Guillain–Barré syndrome (GBS) is an acute polyneuropathy affecting the peripheral nervous system. Ascending paralysis, weakness beginning in the feet and hands and migrating towards the trunk, is the most typical symptom, and some subtypes cause change in sensation or pain as well as dysfunction of the autonomic nervous system. It can cause life-threatening complications, in particular if the respiratory muscles are affected or if there is autonomic nervous system involvement. The disease is usually triggered by an infection.
Types of Guillain-Barré Syndrome
Initially patients complain of lethargy, fatigue, headache, and decreased initiative followed by orthostatic light-headedness, blurring of vision, abdominal pain, diarrhoea, dryness of eyes, and disturbed micturition. The most common symptoms at onset are related to orthostatic intolerance, as well as gastrointestinal and sudomotor dysfunction. Parasympathetic impairment (abdominal pain, vomiting, constipation, ileus, urinary retention, dilated unreactive pupils; loss of accommodation) may also be observed.
Causes of Guillain-Barré Syndrome
All forms of Guillain–Barré syndrome are autoimmune diseases, due to an immune response to foreign antigens (such as infectious agents) that is targeted at host nerve tissues instead, a phenomenon called molecular mimicry. The targets of such immune attack are thought to be gangliosides, compounds naturally present in large quantities in human peripheral nerve tissues. The most common antecedent infection is the bacterium Campylobacter jejuni, followed by cytomegalovirus (CMV). However, 60% of cases do not have a known cause. Some cases may be triggered by the influenza virus, or by an immune reaction to vaccinations.
The end result of this autoimmune attack on the peripheral nerves is damage to the myelin, the fatty insulating layer of the nerve, and a nerve conduction block, leading to muscle paralysis that may be accompanied by sensory or autonomic disturbances.
In mild cases, nerve axon (the long slender conducting portion of a nerve) function remains intact and recovery can be rapid if re-myelination occurs. In severe cases, axonal damage occurs, and recovery depends on the regeneration of this important tissue. Approximately 80% of patients have myelin loss; in the remaining 20%, the pathological hallmark is axon loss.
Guillain–Barré, unlike disorders such as multiple sclerosis (MS) and Lou Gehrig's disease (ALS), is a peripheral nerve disorder and does not in general cause nerve damage to the brain or spinal cord.
Signs & Symptoms of Guillain-Barré Syndrome
The disorder is characterized by symmetrical weakness that usually affects the lower limbs first, and rapidly progresses in an ascending fashion. Patients generally notice weakness in their legs, manifesting as "rubbery legs" or legs that tend to buckle, with or without numbness or tingling. As the weakness progresses upward, usually over periods of hours to days, the arms and facial muscles also become affected. Frequently, the lower cranial nerves may be affected, leading to drooling, difficulty swallowing and respiratory difficulties. Facial weakness is also common. Eye movement abnormalities are not commonly seen in ascending GBS, but are a prominent feature in the Miller-Fisher variant.
Sensory loss, if present, usually takes the form of loss of proprioception (position sense) and complete loss of deep tendon reflexes, an important feature of GBS. Loss of pain and temperature sensation is usually mild. In fact, pain is a common symptom in GBS, presenting as deep aching pain, usually in the weakened muscles, which patients compare to the pain from over-exercising. These pains are self-limited and may be treated with standard analgesics. Bladder dysfunction may occur in severe cases but is usually short-lived.
In severe cases of GBS, loss of autonomic function is common, manifesting as wide fluctuations in blood pressure, orthostatic hypotension (a fall in blood pressure on standing, leading to an increased risk of collapse), and cardiac arrhythmias.
Treatment of Guillain-Barré Syndrome
Supportive care is the cornerstone of successful management in the acute patient. During the acute phase, this is aimed at decreasing the functional loss, and in the recovery phase, at hastening the return of function. Approximately 80% of patients have a complete recovery within a few months to a year, although minor findings may persist. About 5–10% of patients have one or more relapses, which is classified as Chronic Inflammatory Demyelinating Polyneuropathy (CIDP).
Expert preventative healthcare
Dr Paul Masters
Dip Hum Sci (Chiro), LCSP, BSc (Comp Ther), MSc (Chiro), DC
+65 8655 2652