What is the most common feature of familial Mediterranean fever?

The Most Common Feature of Familial Mediterranean Fever

Recurrent attacks of fever and serosal inflammation are the most common features of Familial Mediterranean Fever (FMF). 1

Clinical Presentation

• FMF is characterized by brief, recurring, self-limited episodes of fever accompanied by inflammation of serosal surfaces, resulting in:

  • Abdominal pain (affects 95% of patients) 2
  • Joint pain (arthritis/synovitis) 1, 3
  • Chest pain (pleuritis) 4
  • Rarely, pericarditis 4

• These attacks typically last 1-3 days and are accompanied by marked elevation of acute phase reactants 1, 5

• Between attacks, patients may appear completely well, though subclinical inflammation can persist 6

Disease Course Patterns

FMF follows three distinct clinical patterns, each affecting approximately one-third of patients 1:

• Monocyclic pattern: Single episode with remission within 1 year 1
• Polycyclic/intermittent pattern: Recurrent flares with complete remission between episodes 1
• Chronic pattern: Persistent symptoms with varying severity 1

Diagnostic Considerations

• FMF is the most common monogenic autoinflammatory disease, particularly prevalent in Mediterranean and Middle Eastern populations 1

• Diagnosis is primarily clinical, though genetic testing for MEFV gene mutations can confirm the diagnosis 1

• Differential diagnosis includes:

  • Other periodic fever syndromes (TRAPS, hyper-IgD syndrome) 1, 5
  • Infectious diseases (viral syndromes) 1
  • Neoplastic disorders (leukemia, lymphoma) 1

Complications

• The most serious long-term complication is AA amyloidosis, which can lead to renal failure if untreated 7, 4

• Regular colchicine treatment significantly reduces the risk of amyloidosis from 60% to less than 13% 6

Treatment Approach

• Colchicine is the first-line treatment and should begin immediately upon clinical diagnosis 6

• Dosing is weight-based and age-dependent:

  • Children <5 years: ≤0.5 mg/day 6
  • Children 5-10 years: 0.5-1.0 mg/day 6
  • Children >10 years and adults: 1.0-1.5 mg/day 6

• For colchicine-resistant or intolerant patients, IL-1 inhibitors are an effective alternative 7, 3

• Regular monitoring of acute phase reactants is necessary even during asymptomatic periods to detect subclinical inflammation 6

Key Points for Clinicians

• Episodic abdominal pain is the most frequently encountered symptom (95% of patients), often leading to extensive gastrointestinal workups before diagnosis 2

• Attacks are self-limited but require lifelong prophylaxis with colchicine to prevent both attacks and amyloidosis 6, 4

• Treatment adherence is crucial, particularly in adolescents and adults 6

• Colchicine should be used with caution in patients with renal impairment 8