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Guillain-Barré syndrome (GBS) is an acute, autoimmune, polyradiculoneuropathy affecting the peripheral nervous system, usually triggered by an acute infectious process. There are several types of GBS, but unless otherwise stated, GBS refers to the most common form, acute inflammatory demyelinating polyneuropathy (AIDP). It is frequently severe and usually exhibits as an ascending paralysis noted by weakness in the legs that spreads to the upper limbs and the face along with complete loss of deep tendon reflexes. With prompt treatment with immunoglobulins and supportive care, majority of patients will regain full functional capacity. However, death may occur if severe pulmonary complications and dysautonomia are present.
Pathophysiology All forms of Guillain-Barre syndrome are due to an autoimmmune response to foreign antigens (such as infectious agents, vaccines) that are mistargeted to host nerve tissues instead. The targets of such immune attack are thought to be gangliosides, which are complex glycosphingolipids that are present in large quantities on human nerve tissues, especially in the nodes of Ranvier. An example is the GM1 ganglioside, which can be affected in as many as 20-50% of cases, especially in those preceded by Campylobacter jejuni infections. Another example is the GQ1b ganglioside, which is the target in the Miller-Fisher syndrome variant (see below). The end result of such autoimmune attack on the peripheral nerves is loss of myelin and subsequent conduction block. However, axonal function remains intact and recovery can be rapid as remyelination occurs. If axonal degeneration occurs in severe GBS, recovery becomes much slower and will leave a greater degree of residual damage. If primary axonal damage occurs, such as in the AMAN or AMSAN variants (see below), nerve connections become disrupted and recovery depends on axonal regeneration. Recent studies on the disease have demonstrated that approximately 80% of the patients have myelin loss, whereas, in the remaining 20%, the pathologic hallmark of the disease is indeed axon loss. Cause About 75% of patients with GBS have a history of acute infection within the past one to four weeks, usually respiratory or gastrointestinal. 20-30% of these cases are due to Campylobacter jejuni and a similar proportion due to cytomegalovirus or Epstein-Barr virus. The risk of developing Guillain-Barré syndrome following campylobacter infection is less than 2 per 10,000 in the following two months.• Less common infectious agents include Mycoplasma pneumoniae, HIV, and herpes simplex virus. Immunizations have also been implicated in GBS. Notable are the swine influenza vaccine administered in the U.S. in 1976, and older types of rabies vaccines. Other associated conditions associated with GBS include Hodgkin's disease and systemic lupus erythematosus (SLE). GBS is a rare disease affecting about 1 to 2 people in every 100,000 annually. It does not discriminate with regard to the age or sex of sufferers. When diagnosed in young teenagers, it generally does not recur for many years, although when it does, it often does so in the fourth or fifth decade of life, long after the patients may have forgotten the details of the original episode. Signs and symptoms Extensive inflammation of myelin in the peripheral nervous system leads to a rapidly evolving flaccid paralysis with or without sensory or autonomic disturbances. The distribution is usually in an ascending fashion, affecting the lower limbs first. Patients generally notice weakness in their legs, manifesting as "rubbery legs" or legs that tend to buckle, with or without dysthesias (numbness or tingling). As the weakness progresses upward, usually over periods of hours to days, the arms and facial muscles may also become affected. Frequently, the lower cranial nerves may be affected, leading to bulbar weakness (causing difficulty with eye movements, double vision), oropharyngeal dysphagia (difficulty with swallowing, drooling), and/or maintaining an open airway. Most patients require hospitalization and about 30% require ventilatory assistance. Sensory loss, if present, usually takes on the form of loss of proprioception (position sense) and areflexia (complete loss of deep tendon reflexes), an important feature of GBS. Loss of pain and temperature is usually mild. Bladder dysfunction may occur in severe cases but should be transient. If severe, spinal cord disease should be suspected. Fever and other constitutional symptoms are initially, and if present, another diagnosis should be suspected. In severe cases of GBS, loss of autonomic function is common, manifesting as wide fluctuations in blood pressure, orthostatic hypotension, and cardiac arrhythmias. Pain is also common in GBS, presenting as deep aching pain usually in the weakened muscles, which patients usually compare to the pain from overexercising. These pains are self-limited and should be treated with standard analgesics. Clinical variants Although ascending paralysis is the most common form of spread in GBS, other variants also exist. Diagnosis The diagnosis of GBS usually depends on the typical clinical findings such as rapidly evolving flaccid paralysis, areflexia, absence of fever, and a likely inciting event. CSF and electrodiagnostics may be useful, but because of the acute nature of the disease, they may not become abnormal until the end of the first week. Diagnostic criteria Differential diagnosis Treatment Supportive care with monitoring of all vital functions is the cornerstone of successful management in the acute patient. Of greatest concern is respiratory failure due to paralysis of the diaphragm. Early intubation should be considered in any patient with a vital capacity (VC) <20 ml/kg, a Negative Inspiratory Force (NIF) <-25 cmH2O, more than 30% decrease in either VC or NIF within 24 hours, rapid progression of disease, or autonomic instability. Once the patient is stabilized, treatment of the underlying condition should be initated as soon as possible. Either high-dose intravenous immunoglobulins (IVIg) or plasmapheresis can be administered, as they are equally effective and a combination of the two is not significantly better than either alone. Therapy is no longer effective after 2 weeks after the first motor symptoms appear, so treatment should be instituted as soon as possible. IVIg is usually used first because of its ease of administration and safety profile, with a total of five daily infusions for a total dose of 2 g/kg body weight. The use of intravenous immunoglobulins is not without risk, occasionally causing hepatitis, or in rare cases, renal failure if used for longer than five days. Glucocorticoids have not been found to be effective in GBS. If plasmapheresis is chosen, a dose of 40-50 mL/kg plasma exchange (PE) is administered four times over a week. Following the acute phase, the patient may also need rehabilitation to regain lost functions. This treatment will focus on improving ADL (activities of daily living) functions such as brushing teeth, washing and getting dressed. Depending on the local structuring on health care, there will be established a team of different therapists and nurses according to the patients needs. An occupational therapist can offer equipment (such as wheel chair and cutlery) to help the patient achieve ADL independence. A physiotherapist would plan a progressive training programme, and guide the patient to correct, functional movement, avoiding harmful compensations which might have a negative effect in the long run. There would also be a doctor, nurse and perhaps a speech trainer involved, depending on the needs of the patient. This team contribute with their knowledge to guide the patient towards his goal, and it is important that all goals set by the separate team members are relevant for the patient's own priorities. After rehabilitation the patient should be able to function in his own home and attend necessary training as needed. Prognosis Approximately 80% of patients have a complete recovery within a few months to a year, although minor findings may persist, such as areflexia. About 5-10% recover with severe disability, with most of such cases involving severe proximal motor and sensory axonal damage with inability of axonal regeneration. However, this is a grave disease and despite all improvements in treatment and supportive care, the death rate among patients with this disease is still about 2-3% even in the best intensive care units. Worldwide, the death rate runs slightly higher (4%), mostly from a lack of availability of life support equipment during the lengthy plateau lasting 4 to 6 weeks when a ventilator is needed in the worse cases. About 5-10% of patients have one or more late relapses, in which case they are then classified as having chronic inflammatory demyelinating polyneuropathy (CIDP). History The disease was first described by the French physician Jean Landry in 1859. In 1916, Georges Guillain, Jean Alexandre Barré and Andre Strohl discovered the key diagnostic abnormality of increased spinal fluid protein production, but normal cell count. A peer-reviewed study published in 2003, concluded that Franklin Delano Roosevelt's 1921 paralytic illness was probably Guillain-Barré syndrome, not polio as previously assumed. The Bayesian analysis in the study found that six of eight posterior probabilities favored a diagnosis of Guillain-Barré syndrome over poliomyelitis. Joseph Heller, author of Catch-22, suffered Guillain-Barre syndrome. His experiences with the illness make up a large portion of his non-fiction No Laughing Matter. GBS is also known as acute inflammatory demyelinating polyneuropathy, acute idiopathic polyradiculoneuritis, acute idiopathic polyneuritis, French Polio and Landry's ascending paralysis. | ||||||||
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