Some myopathies, especially when they’re present from birth, have life-threatening complications. But, with time and physical therapy, some people born with myopathies can gain muscle strength. Others often can manage their symptoms through medication, lifestyle modifications, or use of orthopedic and respiratory equipment.
Myopathies aren’t caused by overexertion. However, exercise can aggravate some of the myopathies, because of mutations that change the way muscles respond to activity.
People with Andersen-Tawil syndrome need to be wary of potential heart problems, and should be closely monitored by a cardiologist. Medications called carbonic anhydrase inhibitors and potassium-sparing diuretics, as well as potassium supplements, are sometimes prescribed.
Cardiac medications also may be part of the treatment plan, and an implantable pacemaker or defibrillator is sometimes recommended.
Autosomal centronuclear myopathies
There are no specific treatments for these diseases, although supportive care, such as physical therapy to minimize contracture development, can be helpful.
Central core disease
Unlike the case for other myopathies, people with this disease can benefit from exercise. Someone with a severe form of central core disease might need a walker or other support devices for mobility, but many people require none.
Scoliosis and other skeletal problems can usually be corrected by use of orthopedic devices or by surgery. Your doctor or MDA clinic director can tell you more about the risks of surgery, and about anesthetic drugs that are safe.
Before having surgery, people who have a personal or family history of central core disease — or any other myopathy — should consult their doctors about the risks of anesthesia and about the availability of “nontriggering” anesthetics to reduce the risk of malignant hyperthermia.
Hyperkalemic periodic paralysis (HyperKPP)
In this form of periodic paralysis, attacks of weakness are associated with an increase in blood potassium level. This increase can indirectly cause an irregularity in the rhythmic contraction of the heart. People with hyperKPP should be wary of potential heart problems and have their cardiac function checked by a specialist.
To keep hyperKPP attacks to a minimum, stick to a diet rich in carbohydrates and low in potassium, and avoid strenuous exercise. When you do exercise, be sure to “cool down” with mild activity before resting.
During an attack, certain prescription drugs can be used to alleviate symptoms. Your MDA clinic director can give you more specific information on how to manage hyperKPP through appropriate exercise, diet and medication.
Hypokalemic periodic paralysis (HypoKPP)
In this form of periodic paralysis, attacks of weakness are associated with a decrease in blood potassium level. This decrease can indirectly cause an irregularity in the rhythmic contraction of the heart. People with hypoKPP should be wary of potential heart problems and have their cardiac function checked by a specialist.
As in hyperKPP, attacks of hypoKPP can be prevented by avoiding strenuous activity and alleviated by medications. The dietary precautions, however, are nearly opposite. High-carbohydrate foods can trigger hypokalemia and contribute to an attack, while potassium intake can restore serum potassium levels and stem an oncoming attack. Ask your MDA clinic director for specific recommendations about diet, exercise and medications.
Restoring normal levels of the thyroid hormones can be achieved with anti-thyroid drugs, but sometimes requires partial or complete surgical removal of the thyroid (thyroidectomy).
Thyroid hormone levels can be brought up to normal with oral medication.
Stiffness caused by myotonia congenita can interfere with simple activities like walking, grasping and chewing, but is usually manageable by doing warm-up movements.
Someone who has myotonia congenita can lead a long, productive life, and can even excel at sports where strength is more important than agility. Your MDA clinic director can tell you about appropriate exercises, and if necessary, appropriate medications for dealing with muscle stiffness.
Until recently, nearly all infants with myotubular myopathy died within their first few months of life. But it’s now clear that intensive, continuous support of feeding and ventilation can significantly improve their life expectancy and allow a high quality of life.
In myotubular myopathy, an inadequate oxygen supply to the body during severe bouts of respiratory weakness can lead to heart problems. People with this condition should be monitored by a cardiologist.
If spinal curvature develops, surgery to straighten the spine may be necessary.
An infant with nemaline myopathy usually requires a feeding tube to deliver nutrition and mechanical ventilation to support respiration. Children and adults also can benefit from respiratory support, since respiratory failure during sleep can be a persistent danger.
Also in nemaline myopathy, an inadequate oxygen supply to the body during severe bouts of respiratory weakness can lead to heart problems. People with this condition should be monitored by a cardiologist.
Affected children usually attain motor milestones slowly, and at puberty they might experience further weakening, necessitating use of a wheelchair.
Mobility and strength can be improved significantly by physical and orthopedic therapies. If you or your child has nemaline myopathy, your MDA clinic director can provide further information about treatments.
By avoiding strenuous exercise and cold, most people with this condition can largely escape disability. But medications can be beneficial, especially for those who experience symptoms independent of exercise and cold. Your MDA clinic director can give you more information about these medications.