Bickerstaff's encephalitis
Encyclopedia
Bickerstaff's encephalitis is a rare inflammatory disorder of the central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...

, first described by Edwin Bickerstaff in 1951.
It may also affect the peripheral nervous system
Peripheral nervous system
The peripheral nervous system consists of the nerves and ganglia outside of the brain and spinal cord. The main function of the PNS is to connect the central nervous system to the limbs and organs. Unlike the CNS, the PNS is not protected by the bone of spine and skull, or by the blood–brain...

, and has features in common with both Miller Fisher syndrome and Guillain-Barré syndrome
Guillain-Barré syndrome
Guillain–Barré syndrome , sometimes called Landry's paralysis, is an acute inflammatory demyelinating polyneuropathy , a disorder affecting the peripheral nervous system. Ascending paralysis, weakness beginning in the feet and hands and migrating towards the trunk, is the most typical symptom...

.

Signs and symptoms

In order to diagnose Bickerstaff's encephalitis, ataxia
Ataxia
Ataxia is a neurological sign and symptom that consists of gross lack of coordination of muscle movements. Ataxia is a non-specific clinical manifestation implying dysfunction of the parts of the nervous system that coordinate movement, such as the cerebellum...

 and ophthalmoplegia must be present. These are also diagnostic features of Miller Fisher syndrome, and so Bickerstaff's is only diagnosed if other features are present which exclude Miller Fisher syndrome. These may include drowsiness, coma
Coma
In medicine, a coma is a state of unconsciousness, lasting more than 6 hours in which a person cannot be awakened, fails to respond normally to painful stimuli, light or sound, lacks a normal sleep-wake cycle and does not initiate voluntary actions. A person in a state of coma is described as...

 or hyperreflexia
Hyperreflexia
Hyperreflexia is defined as overactive or overresponsive reflexes. Examples of this can include twitching or spastic tendencies, which are indicative of upper motor neuron disease as well as the lessening or loss of control ordinarily exerted by higher brain centers of lower neural pathways...

. When the condition is defined in this way, a number of other features are commonly but not always found: among these are weakness of the limbs, the face, and/or the bulbar muscles; abnormalities of the pupils; and absent reflexes.
Like some other autoimmune disease
Autoimmune disease
Autoimmune diseases arise from an overactive immune response of the body against substances and tissues normally present in the body. In other words, the body actually attacks its own cells. The immune system mistakes some part of the body as a pathogen and attacks it. This may be restricted to...

s, the condition usually follows a minor infection, such as a respiratory tract infection
Respiratory tract infection
Respiratory tract infection refers to any of a number of infectious diseases involving the respiratory tract. An infection of this type is normally further classified as an upper respiratory tract infection or a lower respiratory tract infection...

 or gastroenteritis
Gastroenteritis
Gastroenteritis is marked by severe inflammation of the gastrointestinal tract involving both the stomach and small intestine resulting in acute diarrhea and vomiting. It can be transferred by contact with contaminated food and water...

.

Pathophysiology

The clinical features and course of the condition, the associated auto-antibodies against relevant antigens, and the response to treatment, all suggest that Bickerstaff's encephalitis is an autoimmune disease
Autoimmune disease
Autoimmune diseases arise from an overactive immune response of the body against substances and tissues normally present in the body. In other words, the body actually attacks its own cells. The immune system mistakes some part of the body as a pathogen and attacks it. This may be restricted to...

. However, each of these criteria fails to fit a substantial proportion of patients, and there is no single test or feature which is diagnostic of Bickerstaff's encephalitis. It is therefore possible that a proportion of cases are due to other causes, such as infection
Infection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...

 or lymphoma
Lymphoma
Lymphoma is a cancer in the lymphatic cells of the immune system. Typically, lymphomas present as a solid tumor of lymphoid cells. Treatment might involve chemotherapy and in some cases radiotherapy and/or bone marrow transplantation, and can be curable depending on the histology, type, and stage...

, but remain undiagnosed. It is also possible that there is more than one autoimmune disease that can cause an illness which would currently be diagnosed as Bickerstaff's. There is certainly overlap between Guillain-Barré syndrome
Guillain-Barré syndrome
Guillain–Barré syndrome , sometimes called Landry's paralysis, is an acute inflammatory demyelinating polyneuropathy , a disorder affecting the peripheral nervous system. Ascending paralysis, weakness beginning in the feet and hands and migrating towards the trunk, is the most typical symptom...

, Miller Fisher syndrome and Bickerstaff's encephalitis, as well as other conditions associated with anti-ganglioside antibodies
Anti-ganglioside antibodies
Anti-ganglioside antibodies that react to self-gangliosides are found in autoimmune neuropathies. These antibodies were first found to react with cerebellar cells...

 such as chronic ophthalmoplegia with anti-GQ1b antibody.
and the pharyngo-cervico-brachial variant of GBS.

Diagnosis

Anti-GQ1b antibodies are found in two-thirds of patients with this condition. This antibody is also found in almost all cases of Miller Fisher syndrome. The EEG
EEG
EEG commonly refers to electroencephalography, a measurement of the electrical activity of the brain.EEG may also refer to:* Emperor Entertainment Group, a Hong Kong-based entertainment company...

 is often abnormal, but shows only slow wave activity, which also occurs in many other conditions, and so is of limited value in diagnosis. Similarly, raised CSF
Cerebrospinal fluid
Cerebrospinal fluid , Liquor cerebrospinalis, is a clear, colorless, bodily fluid, that occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord...

 protein levels and pleocytosis are frequent but non-specific. It was originally thought that raised CSF protein without pleocytosis ('albuminocytological dissociation') was a characteristic feature, as it is in Guillain-Barré syndrome
Guillain-Barré syndrome
Guillain–Barré syndrome , sometimes called Landry's paralysis, is an acute inflammatory demyelinating polyneuropathy , a disorder affecting the peripheral nervous system. Ascending paralysis, weakness beginning in the feet and hands and migrating towards the trunk, is the most typical symptom...

, but this has not been supported in more recent work. In only 30% of cases is a MRI brain scan abnormal. Nerve conduction studies may show an axonal polyneuropathy
Polyneuropathy
Polyneuropathy is a neurological disorder that occurs when many peripheral nerves throughout the body malfunction simultaneously. It may be acute and appear without warning, or chronic and develop gradually over a longer period of time. Many polyneuropathies have both motor and sensory...

.

Treatment and prognosis

Most patients reported in the literature have been given treatments suitable for autoimmune neurological diseases, such as corticosteroids, plasmapheresis
Plasmapheresis
Plasmapheresis is the removal, treatment, and return of blood plasma from blood circulation. It is thus an extracorporeal therapy...

 and/or intravenous immunoglobulin
Intravenous immunoglobulin
Intravenous immunoglobulin is a blood product administered intravenously. It contains the pooled IgG extracted from the plasma of over one thousand blood donors. IVIG's effects last between 2 weeks and 3 months...

, and most have made a good recovery. The condition is too rare for controlled trials to have been undertaken.
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