Encéphalite du tronc cérébral de Bickerstaff

Bickerstaff's brainstem encephalitis (BBE) is an immune disorder of unknown aetiology. It is characterised by:

• Acute, progressive cranial nerve dysfunction.

• Associated cerebellar ataxia.

• Coma.

There is a clinical continuum between BBE and Fisher's syndrome¹.

Bickerstaff reported eight patients who, in addition to acute ophthalmoplegia (diplopia) and ataxia, showed drowsiness, extensor plantar responses or hemisensory loss².

Épidémiologie

• It is very rare and mostly reported in adults; however, cases affecting children have also been reported³.

• Very often it follows an illness, and an association with certain infections, including cytomegalovirus, Campylobacter jejuni, typhoid fever and Mycoplasma pneumoniae, has been documented⁴⁵⁶.

Présentation

• Acute diplopia.

• Ataxie.

• Pyramidal tract paralysis.

• Trouble de la conscience.

• Headache is common.

• Progressive, symmetrical ophthalmoplegia, ataxia and either disturbance of consciousness or hyperreflexia.

• Facial palsy, extensor plantar reflex, pupillary abnormality, nystagmus and bulbar palsy.

• It may result in apnoea and a reversible brain death picture.

Diagnostic différentiel⁷

Sclérose en plaques.
Maladie de Behçet.
maladie de Lyme.
Progressive multifocal leukoencephalopathy.
Sarcoïdose.
Maladie de Whipple.
Listeria rhombencephalitis.
Vasculitis due to lupus érythémateux systémique (LES).
Acute disseminated encephalomyelitis.

Enquêtes

• One review of 62 patients found positive serum anti-GQ1b immunoglobulin G (IgG) antibody in 66%, and brain abnormality on MRI scan in 30% of patients⁴⁸.

• The presence of anti-GQ1b antibodies and an abnormal brain MRI scan can help to support its diagnosis but absence of anti-GQ1b antibodies and a normal MRI scan result do not exclude the diagnosis, which remains based on clinical criteria and exclusion of other aetiologies⁹.

• Electrodiagnostic study results suggested peripheral motor axonal degeneration.

Maladies associées

• A large number of patients have associated Guillain-Barré syndrome, suggesting that the two disorders are closely related⁸.

• Miller Fisher's syndrome (ophthalmoplegia, ataxia and absent reflexes)¹⁰.

Gestion

Success has been achieved with treatment with steroids plus double filtration plasmapheresis¹¹. It has also been achieved with immunoglobulin therapy¹². However, there are no randomised controlled trials of immunomodulatory therapy¹³.

Pronostic

Although the initial presentation is severe, there is usually a good outcome with complete resolution¹⁴. Cases of recurrent BBE have been reported⁹.