The complications of Kawasaki disease can be significant and, in some cases, life-threatening if the condition is not identified and treated promptly.
Most children get better if treated early. Still, Kawasaki disease remains a top cause of heart problems in kids in developed countries. It can harm the coronary arteries—the ones that bring blood to the heart. That’s why regular check-ups are very important for months or even years after diagnosis.
Doctors use IVIG and aspirin to reduce risks. These treatments help a lot. But if doctors diagnose the disease late or if the child doesn’t respond well, serious problems can still happen. These issues usually fall into two groups: heart-related or not.
1. Coronary Artery Aneurysms (CAAs)
One of the most serious issues is coronary artery aneurysms. These are bulges in the coronary arteries caused by swelling and damage. They often show up 1 to 4 weeks after the disease starts. They’re more common in kids who don’t get treatment quickly or don’t respond to it.
Small aneurysms (under 5 mm) may go away on their own.
Medium ones (5–8 mm) might also shrink, but doctors need to watch them over time.
Large aneurysms (over 8 mm) are more dangerous. They can lead to clots, narrowed arteries, or even breaks in the artery wall. These raise the risk of heart attacks, especially in older kids. Regular heart scans and blood-thinning medicine are often needed.
2. Myocarditis and Pericarditis
Some children with Kawasaki disease get myocarditis. This means the heart muscle becomes swollen, which can lower heart function. Signs include fast breathing, tiredness, poor feeding, and low blood pressure.
Others may get pericarditis, or swelling around the heart. This can cause chest pain, fussiness, or fluid around the heart. Treatment usually helps these problems go away, but they can get worse without care.
3. Valvular Heart Disease
The disease can also affect heart valves. This often causes mitral regurgitation, where one valve leaks a little. It’s usually mild and goes away, but doctors may need to keep an eye on it. In rare cases, surgery is needed.
4. Arrhythmias and Conduction Problems
Some children develop abnormal heart rhythms. These can include:
- Slowed or fast heart rates
- Skipped beats
- Long QT intervals
- Blocks in the heart’s signals
These are usually short-term and don’t cause symptoms. Still, doctors may check with ECGs, especially if kids feel dizzy or faint.
5. Thrombosis and Heart Attacks
Large aneurysms can lead to blood clots. If a clot blocks an artery, it can cause a heart attack. This is rare in children but very serious.
Kids may show signs like sudden tiredness, chest pain, throwing up, or acting restless. Quick treatment with blood thinners or surgery is key in these cases.
6. Peripheral Artery Aneurysms
Sometimes, aneurysms show up in other arteries, like in the arms or legs. These are not as dangerous as heart-related ones but still need checking. Doctors often find them using ultrasound.
7. Recurrence of Kawasaki Disease
Kawasaki disease can come back, though it’s not common. It happens in about 1–3% of kids. The second time may be harder to notice and could bring more heart risks.
Parents should know it can return and seek help fast if symptoms appear again.
8. Hearing Loss
Some studies show that a few children may lose hearing after Kawasaki disease. This may happen due to swelling or changes in blood flow to the inner ear. Kids who had a tough case might need a hearing test.
9. Neurocognitive and Emotional Effects
Though Kawasaki disease mainly affects the heart, it may also impact a child’s brain and mood. Some kids may:
- Struggle to focus
- Forget things easily
- Feel more anxious or emotional
These problems are often short-term. Still, parents and teachers should watch for any changes, especially if the child had a long illness or hospital stay.
10. Complications from Treatment
The treatments for Kawasaki disease help a lot but can have side effects.
- IVIG may sometimes cause allergic reactions, headaches, or a form of swelling in the brain lining.
- Aspirin, in large amounts, can upset the stomach or cause bleeding. Very rarely, it might lead to Reye’s syndrome.
- Steroids may raise infection risks, lead to weight gain, or affect mood.
Doctors monitor kids closely to keep them safe while on these medicines.
11. Long-Term Cardiac Follow-Up
If a child had heart problems during Kawasaki disease, long-term care is crucial. Follow-up may include:
- Regular heart scans and tests
- Stress tests to check heart function
- CT or MRI scans
- Daily blood-thinning medicine
Children with large aneurysms or past heart attacks face higher heart risks later in life. These kids need healthy diets, exercise plans, and sometimes limits on intense activity.
Final Thoughts
The complications of Kawasaki disease span a wide spectrum, from mild and temporary to severe and life-altering.
Modern care helps reduce most serious risks. Still, it’s key to catch the disease early and follow up with care. Knowing what to watch for helps doctors support families and protect children’s hearts.
With the right care, most kids fully recover and live healthy lives.
