Familial Mediterranean fever in which Crohn's disease was suspected: a case report

Familial Mediterranean fever is a hereditary autoinflammatory disease, mainly characterized by periodic fever and serositis. The level of awareness about familial Mediterranean fever is far from sufficient, and it is assumed that there may be many patients with this disease who are under observation without an accurate diagnosis.

A 30-year-old Japanese man presented to us with a few years' history of recurrent episodes of fever, abdominal pain and diarrhea. He often visited a hospital when the attacks occurred; however, acute enteritis was diagnosed each time, and the symptoms resolved spontaneously within a few days. When he noticed a shortening of the interval between the attacks, he visited the hospital again. Upper endoscopy and colonoscopy performed at this hospital revealed no significant abnormal findings. He was then referred to our hospital under the suspicion of a small intestinal disease. Abdominal computed tomography revealed wall thickening and increased density of the mesenteric adipose tissue in the jejunum, which led us to suspect Crohn's disease. Oral double-balloon enteroscopy was performed; because this revealed only mild mucosal edema in the jejunum, Crohn's disease was considered to be highly improbable. Based on the patient's clinical course, we suspected familial Mediterranean fever. As the Livneh criteria for familial Mediterranean fever were satisfied, the patient was started on oral colchicine for the purpose of diagnostic treatment. A definitive diagnosis of familial Mediterranean fever was then made based on the detection of a mutation of the Mediterranean fever gene. A marked reduction in the frequency of attacks was observed in response to colchicine treatment.

Although Crohn's disease may be considered first in the differential diagnosis of young patients presenting with periodic fever, abdominal pain and diarrhea, the possibility of familial Mediterranean fever should also be borne in mind.