Kawasaki Disease (KD), also known as Mucocutaneous Lymph Node Syndrome, is an acute, self-limited vasculitis primarily affecting children under five years old. First described by Dr. Tomisaku Kawasaki in Japan in 1967, the disease causes inflammation of blood vessels throughout the body. If untreated, this inflammation can lead to coronary artery disease and long-term cardiac complications.
Cause and Risk Factors
The exact cause of Kawasaki Disease remains unknown, but several factors are thought to contribute:
- Infectious triggers: Some researchers suspect an infectious agent (bacterial or viral) triggers an abnormal immune response in genetically susceptible individuals, though no specific pathogen has been identified.
- Genetic predisposition: A genetic component is likely since children of Asian descent, particularly Japanese and Korean children, have a higher incidence of the disease.
- Age and gender: Kawasaki Disease primarily affects children under five, with peak incidence between 18 and 24 months. Boys are 1.5 times more likely than girls to be affected.
Clinical Presentation
Kawasaki Disease typically presents in three stages:
1. Acute Phase (Days 1–14)
- High fever lasting more than five days, unresponsive to antipyretics.
- Conjunctival injection (red eyes without discharge).
- Rash, which may appear in the groin, limbs, or chest.
- Swelling and redness of hands and feet.
- Strawberry tongue and cracked, red lips.
- Cervical lymphadenopathy, often unilateral.
2. Subacute Phase (Weeks 2–4)
- Peeling skin (desquamation), especially on fingers and toes.
- Joint pain or swelling due to arthritis or arthralgia.
- Coronary artery aneurysms (CAA) are most likely to occur during this phase if left untreated.
3. Convalescent Phase (Weeks 4–8)
- Symptoms gradually resolve.
- Laboratory abnormalities such as thrombocytosis and elevated inflammatory markers (CRP, ESR) may persist.
Diagnostic Criteria
Kawasaki Disease is diagnosed based on clinical features rather than specific tests. Classical criteria include fever lasting more than five days along with four of the following five symptoms:
- Conjunctival injection in both eyes.
- Oral mucosal changes (strawberry tongue, red lips).
- Peripheral changes (swelling, redness, desquamation).
- Polymorphous rash.
- Cervical lymphadenopathy (≥1.5 cm, often unilateral).
Atypical or Incomplete KD
Some children may not meet all the criteria but still develop coronary artery complications. In these cases, diagnosis is supported by echocardiography and elevated laboratory markers (CRP, ESR).
Complications
The most serious complications of Kawasaki Disease involve the heart, particularly the coronary arteries:
- Coronary artery aneurysms (CAA): Occur in 15–25% of untreated cases, potentially leading to myocardial infarction or ischemic heart disease.
- Myocarditis, pericarditis, and valve dysfunction: These can occur during the acute phase.
- Long-term risks: Coronary artery stenosis and a heightened risk of cardiovascular disease in adulthood.
Management and Treatment
Early diagnosis and treatment are crucial to preventing coronary artery complications. The standard treatment includes:
- Intravenous Immunoglobulin (IVIG): When administered within the first ten days, IVIG significantly reduces the risk of coronary artery aneurysms.
- Aspirin: High-dose aspirin is used during the acute phase for its anti-inflammatory effects, while low-dose aspirin is continued during the subacute phase to prevent thrombosis in cases of coronary artery involvement.
- Corticosteroids: May be considered in patients with IVIG-resistant Kawasaki Disease.
Follow-up and Prognosis
- Echocardiography: Repeat echocardiograms are recommended to monitor coronary artery abnormalities both in the acute/subacute stages and long-term.
- Prognosis: With timely treatment, most children recover fully, and the risk of coronary artery complications is reduced to under 5%. Children with coronary artery aneurysms require ongoing monitoring for stenosis, thrombosis, and ischemic heart disease.
Recent Developments and Research
- Biologics: Research is exploring the use of biologic agents like TNF-α inhibitors in refractory cases of Kawasaki Disease.
- Genetic Studies: Ongoing research into genetic markers aims to understand why certain populations, particularly Asian children, are more susceptible to the disease.
Conclusion
Kawasaki Disease is a serious pediatric condition that demands prompt recognition and treatment to prevent life-threatening coronary artery complications. While the cause remains uncertain, advancements in treatment, particularly with IVIG, have greatly improved outcomes, reducing the risk of coronary artery aneurysms and long-term cardiovascular issues
