Protracted febrile myalgia syndrome in a patient with familial Mediterranean fever homozygous for the E148Q mutation

Protracted febrile myalgia as a first and challenging manifestation of familial Mediterranean fever

OBJECTIVES

Familial Mediterranean fever (FMF) is an auto-inflammatory disease that causes recurrent episodes of fever, abdominal pain, chest pain, and arthritis. Although FMF is well known, protracted febrile myalgia syndrome (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-centre study. We evaluated patients who had been diagnosed with PFMS at our paediatric 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 three 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 11 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.

Protracted febrile myalgia syndrome as the first manifestation of familial Mediterranean fever in children: case-based review

Protracted febrile myalgia syndrome (PFMS) is one of the rare conditions characterized by long standing severe myalgia and fever in familial Mediterranean fever (FMF) patients. Laboratory studies show elevated values of inflammatory markers and normal creatinine phosphokinase (CPK) levels. Rarely, PFMS may be the first manifestation of FMF and this makes the diagnosis of FMF and PFMS challenging. The aim of this report was to describe case series of PFMS patients without previous diagnosis of FMF and discuss with other pediatric PFMS cases described in the literature. Six patients with PFMS as the first manifestation of FMF from two Pediatric Rheumatology clinics were presented. The male: female ratio was 1:1. The median (min-max) age at diagnosis was 7.05 (5.5-15.5) years. All patients had severe myalgia. No fever was detected in two patients. Only one patient had rash. Markedly elevated acute phase reactants were observed in all patients. CPK levels were normal in all patients. Also, we searched the PubMed/MEDLINE, Google Scholar, Web of Science and Scopus databases from inception to May 2020, using the keywords 'familial Mediterranean fever, protracted febrile myalgia, child' and 52 pediatric PFMS were found. In the literature, three patients did not have fever, and nineteen patients were not previously diagnosed with FMF as our patients. As a conclusion, PFMS may be the first manifestation of FMF. It should be suspected in cases with prolonged severe myalgia with or without fever, and high acute phase reactants.

Protracted febrile myalgia syndrome in a Japanese patient with fasciitis detected on MRI

Protracted febrile myalgia syndrome (PFMS) is a rare manifestation of familial Mediterranean fever characterized by prolonged severe myalgia. We herein describe a case of PFMS with fasciitis on magnetic resonance imaging. The response to corticosteroid therapy was prompt, as is typical for PFMS. An MEFV gene analysis revealed the patient to be homozygous for E148Q and compound heterozygous for P369S-R408Q. This is the first case report of a Japanese patient with PFMS. MRI findings may help to diagnose such cases.

Concurrent protracted febrile myalgia syndrome in a child with diabetic ketoacidosis

Familial Mediterranean Fever (FMF), characterized by recurrent attacks of inflammation in predominantly serosal and synovial membranes, is caused by MEFV gene mutations resulting in abnormal pyrin. Protracted febrile myalgia syndrome (PFMS), a kind of vasculitis requiring corticosteroid treatment, is associated with M694V mutation of MEFV gene. Here, we report a case where the patient developed PFMS leading to the diagnosis of FMF concurrently at the time of treatment for diabetic ketoacidosis (DKA) of new-onset type 1 diabetes mellitus and discuss the possible mechanisms of simultaneous DKA and FMF-associated PFMS. DKA-associated cytokine release may be a predisposing factor or trigger for FMF-associated PFMS.