Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is a heterogeneous group of autoimmune polyradiculopathies, involving sensory, motor, and autonomic nerves. It is the most common cause of rapidly progressive flaccid paralysis. It is believed to be one of a number of related conditions, sharing a similar underlying autoimmune abnormality.

Epidemiology

Most cases are preceded by upper respiratory tract infections or diarrhea one to three weeks before their onset, most commonly caused by Campylobacter jejuni (25-40% of patients are seropositive) ^1,3. Molecular mimicry with the bacterial agents is thought to cause the autoimmunity with the development of anti-GQ1b IgG antibodies. 

Other predisposing factors include recent surgery, lymphoma, and systemic lupus erythematosus (SLE) ². The relationship between the administration of COVID-19 vaccines and the onset of Guillain-Barré syndrome is unclear ⁹.

Clinical presentation

The classical presentation of Guillain-Barré syndrome includes symmetrical ascending weakness, areflexia/hyporeflexia, and variable sensory or autonomic involvement.

Several subtypes have been described, including:

• acute inflammatory demyelinating polyradiculoneuropathy (AIDP)

  • most common form (60-90%) and is often used synonymously with Guillain-Barré syndrome

• axonal subtypes

  • acute motor axonal neuropathy (AMAN) (historically Chinese paralytic syndrome)

  • acute motor-sensory axonal neuropathy (AMSAN)

    • both axonal subtypes are thought to be due to antibodies to gangliosides which result in macrophages invading the axons at the nodes of Ranvier ³

• regional GBS syndromes

  • Miller Fisher syndrome (MFS/MFV)

    • characterized by ataxia, ophthalmoplegia, and areflexia without weakness

    • anti-GQ1b antibodies are present in most cases

  • polyneuritis cranialis ⁶

Cerebrospinal fluid (CSF) abnormalities are characterized by increased protein without pleocytosis (i.e. albuminocytologic dissociation), which is a non-specific finding, seen in many of the conditions which mimic Guillain-Barré syndrome clinically and on imaging ^1,2.

Nerve conduction abnormalities include slow or blocked nerve conduction, prolongation of distal motor latencies and and F-waves.

Radiographic features

Radiological studies are requested to exclude other causes and in cases where nerve conduction studies and CSF examination are equivocal. MRI of the spine is most useful, helping to exclude other etiologies, such as transverse myelitis and compressive causes of polyradiculopathy.

MRI

It is essential that contrast is administered if the diagnosis is suspected as non-contrast sequences are essentially normal ².

Typical findings in Guillain-Barré syndrome are thickening and contrast enhancement of the spinal nerve roots, especially in the region of the cauda and conus medullaris ².

The most common site of enhancement in Guillain–Barré syndrome is considered to be anterior nerve roots, although enhancement of the posterior nerve roots is also seen ².

In the brain, the facial nerve (CN VII) is the most commonly affected cranial nerve ¹.

Treatment and prognosis

Guillain-Barré syndrome is primarily managed with IV immunoglobulin or plasmapheresis along with supportive measures, which can speed up recovery ¹. Typically improvement occurs after a number of weeks to months ¹ although there is significant mortality (3-10%) ⁵.

History and etymology

The syndrome was named after Georges Charles Guillain (1876-1961) and Jean Alexandre Barré (1880-1967), French neurologists. André Strohl (1887-1977), a French physiologist, worked together with both neurologists and is the third author in the description done in 1916, and for this reason, the syndrome is also referred to as Guillain-Barré-Strohl syndrome.

Differential diagnosis

The differential is essentially that of nerve root/cauda equina enhancement: 

• AIDS-related polyradiculopathy

• arachnoiditis from any cause (e.g. postoperative, or post intrathecal injection)

• neurosarcoidosis

• leptomeningeal carcinomatosis and lymphoma

• chronic inflammatory demyelinating polyneuropathy (CIDP)

  • acute presentation of CIDP can be similar to GBS

  • difficult to differentiate in the first 6 weeks

  • after 6-8 weeks GBS should be improving whereas CIDP will demonstrate chronic inflammation ⁴

• Lyme disease ⁷

• rabies encephalitis (paralytic variant): similar presentation, but more fulminant course resulting in rapid demise in almost all cases