Characteristic findings in Guillain–Barré syndrome are an elevated protein level, usually greater than 0.55 g/L, and fewer than 10 white blood cells per cubic millimeter of fluid ("albuminocytological dissociation"). This pattern distinguishes Guillain–Barré syndrome from other conditions (such as lymphoma and poliomyelitis) in which both the protein and the cell count are elevated. Elevated CSF protein levels are found in approximately 50% of patients in the first 3 days after onset of weakness, which increases to 80% after the first week.Repeating the lumbar puncture during the disease course is not recommended. The protein levels may rise after treatment has been administered. Neurophysiology
Directly assessing nerve conduction of electrical impulses can exclude other causes of acute muscle weakness, as well as distinguish the different types of Guillain–Barré syndrome. Needle electromyography (EMG) and nerve conduction studies may be performed. In the first two weeks, these investigations may not show any abnormality. Neurophysiology studies are not required for the diagnosis.Formal criteria exist for each of the main subtypes of Guillain–Barré syndrome (AIDP and AMAN/AMSAN, see below), but these may misclassify some cases (particularly where there is reversible conduction failure) and therefore changes to these criteria have been proposed. Sometimes, repeated testing may be helpful. Clinical subtypes
A number of subtypes of Guillain–Barré syndrome are recognized. Despite this, many people have overlapping symptoms that can make the classification difficult in individual cases. All types have partial forms.
Intravenous immunoglobulins were introduced in 1988, and studies in the early 1990s demonstrated that they were no less effective than plasma exchange. Research directions
The understanding of the disease mechanism of Guillain–Barré syndrome has evolved in recent years. Development of new treatments has been limited since immunotherapy was introduced in the 1980s and 1990s. Current research is aimed at demonstrating whether some people who have received IVIg might benefit from a second course if the antibody levels measured in blood after treatment have shown only a small increase. Studies of the immunosuppressive drugs mycophenolate mofetil, brain-derived neurotrophic factor and interferon beta (IFN-β) have not demonstrated benefit to support their widespread use.An animal model (experimental autoimmune neuritis in rats) is often used for studies, and some agents have shown promise: glatiramer acetate, quinpramine, fasudil (an inhibitor of the Rho-kinase enzyme), and the heart drug flecainide. An antibody targeted against the anti-GD3 antiganglioside antibody has shown benefit in laboratory research. Given the role of the complement system in GBS, it has been suggested that complement inhibitors (such as the drug eculizumab) may be effective. In animals it is called acute polyradiculoneuritis or "coonhound paralysis", and may onset in the coonhound 7 to 10 days after transmission from raccoons. If the coonhound has not been around raccoons, the disease is called acute idiopathic polyradiculoneuritis. References
Further reading
Steinberg GJ, Parry JS (2006). Guillain–Barré syndrome: from diagnosis to recovery. New York: Demos; ANN Press (American Academy of Neurology). ISBN 9781932603569. == External links ==