KAWASAKI DISEASE

·         Medium-vessel vasculitis (predilection for coronary arteries)

·         a.k.a. Mucocutaneous Lymph node Syndrome or Infantile Polyarteritis Nodosa.

·         Most common cause of acquired heart disease in children in US & Japan (Kawasaki > Acute Rheumatic Fever)

·         Most common age of presentation - ≤ 2 yrs (80% cases < 5yrs)

·         Pathogenesis and Pathology-

§  Transmural inflammation with destruction of the internal elastic lamina.

§  Predominance of macrophages and lymphocytes (CD8 T cells + IgA plasma cells)

·         Clinical Features –

PHASES OF KAWASAKI DISEASE
Acute phase	·         Febrile phase ·         Lasts for 1-2 wk ·         Edema + erythema + lymphadenopathy + rash
Subacute phase	·         Starts once acute phase is over. ·         Lasts till 4th wk. (after disease onset) ·         Phase with the highest risk of sudden death ·         Desquamation + Thrombocytosis + Coronary artery aneurysm development
Convalescent phase	·         From end of all clinical signs of illness to returning of ESR back to normal. ·         Lasts till 6-8 wks (after disease onset)

  

DIAGNOSTIC CRITERIA	FEATURES
Fever lasting for at least 5 days	High grade Lasts for 1-2 wk (maybe up to 3-4 wk) Prolonged fever - ↑ risk of Coronary Artery Disease (CAD)
PLUS
Presence of at least 4 out of 5 clinical features given below :-
1.       Bilateral nonpurulent bulbar conjunctival congestion
2.       Involvement of oropharyngeal mucosa – congestion of pharynx, erythema and/or dry fissured lips, strawberry tongue	Perineal desquamation (acute phase)
3.       Involvement of the peripheral extremities - edema and/or erythema of the hands or feet in the acute phase; or periungual desquamation in the subacute phase
4.       Polymorphous, nonvesicular rash/exanthema (primarily truncal)	Accentuated in groin
5.       Acute non-purulent cervical lymphadenopathy - ≥1.5 cm (usually unilateral)

OTHER CLINICAL FEATURES
Cardiac Involvement	·         Most important manifestation ·         Myocarditis (50%) – Ventricular dysfunction and tachycardia ·         Coronary artery aneurysm (25%) and thrombosis (greatest risk of complications with aneurysm ≥ 8mm internal diameter) ·         Pericarditis ·         Myocardial ischemia and infarction
Arthritis	·         Female > Male
Aseptic meningitis	·         More common in Infants
Urethritis + meatitis + sterile pyuria	·         Infants

·         Cause of death – (2.8%)

§  Myocardial infarction

§  Coronary aneurysm rupture

·         Poor prognostic factors

§  Male

§  Age < 1 yr

§  Prolonged fever

§  Recurrent fever (after an afebrile period)

§  Laboratory values at presentation:

§  ↓ Hb

§  ↓ Platelets

§  ↑ Neutrophil and band counts

§  ↓ Albumin and age-adjusted serum IgG levels.

·         Diagnosis

§  Clinical - based on diagnostic criteria mentioned above.

§  Lab Findings –  (characteristic features)

§  Acute phase- (may persist for 4-6 wk i.e. during subacute & convalescent phase)

·         ↑ ESR

·         ↑ C-reactive protein

·         Anemia (normocytic)

§  Subacute phase-

·         Thrombocytosis (may exceed 1,000,000/mm³)

§  Radiological –

§  Two-dimensional echocardiography –

·         Most important test to monitor the potential development of coronary artery lesions.

·         Performed at time of presentation with follow-ups at end of each clinical phase.

·         Treatment

PHASE	TREATMENT
Acute phase	Intravenous Immunoglobulin (2 g/kg single infusion over 10-12 hr) + Aspirin (100 mg/kg per day for 14 days)
Convalescent Phase	Aspirin (3-5 mg/kg once daily orally until 6-8 wk after illness onset)
Acute Coronary Thrombosis	Prompt Fibrinolytic Therapy with tissue plasminogen activator, streptokinase, or urokinase
Long-term therapy in coronary abnormalities	Aspirin (3-5 mg/kg once daily orally) ± Dipyridamole (4-6 mg/kg/24 hr divided in two or three doses orally) ± Warfarin (high risk of thrombosis)
Coronary Artery Aneurysms	Surgery
Coronary Artery Stenosis	Surgery ·         Catheter intervention with percutaneous transluminal coronary rotational ablation. ·         Directional coronary atherectomy + stent implantation.