Protracted Febrile Myalgia as a First and Challenging Manifestation of Familial Mediterranean Fever

Mod Rheumatol. 2022 Aug 3;roac087. doi: 10.1093/mr/roac087. Online ahead of print.

Abstract

Objectives: Familial Mediterranean fever (FMF) is an autoinflammatory disease that causes recurrent episodes of fever, abdominal pain, chest pain, and arthritis. Although FMF is well known, PFMS is a clinical condition that is rare and difficult to diagnose than other symptoms of FMF. PFMS causes fever, myalgia and acute phase reactant elevation that lasts 2-4 weeks if corticosteroid treatment is not given. In some cases, fever may not be seen. The purpose of this report is to share our experience with PFMS patients in our clinic.

Methods: This is an observational, retrospective, single-center study. We evaluated patients who had been diagnosed with PFMS at our pediatric rheumatology clinic.

Results: Protracted febrile myalgia syndrome was observed in 14 patients. Nine of the patients were female. The median age at the time of diagnosis of PFMS was 10 years. Only 3 patients had previously been diagnosed with FMF. Most of our patients were patients who had no previous complaint of FMF. PFMS attack was seen as the first clinical manifestation of FMF in eleven patients. Two patients who did not respond to steroid treatment improved with anakinra treatment.

Conclusions: PFMS is a rare condition of FMF disease. It may be the first clinical manifestation of FMF disease. Fever may not be seen in all patients. Clinicians should be aware of this situation.

Keywords: child; familial Mediterranean fever; myalgia; protracked febrile myalgia.