Late-onset-case of Familial Mediterranean fever (FMF)-exotic but rising differential diagnosis of "unclear abdominal illness" in Germany due to increasing migration over the past decade.

backgroundRecurrent fever and acute abdominal pain are common reasons for emergency visits, particularly in adolescents. These symptoms often lead to misdiagnosis and unnecessary surgeries like appendectomy. Familial Mediterranean fever (FMF), a rare autoinflammatory disorder, should be considered in patients with periodic febrile abdominal episodes, especially in those with a migration background. CASE PRESENTATION: A 19-year-old male of Syrian origin presented with acute right lower quadrant abdominal pain, fever, arthralgia, and pleuritic chest pain. Similar episodes had occurred in the past and resolved spontaneously. Physical examination revealed signs of peritonism; laboratory results showed elevated C‑reactive protein (CRP; 35 mg/L) with normal white blood cell counts. Abdominal ultrasound excluded appendicitis. Conservative treatment (fluids, analgesics, dietary rest) led to full symptom resolution within 2 days. After recovery, a detailed family history revealed consanguinity and a relative with similar symptoms. The diagnosis of FMF was made based on the Tel Hashomer criteria. Colchicine therapy (1.0 mg/day) was initiated.

conclusionThis report illustrates a case of late-onset FMF in a migrant adolescent, with typical symptoms but without definitive serositis or confirmed genetic diagnosis at the time of treatment. The case underscores the importance of thorough history-taking and highlights the need to avoid unnecessary CT scans in similar settings. Awareness of FMF is crucial in nonendemic regions experiencing increased migration from high-incidence countries.