Crohn's disease

(Burrill Bernard Crohn, 1884 - 1983, American physician), a chronic enteropathic disorder of unknown cause associated with musculoskeletal abnormalities. This disease is a recurrent granulomatous process that involves mainly the terminal ileum and proximal portion of the colon. For a general description, see Crohns disease.

The musculoskeletal manifestations may consist of peripheral joint arthralgias and arthritis, sacroiliitis and spondylitis, and various other abnormalities. In the peripheral joints a migratory synovitis of one or several joints is the most frequent finding, with the knee being the most common site of abnormality. Pain, swelling, tenderness, and restricted motion are typical. The radiographic abnormalities are not diagnostic and consist of soft tissue swelling and regional osteoporosis. The sacroiliitis and spondylitis occurring in Crohn's disease are identical radiographically to those of classic ankylosing spondylitis (bilateral sacroiliac joint narrowing; erosion and sclerosis of the ilium and sacrum; erosion, sclerosis, and squaring of the vertebrae; syndesmophytosis; and apophyseal joint erosion, sclerosis, and spinal narrowing) (see intestine (III:1), Fig. 1). If the alterations are progressive, a bamboo spine can result. Digital clubbing is seen in Crohn's disease. Granulomatous and infectious processes of bone also have been reported in this disease. Some investigators regard Crohn's disease as the leading cause of psoas abscesses. Crohn's disease can lead to retarded skeletal maturation, decreased linear growth, and osteopenia.

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