Overview

Kawasaki disease is a rare but serious inflammatory condition that primarily affects children under the age of five. It causes inflammation in the walls of medium-sized arteries throughout the body, especially the coronary arteries, which supply blood to the heart muscle. Kawasaki disease is the leading cause of acquired heart disease in children in developed countries. While the exact cause remains unknown, early diagnosis and treatment are essential to prevent long-term complications such as coronary artery aneurysms.

Causes

The exact cause of Kawasaki disease is still unknown, but several factors are believed to contribute to its development:

• Infectious Triggers: Many experts suspect an abnormal immune response to a viral or bacterial infection, though no specific pathogen has been identified.
• Genetic Susceptibility: Kawasaki disease appears more frequently in children of Asian descent, particularly Japanese children, suggesting a genetic predisposition.
• Environmental Factors: Certain environmental triggers, including seasonal patterns, have been observed, with more cases occurring in winter and early spring.
• Immune System Dysregulation: The condition is thought to involve an overactive immune response that leads to widespread blood vessel inflammation (vasculitis).

Symptoms

Kawasaki disease develops in phases, with distinct symptoms:

Acute Phase (1-2 weeks)

• High fever lasting more than five days
• Red, bloodshot eyes without discharge (conjunctivitis)
• Bright red lips, tongue (strawberry tongue), and mouth lining
• Swelling and redness of hands and feet
• Skin rash, often on the torso and extremities
• Swollen lymph nodes, particularly in the neck

Subacute Phase (2-4 weeks)

• Peeling skin on hands and feet, especially around fingertips and toes
• Joint pain and irritability
• Gastrointestinal symptoms such as vomiting, diarrhea, or abdominal pain
• Increased risk of coronary artery complications during this phase

Convalescent Phase (4-8 weeks)

• Gradual resolution of symptoms
• Laboratory abnormalities may persist, such as elevated inflammatory markers

Diagnosis

There is no specific test for Kawasaki disease; diagnosis is based on clinical criteria and supportive laboratory and imaging studies:

• Clinical Criteria: Diagnosis is made when a child has a fever for more than five days and at least four out of five principal features (rash, conjunctivitis, red lips/tongue, swollen hands/feet, and enlarged lymph nodes).
• Laboratory Tests: Blood tests often show elevated inflammatory markers (ESR, CRP), high white blood cell count, anemia, and low albumin.
• Echocardiogram: An ultrasound of the heart is crucial to evaluate for coronary artery abnormalities.
• Other Imaging: In some cases, additional imaging like coronary artery angiography may be used if complications are suspected.

Treatment

Prompt treatment of Kawasaki disease significantly reduces the risk of heart complications. The main treatment options include:

• Intravenous Immunoglobulin (IVIG): High doses of IVIG are administered early, typically within the first 10 days of illness, to reduce inflammation and prevent coronary artery damage.
• Aspirin: High-dose aspirin is used initially to reduce fever and inflammation, followed by a lower maintenance dose to prevent blood clots.
• Corticosteroids: In some high-risk or IVIG-resistant cases, corticosteroids may be added to therapy.
• Hospital Monitoring: Hospitalization is usually required during the acute phase to monitor heart function and manage symptoms.
• Long-Term Follow-Up: Regular echocardiograms and pediatric cardiology follow-up are essential to monitor heart health, especially in children with coronary involvement.

Prognosis

The prognosis for Kawasaki disease is generally good with early treatment. Most children recover fully within a few weeks. The risk of long-term complications, particularly coronary artery aneurysms, is significantly reduced with timely IVIG treatment. About 15-25% of untreated children develop coronary artery complications, but this risk drops to less than 5% with proper management. Lifelong follow-up may be necessary for children with heart involvement. Overall, early diagnosis and aggressive treatment offer excellent outcomes for most children affected by Kawasaki disease.