Dr. Yadollah Harati is a professor of neurology at Baylor College of Medicine in Houston, where he also directs the Muscle and Nerve Pathology Laboratory and conducts research at the MDA/ALS Center. Dr. Harati is chief of the neurology service at the Veterans Affairs Medical Center in Houston.

Dr. Harati:  With today's medications, myasthenia can usually be improved so that chewing and swallowing aren't a problem. However, while the disease is being brought under control, dangerous choking can occur.

A person with myasthenia gravis may find that her chewing muscles are tired after a few bites, especially with tough foods like meat. Swallowing difficulties may cause liquids to "come back up" through the nose or be inhaled into the lungs.

It's very important for people not to eat or drink foods that make them choke. Food or liquid that gets into the lungs can cause what's known as aspiration pneumonia. This is not only bad in itself, but, like other infections, it also makes myasthenia worse.

Myasthenia is also made worsenheat, so I advise taking cold food and drink during acute phases of the disease. Foods that are hot (in temperature, not spiciness) can adversely affect the swallowing muscles.

If swallowing really becomes a problem, the patient's doctor can insert a nasogastric (nose-to-stomach) tube through which liquid food can be taken until medication brings the disease under control.

Nasal speech and impaired breathing often accompany chewing and swallowing difficulties.

A.  I usually tell patients that they can do what they want, but that as soon as they're tired, they should stop. An extra five minutes or half hour might have serious adverse effects. When a person feels myasthenic symptoms coming back, he or she should rest. If people push themselves too far, they could develop more weakness or breathing problems.

A.  Avoiding exposure to excessive heat is important for people with myasthenia, so they should not exercise in hot environments or do exercise that raises body temperature a lot. Swimming is best, because the water cools the body while the person is exercising.

Gentle walking is also all right. Most activities that require vigorous and repetitive use of muscles are not good.

A.  Yes. Most patients with myasthenia have an increased sleep requirement. One of the earliest symptoms of myasthenia gravis is increasingly frequent napping. In the early stages of the disease, a nap may make all the symptoms go away. Early in the disease, if a patient sees his doctor only when well rested, it may be difficult to make a correct diagnosis. People have occasionally received a mistaken diagnosis of a psychiatric illness.

A.  Emotional stress of all kinds makes people with myasthenia feel weaker. Even good stress, like preparing for a wedding, can do this. We don't really know how stress affects myasthenia, but this is one condition in which there seems to be a direct effect of the mind on the body.

A.  Pregnancy often causes changes in myasthenia gravis symptoms for better and for worse. In general, women with myasthenia gravis tend to get worse during the first three months and may get better during the last six months of pregnancy.

After the baby is born, the woman's responsibilities increase, her rest time is reduced, and her myasthenia may get out of control. A patient must have plenty of help after the baby is born so she isn't suddenly overwhelmed by the physical demands.

A woman with myasthenia gravis who's planning a pregnancy should have her myasthenia in optimal control before getting pregnant and will need close monitoring by a physician during her pregnancy. I refer my patients to obstetricians who specialize in high-risk pregnancies.

A.  Myasthenia gravis may make labor and delivery more difficult because of muscle weakness, so that a forceps or even cesarean delivery may be necessary. Pregnancy may also be complicated by weakness of abdominal and pelvic muscles.

The obstetrician and anesthesiologist should know about the patient's myasthenia gravis and should avoid giving drugs, such as those containing magnesium, that are known to make myasthenia worse. (Magnesium sulfate is sometimes used to treat severe high blood pressure during pregnancy.)

Some of the medications used to treat the mother's myasthenia gravis, such as immunosuppressants, can adversely affect the baby. These drugs are best avoided during pregnancy.

About 12 percent of babies of myasthenic mothers are born with temporary myasthenia and have feeding difficulties, a weak cry, weakness and breathing problems at birth. This happens because the baby may get some of the mother's muscle-attacking antibodies. Fortunately, most of these babies are better within a few days to two weeks, with a rare baby showing symptoms for three months.