Guillain-Barré syndrome classification


 * Associate Editors-In-Chief: Priyamvada Singh, MBBS [mailto:psingh@perfuse.org]

Overview
Guillain-Barré syndrome (GBS) is an acute, autoimmune, polyradiculoneuropathy affecting the peripheral nervous system, usually triggered by an acute infectious process. It is included in the wider group of peripheral neuropathies. There are several types of GBS, but unless otherwise stated, GBS refers to the most common form, acute inflammatory demyelinating polyneuropathy (AIDP). It is frequently severe and usually exhibits as an ascending paralysis noted by weakness in the legs that spreads to the upper limbs and the face along with complete loss of deep tendon reflexes. The other less common variants involve Miller Fisher syndrome, Acute motor axonal neuropathy (AMAN), Acute motor sensory axonal neuropathy(AMSAN), Acute panautonomic neuropathy, and Bickerstaff's brainstem encephalitis (BBE)

Acute inflammatory demyelinating polyneuropathy
===Acute motor axonal neuropathy (AMAN) ===
 * Commonest form of GBS, and the term is often used synonymously with GBS.
 * Caused by an auto-immune response directed against Schwann cell membranes.
 * Commonly preceded by a bacterial or viral infection.
 * Campylobacter jejuni is the commonest causative agent (positive in approximately 2 out of 5 patients).
 * Peripheral nerve demyelination is present. Symptoms generally resolve with remyelination.
 * Also known as Chinese paralytic syndrome
 * Prevalent in China and Mexico.
 * The disease may have seasonal variations.
 * Recovery can be rapid.
 * Due to auto-immune response directed against the axoplasm and nodes of Ranvier of peripheral nerves.
 * Anti-GD1a antibodies are present. Anti-GD3 antibodies are commonly found associated with it.

Acute motor sensory axonal neuropathy''' (AMSAN)

 * It is similar to AMAN however unlike AMAN it also affects sensory nerves.
 * It is probably due to an auto-immune response directed against the axoplasm of peripheral nerves.
 * Recovery is slow and often incomplete.

Pure sensory

 * Rapid onset of sensory loss and areflexia in a symmetric pattern.
 * Lumbar puncture studies show albuminocytologic dissociation as seen with other GBS
 * Electromyography show characteristic signs of a demyelination.
 * Prognosis is usually good.

Miller Fisher syndrome

 * Accounts for approximately 5% of GBS cases
 * Unlike Acute inflammatory demyelinating polyneuropathyit manifests as a descending paralysis
 * It usually affects the eye muscles first and presents with the triad of ophthalmoplegia (external), ataxia, and areflexia.
 * The ataxia predominantly affects the gait and trunk, with the limbs relatively spared.
 * Anti-GQ1b antibodies are present in 90% of cases.

Acute panautonomic neuropathy

 * Most rare variant of GBS
 * Prognosis may be poor because of its association with encephalopathy and cardiovascular involvement, and associated dysrhythmias.
 * Initial symptoms of lethargy, fatigue, headache can be present.
 * Common symptoms include impaired sweating, lack of tear formation, photophobia, dryness of nasal and oral mucosa, itching and peeling of skin, nausea, dysphagia, and constipation or alternating with diarrhea.
 * Autonomic symptoms like orthostatic hypotension, lightheadedness, blurring of vision, abdominal pain, diarrhea, dryness of eyes, and disturbed micturition can be seen.
 * Parasympathetic impairment (abdominal pain, vomiting, constipation, ileus, urinary retention, dilated unreactive pupils, loss of accommodation) may also be observed.

Bickerstaff's brainstem encephalitis (BBE)

 * Another rare variant of GBS
 * Associated with acute onset ophthalmoplegia, ataxia, disturbance of consciousness, hyperreflexia or Babinski's sign. * It can have monophasic or remitting-relapsing progression.
 * Neuroimaging with Magnetic resonance imaging (MRI) plays a critical role in the diagnosis.
 * Large, irregular hyperintense lesions located mainly in the brainstem, especially in the pons, midbrain and medulla can be seen.
 * Prognosis is good despite the initial severe presentation
 * It is commonly found associated with axonal Guillain–Barré syndrome suggesting some linking between the two disorders