1) Disease Description (Causes and Symptoms)
- Definition and pathophysiology: Kawasaki disease is a systemic vasculitis of the small and medium-sized arteries that occurs mainly in infants and young children under 5 years of age. Although the cause is unknown, it is thought to begin with an abnormal immune response following an infection in individuals with genetic susceptibility, causing vascular endothelial damage that leads to coronary artery lesions (dilatation and aneurysms) and myocarditis.
- Main symptoms (clinical features): High fever (usually ≥5 days), nonpurulent bilateral conjunctival injection, changes in the oral and pharyngeal mucosa (red lips and strawberry tongue), generalized rash, swelling and erythema of the extremities (hands and feet), periungual desquamation during recovery, and cervical lymphadenopathy (≥1.5 cm), among others. Abdominal pain, diarrhea, vomiting, abnormal liver function, pyuria, and, rarely, neurological symptoms and arthritis may also occur.
- Epidemiological features: It occurs most often in children aged 5 years or younger, and seasonal (spring and winter) and 2–4-year epidemic cycles have been reported. Infants (<6 months) and older children have a higher risk of severe disease and complications.
2) Treatment Methods and Precautions
- Acute treatment (standard)
- Intravenous immunoglobulin (IVIG) 2 g/kg as a single intravenous infusion (administered over 10–12 hours) — administration within 10 days of fever onset, if possible, is important for suppressing coronary artery complications.
- Aspirin: During the acute phase, a high dose (generally in the range of 30–100 mg/kg/day, varying by country and guideline) is used for anti-inflammatory and antipyretic purposes; after the fever resolves, a low dose (3–5 mg/kg/day) is maintained as antiplatelet therapy for approximately 6–8 weeks (continued long term if coronary artery abnormalities are present).
- Additional treatment for IVIG-resistant disease or high-risk patients
- Steroids (e.g., methylprednisolone) — considered for IVIG-resistant disease or high-risk patients.
- Biologics (e.g., infliximab), cyclosporine, anakinra (IL-1 inhibition), etc.; may be used in refractory cases.
- Thrombosis prevention/anticoagulation: For giant coronary artery aneurysms (e.g., an internal diameter ≥8 mm or a large Z-score), combined anticoagulation such as low-molecular-weight heparin plus warfarin may be considered (as determined by a cardiologist).
- Monitoring and follow-up tests
- Electrocardiography (ECG) and echocardiography (echo) are performed at diagnosis. Follow-up echocardiography is usually performed at 1–2 weeks and 4–6 weeks; more frequent follow-up and long-term monitoring (such as annual stress testing and nuclear medicine testing) are required when coronary artery abnormalities are present.
- Precautions / risk of complications / self-care
- Major complications include coronary artery aneurysms and coronary artery stenosis, as well as heart-related problems such as myocarditis, pericardial effusion, and arrhythmias. Coronary artery aneurysms may resolve within several years in some patients, but structural changes in the blood vessels may remain.
- Allergic reactions (hives, fever, and rarely anaphylaxis) and, rarely, hemolytic reactions may occur after IVIG administration.
- After high-dose IVIG administration, responses to live vaccines (MMR, varicella, etc.) may be suppressed; therefore, the timing of live vaccination after high-dose IVIG administration (generally, a delay of approximately 6–11 months is recommended) should be confirmed.
- Consider the risk of bleeding while taking aspirin (gastrointestinal bleeding and Reye syndrome [rare but requiring caution]); particular caution is needed regarding aspirin use in children when a viral infection is suspected.
- If fever persists or signs suggestive of myocardial ischemia or heart failure appear, such as chest pain, difficulty breathing, coma, pallor of the limbs, or shortness of breath during activity, emergency medical care should be sought immediately.
3) Checklist Before an Outpatient Visit (Items, Records, and Example Questions)
- Items and documents to bring
- List of currently taken medications (including dosage and administration times)
- Medical history: records of previous hospitalizations, surgeries, and allergies (especially to IVIG, blood products, and aspirin)
- Recent test results (copies of blood tests, liver function tests, urinalysis, and echocardiography results, if available)
- Notes documenting the date symptoms and fever began and their progression (number of days with fever; photograph the rash and lip changes if possible)
- Vaccination history (whether live vaccines such as MMR or varicella were recently administered)
- Key information to report to the doctor during the visit (prepare your answers)
- The day the fever started (which day of illness it is) and whether there was a response to antipyretics or antibiotics
- The onset and changes of conjunctival injection, oral mucosal changes, rash, swelling of the extremities, and enlarged lymph nodes
- Urine output, energy level, food intake, difficulty breathing, phlegm, abdominal pain, and vomiting
- Examples of questions to prepare in advance for the outpatient visit (things to organize before asking the doctor)
- Are these symptoms consistent with the characteristic findings of Kawasaki disease?
- By when should emergency tests (such as echocardiography) be performed?
4) Examples of General Questions to Ask the Doctor
- What are the expected benefits and possible side effects of this treatment (IVIG and aspirin)?
- What are my child's echocardiography results (coronary artery Z-score)? How will long-term follow-up be conducted?
- What precautions should we take when resuming daily activities (feeding, exercise, daycare, etc.) after discharge?
- When can live vaccinations be resumed?
- What are the chances of recurrence and the prognosis (risk of cardiac complications)?
5) Examples of Disease-Specific Questions
- What is my child's coronary artery Z-score (or coronary artery size), and is it at a level requiring anticoagulants or long-term aspirin use?
- If my child does not respond to IVIG, which of the next treatment options (steroids, infliximab, etc.) would you recommend, and what would the follow-up plan be?
(If necessary, bringing recent echocardiographic images and test results may help with consultation and decision-making.)