Guillain Barre Syndrome: When Legs (and more) Turn to Rubber
Looking on helplessly while a wave of weakness climbs one's body
from the ankles upward can cause dismay. This is what happens in
Guillain Barre (pronounced GHEE-on bah-RAY) syndrome, known more
formally as acute inflammatory demyelinating
polyradiculoneuropathy. Occurring in just one or two people per
year in a population of 100,000, Guillain Barre syndrome makes
up for its rarity by taking people by surprise and quickly
disabling them.
Acute inflammatory demyelinating polyradiculoneuropathy is about
as bulky and awkward a name as there is, but the terminology has
the endearing feature of encoding the disease's essential
features. Starting from the back end and working forwards,
"-pathy" means illness; "neuro" says that the peripheral nerves
are involved; "radiculo" means that the spinal nerves emanating
from the spinal cord are also affected; "poly" means it's a
widespread process; "demyelinating" means that the nerve-fibers
are stripped of their sheath-like myelin coverings;
"inflammatory" means a local tissue reaction to biochemical or
physical irritation; and "acute" means that the disease develops
rapidly over a matter of days. Despite the lesson in medical
terminology provided by the full name, it's easy to see why the
condition often goes by the shorter names of AIDP or Guillain
Barre Syndrome (GBS).
Georges Guillain and Jean-Alexandre Barre described cases of
this condition among French soldiers in the First World War. It
is noteworthy that the condition is labeled a "syndrome," rather
than a disease, because it is likely that multiple
disease-processes can produce the same pattern of clinical
illness (syndrome).
Diagnosing GBS involves recognizing the typical pattern of
progressing symptoms in which a loss of strength works its way
up the legs and often even into the arms and breathing muscles.
The symptoms quickly worsen over a matter of days, even hours,
and the weakness typically peaks within 2-3 weeks of the onset
of symptoms. Although the affected peripheral nerves and spinal
nerves also conduct messages concerning bodily sensation,
sensory loss in GBS is typically a minor component, while
weakness -- caused by disruption of nerves carrying messages to
muscles -- predominates.
The physical exam confirms the muscular weakness and, when
present, the associated numbness. Another classic finding on
examination is a loss of (rubber-hammer-type) tendon reflexes.
Supplemental tests that help confirm the diagnosis -- or,
depending on their outcome, point in another direction -- are
nerve conduction studies and cerebrospinal fluid analysis. Nerve
conduction studies check the electrical characteristics of the
peripheral nerves. In GBS the nerve impulses are often slowed or
blocked on their way from one part of the nerve to another.
Cerebrospinal fluid is the watery liquid bathing the outside of
the brain, spinal cord and spinal nerves. It is obtained for
analysis by means of a lumbar puncture, also known as spinal
tap. In GBS the protein content of the fluid is increased
without any corresponding increase in the numbers of red or
white blood cells in the fluid.
The cause of GBS is unknown, but because it often follows an
infection or other challenge to the body's immune system and
also involves inflammation, it seems likely that GBS is the
result of an overactive immune system. If so, GBS is one of
several so-called autoimmune diseases in which the body's own
immune system mistakenly attacks a component of the body, in
this case the myelin coverings of individual nerve-fibers. Other
examples of autoimmune disease are rheumatoid arthritis, in
which the immune system attacks the joints, and psoriasis, in
which the immune system attacks the skin.
A case series refers to a collection of consecutive cases
sharing agreed-upon features. Analyzing a case series provides
insight into how variable the illness can be as well as which
features are more constant.
Between 1995 and 2003 researchers at the Aga Khan University
Hospital in Karachi, Pakistan, collected a case series of 34
patients with GBS. The ages of the patients ranged from 3 to 70,
and 62% were male. In 35% of the cases there was a preceding
gastrointestinal infection and in another 26% of the cases there
was a preceding respiratory infection. Breathing failed in 56%
of the cases, requiring mechanical ventilation. One patient died.
Despite the frequently devastating nature of GBS, most patients
improve, albeit slowly. Compiling a separate case series,
investigators at the Centre for Rehabilitation Research in
Orebro, Sweden, tracked the progress of 42 patients with this
illness. Mechanical ventilation was necessary in just 21% of
their cases. At 2 weeks, 1 year and 2 years after the onset of
symptoms, 0%, 38% and 45% of patients had completely normal
strength. At the same time points, 38%, 90% and 93% were able to
walk 30 feet without assistance.
Treatment is available for patients with GBS. Of course, when
patients can't breathe on their own, using a mechanical
ventilator to support respiration is a form of treatment and is
usually life-saving. Two other treatments have been shown by
randomized, controlled trials -- the gold standard method for
evaluating a treatment -- to hasten recovery in GBS.
One is plasmapheresis, also known as plasma exchange, in which
the liquid portion of the blood (plasma) is separated from the
blood cells. The blood cells are then returned to the patient's
body, and the body produces more plasma on its own to replace
the plasma that was removed. The reason plasmapheresis works is
uncertain, but it probably removes damaging antibodies from the
bloodstream.
Infusing immunoglobulin into the patient's bloodstream is the
other treatment of proven effectiveness. The immunoglobulin
preparation contains antibodies pooled from a large number of
healthy donors. These healthy antibodies presumably counteract
the injurious antibodies produced in the GBS patient.
One might think that two treatments -- plasmapheresis and
immunoglobulin infusion -- administered together or in
succession would be better than just one, but that is not the
case. A study showed that the two treatments in combination were
no better in hastening recovery than one treatment.
(C) 2006 by Gary Cordingley