Lambert–Eaton Myasthenic Syndrome (LEMS)


Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune condition in which antibodies attack the nerve endings and stop muscles contracting, thus causing muscle fatigue. For half of people, LEMS is an early sign of lung cancer. The condition is an unusual reaction against the cancerous cells.

The difference between LEMS and MG


Unlike myasthenia gravis, LEMS symptoms start in the lower body. The legs feel heavy, a sensation described as walking through treacle. It can also affect arms but it is less common for it to affect facial muscles. Some people experience problems with automatic bodily functions (dry mouth, constipation, impotence in men).


Blood tests are used to detect the antibodies that cause the disease. Some people are offered a test to assess muscle activity.


Steroids and immunosuppressants: Immune suppressing drugs, including steroids, are often used in people who have become disabled.

Pyridostigmine: Some people can control their myasthenia with enzyme blocking drugs. The drug boosts the message from the nerve to the muscle. Find out more.

Side effects: Stomach cramps, digestive problems and an urgent need to urinate.

Immunosuppressive drugs: The steroid prednisolone is often used (typically on alternate days); doses may have to be built up high before a lower maintenance level is found. Benefits typically kick in after 2-3 months.

Side effects: Can include weight gain, hypertension, glaucoma and cataract and / or osteoporosis. Care should also be taken to monitor patients at risk of tuberculosis or peptic ulceration.

3,4-diaminopyridine (3,4-DAP): This works by boosting the feeble ACh release. It makes the electrical messages in the nerves last longer. DAP has to be used carefully; it is sometimes combined with pyridostigmine.

Side effects: 3,4-DAP can cause short-term tingling around the mouth or in the fingers and toes. At high doses it can also affect the brain causing anxiety, over-excitement and even epileptic fits but this is very rare below 100 mg per day.

Those taking steroids may find they suffer from thinning of the stomach lining causing acid indigestion and potentially stomach ulcers. Other side effects may include mood swings, increased appetite, high blood pressure, increased sweating, increased hair growth and thrush. Prolonged use of steroids can thin the bones. People on steroids are also at an increased risk of infection so should visit their GP at the first sign of illness and not be given live vaccines.

For acute exacerbation's there are two treatments that may offer rapid (within a few days) improvement plasma exchange and IVIG. They are of similar efficacy but each presents resource issues and the specialist will decide which is most appropriate. Benefit only lasts a few weeks, but this gives time for other treatments to become effective.

Plasma exchange: In severe cases people will be admitted to hospital for plasma exchange, an emergency treatment to remove antibodies from the blood, or an infusion of intravenous immunoglobulin. The benefits of these emergency treatments last for about six weeks.

Side effects: feeling faint or light headed, numbness and tingling.

IVIG (Intravenous Immunoglobulin): This treatment takes place in hospital. The treatment involves being injected with normal antibodies from donated blood and this will temporarily change the way your immune system operates.

Side effects: IVIG is a blood thickening treatment so there is a very slight increase in the risk of heart attack and stroke. Read more.

Drugs that can make myasthenia worse

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