Becker's muscular dystrophy

Alternative names:

benign pseudohypertrophic muscular dystrophy

Symptoms:

• muscle weakness, slowly progressive
• frequent falls
• difficulty with muscle skills (running, hopping, jumping)
• progressive difficulty walking
  • loss of walking ability occurs slowly
  • ability to walk may continue into adulthood (up to age 40)

• intellectual retardation
• skeletal deformities, chest and back (scoliosis)
• muscle deformities - contractures of heels, legs
  • pseudohypertrophy of calf muscles

• fatigue

Signs and tests:

The pattern of symptom development resembles that of Duchenne's muscular dystrophy, but with a much slower rate of progression. Muscle wasting begins in the legs and pelvis, then progresses to the muscles of the shoulders and neck, followed by loss of arm muscles and respiratory muscles. Calf muscle enlargement (pseudohypertrophy) is quite obvious. Cardiomyopathy is commonly present but development of congestive heart failure or arrhythmias (irregular heartbeats) is rare. The ability to walk may continue to age 40 or more.

• A CPK may be elevated.
• An EMG (electromyography) shows that weakness is caused by destruction of muscle tissue rather than by damage to nerves.
• A muscle biopsy confirms the diagnosis.