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OverviewAetiologyPathophysiologyClinical features and red flagsInvestigationsDifferential diagnosisManagementComplicationsMonitoring and follow-upSpecial situationsCommon pitfallsQuestionsSources
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Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.

Kawasaki disease and coronary risk

Paediatrics and child health · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

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Shock, myocarditis or coronary thrombosis

Kawasaki disease can cause distributive or cardiogenic shock, ventricular dysfunction, arrhythmia, pericardial effusion or coronary aneurysm and thrombosis; severe abdominal pain, chest pain, collapse or poor perfusion is not routine fever.

Action: Use ABCDE, call senior paediatric, cardiology and intensive-care teams, obtain cultures, gas, lactate, ECG, troponin, BNP and urgent echocardiography, and treat sepsis or toxic shock when plausible. Give carefully reassessed fluid because myocardial dysfunction may limit tolerance, start IVIG and aspirin promptly once the diagnosis is supported, and use specialist anticoagulation or reperfusion pathways for giant aneurysm or suspected coronary thrombosis.

Overview

Recognise complete and incomplete Kawasaki disease, exclude dangerous mimics without delaying treatment, give complete IVIG and aspirin regimens, and stratify coronary surveillance and thrombosis risk.

The cause is not fully defined. An abnormal immune response to an infectious trigger in a genetically susceptible child is suspected, but Kawasaki disease is not diagnosed by finding one organism and is not treated as a routine contagious infection.

Vascular inflammation affects endothelial and smooth-muscle layers. Coronary arteritis can weaken the wall, producing ectasia or aneurysm, while platelet activation and disturbed flow create thrombosis risk.

Clinical criteria are descriptive rather than a perfect test. Conjunctivitis is bilateral and non-purulent; oral features include red cracked lips and strawberry tongue; rash is polymorphous and usually not vesicular.

Extremity change begins with erythema or oedema of palms and soles; peeling around fingertips and toes usually appears in the subacute phase after fever. Waiting for peeling delays acute treatment.

Cervical lymphadenopathy is often unilateral and greater than 1.5 cm but is the least frequent criterion. Fever and marked irritability may be the only early clues in a young infant.

Practice

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Paediatrics and child healthOriginal SBA

Incomplete Kawasaki infant

A 4-month-old has seven days of unexplained fever, marked irritability, red cracked lips, raised CRP, anaemia, low albumin and sterile pyuria. The first echocardiogram is normal. What is the safest next step?

Choose one answer, then submit
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Sources and review status4 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

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.

  • NHS Kawasaki diseaseCurrent national recognition, investigation, treatment and coronary-risk information.
  • NNUH Kawasaki disease guidelineUK hospital diagnostic, IVIG, aspirin and follow-up regimens.
  • University Hospitals Sussex Kawasaki diseaseUpdated February 2026 UK treatment and family safety information.
  • Great Ormond Street Kawasaki diseaseUK tertiary paediatric explanation of inflammation and coronary care.

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateComplete draftClinical stateAwaiting reviewJurisdictionUnited Kingdom
Inflammation commonly produces neutrophilia, anaemia, hypoalbuminaemia, hyponatraemia and raised transaminases. Platelets may be normal initially and rise during the second or third week, so early absence of thrombocytosis is not reassuring.

Sterile pyuria, aseptic meningitis, arthritis, gastrointestinal inflammation and gallbladder hydrops show that disease is systemic. Severe gastrointestinal and shock presentations overlap with PIMS-TS and require SARS-CoV-2 context and myocardial assessment.

Echocardiography should be obtained promptly, but small children can have technically limited proximal coronary views. Serial studies detect evolving dilatation, and z scores avoid calling the same diameter normal in one body size and aneurysmal in another.

IVIG suppresses vascular inflammation and lowers coronary complication risk. Infusion reactions, haemolysis, thrombosis, renal effects and fluid load require baseline assessment and monitored administration.

Aspirin is unusual in paediatrics because specialist benefit outweighs Reye-syndrome and bleeding concerns. Higher divided doses address inflammation in the febrile phase; low once-daily dosing provides antiplatelet effect during coronary risk.

Persistent fever after IVIG can mean resistant Kawasaki disease, but infection, wrong diagnosis and infusion reaction must also be reconsidered. Escalation depends on risk, coronary findings and the local specialist pathway.

Follow-up is based on the maximum coronary abnormality, not merely the final fever response. A child with no dilatation may leave cardiology after planned normal studies, while aneurysm requires long-term imaging, exercise and thrombosis management.

Key points

  • Kawasaki disease is an acute systemic medium-vessel vasculitis, usually in children under 5 years, with a particular tendency to inflame and dilate coronary arteries.
  • Classic diagnosis is fever for at least five days plus four of five features: bilateral non-exudative conjunctivitis, oral change, polymorphous rash, hand or foot change and usually unilateral cervical lymphadenopathy.
  • Features evolve rather than appearing together. Perineal erythema, marked irritability, sterile pyuria, gallbladder hydrops, arthritis and later periungual peeling support the diagnosis.
  • Incomplete Kawasaki disease means prolonged fever with fewer criteria but supportive inflammation, laboratory or echocardiographic findings; young infants deserve a low threshold for this pathway.
  • Initial tests include blood count, CRP or ESR, renal, liver, albumin, sodium, urinalysis and culture, blood culture, ECG and echocardiography, plus targeted tests for sepsis, scarlet fever, measles, adenovirus, toxic shock and PIMS-TS.
  • Echocardiography assesses coronary dimensions using age- and body-size-adjusted z scores, ventricular and valve function and pericardial fluid. A normal first scan does not exclude disease.
  • Preferred acute treatment is IVIG 2 g/kg as one IV infusion over 12 hours, started as early as possible and ideally within 10 days; treat later if fever or inflammation persists.
  • NNUH aspirin regimen is 30–50 mg/kg/day orally in four divided doses until afebrile for 48–72 hours, maximum 14 days, then 3–5 mg/kg once daily until the 6–8-week coronary review if imaging is normal.
  • High-risk disease, shock, early aneurysm or IVIG resistance requires cardiology and rheumatology or infectious-disease input for corticosteroid, repeat IVIG or other immunomodulation rather than repeated empirical antibiotics alone.
  • Coronary aneurysm changes antithrombotic intensity and lifelong follow-up. Giant aneurysm may require aspirin plus anticoagulation and urgent specialist plans for thrombosis or ischaemia.
  • Families need aspirin safety advice, urgent contact after influenza or varicella exposure or illness, and an immunisation plan because high-dose IVIG changes the timing of some live vaccines.

Aetiology

01

Immune-triggered inflammation

An unidentified infectious exposure may activate an excessive innate and adaptive immune response rather than directly invading coronary arteries.

02

Genetic susceptibility

Variation in immune-regulatory pathways and higher incidence in some ancestries support inherited susceptibility without a simple Mendelian pattern.

03

Young-child vulnerability

Most disease occurs before age five, while infants often show fewer diagnostic signs and develop coronary injury more readily.

Pathophysiology

  1. 1
    Medium-vessel vasculitis

    Inflammatory cells injure arterial endothelium and wall layers, particularly in proximal coronary segments, producing oedema and necrosis.

  2. 2
    Aneurysm formation

    Loss of wall integrity under arterial pressure allows ectasia and focal dilatation that is classified against body-size-adjusted coronary dimensions.

  3. 3
    Thrombotic surface

    Endothelial injury, platelet activation and slow disturbed flow within larger aneurysms favour coronary thrombosis and myocardial infarction.

  4. 4
    Myocardial involvement

    Inflammation can affect myocardium, valves and pericardium, causing ventricular dysfunction, regurgitation, effusion, arrhythmia or haemodynamic shock.

Clinical features and red flags

Persistent fever

Usually high and unremitting fever reaches day five without a convincing alternative and the child is often unusually irritable.

Mucocutaneous cluster

Non-exudative red eyes, cracked lips, strawberry tongue, polymorphous rash and red or swollen hands or feet evolve over days.

Incomplete infant disease

Prolonged unexplained fever with inflammation, anaemia, low albumin, pyuria or coronary change may be enough despite few criteria.

Subacute clues

Periungual peeling and thrombocytosis emerge after the acute window and corroborate rather than time the treatment decision.

Cardiac involvement

Tachycardia out of proportion to fever, gallop, new murmur, shock, ECG change or troponin and BNP elevation indicates myocardial assessment.

Coronary ischaemia

Chest or abdominal pain, pallor, vomiting, collapse or arrhythmia in a child with aneurysm can be an age-atypical infarction presentation.

Red flags requiring action

  • Fever for five days or longer with bilateral non-exudative conjunctivitis, oral change, rash, extremity change or cervical lymphadenopathy should trigger Kawasaki assessment.
  • Infants under 6 months can have prolonged unexplained fever with few classic signs yet carry greater coronary risk; incomplete presentation must not be dismissed.
  • Hypotension, cool peripheries, altered consciousness, significant abdominal symptoms, breathlessness or myocardial markers suggests shock, PIMS-TS, myocarditis or severe Kawasaki disease.
  • A normal early echocardiogram does not exclude Kawasaki disease and must not delay IVIG when clinical and inflammatory evidence is convincing.
  • Persistent or recurrent fever at least 36 hours after IVIG completion indicates treatment resistance and needs urgent specialist reassessment.
  • Chest pain, pallor, collapse, new ECG changes or ventricular dysfunction in a child with coronary aneurysm may represent coronary thrombosis or myocardial ischaemia.

Investigations

  1. 01
    Initial inflammatory and organ profileFirst step
    Why
    Support the syndrome, grade severity and identify safe treatment parameters.
    Interpretation and limitations
    Raised CRP or ESR with neutrophilia, anaemia, low albumin, hyponatraemia or liver change supports but does not independently diagnose Kawasaki disease.
  2. 02
    Urinalysis, cultures and targeted infection testing
    Why
    Identify sterile pyuria and exclude bacterial or viral mimics without delaying emergency treatment.
    Interpretation and limitations
    Pyuria with negative culture supports systemic inflammation; a positive pathogen does not automatically explain every Kawasaki-compatible feature.
  3. 03
    ECG, troponin and BNP
    Why
    Assess conduction, myocardial inflammation, ventricular strain and possible ischaemia.
    Interpretation and limitations
    Nonspecific changes are common; dynamic ST change, arrhythmia or marked biomarkers requires urgent cardiology assessment.
  4. 04
    Early paediatric echocardiography
    Why
    Measure coronary arteries and assess ventricular, valve and pericardial involvement.
    Interpretation and limitations
    Use coronary z scores and document image quality; a normal initial study does not exclude disease or remove the need for serial imaging.
  5. 05
    Serial coronary imaging
    Why
    Detect evolving, regressing or persistent aneurysm and thrombosis.
    Interpretation and limitations
    Timing and modality follow maximum coronary involvement; CT, MRI or angiography may supplement echocardiography in complex aneurysm anatomy.
  6. 06
    PIMS-TS and shock work-up
    Why
    Distinguish overlapping post-infectious inflammation and quantify organ dysfunction.
    Interpretation and limitations
    SARS-CoV-2 testing, coagulation, ferritin and cardiac markers inform the pathway but are interpreted with timing and phenotype.

Differential diagnosis

01

Scarlet fever

Streptococcal sore throat, sandpaper rash and microbiological evidence support scarlet fever, but treatment response and full phenotype require review.

02

Adenovirus or measles

Exudative conjunctivitis, prominent respiratory features or Koplik spots favour infection; vaccination and exposure history guide targeted testing.

03

PIMS-TS

Recent SARS-CoV-2 exposure, shock, severe abdominal symptoms and marked myocardial involvement suggest multisystem inflammatory syndrome, which can overlap.

04

Toxic shock or sepsis

Hypotension, organ dysfunction and rash demand cultures and immediate antimicrobial management while inflammatory cardiac disease is assessed in parallel.

05

Systemic juvenile arthritis

Quotidian fever, evanescent rash, arthritis, hepatosplenomegaly and extreme ferritin support another inflammatory pathway, although early disease can be ambiguous.

Management

01SuspectTreat the evolving phenotypeFirst stepFever reaches five days with classic features, or incomplete disease is supported by inflammation or coronary findings.+
  1. 1Admit under paediatrics, document each feature and onset, and involve cardiology for prompt echocardiography.
  2. 2Obtain inflammatory, organ, urine, culture and cardiac tests and actively assess sepsis, toxic shock and PIMS-TS.
  3. 3Do not wait for peeling, thrombocytosis or an abnormal first echo when the clinical case supports treatment.
02Acute treatmentSuppress inflammation promptlyComplete or supported incomplete Kawasaki disease is confirmed by senior review.+
  1. 1Give IVIG 2 g/kg as one IV infusion over 12 hours with product-specific observation and fluid assessment.
  2. 2Give aspirin 30–50 mg/kg/day orally in four divided doses until afebrile for 48–72 hours, no longer than 14 days in the cited NNUH pathway.
  3. 3Assess high-risk features and discuss adjunctive corticosteroid or other immunomodulation with paediatric cardiology and rheumatology or infectious disease.
03Afebrile phaseProtect coronaries and re-imageFever has resolved and inflammatory markers and clinical state are improving.+
  1. 1Reduce aspirin to 3–5 mg/kg orally once daily and reconcile the exact formulation and weight-based dose.
  2. 2Repeat echocardiography at the specialist intervals, commonly around 2 and 6–8 weeks, and stop aspirin only when the plan confirms normal coronaries.
  3. 3Give influenza, varicella and post-IVIG live-vaccine advice through the immunisation and cardiology teams.
04Resistant or aneurysmalEscalate immune and antithrombotic careEscalationFever persists or recurs after IVIG, or coronary dilatation or aneurysm is detected.+
  1. 1Recheck infection and diagnosis and discuss repeat IVIG, corticosteroid or another agent with the specialist multidisciplinary team.
  2. 2Classify coronaries by maximum z score and select antiplatelet or anticoagulant intensity through paediatric cardiology and haematology.
  3. 3Create an emergency ischaemia pathway and lifelong imaging and exercise plan for significant persistent aneurysm.
Key medicines and prescribing safety2 treatments · regimens, roles and cautions+
Suppresses acute vascular inflammation and substantially reduces the risk of coronary artery injury when given promptly in Kawasaki disease.

Intravenous normal immunoglobulin

Give 2 g/kg IV as a single infusion over 12 hours as soon as possible after senior-confirmed diagnosis, ideally within 10 days of illness onset; later treatment remains indicated when fever or laboratory inflammation persists.

Use actual prescribing weight and the selected product protocol. Check IgA or prior reaction history, renal and thrombotic risk and fluid tolerance; monitor throughout for infusion reaction, haemolysis, hypotension and overload, and arrange live-vaccine timing advice after high-dose IVIG.

Provides anti-inflammatory treatment during the febrile phase and antiplatelet protection during the period of coronary endothelial injury and aneurysm-related thrombosis risk.

Aspirin for Kawasaki disease

NNUH regimen: 30–50 mg/kg/day orally in four divided doses until afebrile for 48–72 hours, maximum 14 days, then 3–5 mg/kg orally once daily until the 6–8-week echocardiographic review permits stopping; coronary aneurysm may require longer treatment.

Aspirin in a child must be specialist prescribed. Check bleeding, liver, renal, asthma and interacting anticoagulant risks; stop other NSAIDs unless specifically directed, provide influenza and varicella advice because of Reye-syndrome concern, and use gastroprotection when individual bleeding risk warrants.

Complications

01

Coronary aneurysm

Inflamed wall dilates and may later remodel, persist, stenose or calcify, with risk determined by maximum z score and anatomy.

02

Coronary thrombosis and infarction

Larger aneurysms promote stagnant flow and platelet activation, causing acute myocardial ischaemia, arrhythmia or sudden death.

03

Myocarditis and shock

Inflammatory ventricular dysfunction and systemic vasodilatation can combine into dangerous low output requiring intensive haemodynamic support.

04

Valve and pericardial disease

Mitral regurgitation and pericardial effusion may accompany acute inflammation and usually improve but need echocardiographic follow-up.

05

Treatment adverse effects

IVIG can cause infusion reaction, haemolysis or thrombosis, while aspirin creates bleeding and infection-associated Reye-syndrome concerns.

Monitoring and follow-up

  • Record temperature accurately during and for at least 36 hours after IVIG because persistent or recrudescent fever defines possible resistance.
  • Monitor haemodynamics, urine output, fluid balance and infusion reactions during IVIG, especially when myocarditis or shock reduces fluid tolerance.
  • Trend CRP, blood count, platelets, albumin, sodium, liver and renal function to assess inflammation, complications and medicine safety.
  • Repeat echocardiography at the specialist acute, approximately 2-week and 6–8-week intervals, with closer imaging for early coronary abnormality.
  • Check the aspirin dose against changing weight and give bleeding, influenza, varicella and vaccination safety advice before discharge.
  • For aneurysm, maintain lifelong cardiology review with coronary imaging, ischaemia assessment, exercise advice and antithrombotic adherence monitoring.

Special situations

Features arrive asynchronously

A parent photograph or earlier examination may document rash or red eyes that disappeared before the full syndrome became apparent.

Platelets rise late

Thrombocytosis is a subacute response, so a normal early platelet count cannot be used to reject acute Kawasaki disease.

Echo cannot rule out early disease

Coronary change may evolve after presentation, making clinical treatment and scheduled serial imaging more important than one normal scan.

Infants are incomplete but high risk

The youngest babies can show fever alone or only subtle criteria while carrying disproportionate coronary aneurysm risk.

Aneurysm size drives the future

Maximum body-size-adjusted coronary dimensions determine thrombosis prevention, imaging intensity, exercise counselling and duration of specialist follow-up.

Common pitfalls

  1. 01

    Do not wait for every classic feature to occur at the same examination.

  2. 02

    Do not wait for fingertip peeling before starting acute treatment.

  3. 03

    Do not exclude incomplete disease in a persistently febrile infant.

  4. 04

    Do not let a normal early echocardiogram delay IVIG in a convincing case.

  5. 05

    Do not treat shock with repeated unrestricted fluid without assessing myocardial function.

  6. 06

    Do not give over-the-counter aspirin to a child or omit specialist infection safety advice.

  7. 07

    Do not call recurrent fever after IVIG routine without reassessing resistance and infection.

  8. 08

    Do not discharge coronary aneurysm without an explicit antithrombotic and emergency chest-pain plan.