What Is Lambert-Eaton
syndrome (LEMS) is a rare autoimmune disease that affects your ability to
move. Your immune system attacks muscle tissue which leads to difficulty
walking and other muscular problems.
The disease can’t be cured, but
symptoms can temporarily lessen if you exert yourself. You can manage the
condition with medication.
What Are the Symptoms of
Lambert-Eaton Myasthenic Syndrome?
The primary symptoms of LEMS are leg
weakness and difficulty walking. As the disease progresses, you’ll also
- weakness in facial muscles
- involuntary muscular symptoms
- dry mouth
- bladder problems
Leg weakness often improves
temporarily upon exertion. As you exercise, acetylcholine builds up in large
enough amounts to allow strength to improve for a short time.
There are several complications
associated with LEMS. These include:
- trouble breathing and swallowing
- injuries due to falling or problems with coordination
What Causes Lambert-Eaton
In an autoimmune disease, your body’s
immune system mistakes your own body for a foreign object. Your immune system
produces antibodies that attack your body.
In LEMS, your body attacks nerve
endings that control the amount of acetylcholine your body
releases. Acetylcholine is a neurotransmitter that triggers muscle
contractions. Muscle contractions allow you to make voluntary movements such as
walking, wiggling your fingers, and shrugging your shoulders.
Specifically, your body attacks a
protein called voltage gated calcium channel (VGCC). VGCC is required for
the release of acetylcholine. You don’t produce enough acetylcholine when VGCC
is attacked, so your muscles are unable to work properly.
Many cases of LEMS are associated with
lung cancer. Researchers believe that the cancer cells produce the VGCC
protein. This causes your immune system to make antibodies against VGCC. These
antibodies then attack both the cancer cells and the muscle cells. Anyone can
develop LEMS in their lifetime, but lung cancer may increase your risk of
developing the condition. If there is a history of autoimmune diseases in your
family, you may be at higher risk of developing LEMS.
To diagnose LEMS, your doctor will
take a detailed history and perform a physical examination. Your doctor will
- decreased reflexes
- muscle tissue loss
- weakness or trouble moving that gets better with
Your doctor may order several tests to confirm the condition. A
blood test will look for antibodies against VGCC (anti-VGCC antibodies). An
electromyography (EMG) tests your muscle fibers by seeing how they react when
stimulated. A small needle is inserted into the muscle and connected to a
meter. You’ll be asked to contract that muscle, and the meter will read how
well your muscles respond.
Another possible test is
the nerve conduction velocity test (NCV). For this test, your doctor will place
electrodes on the surface of your skin covering a major muscle. The patches
give off an electrical signal that stimulates the nerves and muscle. The
activity that results from the nerves is recorded by other electrodes and is
used to find out how quickly the nerves react to stimulation.
This condition cannot be cured. You’ll
work with your doctor to manage any other conditions, such as lung cancer.
Your doctor may recommend intravenous immunoglobulin (IVIG)
treatment. For this treatment, your doctor will inject a nonspecific antibody
that calms the immune system. Another possible treatment is plasmapheresis.
Blood is removed from the body, and the plasma is separated out. The antibodies
are removed, and the plasma is returned to the body.
Drugs that work with your muscular
system can sometimes relieve symptoms. These include mestinon (pyridostigmine)
and 3, 4 diaminopyridine (3, 4-DAP).
These medications are hard to obtain,
and you should talk to your doctor to find out more information.
What Is the Long-Term
Symptoms may improve by treating other
underlying conditions, suppressing the immune system, or removing the
antibodies from the blood. Not everyone responds well to treatment. Work with
your doctor to come up with an appropriate treatment plan.