Guillain-Barré Syndrome (GBS) is an acute polyradiculoneuropathy characterized by rapidly progressive, symmetrical weakness of the extremities, often following an infectious event
Pathophysiology
- The pathogenesis of GBS involves molecular mimicry of pathogen-borne antigens, leading to the generation of cross-reactive antibodies that also target gangliosides
- The subtype and severity of the syndrome are partly determined by the nature of the antecedent infection and specificity of such antibodies
Clinical course
- GBS typically presents with progressive, relatively symmetrical weakness with decreased or absent myotatic reflexes, reaching maximal intensity within 4 weeks of onset
- About 25% of patients develop respiratory insufficiency, and many show signs of autonomic dysfunction
- The disease course is usually monophasic, with disease nadir reached within 2 weeks in 80% of patients, within 4 weeks in 97%, and within 6 weeks in all patients
Prognosis
- The prognosis of GBS can be assessed using the modified Erasmus GBS Outcome Score, recognizing that the risk of being unable to walk unaided after 4 and 26 weeks is increased in older patients, patients with preceding diarrhea/gastroenteritis, and in patients with higher GBS Disability Score grade or severe limb weakness at hospital admission
- Despite medical treatment, GBS often remains a severe disease; 3–10% of patients die, and 20% are still unable to walk after 6 months
Risk factors
- GBS is usually triggered by infections, and its incidence can increase during outbreaks of infectious diseases, as was seen during the Zika virus epidemics in 2013 in French Polynesia and 2015 in Latin America
- Several microorganisms have been associated with GBS, most notably Campylobacter jejuni, Zika virus, and in 2020, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)
In conclusion, Guillain-Barré Syndrome is a potentially life-threatening post-infectious disease characterized by rapidly progressive, symmetrical weakness and decreased reflexes. Its pathogenesis involves molecular mimicry leading to an autoimmune response against peripheral nerves. The clinical course is typically monophasic, but GBS can result in significant morbidity and mortality, with some patients experiencing long-term disability. Prognosis is influenced by factors such as age, severity at onset, and antecedent infections. Infections are the primary risk factors, with several pathogens implicated in triggering the autoimmune response.