Guillain-Barré Syndrome (GBS) is an acute, inflammatory neuropathy that primarily affects the peripheral nervous system. It is a rare condition, with an estimated incidence of 2/100,000 per year in the UK. This number increases with age and is more common in men than women.
The source of Guillain-Barré Syndrome is not fully understood, but two-thirds of patients with GBS have a prior history of an upper respiratory tract infection or gastroenteritis.
Although there are treatments that can improve patient outcomes, management focuses on reducing the risk of respiratory failure which is the main risk associated with GBS. Respiratory failure is seen in roughly 20-30% of GBS patients.
Around two-thirds of GBS cases are linked to a prior history of upper respiratory tract infection or gastrointestinal infection. The most commonly associated organisms are cytomegalovirus, Epstein-Barr virus, Mycoplasma, and Campylobacter jejuni.
Guillain-Barré Syndrome is thought to be an autoimmune condition. Evidence suggests that it is caused by the immune system misidentifying components of peripheral nerves for a virus, a phenomenon known as molecular mimicry.
This leads to demyelination of both motor and sensory peripheral nerves, which can result in paraesthesia and weakness. There have also been reports of GBS linked to cases of Zika virus and very rarely COVID-19.
GBS can be divided into four subtypes: Acute inflammatory demyelinating polyneuropathy (AIDP), Acute motor axonal neuropathy (AMAN), Acute motor sensory axonal neuropathy (AMSAN), and Miller-Fisher syndrome. It is important to identify the subtype as this can determine the degree of respiratory involvement and the necessity of early treatments or intensive care unit admission.
Guillain-Barre Syndrome (GBS) can present at any age, however is more commonly seen in older men. The typical history includes a recent viral infection or travel abroad which increases the risk of Campylobacter infection, with neurological signs presenting around 2-4 weeks post-infection.
Typical symptoms of GBS include:
The progression of symptoms can vary and can take hours, days, or weeks to resolve. Symptoms will continue for up to 4 weeks after which two-thirds of patients will recover and regain normal function within 6-12 months.
A thorough neurological examination (including upper limbs, lower limbs and cranial nerves) should be carried out on all patients suspected of Guillain-Barré Syndrome.
Typical clinical findings on neurological examination include:
Differential diagnoses to consider which also cause acute, potentially progressive paralysis include:
Guillain-Barré Syndrome is a clinical diagnosis. However, investigations help stratify risk in patients. Due to the rare and complex nature of GBS, all suspected cases should be referred to hospital for specialist review and possible admission.
Relevant bedside investigations include:
Relevant laboratory investigations to help diagnose Guillain-Barré Syndrome (GBS) include a full blood count, urea and electrolytes, liver function tests, glucose levels, and creatine kinase. Furthermore, Anti-GQIB testing is used to specifically rule out Miller-Fisher Syndrome. Imaging is not definitive for GBS, but can be used to rule out myelopathy.
Nerve conduction studies measure the rate at which electrical signals travel across the nerves - usually significantly slower than normal due to the diffuse polyneuropathy affecting both sensory and motor neurons. Lumbar puncture may show cerebrospinal fluid containing increased protein and normal cell count, although this is usually only seen after the first week of the illness.
Due to the risk of rapid deterioration, patients with GBS should be admitted for assessment and monitoring. General management includes serial lung function tests every four hours to screen for respiratory compromise, supportive treatment such as intravenous fluids and heart rate control, venous thromboembolism prophylaxis, eye care, pressure sore screening and management, pain relief, physiotherapy, and swallow assessment. Corticosteroids have not been proven effective.
To minimize autoimmune damage to the nerves, two therapies are available: plasma exchange and intravenous immunoglobulin. Plasma exchange removes plasma from the blood, filters it to remove autoantibodies, and returns it to the patient's circulation. Intravenous immunoglobulin neutralizes autoantibodies and helps to modulate the immune system.
Guillain-Barre Syndrome is an acute, diffuse polyneuropathy typically affecting the lower limbs first and progressing to the arms, trunk, face. The specific cause is not entirely known, but it often occurs 2-3 weeks after a viral infection (respiratory or gastrointestinal). Common symptoms include ascending paraesthesia and muscle weakness first affecting the legs and arms and then moving onto the rest of the body. This may result in respiratory compromise, most commonly seen as the most serious complication of GBS.
Diagnosis is made clinically but can be aided by nerve conduction studies and lumbar puncture.
Patients with GBS require monitoring of vitals, including pulmonary function tests, blood pressure, and heart rate, and may require VTE prophylaxis, eye and pressure sore care, and long-term physiotherapy.
More targeted treatments such as plasma exchange or IV immunoglobulin therapy (IVIg), which involves an infusion of donor immunoglobulins (antibodies) to dilute the ability of the autoantibodies, can be considered in severe cases. In order to achieve improved clinical outcomes, these therapies must be started within two weeks of symptom onset.
Low threshold for ICU admission should be considered for patients at high risk of respiratory compromise, rapidly progressing disease or aspiration pneumonia.
The general prognosis is good with 80% of patients regaining the ability to walk six months following the course of the disease. However, 20% of patients have persistent neurological dysfunction, with a mortality rate of 3-10%.
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