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IntroductionFamilial Mediterranean fever (FMF) is classically manifested with painful, irregularly recurrent, short-lasting bouts of serosal infl ammation (mainly peritonitis, synovitis or pleuritis), accompanied by fever, and resolving spontaneously [ 1 ]. A rise then fall of acute-phase reactants is typical, but some patients might suffer from continuous infl ammation and its associated manifestations [ 2 ]. The disease onset is usually in childhood or adolescence, but, in some patients, the initial symptoms develop later in life, during the ages of 20-40 years and sometimes even later [ 3 ]. In general, late-onset FMF has a mild phenotype and its genotype lacks the homozygous M694V genotype [ 3 ]. The clinical manifestations may vary between patients, including members of the same family and even between identical twins 48 [ 4 , 5 ]. Clinical diversity may also be seen in the same individual, with different site of attacks in different episodes. Approximately 50 % of FMF patients experience a prodrome over the day preceding the attack, usually manifested as discomfort at the impending attack site and various constitutional, emotional, and physical manifestations [ 6 ]. Many factors have been described as triggers of the FMF attack, including stressful experiences [ 7 ], exposure to cold weather, surgical operations, drugs, certain food items, and menstrual cycles [ 8 , 9 ]. The typical length of the attacks is 24-72 h. The most frequent clinical manifestations of FMF are peritonitis (in ~95 % of FMF patients), fever (>90 %), acute arthritis or arthralgia (~50 %), myalgia (~40 %), pleuritis (~30 %), and erysipelas-like erythema (ELE) (~5 %) [ 10 , 11 ]. Other clinical features are less frequent, including pericarditis, protracted febrile myalgia, protracted arthritis, and tunica vaginalitis (resembling orchitis).In this chapter, we describe the classic manifestations of adult FMF, as well as other manifestations, usually not in the mainstream of the FMF routine daily doings, involving the neurologic, skin, cardiovascular (CV), renal, hepatobiliary, and pulmonary systems.
Classic Manifestations of FMF
The Peritoneal AttackThe most common site of acute FMF attack is the abdomen, and the majority of abdominal attacks are accompanied by fever. The abdominal attack is caused by infl ammation of the peritoneum, and therefore, the classical attack in its most severe presentation simulates acute abdomen of a perforated viscera. This fact is important when contemplating a diagnosis of FMF. The presence of peritoneal irritation turns recurrent episodes of abdominal pain from a highly nonspecifi c manifestation into a diagnostic clue. In fact, many FMF patients have a history of appendectomy, with an erroneous removal of benign appendix (white appendix). During the abdominal attack, physical examination will elicit peritoneal signs (rebound, rigidity), distention, and decreased peristalsis. A plain abdominal fi lm may show air-fl uid levels in the intestine. Usually constipation characterizes the abdominal attack, but i...