Guillain-Barre syndrome overview

# Overview
Guillain-Barre 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
The disease was first described by the French physician Jean Landry in 1859. In 1916, Georges Guillain, Jean Alexandre Barre and Andre Strohl diagnosed two soldiers with motor weakness, areflexia and a the key diagnostic abnormality of increased spinal fluid protein production, but normal cell count. Later, it was called Guillain-Barre syndrome after them. GBS is also known as acute inflammatory demyelinating polyneuropathy, acute idiopathic polyradiculoneuritis, acute idiopathic polyneuritis, French Polio and Landry's ascending paralysis.

# Classification
Guillain Barre syndrome may be classified according to the underlying pathophysiology into four groups: Acute motor axonal neuropathy (AMAN), acute motor axonal neuropathy (AMAN), acute motor and sensory axonal neuropathy and Miller Fisher syndrome.

# Pathophysiology
The exact pathogenesis of Guillain Barre syndrome is not completely understood but in 2/3 of cases there is a history of an infectious disease in the past month.The most common pathogens responsible for these antecedent infections are: Campylobacter jejuni, cytomegalo virus and Hemophilus influenzae. It is believed that the main underlying etiology of GBS is an autoimmune reaction due to molecular mimicry. On microscopic histopathological analysis: Lymphocyte and macrophage infiltration, demyelination in AIDP, Macrophage infiltration and axolemma disruption in motor fibers in AMAN, disruption of both motor and sensory fibers. Little lymphocyte infiltration in AMSAN and Oculomotor nerve demyelination in Miller Fisher type.

# Causes
Guillain Barre syndrome may be caused by Campylobacter jejuni, Cytomegalovirus, haemophilus influenza, epstein-Barr virus, Varicella zoster virus and HIV-1.

# Differentiating Guillain-Barre syndrome from other diseases
Guillain Barre syndrome must be differentiated from: Acute Flaccid Myelitis, adult botulism, infant botulism, Eaton-Lambert syndrome, myasthenia gravis, electrolyte disturbance, organophosphate toxicity, tick paralysis, tetrodotoxin poisoning, stroke, poliomyelitis, transverse myelitis, neurosyphilis, muscular dystrophy, multiple sclerosis exacerbation, amyotrophic lateral sclerosis and inflammatory myopathy.

# Epidemiology and Demographics
Incidence vary from 0.4 to 4.0 cases per population of 100 000. In previous studies, Guillain-Barre syndrome mortality rate was 2.58%. It can happen in any age group but its more common in late adolescence. The reason behind this is that immune suppressor mechanisms will decrease with age. It was demonstrated in one study that the incidence rate for whites were 0.44 and for blacks were 0.28 per 100,000, but it seems that despite all of these, the incidence is similar across different races. It is more common among males compared to females. Male to female ratio 1.5:1.

# Risk Factors
Risk factors in the development of Guillain Barre syndrome include: Rabies vaccine and swine-flu influenza vaccine.

# Screening
There is insufficient evidence to recommend routine screening for Guillain Barre syndrome.

# Natural History, Complications and Prognosis
The symptoms of Guillain Barre syndrome typically develop 1 to 3 weeks after the Antecedent Infection. If left untreated, 65% of patients with Guillain Barre syndrome will recover with no permanent disability. 35% of them will not fully recover. 8% of these 35% will die from complication and others will have permanent disabilities.
Common complications of GBS include: respiratory failure, autonomic failure, bulbar pulsy, Deep vein thrombosis, Cardiac arrhythmia, Pain, Urinary retention, Ileus and persistent fatigue

# Diagnosis

## Diagnostic Study of Choice
There is no single diagnostic study of choice for Guillain Barre syndrome, though GBS may be diagnosed based on NINDS criteria established by National Institute of Neurological Disorders and Stroke: Progressive ascending weakness or paralysis usually starting from legs, involving are 4 limbs, the trunk, bulbar and facial muscles, and external ocular muscles and Areflexia or decreased reflexes in affected limbs.

## History and Symptoms
Patients with Guillain Barre syndrome may have a positive history of: Prior infection with Campylobacter jejuni, Cytomegalovirus, Haemophilus influenzae, Epstein-Barr virus, Varicella zoster virus and HIV-1, recent vaccination with influenzae or rabies vaccine, limb tingling and paresthesia, lower extremity weakness and muscle pain.
Common symptoms of Guillain Barre syndrome include: Symmetrical ascending weakness and paralysis, tingling and paresthesia and pain.

## Physical Examination
Physical examination of patients with Guillain Barre syndrome is usually remarkable for abnormal gait, heart rate and blood pressure disturbance, ophthalmoplegia, papilledema, facial myokymia, vocal cord paralysis, urinary retention,  hyperreflexia or areflexia, bilateral distal and proximal muscle weakness and unilateral or bilateral sensory abnormality.

## Laboratory Findings
Laboratory findings consistent with the diagnosis of Guillain Barre syndrome include: Elevated CSF protein level, normal CSF WBC count, normal CSF cell count (in some cases there is mildly elevated cell count) and serum IgG antibody to GQ1b in Miller Fisher syndrome.

## Electrocardiogram
The dysautonomia seen in Guillian Barre syndrome may lead to some conduction and rhythm disturbances. Findings on an ECG suggestive of Guillain Barre syndrome include: ST segment depresion, T wave inversion, QT prolongation and Ttachycardia.

## X-Ray
There are no characteristic x-Ray findings associated with Guillain Barre disease.

## Echocardiography/Ultrasound
There are no characteristic echocardiography/ultrasound findings associated with Guillain Barre syndrome.

## CT Scan
There are no  characteristic CT scan findings associated with Guillain Barre syndrome but we can perform CT scan to exclude other etiologies.

## MRI
Findings on MRI suggestive of Guillain Barre syndrome include: Anterior and posterior nerve root and cauda equina enhancement.

## Other Imaging Findings
There are no other imaging findings associated with Guillain Barre sydnrome.

## Other Diagnostic Studies
Nerve conduction studies and needle electromyography may be helpful in the diagnosis of Guillain Barre syndrome and differentiating various sub types. Findings diagnostic of demyelinating forms of Guillain Barre syndrome include: Reduced conduction velocity of motor nerves, increased distal motor latency, increased latency of F wave, conduction block and Temporal scattering. Findings diagnostic of  axonal forms of Guillain Barre syndrome include: Reduced amplitude of distal motor and/or sensory nerve impulses and conduction block of motor nerves.

# Treatment

## Medical Therapy
Supportive therapy for Guillain Barre syndrome include: Respiratory assistance, Heart rate and blood pressure monitoring, prevention of thromboembolic complications by heparin, minimal sedation in intensive care units, pain control and early passive movements. Immunomodulating therapy for Guillain Barre syndrome include: Plasma exchange, High dose immunoglobulin and Corticosteroids.

## Surgery
Surgical intervention is not recommended for the management of Guillain Barre syndrome.

## Primary Prevention
There are no established measures for the primary prevention of Guillain Barre syndrome.

## Secondary Prevention