Reference no: EM133289881

Assignment:

History: James Fenlow, a 19-year old male, is immobile and hospitalized for pneumonia. He has a long history of progressive weakening of his muscles. In the first year of his life, James reached many gross motor skill milestones, such as holding his head up, rolling over, sitting, and standing, at normal times. However, he did not walk until age 16 months, and by age two, started to assume a lordotic posture while standing but not while sitting. A Gower's sign was noted by age four, as was a Trendelenberg gait. Over the next several years, he suffered progressive muscle weakness, most notably in the proximal musculature of the arms, pelvis, and legs. By age 9, he required orthotic braces to assist his walking, and by age 11, he was confined to wheelchair ambulation.

In his early teen years, James was still able to use eating utensils, write, and type on a keyboard, though these functions have declined over the past year. At 16, he was hospitalized with bronchitis requiring antibiotic treatment, but recovered. Throughout the years, James has had no history of muscle pain or spasm, chest pain, or irregular heartbeat. He was diagnosed with a learning disability in the fourth grade, but has progressed through the grades with tutorial assistance. The only medications that he normally takes are calcium and fluoride supplements. James has a younger sister in good health and a younger brother (age 10) who is confined to a wheelchair with problems similar to James's. No other immediate or distant family members have musculoskeletal difficulties.

Question: At age 4, James underwent a biopsy of the right gastrocnemius muscle. The pathologist's report noted histopathologic changes suggestive of Duchenne muscular dystrophy. Describe in detail the typical microscopic changes noted in the muscle tissue of someone with Duchenne's muscular dystrophy.

Which muscles are most severely affected by this disease process?