopia: This results from paresis of one or more of the six cranial nerves that control eye movement.
• Ataxia: Patients may experience unsteadiness and coordination problems due to involvement of the brainstem and cerebellum.
• Areflexia: The absence or decrease of reflexes is a common feature, similar to that observed in Guillain-Barré syndrome.

Additional symptoms may include altered consciousness, ranging from drowsiness to coma, and long-tract signs such as spasticity and hyperreflexia. Facial weakness, bulbar palsy, and sensory disturbances may also occur.

Etiology

The exact cause of BBE is not fully understood, but it is believed to be an autoimmune disorder triggered by a preceding viral or bacterial infection. The immune system mistakenly attacks the body's own tissues, specifically targeting the myelin sheath of the nerves in the brainstem. This demyelination disrupts normal nerve signal transmission. Several pathogens, including Campylobacter jejuni, Cytomegalovirus (CMV), Epstein-Barr virus (EBV), and Mycoplasma pneumoniae, have been associated with the onset of BBE.

Diagnosis

Diagnosis of BBE is primarily clinical, based on the characteristic symptom triad and supported by findings from magnetic resonance imaging (MRI) of the brain, which may show hyperintense lesions in the brainstem. Lumbar puncture (spinal tap) can reveal albuminocytological dissociation (elevated protein with normal white cell count) in the cerebrospinal fluid (CSF), similar to that seen in Guillain-Barré syndrome. Electrophysiological studies may show evidence of demyelination.

Treatment

Treatment of BBE is largely supportive, focusing on managing symptoms and complications. In severe cases, immunotherapies such as intravenous immunoglobulin (IVIG) or plasmapheresis (plasma exchange) may be used to reduce the severity and duration of the illness by removing or diluting the antibodies that are attacking the nervous system.

Prognosis

The prognosis for patients with Bickerstaff Brainstem Encephalitis is generally good, with most patients making a full recovery. However, the recovery period can vary, ranging from a few weeks to several months. Some patients may experience residual symptoms, such as mild ataxia or weakness.

Epidemiology

BBE is a rare condition, with a poorly defined incidence due to its rarity and overlap with other neurological disorders such as Guillain-Barré syndrome. It affects males and females equally and can occur at any age, although it is most commonly reported in adults.

See Also

• Guillain-Barré syndrome
• Miller Fisher syndrome
• Encephalitis

External Links

• National Center for Biotechnology Information - Bickerstaff Brainstem Encephalitis