The pattern of muscle loss in BMD usually begins with the hips and pelvic area, the thighs and the shoulders. To compensate for weakening muscles, the person may walk with a waddling gait, walk on his toes or stick out the abdomen.
The rate of muscle degeneration varies a great deal from one person to another. Some men require wheelchairs by their 30s or later, while some manage for many years with minor aids, such as canes.
Because muscular dystrophy doesn’t affect nerves directly, touch and other senses remain normal, as does control over the smooth, or involuntary, muscles of the bladder and bowel, and sexual functions.
Muscle deterioration in BMD usually isn’t painful in itself. Some people report muscle cramps at times; these usually can be treated with over-the-counter pain relievers.
Like muscles in the limbs, heart muscles also can be weakened by lack of dystrophin. People with BMD often develop cardiomyopathy — heart muscle weakness — because of a deficiency of dystrophin. The muscle layer (myocardium) of the heart deteriorates, just as the skeletal muscles do.
Damage done by BMD to the heart can become life-threatening as early as the teen years, and some people with BMD have mild skeletal muscle involvement but severe cardiac problems. For these reasons, everyone with BMD should be monitored by a cardiologist. See the Medical Management section for more information on managing heart problems in BMD.
To view a presentation by cardiologist Elizabeth McNally about the heart in BMD, see the August 2012 video Cardiac Complications and Management in BMD.
Respiratory muscles often stay strong in BMD for many years, but eventually, they may become weaker than is optimal for breathing and coughing (to clear secretions from the respiratory tract).
To view a presentation by pulmonary medicine specialist Lisa Wolfe at Northwestern University in Chicago, see the August 2012 video Lung Health in Neuormuscular Disease.
Doctors believe that dystrophin abnormalities in the brain may cause subtle cognitive and behavioral deficits. The learning problems seen in some people with BMD seem to occur in three general areas: attention focusing, verbal learning and memory, and emotional interaction. For more on coping with intellectual effects, see Medical Management.