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Guillain-Barre syndrome (GBS) is a disorder in which the body's immune system
attacks parts of the peripheral nervous system. The peripheral nervous system is
a network of nerves throughout the body, connecting muscles, skin, blood vessels,
and glands to the spinal cord and brain. Some peripheral nerve pathways carry
impulses from the brain to the periphery (triggering muscles to contract, for
example), while others carry information to the brain (pain perception from the
skin receptors, for example).
Guillain-Barre syndrome can affect anybody. It can strike at any age
and both sexes are equally prone to developing this disorder. It is uncommon, affecting only about one person in 100,000.
GBS can develop as the result of a respiratory or gastrointestinal viral
infection, although occasionally surgery or vaccinations will also trigger the
syndrome. The disorder can develop over the course of hours or days, or it might
take up to three to four weeks. Most people reach the stage of greatest weakness within
the first two weeks after symptoms appear. By the third week of the illness, 90
percent of all patients are at their weakest.
Symptoms of GBS
The first symptom of this disorder is usually a feeling of numbness or
tingling in the toes. It is generally followed by weakness in the arms and legs. In
many instances, the weakness and abnormal sensations spread to the arms and upper
body. These symptoms can increase in intensity until the muscles cannot be used
at all and the patient is totally paralyzed.
As mentioned above, symptoms
usually develop over a period of days to weeks, with nearly all patients
reaching their maximum weakness within three to four weeks. In severe cases, the
disorder is life threatening — potentially interfering with breathing and, at
times, with blood pressure or heart rate — and is considered a medical
emergency. The patient is often put on a respirator to assist with breathing and
is watched closely for problems such as an abnormal heartbeat, infections, blood
clots, and high or low blood pressure. Most patients recover from even the most
severe cases of GBS, although some continue to have some
degree of weakness.
Additional symptoms associated with GBS include:
- Blurred vision
- Difficulty moving facial muscles
- Dizziness
- Drooling
- Heart palpitations
- Difficulty beginning to urinate
- Incontinence
- Constipation
- Muscle contractions
If any of the following symptoms occur, it should be considered an emergency
situation and medical help should be sought immediately:
- Difficulty swallowing
- Difficulty breathing
- A feeling of being unable to take a deep
breath
- Fainting
Causes of GBS
It is unknown why GBS strikes some people and not others. Nor is it known
exactly what sets the syndrome in motion. What scientists do know is that the
body's immune system begins to attack the body itself, causing what is known as
an autoimmune disease. Usually the cells of the immune system attack only
invading organisms or objects. In GBS, however, the immune system starts to
destroy the myelin sheath (insulation) that surrounds the axons of many
peripheral nerves, or even the axons themselves. (Axons are long, thin extensions
of the nerve cells that carry nerve signals.) The myelin sheath surrounding the
axons speeds up the transmission of nerve signals and allows the transmission of
signals over long distances.
As a result of myelin or axon loss, impulse transmission along nerve pathways
is disrupted, giving rise to weakness, sensory loss, and unusual sensory symptoms
such as tingling and burning.
Diagnosing GBS
GBS is called a syndrome rather than a disease because it is not clear that a
specific disease-causing agent is involved. A syndrome is a medical condition
characterized by a collection of symptoms (what the patient feels) and signs
(what a doctor can observe or measure).
Several disorders have symptoms similar to those found in GBS, so doctors
examine and question patients carefully before making a diagnosis. Collectively,
the signs and symptoms form a certain pattern that helps doctors differentiate
GBS from other disorders. For example, doctors will note whether the symptoms
appear on both sides of the body (most common in GBS) and the quickness with
which the symptoms appear. (In other disorders, muscle weakness might progress over
months rather than days or weeks.) In GBS, reflexes such as knee jerks are
usually lost. Because the signals traveling along the nerve are slower, an EMG
test to measure nerve conduction velocity can be performed to aid in the diagnosis.
Another test to assist doctors in diagnosing GBS is a lumbar puncture, also
known as a spinal tap. Patients with GBS have elevated levels of protein in
their cerebrospinal fluid, a fluid that bathes the spinal cord and brain. During
a spinal tap, the doctor inserts a needle between vertebrae in the lower back to
collect cerebrospinal fluid for analysis.
Treating GBS
There is no known cure for GBS. However, there are therapies that lessen the
severity of the illness and accelerate the recovery in most patients. There are
also a number of ways to treat the complications and symptoms of the syndrome.
Currently, plasmapheresis and high-dose immunoglobulin therapy (IVIG) are
used. Both of them are equally effective, but immunoglobulin is easier to
administer.
Plasmapheresis is a method by which whole blood is removed from the body and
processed so that the red and white blood cells are separated from the plasma,
or liquid portion of the blood. The blood cells are then returned to the patient
without the plasma, which the body quickly replaces. Scientists still don't know
exactly why plasmapheresis works, but the technique seems to reduce the severity
and duration of the GBS episode. This might be because the plasma portion of the
blood contains antibodies directed against the myelin.
During IVIG therapy, injections of these immunoglobulins — derived from a pool
of thousands of normal donors — can lessen the immune attack on the nervous
system. It’s unclear why or how this works.
The most critical part of the treatment for GBS consists of keeping the
patient's body functioning during recovery of the nervous system. This can
sometimes require placing the patient on a respirator, a heart monitor, or other
machines that assist body function. The need for this sophisticated machinery is
one reason why GBS patients are usually treated in hospitals, often in intensive
care units. In the hospital, doctors can also look for and treat the many
problems that can affect any paralyzed patient — complications such as
pneumonia or bedsores.
Often, even before recovery begins, caregivers might be instructed to manually
move the patient's limbs to help keep the muscles flexible and strong. Later, as
the patient begins to recover limb control, physical therapy begins.
GBS can be a devastating disorder because of its sudden and unexpected onset.
In addition, recovery is not necessarily quick. As noted above, patients usually
reach the point of greatest weakness or paralysis within one month after the
first symptoms occur. Symptoms then stabilize at this level for a period of
days, weeks, or — sometimes — months. The recovery period might be as little as a
few weeks or as long as a few years. About 30 percent of those with GBS still
have a residual weakness after three years. About 3 percent might suffer a relapse of
muscle weakness and tingling sensations many years after the initial attack.
As with many other conditions, education about this syndrome, as well as
the help of local support groups can provide tools for managing the disorder and preventing
complications. The following organizations can provide additional information
about GBS:
National Institute of Neurological Disorders and Stroke (NINDS)
P.O. Box 5801
Bethesda, MD 20824
Phone: (800) 352-9424
www.ninds.nih.gov
Guillain-Barre Syndrome Foundation International
P.O. Box 262
Wynnewood, PA 19096
(610) 667-0131
www.gbsfi.com
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