In Europe and the United States, 60–80% of people with Guillain–Barré syndrome have the demyelinating subtype (AIDP), and AMAN affects only a small number (6–7%). In Asia and Central and South America, that proportion is significantly higher (30–65%). This may be related to the exposure to different kinds of infection, but also the genetic characteristics of that population. Miller Fisher variant is thought to be more common in Southeast Asia. History
Jean-Baptiste Octave Landry first described the disorder in 1859. In 1916, Georges Guillain, Jean Alexandre Barré, and André Strohl diagnosed two soldiers with the illness and described the key diagnostic abnormality—albuminocytological dissociation—of increased spinal fluid protein concentration but a normal cell count.C. Miller Fisher described the variant that bears his name in 1956. British neurologist Edwin Bickerstaff described the encephalitis type in 1951 and made further contributions with another paper in 1957. Guillain had reported on some of these features before their full description in 1938. Further subtypes have been described since then, such as the form featuring pure ataxia and the type causing pharyngeal-cervical-brachial weakness. The axonal subtype was first described in 1986.Diagnostic criteria were developed in the late 1970s after the series of cases associated with swine flu vaccination. These were refined in 1990. The case definition was revised by the Brighton Collaboration for vaccine safety in 2009, but is mainly intended for research. Plasma exchange was first used in 1978, and its benefit was confirmed in larger studies in 1985.
The consequent vaccine transfection and translation in the nerves may spur an immune response against nerve cells potentially causing an autoimmune nerve damage, leading to conditions like Guillain–Barré syndrome. Diagnosis
The diagnosis of Guillain–Barré syndrome depends on findings such as rapid development of muscle paralysis, absent reflexes, absence of fever, and absence of a likely cause. Cerebrospinal fluid analysis (through a lumbar spinal puncture) and nerve conduction studies are supportive investigations commonly performed in the diagnosis of GBS. Testing for antiganglioside antibodies is often performed, but their contribution to diagnosis is usually limited. Blood tests are generally performed to exclude the possibility of another cause for weakness, such as a low level of potassium in the blood. An abnormally low level of sodium in the blood is often encountered in Guillain–Barré syndrome. This has been attributed to the inappropriate secretion of antidiuretic hormone, leading to relative retention of water.In many cases, magnetic resonance imaging of the spinal cord is performed to distinguish between Guillain–Barré syndrome and other conditions causing limb weakness, such as spinal cord compression. If an MRI scan shows enhancement of the nerve roots, this may be indicative of GBS. In children, this feature is present in 95% of scans, but it is not specific to Guillain–Barré syndrome, so other confirmation is also needed. Spinal fluid
Cerebrospinal fluid envelops the brain and the spine, and lumbar puncture or spinal tap is the removal of a small amount of fluid using a needle inserted between the lumbar vertebrae.