Guillain Barre Syndrome - Acute Inflammatory Polyneuropathy
Epidemiology
It is uncommon. The annual incidence is about 1-2:100,000. It is slightly more
common in males than females. It occurs at any age.
Pathophysiology
It is an inflammatory neuropathy; microscopically there is a perivascular inflammatory
infiltrate. The nerve roots and proximal portions of the peripheral nerves are
predominantly affected causing segmental demyelination.
Axonal loss occurs in some cases; associated involvement of the central nervous
system is rare. A history of preceding infection is common; an association with
campylobacter jejuni (an infective cause of diarrhoea) has been established.
There are sporadic reports of an association with vaccination.
The Miller Fisher syndrome, a variant of Guillain Barre syndrome, is associated
with antibodies to GQ1b gangliosides.
Clinical Features
A "flu-like" illness or diarrhoea may occur a week or two before
the neurological symptoms begin.
Weakness usually begins in the legs; it is commonly associated with pain, which
may be severe. As the weakness is more pronounced proximally, activities such
as walking upstairs and standing up from a chair or bed are often noticed first.
The weakness usually spreads to the arms and worsens over a few days or a couple
of weeks. Weakness continuing to progress after 4 weeks will require an alternative
diagnosis. Sensory symptoms and signs are often minor and the bladder is usually
spared.
The weakness progresses over 1-3 weeks such that the majority of patients are
unable to stand or walk and are admitted to hospital. Bilateral facial weakness
and bulbar weakness (difficulty with speech and swallowing) are common. Involvement
of the ocular muscles can occur.
About 30% require mechanical ventilation due to respiratory muscle weakness.
The deep tendon reflexes in arms and legs are usually absent, although are sometimes
present in the early stages; the plantar responses are flexor.
The Miller Fisher variant is a clinical syndrome of ataxia, areflexia and external
ophthalmoplegia (unable to move the eyes). The GQ1b antibody is usually positive
and the prognosis is excellent.
Investigation
The diagnosis is straightforward if the clinical features are typical, although
is usual to screen for other causes of acute weakness. Electromyography (EMG)
shows a demyelinating neuropathy, although may be normal in the early stages
when the diagnosis is still in doubt. Similarly the classical lumbar puncture
findings of an acellular CSF with a raised CSF protein often develop in the
second or third week.
Management
Hospital admission is the rule for most patients. Close monitoring of respiratory
function is mandatory, as respiratory failure can be rapid in onset. Similarly,
regular monitoring of pulse and blood pressure (ideally with a cardiac monitor)
is required as autonomic neuropathy can cause rapid circulatory changes.
Transfer to an intensive therapy unit is required for ventilation. Intravenous
gammaglobulin or plasma exchange is given if the weakness is severe enough to
prevent the patient from standing.
There is usually an extended period of rehabilitation, lasting several months,
which requires input from a multidisciplinary team.
Prognosis
Recovery occurs in about two thirds of cases, but can take up to a year. Up
to 10% cases die during the course of the illness; the remainder are left with
varying degrees of disability.
References and Links
Hughes RA et al. Pathogenesis of Guillain Barre syndrome. J Neuroimmunol
1999; 100: 74-97.
Randomised trial of plasma exchange, intravenous immunoglobulin, and combined
treatments in Guillain-Barre syndrome. Plasma Exch
