IS Case 609: Duchenne's muscular dystrophy
Imaging Sciences URMC 2011
Publication Date: 2011-12-12
History
The patient is a 21-year-old male, with history of Duchenne’s muscular dystrophy and nephrolithiasis, presenting with flank pain.
Diagnosis
Duchenne's muscular dystrophy
Discussion
Duchenne’s muscular dystrophy is an X-linked neuromuscular degenerative disorder caused by a mutation in the gene for dystrophin located on chromosome 21. This protein plays a role in sarcolemmal stability. Histologically, there is initial myonecrosis with replacement by fatty and connective tissue, causing pseudohypertrophy. The forearms and calves particularly demonstrate pseudohypertrophy. Patients who have this disorder are male or females with Turner’s syndrome, and an early sign of this disorder is Gower’s sign, where the young boy pushes on his knees to stand, secondary to proximal muscle weakness. A key feature is symmetric muscle involvement. It is progressive, with no known cure, and is diagnosed by a muscle biopsy, with laboratory tests demonstrating increased creatine phosphokinase levels.
Other findings associated with this disease include pes cavus, scoliosis, loss of bladder control, and respiratory difficulty. These features can be seen on imaging with CT, MRI, US, and radiographs, demonstrating fatty infiltration of the muscles, with associated secondary features such as hypoventilation, scoliosis, gracile bones, contractures, and calf/forearm muscle pseudohypertrophy.
References
- Ozsarlak O, Schepens E, Parizel PM, et al. Hereditary neuromuscular diseases. Eur J Radiol. 2001 Dec;40(3):184-97. PMID: 11731207
- Mellion ML, Tseng BS. Dystrophinopathies. eMedicine-Medscape. Updated: Dec. 16, 2010. http://emedicine.medscape.com/article/1173204-overview
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