Sunday, March 22, 2015

progressive clumsiness and difficulty walking

A 2-year-old boy presents with progressive clumsiness and difficulty walking. On physical examination, the child has large calves. He has difficulty walking on his toes and has a waddling gait.
Gower maneuver is positive.

Which of the following is the most likely diagnosis?

a. Becker muscular dystrophy
b. Myotonic dystrophy
c. Facioscapulohumeral dystrophy

d. Duchenne muscular dystrophy

The answer is d. Children with Duchenne muscular dystrophy (DMD) present between the ages of
2 and 6 years with fatigability, clumsiness, difficulty standing, difficulty walking on toes, pseudohypertrophy of the calf muscles, and a waddling gait. DMD results from a deficiency of dystrophin, while Becker MD is the result of abnormal dystrophin. Becker MD is less severe than DMD and occurs after the age of 5 years. Both Becker and Duchenne MD are X-linked
myopathies. The autosomal dominant myopathies are myotonic dystrophy and facioscapulohumeral dystrophy. Myotonic dystrophy occurs in adolescence and is characterized by diminished facial movements, cataracts, testicular atrophy, and muscle weakness.

Facioscapulohumeral dystrophy occurs between the ages of 10 and 20 years and is characterized by facial and shoulder girdle weakness. The Gower maneuver (pushing off with the hands when rising from the floor because of proximal muscle weakness) is positive in muscular dystrophy.


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