GUILLAIN-BARRE SYNDROMEAla Nozari, MD, PhD, Corey R. Fehnel, MD, and Lee H. Schwamm, MD, FAHACH

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1. What is Guillain-Barre syndrome (GBS)?Also known as acute polyradiculoneuritis, GBS is an acute onset of peripheral neuropathy withprogressive muscle weakness and areflexia that reaches maximum over 3 days to 3 weeks. It hasa number of variants, including pure motor or motor-sensory variants, Miller Fisher variant,bulbar variant, and primary axonal GBS.

2. Describe the pathophysiology of GBS.GBS is a collection of syndromes with inflammatory demyelinating polyradiculoneuropathy. It istriggered by both humoral and cell-mediated autoimmune response to an immune sensitizingevent such as an upper respiratory tract infection or cytomegalovirus, herpes simplex virus,Campylobacter jejuni, or mycoplasma infections. A clear antecedent infection is often difficult toidentify. Antibodies to gangliosides and glycolipids trigger myelin disruption in the peripheralnervous system. Axonal antibodies occur in some cases, typically after campylobacterinfection, and carry a worse prognosis for complete recovery. An increased incidence has beenreported in patients with lymphoma or lupus. In the United States, it is a sporadic disease, butvariants in Asia are often epidemic in the summer months, presumably because of increasedhuman exposure to zoonotic infections from domesticated livestock.

3. What is the typical clinical presentation of GBS?GBS is an ascending paralysis that is typically characterized by symmetric weakness, sensorydysesthesias, and hyporeflexia.Mild casesmaypresentwith onlymildweaknessor as variants (e.g.,ataxia, ophthalmoplegia, and hyporeflexia) without significant appendicular weakness. Fulminantcases may cause severe ascending weakness leading to complete tetraplegia and with paralysis ofcranial nerves and respiratory muscles (involvement of the phrenic and intercostal nerves).

4. Describe the diagnostic criteria for GBS.Clinical features required for the diagnosis of GBS include areflexia and progressive motorweakness of more than one limb. Features strongly supportive of the diagnosis includeprogression of the motor weakness, relative symmetry, cranial nerve involvement, mild sensorysymptoms, autonomic dysfunction, and recovery within 2 to 4 weeks after progression stops.

5. What is the differential diagnosis of subacutely evolving, generalized motorweakness?Disorders frequently mimicking GBS include acute intermittent porphyria, transverse myelitis,tick paralysis, myasthenia gravis, hypophosphatemia, and carcinomatous or lymphomatousmeningitis. Severe peripheral neuropathies due to vasculitis or toxins such as lead,nitrofurantoin, dapsone, thallium, arsenic, and many others should also be considered.

6. Describe laboratory and radiologic findings for GBS.Cerebrospinal fluid (CSF) analysis shows elevated protein level without pleocytosis(albuminocytologic dissociation). Electromyogram and nerve conduction study results may benormal in the early acute period but after 1 to 2 weeks reveal characteristic segmental demyelinationand reduction of conduction velocity. Dispersion or absence of F waves is an important early finding

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