Guillain-Barré syndrome overview


 * Associate Editors-In-Chief: Priyamvada Singh, MBBS [mailto:psingh@perfuse.org]

Overview
Guillain-Barré syndrome (GBS) is an acute, autoimmune, polyradiculoneuropathy affecting the peripheral nervous system, usually triggered by an acute infectious process. It is included in the wider group of peripheral neuropathies.

Historical perspective
It was first reported by Landry in 1859 as a case study of 10 patients with ascending paralysis. Later the characteristic features of the disease like flaccid paralysis, areflexia and CSF findings were reported by Guillain, Barré, and Strohl. The syndrome was later named Guillain-Barré syndrome after these physicians.

Pathophysiology
It involves an auto-immune mechanism in which the antibodies formed against the lipopolysaccharides of bacteria or certain vaccines cross reacts with the gangliosides present in myelin of peripheral nerves. As a result of which, myelin degeneration occurs leading to conduction defects that manifests as flaccid paralysis.

Epidemiology and demographics
The incidence is approximately 1.2 - 3 / 100,000 persons per year across the world. It is commoner in males compared to female and has two peaks (15-35 years and 50-75 years). Incidence is similar across different races.

Risk factors
Anyone can develop GBS; however, it is more common among older adults. The incidence of GBS increases with age, and people older than 50 years are at greatest risk for developing GBS. Since 1976, many studies have been done to see if other flu vaccines may cause GBS. In most studies no link was found between the flu vaccine and GBS. For the most part, the chance of getting very ill from flu is far higher than the chance of getting GBS after getting the flu vaccine.

Natural history, complications and prognosis
Approximately 80% of patients have a complete recovery within a few months to a year, although minor findings may persist. A patient's outcome is most likely to be very good when the symptoms go away within 3 weeks after they first started. Complications like paralysis, respiratory failure and hypotension can be seen in these patients.

Classification
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. The other less common variants involve Miller Fisher syndrome, Acute motor axonal neuropathy (AMAN), Acute motor sensory axonal neuropathy(AMSAN), Acute panautonomic neuropathy, and Bickerstaff's brainstem encephalitis (BBE).

Causes
The exact cause of Guillain-Barre syndrome is unknown. However, it has been associated with an antecedence of minor infections (lung, sinus or diarrhea) with campylobacter jejuni. It has also been linked to flu vaccine but the incidence is rare.

History and symptoms
Patient may present with an antecedence of mild infection of respiratory or gastrointestinal infections that may disappear before the onset of weakness. Many patients also give a history of pins and needles sensation before the onset of weakness of limbs. Symmetrical, bilateral, weakness of lower limbs followed by upper limb, trunk and cranial nerve may be seen. Sensory symptoms are usually mild and patients may complain of decreased or increased pain sensation, decreased touch and difficulty walking (loss of position sense) depending on stage and type of GBS. Autonomic involvement in form of urinary retention, constipation and awareness of own's heartbeat can be found. Cranial nerve involvement in form of blurred vision, facial drooping, difficulty in swallowing and speaking can be seen.

Physical examination
The physical examination findings usually indicates features due to autonomic dysfunction and demyelination of peripheral nerves. Fluctuation in vitals can be seen and may present as hyper or hypothermia, hypo or hypertension, brady or tachycardia. Progressive, symmetric, bilateral, flaccid, ascending paralysis progressing over weeks to days time is the common finding. Hypotonia, hyporeflexia, areflexia can be seen.Sensory system may be involved but generally it is mild. Ataxia and difficulty in walking may be seen despite great muscle strength due to involvement of proprioception and oculoparesis.

Lab tests
Guillain-Barré syndrome (GBS) is usually diagnosed clinically. Lab tests are done to exclude other diagnosis and assess prognosis. The lab tests ordered are basic labs (CBC, ESR), lumbar puncture (GBS has characteristic albuminocytological dissociation), serological markers.

MRI

 * MRI may be used as an adjunct to the clinical and Laboratory tests. MRI findings suggestive of Guillian Barre syndrome are anterior and cauda equina nerve root enhancement.

Other diagnostic studies

 * Nerve conduction study may show prolonged distal latencies, conduction slowing, conduction block, and temporal dispersion of compound action potential in demyelinating cases. Forced vital capacities also help in taking decisions regarding ventilators.

EKG
The dysautonomia seen in Guillian Barre syndrome may lead to some conduction and rhythm disturbances. Features of GBS on EKG can be 2nd or 3rd degree conduction block, QRS prolongation and T wave abnormality. However, the EKG changes are non-specific and they act as supportive not definitive diagnostic tools.

Medical therapy
With prompt treatment of plasmapheresis followed by immunoglobulins and supportive care, the majority of patients will regain full functional capacity. However, death may occur if severe pulmonary complications and dysautonomia are present.

Physical therapy, Occupational therapy, Speech therapy
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 patient 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.