Familial Mediterranean fever (FMF) (also known as recurrent polyserositis) is a genetic autoimmune condition that is notable for its spontaneous self-limiting acute episodes of fever and serositis, especially peritonitis and synovitis.
Familial Mediterranean fever tends to be ethnic specific, the vast majority of patients being Turkish, Jewish, Arabs and Armenians. The largest number of patients globally are found in Turkey, with a disease prevalence between 1 in 150 and 1 in 10,000 patients 1. It is slightly more common in the male population 1.
Familial Mediterranean fever is characterized by:
- spontaneous serial acute attacks
- fever (typically >38°C), and
- symptoms of serosal inflammation
- abdominal pain (peritonitis) and joint pains (synovitis): most common
- occasional pleuritis, pericarditis etc.
- flu-like symptoms common, e.g. arthralgia, myalgia, etc.
- episodes last minimum 12 hours, subsiding within 3-4 days
- 90% first episode is seen in patients <20 years old
- 60% the age of initial onset is <10 years old
- development of this sequela, and associated amyloid-related chronic renal failure, is a major determinant of the long term prognosis of familial Mediterranean fever
Familial Mediterranean fever is a single gene defect disorder with an autosomal recessive pattern of inheritance. The MEFV gene is found on chromosome 16p13·3 and it encodes a protein named pyrine. Pyrine is important in the regulatory control of apoptosis and inflammation, however its physiology is still being teased out. Point mutations in MEFV, are typically found in those with familial Mediterranean fever.
CT is the mainstay of investigation of familial Mediterranean fever. The findings are non-specific and only seen during an acute episode 3,4:
The diagnosis of familial Mediterranean fever is usually not considered by radiologists/clinicians unless there is a known history of the condition.
Treatment and prognosis
Colchicine is the primary therapy and in the pre-colchicine era, the prognosis was very poor
- familial Mediterranean fever is in the differential for an acute abdomen, and occasionally surgery is erroneously performed because of this 1
- 1. Sarı İ, Birlik M, Kasifoğlu T. Familial Mediterranean fever: An updated review. (2014) European journal of rheumatology. 1 (1): 21-33. doi:10.5152/eurjrheum.2014.006 - Pubmed
- 2. Zissin R, Rathaus V, Gayer G, Shapiro-Feinberg M, Hertz M. CT findings in patients with familial Mediterranean fever during an acute abdominal attack. (2003) The British journal of radiology. 76 (901): 22-5. doi:10.1259/bjr/32051823 - Pubmed
- 3. Ishak GE, Khoury NJ, Birjawi GA, El-Zein YR, Naffaa LN, Haddad MC. Imaging findings of familial Mediterranean fever. (2006) Clinical imaging. 30 (3): 153-9. doi:10.1016/j.clinimag.2005.07.002 - Pubmed
- 4. Chae JJ, Aksentijevich I, Kastner DL. Advances in the understanding of familial Mediterranean fever and possibilities for targeted therapy. (2009) British journal of haematology. 146 (5): 467-78. doi:10.1111/j.1365-2141.2009.07733.x - Pubmed