Do you sometimes feel like your legs are weak, you have difficulty getting up from a chair, you feel tired when you climb stairs? Or do you feel tired with symptoms like heavy eyelids, dry mouth, and double vision? These may not just be tiredness. Today we will talk about a condition that you may not have heard of, but is very worth knowing about, Lambert-Eaton Myasthenic Syndrome, or ``(LEMS)`` as we call it for short.
What is Lambert-Eaton Myasthenic Syndrome (LEMS)?
Simply put, Lambert-Eaton Myasthenic Syndrome (LEMS) is an autoimmune disorder. Now you might be wondering what an autoimmune disorder is. Our bodies have an immune system. This is what protects us by fighting off disease-causing germs from outside. It's like the army in our country. But sometimes this immune system goes awry. Then it starts attacking our own healthy cells. That's what happens in LEMS.
In this `(LEMS)`, our immune system attacks the connection between our motor nerves and muscles . To be precise, this connection is called the `neuromuscular junction`. When this junction is damaged, the transmission of messages from the nerves to the muscles is impaired. This is when muscle weakness occurs.
This weakness usually starts in your upper thighs , but it can gradually spread to your arms, breathing, swallowing, and speaking muscles.
Who is more likely to develop this `(LEMS)`?
There are two main groups that make up `(LEMS)`.
1. Associated with cancer: About 60% of people with LEMS have some form of cancer. The most common type is small-cell lung cancer . Surprisingly, sometimes the symptoms of LEMS can appear months or even years before the cancer develops. Most of these people are over the age of 60, are male, and have used tobacco products.
2. No cancer: The other 40% of people with LEMS have no cancer detected. These people are usually diagnosed at around age 35 and again at around age 60.
LEMS is a very rare condition among young children.
Is only small cell lung cancer (LEMS) associated with this?
No. Small-cell lung cancer is the most common type of cancer, but other types of cancer can also be associated with LEMS. Examples include prostate cancer, thymoma, and lymphoproliferative disorders. Because the symptoms of LEMS can appear before cancer symptoms appear, it is important to have the right tests to check for cancer if your doctor diagnoses you with LEMS.
Is LEMS caused by genetic changes?
Scientists believe that autoimmune diseases in general may have some genetic link. Since LEMS is also an autoimmune disease, it is possible that it also has a genetic influence, but this is not yet fully understood.
How common is `(LEMS)`?
LEMS is a very rare disease . It is estimated that this condition affects about 2.8 million people worldwide. In the United States, there are about 400 reported cases of LEMS. Although there are no exact statistics on how many people there are in our country, it is clear that this is a rare condition.
What are the symptoms of `(LEMS)`?
Let's look at the symptoms of `(LEMS)` one by one. Not all of these symptoms occur at the same time in everyone, some symptoms may appear earlier, some may appear later.
- Muscle weakness and fatigue: especially in the upper legs.
- Difficulty walking: Difficulty climbing stairs or getting up from a chair.
- Muscle pain or stiffness.
- Feeling of numbness in the limbs.
- Drooping eyelids (ptosis): This can look like sleepiness.
- Seeing two things at once (diplopia).
- Dry mouth and eyes (xerostomia): decreased salivation, decreased tears in the eyes.
- Constipation.
- Decreased sweating.
- Weight loss.
- Difficulty urinating.
- Erectile dysfunction in men.
- Difficulty speaking (dysarthria) and difficulty swallowing (dysphagia): These are usually symptoms that develop later in the disease.
- Difficulty breathing (dyspnea) and respiratory distress: This is also a rare, severe symptom that can occur in the late stages of the disease.
Important: If you have one or more of these symptoms, do not assume that it is LEMS. However, if these symptoms persist, it is wise to seek medical advice.
How does LEMS usually appear and progress?
LEMS usually first affects the muscles of the thighs . It can then affect the shoulder muscles, the muscles of the arms and legs, the muscles that help with speech and swallowing, and the muscles of the eyes.
Early in the disease, you may have difficulty getting up from a chair, climbing stairs or hills, or doing strenuous work that requires using your legs.
Symptoms usually develop slowly, over a few weeks to months . However, if you have LEMS with cancer, symptoms may develop more quickly.
What causes LEMS?
As we've discussed before, LEMS is an autoimmune disease . This means that your body's own defenses (antibodies) attack your own healthy tissues. In LEMS, these antibodies attack the place where nerve cells and muscle fibers meet, the neuromuscular junction. Specifically, they attack the calcium channels there. These calcium channels are essential for nerve messages to be transmitted.
Think of it like a row of dominoes. This attack sets off a chain of events:
1. The antibodies bind to the calcium channels at the ends of nerve cells and block them.
2. When calcium channels are reduced, the amount of acetylcholine, a neurotransmitter, released decreases. This acetylcholine is a chemical essential for muscle function.
3. When not enough acetylcholine is released, the "messages" to the muscle fibers don't get through properly. Then your muscles can't function fully.
4. As a result, the muscles do not function normally, resulting in weakness.
Here's how people with small-cell lung cancer develop LEMS: When you have cancer in your body, antibodies get a signal to "go to war." But instead of attacking the cancer cells (specifically, the calcium channels on the surface of the cancer cells), these antibodies mistakenly attack the calcium channels on the ends of nerve cells. Then the same chain of events happens.
Scientists believe that the cause of LEMS in people without lung cancer is simply a malfunction of the immune system. But it is not yet clear why this happens.
How to identify `(LEMS)`?
The first step in diagnosing LEMS is for your doctor to examine you carefully. This will often involve a neurologist, or a doctor who specializes in diseases of the nerves and muscles. Part of this process involves asking about your symptoms, your medical history, and any medications you take. A detailed neurological examination is performed to look for patterns of weakness and signs consistent with LEMS.
The next step is testing. Tests for `(LEMS)` include:
- Blood test: This can check if you have anti-calcium channel antibodies in your blood. About 85% of people with LEMS have these antibodies in their blood.
- Electromyography (EMG): This test looks at how well your muscles and nerves are working together. In LEMS, the EMG test has very specific findings, so it can help confirm the diagnosis.
- Lung X-ray `(X-ray)` or CT scan `(CT scan)` or MRI scan `(MRI)` (of the chest): Because a condition called `(LEMS)` can develop in people with small cell lung cancer, these tests look for signs of lung cancer.
Symptoms of LEMS can begin months to six years before cancer develops. Therefore, after LEMS is diagnosed, you should have cancer screenings every three to six months for at least two years. Your doctor will recommend a screening schedule that is right for you.
How is LEMS treated?
There are several treatments for LEMS.
- Treating the underlying cancer: If LEMS is related to a cancer, such as small cell lung cancer, treating that cancer may also reduce LEMS symptoms. Cancer treatments may include chemotherapy, radiation therapy, and/or surgery. This depends on the type of cancer and your doctor's recommendations.
- Specific treatments for (LEMS): These include medications that relieve symptoms and medications that control the immune system.
Treatment for symptoms
- Amifampridine (Firdapse®), Guanidine: These drugs increase muscle strength. They increase the release of the neurotransmitter acetylcholine at the neuromuscular junction, improving signals to the muscles.
- Pyridostigmine (Pyridostigmine - Mestinon®): Pyridostigmine works by preventing the breakdown of acetylcholine at the neuromuscular junction. This also increases acetylcholine signaling and improves muscle strength. Pyridostigmine is sometimes given in combination with amifampridine to improve muscle function and treat symptoms of LEMS such as dry mouth, dry eyes, constipation, sexual dysfunction, and decreased sweating. However, the use of pyridostigmine for LEMS is an off-label use, meaning the U.S. Food and Drug Administration (FDA) has not approved the drug for this condition.
Immune-modulating treatment
- Immunosuppressants: These drugs help to suppress or control the "defense" function of your immune system. Your doctor may prescribe these drugs if other drugs don't control your symptoms. For example, a drug called prednisone may be given with or without azathioprine or cyclosporine.
- Plasma exchange: In this procedure, a machine separates the liquid part of your blood (plasma) from the blood cells. Your antibodies are in this plasma. After the separation, the blood is put back into your body. Your doctor may consider this treatment if you have severe symptoms and need urgent treatment.
- Immunoglobulins: For some people, high-dose immunoglobulin treatment may help prevent the disease from getting worse.
Can LEMS be prevented?
The exact cause of LEMS is not yet fully understood, so it is not known whether there is a way to prevent the disease.
However, since LEMS can develop in people with lung cancer, you can help prevent lung cancer by:
- Don't smoke. If you use tobacco products, ask your doctor for help quitting.
- Avoid second-hand smoke.
- Check your home for radon gas. Long-term exposure to radon gas can increase your risk of lung cancer.
You can also take steps to maintain a healthy lifestyle:
- Eat more fruits and vegetables. Follow the Mediterranean or DASH diet.
- Maintain a healthy weight.
- Exercise as advised by your doctor.
- Get enough sleep - usually seven to nine hours.
- Reduce your stress levels. Stress can make symptoms worse.
- Avoid bathing in hot water. Heat can worsen the symptoms of LEMS.
- See your doctor regularly, and let them know immediately if your health changes or if you develop new symptoms.
Can LEMS be completely cured?
Unfortunately, there is no cure for LEMS. Treating the underlying cancer associated with LEMS has been shown to improve symptoms of LEMS. Immunosuppressive drugs can help control the autoimmune attack, and there are also treatments that can help relieve symptoms by increasing the amount of acetylcholine in nerve endings and improving muscle strength.
If you have LEMS without cancer, you can expect a normal life expectancy. If you have LEMS and cancer, your symptoms may improve over time (although not completely) if the cancer is detected and managed early.
Your quality of life largely depends on the severity of your symptoms.
When should I contact my doctor if I have `(LEMS)`?
If there is a change in your health, or if your symptoms worsen, contact your doctor at any time . Don't be afraid, don't panic. Doctors are there to help you.
What is the difference between `(LEMS)` and `(Myasthenia Gravis - MG)`?
Lambert-Eaton myasthenic syndrome (LEMS) and myasthenia gravis (MG) share some similar symptoms. Both cause muscle weakness and fatigue.
However, myasthenia gravis (MG) usually first affects the muscles around your eyes and the muscles used for swallowing. Later, it can affect more general muscles, including the muscles of breathing and the muscles of the limbs.
LEMS usually starts with weakness in your upper thighs, then moves to your arms. LEMS can also cause weakness in your eye muscles, but it is usually milder than myasthenia gravis (MG).
In myasthenia gravis (MG), severe weakness of the respiratory muscles (the muscles that help you breathe) can be fatal. This is rare in LEMS.
People with myasthenia gravis (MG) usually do not show many symptoms of autonomic nervous system dysfunction (e.g., dry eyes, dry mouth, constipation, decreased sweating, sexual dysfunction). In contrast, people with LEMS often have these complaints, and these symptoms can sometimes help to distinguish the two diseases.
Finally, things to remember (Take-Home Message)
By now you probably understand that Lambert-Eaton Myasthenic Syndrome (LEMS) is a disease caused by an overactive immune system. Your nerve cells don't send enough messages to your muscle fibers to "contract." The result is muscle weakness and other symptoms.
Remember, about 60% of people with LEMS have small-cell lung cancer. If you have LEMS but don't have cancer, make sure you and your doctor have cancer screenings every few months for at least two years after diagnosis.
There are treatments. These include treating the cancer if it is present, as well as taking drugs that improve nerve cell-muscle fiber communication. Improving communication can improve muscle strength and other symptoms.
I hope this information is helpful to you. Always remember, if you have any health concerns, it is best to talk to a qualified doctor about them.
` Lambert-Eaton myasthenic syndrome, LEMS, autoimmune diseases, muscle weakness, small cell lung cancer, neuromuscular junction, acetylcholine
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