[Recurrent aseptic osteonecrosis in Crohn's disease - extraintestinal manifestation or steroid related complication?].

HISTORY: A 57-year-old woman complained about increasing pain and weakness in her hips and legs. 7 months earlier active (Crohn's) ileocolitis had been diagnosed. She had received several bouts of steroids and had been in clinical remission for 12 weeks under a dosage of 40 mg/d prednisone. INVESTIGATIONS: Clinical examination, laboratory work up, x-rays and MRI of the pelvis, bone scan, neurologic examination and muscle biopsy showed unspecific results. THERAPY AN COURSE: Steroides were tapered and replaced by weekly intramuscular methotrexate 20 mg which resulted in long lasting clinical remission. Pain and weakness persisted. 6 months later MRI revealed osteonecrosis of both femoral heads. 4 1/2 years after the initial diagnosis of Crohn's disease the patient complained about pain in her lower legs without evidence of osteonecrosis in MRI. Another 2 years later avascular osteonecrosis was diagnosed by tibial bone biopsy. Now MRI verified patchy osteonecrosis of the tibiae. Further osteonecrosis of the left foot were diagnosed by MRI ten years after initial diagnosis of Crohn's disease in the now 67-year-old patient. She is still in remission on weekly intramuscular 15 mg methotrexate.
CONCLUSION: The long interval between steroid treatment and recurrent avascular bone necrosis as well as the unusual pattern of bone involvement indicate that osteonecrosis is an extraintestinal manifestation of Crohn's disease. More reports and comparative studies are necessary to give more evidence that avascular osteonecrosis is an extraintestinal manifestation of inflammatory bowel disease.