Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.
Familial Mediterranean fever and periodic-fever syndromes
Essential points for quick revision.
2 min synopsisUK scopeSources checked 27 Aug 2026Clinical review pending
!
Fever with a surgical, septic or macrophage-activation mimic
Periodic-fever diagnoses do not protect against sepsis, meningitis, peritonitis, appendicitis, ectopic pregnancy, testicular torsion or macrophage activation; immunomodulated patients may deteriorate with muted signs.
Action: Assess physiology and localise the acute syndrome, obtain cultures and imaging or surgical review before attributing it to a familiar attack, withhold cytokine inhibitor during serious infection, and treat the emergency while the autoinflammatory history is verified in parallel.
Synopsis
Recognise stereotyped autoinflammatory attacks, distinguish familial Mediterranean fever from other monogenic and acquired fever syndromes, use genetic evidence proportionately, and prevent persistent inflammation and AA amyloidosis with colchicine or cytokine-directed therapy.
Familial Mediterranean fever causes stereotyped attacks lasting about 12–72 hours with fever, peritonitic abdominal pain, pleurisy, monoarthritis or erysipelas-like erythema and complete or near-complete recovery between attacks.
Clinical phenotype and response matter; MEFV testing supports diagnosis but one variant, a variant of uncertain significance or a negative panel neither proves nor excludes FMF by itself.
Longer TRAPS attacks often include migratory myalgia or rash and periorbital oedema; MKD adds cervical nodes, aphthae, diarrhoea and vaccine-triggered fever; CAPS adds urticaria-like rash, conjunctivitis, hearing and CNS disease.
Key red flags
Shock, altered consciousness, meningism, persistent focal peritonism, gastrointestinal bleeding or hypoxaemia requires emergency infection and surgical assessment rather than attack treatment alone.
CAPS spectrum
Cold-triggered or persistent fever with neutrophilic urticaria-like rash, red eyes, sensorineural deafness, meningitic symptoms or bony overgrowth suggests NLRP3 activation.
Investigation priorities
01
First-line attack diary and objective temperatureFirst stepFirst line
Establish stereotypy, duration, interval, triggers and organ pattern before selecting molecular tests.
Management branches
First diagnostic stepCapture an untreated attack and the interval
Recurrent unexplained fever has a stereotyped history but no secure diagnosis.
Record age at onset, family and ancestry, duration, interval, serosal, skin, eye, ear, ulcer, node, joint and neurological features and response to prior medicines.
Obtain inflammatory, blood, renal, liver and urine tests during an early attack and repeat SAA or CRP and urine when clinically well.
FMF first-line managementStart daily colchicine and suppress SAA
The clinical phenotype supports familial Mediterranean fever with or without confirmatory MEFV variants.
Key medicines
ColchicineStart 1–1.5 mg orally each day in one or two divided doses; increase by 0.5 mg steps for attacks or persistent SAA to a maximum of 3 mg daily in adults when tolerated.
CanakinumabFor adults and patients weighing at least 40 kg with FMF, TRAPS, MKD or CAPS, give 150 mg subcutaneously every four weeks; an inadequate response may permit escalation to 300 mg every four weeks under the product pathway.
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.