FAMILIAL MEDITERRANEAN FEVER
Def: Autosomal
recessive autoinflammatory disease usually characterized by recurrent 1-3 day
self-limited episodes of fever, serositis,
mono-
or pauciarticular arthritis, or an erysipeloid rash, sometimes complicated by
AA amyloidosis.
Etiology:-
Caused by mutations in MEFV, a 10 exon gene located on
the short arm of chromosome 16 encoding a
781 amino acid protein denoted pyrin.
FMF occurs
primarily among ethnic groups of Mediterranean ancestry,
most
commonly Jews, Turks, Armenians, Arabs, and Italians.
Most patients
present with symptoms in childhood, with 90% of patients presenting prior to
the age of 20 yr.
Clinical
Manifestations:-
Attacks occur
irregularly, precipitated by minor physical or emotional stress, menstrual
cycle, diet or infection. Attacks resolve within 72 hours.
Between
flares, patients are generally symptom-free but may have persistent elevation
of their inflammatory markers.
The attack
frequency can vary from weekly to 1-2 flares/year.
Clinical
features includes:
- Fever :- Temperatures rise rapidly to 38–40 °C (100.4–104 °F)..
- Serositis presenting as pleuritic chest pain or severe abdominal pain
(peritonitis in 90% of patients and may mimic an acute surgical abdomen),
arthritis, and rash. The pleural pain is typically unilateral, whereas the
abdominal pain can be generalized or localized to 1 quadrant, similar to other
forms of peritonitis.
-
During an episode they often complain of constipation, secondary to the
peritoneal inflammation leading to a temporary paralytic ileus, followed by
diarrhea as the inflammation fades.
-
Arthritis occurs primarily in the large joints, may be
accompanied by large, neutrophil-rich effusions, and is usually nonerosive and
nondestructive.
-
The hallmark cutaneous finding is an erysipeloid erythematous rash that
overlies the ankle or dorsum of the foot .
-
Scrotal pain caused by inflammation of the tunica vaginalis testis,
-
febrile myalgia,
-
Exerciseinduced myalgia (particularly common in children),
-
Association with various forms of vasculitis, including Henoch-Schönlein
purpura in as many as 5% of pediatric patients.