BASICS

DESCRIPTION

• Multisystem acute vasculitis usually involving the small to mid-size arteries during infancy and early childhood.

• Fever for at least 5 days duration plus 4 of the 5 major criteria

– bilateral conjunctival injection

– erythema of the lips or oropharynx

– nonpurulent cervical lymphadenopathy

– erythema and edema of palms and soles with desquamation

– polymorphous truncal rash (1)

EPIDEMIOLOGY

Incidence

• Variable depending on race

– Asian American and Pacific Island: 32.5 per 100,000 children younger than 5 years old.

– African American: 16.9 per 100,000 children younger than 5 years old.

– Hispanic American: 11.1 per 100,000 children younger than 5 years old.

– Caucasian American: 9.1 per 100,000 children younger than 5 years old (2).

Prevalence

• Approximately 4200 hospitalizations associated with Kawasaki disease per year.

– 1.5:1 boy to girl ratio.

– 76% of children are <5 years old.

– More common in winter and early spring.

– Peak mortality occurs 15–45 days after onset of fever (3).

RISK FACTORS

• Genetic susceptibility

• Delayed diagnosis

• Prolonged fever is risk for development of aneurysmal coronary artery disease.

Genetics

Genetic susceptibility: Polymorphism of ITPKC gene (19q13.2) (2)

GENERAL PREVENTION

Sequelae of disease are avoided with early diagnosis and treatment.

PATHOPHYSIOLOGY

• Acute vasculitis of all blood vessels with the mid-size arteries being most predominantly affected.

– Early phase: Neutrophil infiltration with edema and a rapid transition to mononuclear cells (primarily CD8 T-cells, IgA plasma cells, monocytes, and macrophages).

– Second phase: Production of matrix metalloproteinase, which destructs the internal elastic lamina and media.

– Final phase: Replacement of the vessel intima and media with fibrous connective tissue (2).

ETIOLOGY

Thought to be triggered by unidentified infection in genetically susceptible children.

COMMONLY ASSOCIATED CONDITIONS

• Coronary artery aneurysm with secondary thrombosis/ischemia

• Arthritis/arthralgia

• Diarrhea, vomiting, abdominal pain

• Myocarditis

• Anterior uveitis (usually mild)

• Less common conditions

– Superficial punctuate keratitis

– Choroiditis

– Papilledema

DIAGNOSIS

HISTORY

• Fever of at least 5 days duration plus 4 of the 5 major criteria.

– History of recently affected family member may be present.

PHYSICAL EXAM

• Fever (often 104°F or higher)

• Bilateral bulbar conjunctival injection

• Erythema of oropharyngeal mucosa with strawberry tongue

• Dry, cracked lips without ulceration

• Erythema, desquamation, edema of hands and feet (may also affect gluteal cleft). Periungual desquamation of the fingers and toes begins 1–3 weeks after onset.

• Truncal rash

• Nonsuppurative cervical lymphadenopathy

• Other findings may include extreme irritability, aseptic meningitis, diarrhea, mild hepatitis, hydrops of gallbladder, pyuria, otitis media, and arthritis.

DIAGNOSTIC TESTS & INTERPRETATION

Lab

Initial lab tests

• No diagnostic laboratory test but certain findings are often present:

– Anemia (normocytic, normochromic)

– Leukocyte count normal to elevated with neutrophil shift

– Platelet count initially normal

– Elevated ESR and CRP

– Elevated hepatic transaminases

– Pyuria (1)[B]

Follow-up & special considerations

Rapid elevation of platelets in second week of illness.

Imaging

Initial approach

• Echocardiogram during acute phase of illness.

– Coronary artery aneurysm/ectasia may be present in as many as 25% of children with Kawasaki disease (3)[C].

Follow-up & special considerations

• If coronary artery aneurysm is present repeat echocardiogram is needed until resolved.

• For uncomplicated cases, follow-up echocardiogram should be performed at 2 and 8 weeks after onset

• Cardiac stress testing is recommended for children with Kawasaki disease and coronary artery abnormality.

– Angiography is needed if evidence of cardiac ischemia is present.

DIFFERENTIAL DIAGNOSIS

• Scarlet fever

• Toxic shock syndrome

• Measles

• Adenovirus infection

• Drug hypersensitivity (Steven–Johnson syndrome)

• Epidermolysis bullosa

• Conjunctivitis

• Collagen vascular disease (e.g., lupus)

TREATMENT

MEDICATION

First Line

• Single infusion of IVIG at 2 g/kg given within 10 days of onset (2,3) [A].

– Aspirin at 80–100 mg/kg/d given in 4 divided doses (2,3) [C].

– Topical steroids for iritis usually not necessary.

Second Line

• IV prednisolone may play a role in decreasing duration of disease but no standard dose is recommended (3)[C].

• Pentoxifylline has been used as adjunct therapy in small clinical trials but its role is uncertain (3)[C].

ADDITIONAL TREATMENT

General Measures

• Low-dose aspirin (3–5 mg/kg/d) is continued until 6–8 weeks after onset of illness if no coronary changes are present (3)[C].

– Patients not responsive to standard treatment may benefit from repeat IVIG, steroids, or infliximab (3)[C].

Issues for Referral

• Infectious disease and rheumatology consultation may be useful in establishing diagnosis.

– Pediatric cardiologist should be involved in the patient’s care.

Additional Therapies

• Antiplatelet agents (clopidogrel, dipyridamole) may be considered.

• Anticoagulant therapy (warfarin, heparin) may be used in patients at risk of thrombus formation.

• Treatment of acute coronary occlusion secondary to thrombus is controversial but streptokinase, urokinase, and tissue plasminogen activator has been reported (3)[C].

• Activity restriction guided by anticoagulation therapy and cardiac stress testing.

SURGERY/OTHER PROCEDURES

• Cardiac catheterization with stent placement has been useful in specific clinical conditions.

• Coronary bypass graft may be used in children with recurrent myocardial infarct.

– Rarely, cardiac transplant is justified.

IN-PATIENT CONSIDERATIONS

Admission Criteria

Children with at least 4 days of fever with suspected Kawasaki should be admitted for further testing and treatment.

IV Fluids

Use as needed particularly if abdominal symptoms.

Discharge Criteria

• Afebrile for 48 hours after initiating treatment.

– Appropriate testing complete.

– Longer hospitalization may be required if significant coronary disease is present.

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

• Ophthalmologic follow-up is needed only in presence of anterior uveitis or more severe ocular manifestations.

• Systemic follow-up is directed by coronary artery involvement (3)[C].

– Cardiovascular risk assessment recommended at 5 year intervals for children with no coronary artery changes.

– Cardiovascular risk assessment recommended at 3 year intervals for children with transient coronary artery ectasia.

– Annual cardiology follow-up with echocardiogram and electrocardiogram in addition to stress testing every 2 years recommended in children with an isolated small/medium coronary aneurysm.

– Biannual cardiology follow-up with echocardiogram, electrocardiogram and stress testing is recommended for children with large coronary artery aneurysms or coronary artery obstruction.

PATIENT EDUCATION

• Kawasaki Support Group http://www.patient.co.uk/support/Kawasaki-Support-Group.htm

• Kawasaki Disease Foundation http://www.kdfoundation.org/

• Activity restrictions must be discussed in patients taking anticoagulants as well as in patients with severe coronary artery disease.

– Signs and symptoms of ischemic heart disease need be discussed with patient and family.

PROGNOSIS

Early diagnosis and treatment with IVIG and aspirin reduce coronary artery disease to 2–4% (2)[C].

COMPLICATIONS

• Coronary ischemia and arterial thrombosis resulting in myocardial infarction.

• Sudden death

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