creation date: 2026-06-09 18:39
tags: Pathologies
Kawasaki Disease
Background
Definitions
Kawasaki disease is a common form of systemic vasculitis in children. It was previously called mucocutaneous lymph node syndrome.
There is higher incidence in children in East Asia or of Asian ancestry.
Etiology & Pathogenesis
The underlying etiology of Kawasaki disease is unknown. Suspected factors include:
- Genetics
- Trigger by transmissible agent(s)
- Environmental factors (ie. airborne antigenic trigger)
The pathology of Kawasaki disease consist of infiltration of inflammatory cells into the vascular tissues.
- Necrotizing arteritis due to neutrophils through the adventitia, most profound in coronary arteries
- Subacute/chronic vasculitis due to plasma cells, lymphocytes, and eosinophils. In some cases, luminal endothelial cells, elastic lamina, and medial smooth muscle cells are destroyed leading to fusiform aneurysms
- Luminal myofibroblast infiltration causing stenotic lesions that may lead to in situ thrombosis
Clinical Presentation
Signs & Symptoms
Kawasaki disease is a self-limited condition, with manifestations lasting for an average of 12 days without therapy.
Inflammatory features
- High, persistent fever
-
38.5C
- Minimally responsive to antipyretics
-
- Ocular manifestations
- Bilateral nonexudative conjunctivitis
- Uveitis (and photophobia)
- Complications (vitreos poacities, papilledema, subconjunctival hemorrhage)
- Arthritis
- Early involvement: proximal interphalangeal joints of upper extremities
- Late: large joints of lower extremities
- Lymphadenopathy
- Anterior cervical nodes
- Single large nodes on palpation; possibly “cluster of grapes” on ultrasound
Mucocutaneous features
- Mucositis
- Cracked, red lips
- Strawberry tongue (due to sloughing of filiform papillae and denuding of inflammed glossal tissue; bumps are remaining fungiform papillae)
- Rash
- Polymorphous rash
- Initial: perineal erythema and desquamation
- Followed by: macular, morbilliform, or targetoid skin lesions of trunk and extremities
- Extremity changes
- Acute: indurated edema of dorsum of hands and feet, diffuse erythema of palms and soles
- Convalescent phase: sheet-like desquamation beginning in periungual region of fingers and toes, linear nail creases
Cardiac features
- Coronary artery abnormalities
- Dilation, aneurysm, and/or stenosis
- Ventricular dysfunction
- Tachycardia out of proportion
- S3 gallop
- Pericarditis (rare)
Nonspecific features
Nonspecific symptoms occur during prodromes (7-10 days prior)
- Diarrhea, vomiting, abdominal pain
- Irritability
- Cough or rhinorrhea
- Decreased oral intake
- Joint pain
History & Physical Exam
A detailed history for symptoms should be performed for any unexplained fever lasting for at least 5 days. A timely diagnosis is crucial to prevent sequelae.
If suspected in adults (rare), enquire about immunocompromised status.
Diagnosis
Criteria
Formal diagnosis requires:
- Fever lasting ≥5 days, with at least 4/5 of the following:
- Bilateral bulbar conjunctival injection
- Oral mucous membrane changes (injected or fissured lips, injected pharynx, strawberry tongue)
- Peripheral extremity changes
- Polymorphous rash
- Cervical lymphadenopathy (at least one LN >1.5 cm in diameter)
- No alternative explanation
Note, many patients will have “incomplete” Kawasaki disease, which fails to meet the formal criteria. Consider incomplete Kawasaki if:
- Patient <6 months of age with unexplained fever ≥7 days with elevated inflammatory markers but no clinical findings
- Patients of any age with unexplained fever ≥5 days with 2 or 3 findings
Work-up
While diagnosis can be made clinically, laboratory studies can be used when there is uncertainty:
- CRP (≥30 mg/L) or ESR (≥40 mm/hr)
- WBC (≥15000 /mcL)
- CBC (normocytic, normochromic anemia; platelet ≥450000/mcL)
- Liver function tests (ALT >50, albumin ≤3 g/dL)
- Urinalysis (non-neutrophilic pyuria)
Echocardiography is indicated for all patients.
- Coronary artery diameter (Z scores for LAD and RCA)
Differential
Example alternative diagnoses and their suggestive features are:
- Adenovirus (exudative conjunctivitis)
- Streptococcal pharyngitis (exudative pharyngitis)
- Measles (Koplik spots/discrete intraoral lesions)
- Stevens-Johnson syndrome (bullous or vesicular rash)
- EBV (generalized lymphadenopathy, splenomegaly)
Additionally, lymphocytic rather than neutrophilic CBC differential suggests viral infection rather than Kawasaki disease.
Red Flags / Complications
The major life-threatening complications are:
- Shock
- Macrophage activation syndrome
Other concerning sequelae are cardiac abnormalities.
Management
Initial Treatment
Regardless of full or incomplete diagnosis, patients are treated as soon as diagnosis is established (ideally with 7-10 days of onset).
- IVIG 2 g/kg infusion over 8-12 hours
- Aspirin 30-50 mg/kg/day (in four divided doses, with max of 4 g/day), hold if contraindicated
In patients at high risk of IVIG resistance (eg. presents with shock of macrophage activation syndrome) or high risk of CA aneurysm (eg. younger than 6 month, or englarged CA at baseline), adjunctive therapies are indicated. Options are:
- Glucocorticoids for 2-3 weeks (eg. methylprednisolone 2 mg/kg split to BID)
- Infliximab (TNF inhibitor) IV 10 mg/kg
Management of Sequelae
In patients without coronary artery abnormalities during the first month after onset, risk is low. Monitoring consist of routine preventative cardiology counselling but further investigations is unnecessary.
In cases of patients with coronary artery abnormalities, additional therapy is aimed at preventing and treating coronary artery thrombosis. These consist of long term:
- Low dose aspirin
- Statins
- Treatment of ischemic heart disease
Follow-up evaluation at a set interval via history, physical, ECG, and echocardiography is indicated. Specifics on frequency and type depends on severity and status of coronary artery.