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Polyarteritis nodosa in patients with Familial Mediterranean Fever (FMF): a concomitant disease or a feature of FMF?

S Ozen1, E Ben-Chetrit, A Bakkaloglu

  • 1Department of Pediatrics, Hacettepe University, Ankara, Turkey. sozen@gen.hun.edu.tr

Abstract

Insights

Patients with Familial Mediterranean Fever (FMF) who develop polyarteritis nodosa (PAN) show distinct characteristics and a better prognosis compared to other PAN patients. This suggests PAN in FMF may be a unique manifestation of the disease.

Area of Science:

  • Rheumatology
  • Genetics
  • Internal Medicine

Background:

  • Familial Mediterranean Fever (FMF) is a genetic autoinflammatory disorder caused by pyrin gene mutations, presenting with recurrent fever and serositis.
  • Vasculitis, specifically polyarteritis nodosa (PAN), is increasingly observed in FMF patients.
  • No prior studies have evaluated the prognosis of PAN in FMF patients.

Purpose of the Study:

  • To investigate the unique clinical features and prognosis of polyarteritis nodosa (PAN) in patients with Familial Mediterranean Fever (FMF).

Main Methods:

  • A survey involving 17 patients diagnosed with both FMF and PAN across 7 referral centers in Turkey and Israel.
  • PAN diagnosis was confirmed using Chapel Hill consensus criteria for microscopic polyarteritis or classic PAN.
  • Analysis of clinical presentations and vasculitis outcomes, with diagnostic confirmation via angiography, biopsy, or both.

Main Results:

  • PAN onset in FMF patients occurred between 3.5 and 37 years of age.
  • All patients exhibited constitutional symptoms, elevated acute phase reactants, and myalgia at PAN diagnosis.
  • Diagnostic confirmation involved renal angiography (8 patients), renal biopsy (6 patients), and muscle/nodule biopsies (6 patients); some cases showed features of both classic PAN and microscopic polyarteritis.

Conclusions:

  • FMF patients with PAN tend to have an earlier onset, more frequent perirenal hematomas, and a better prognosis than other PAN cohorts.
  • Overlapping features of classic and microscopic PAN in FMF cases challenge current vasculitis classification.
  • The distinct clinical presentation suggests PAN in FMF may represent a specific characteristic of FMF itself.

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