Kawasaki Disease Overview and Pearls
Kawasaki disease (KD) is a common medium vessel systemic vasculitis that primarily affects children younger than 5 years of age.
Why do we care?
Untreated Kawasaki Disease may lead to the formation of coronary artery aneurysms and sudden cardiac death in children.
Who is affected?
It is slightly more prevalent in males than in females. Rates are highest in Asian/Pacific Islanders followed by blacks, whites, and American Indians.
What causes Kawasaki disease?
Many infectious agents have been proposed as having a causative role in Kawasaki disease including multiple viruses, bacteria, spirochetes, and rickettsia. However, none have been confirmed as the definitive source.
What are the principal clinical features?
1. The presence of ≥ 5 days of fever
- Fevers are often high, commonly > 39°C (102.2°F), and potentially > 40°C (104°F)
- The fever may not respond to anti-pyretic drugs, and it generally persists for an average of 10 to 14 days without treatment but may continue for as long as 3 to 4 weeks
2. Conjunctival injection
- Occurs in an estimated 80 - 90% of patients with Kawasaki disease
- It is most commonly bilateral, painless, and non-purulent
3. Oropharyngeal mucous membrane changes
- Dry, fissured, or erythematous lips
- Strawberry tongue
- Erythema of the posterior oropharynx or non-exudative pharyngitis
4. Polymorphous rash
- Present in approximately 80% - 90% of patients
- Develops early in the course of the disease.
- The rash is often found on the truck or extremities and may be present in the perineal area.
- Multiple manifestations including: diffuse and macular, scarlatiniform, scaling plaque, or erythema multiforme like
5.Extremity changes
- Erythema may be limited to the palms of the hands and soles of the feet
- Desquamation of the fingers and toes is also common in children. Occurs late in the disease, often 2 to 3 weeks after the onset of illness.
6.Lymphadenopathy
- Rarest symptom
- Only occurs in 50% to 60% of patients with Kawasaki disease.
- Most commonly unilateral and found in the cervical chain.
- ≥ 1 lymph node with a diameter of at least 1.5 cm
How do we diagnose it?
There are two categories of the disease: Complete or Incomplete.
Complete Kawasaki disease
- Fever≥ 5 days and ≥ 4 principal clinical features OR
- Fever≥ 4 days and 5 principal clinical features
Incomplete Kawasaki disease
- Children with fever ≥ 4 days and presence or history of ≥ 2 principal clinical features OR
- Infants ≤ 6 months with unexplained fever for ≥ 7 days OR
- 3 days of fever and strong clinical suspicion
Ancillary Testing
Inflammatory markers:
- CRP≥ 3.0 mg/dL
- ESR ≥ 40 mm/h
CBC
- WBC counts > 15,000/mm found in at least half of patients
- Thrombocytosis which appears during the second week of illness and peaks in the third or fourth week.
CMP
- Hyponatremia
- Mild to moderate elevations in serum transaminases
Urine analysis
- Sterile pyuria (+WBC, -Bacteria)
EKG: Arrhythmias, Nonspecific T-wave changes, PR or QT interval prolongation.
- EKG changes are most likely to be found during the acute phase and in the first month following diagnosis and they frequently normalize after recovery.
Lumbar puncture:
- Aseptic meningitis is found in approximately 25% of patients with Kawasaki disease
- Predominance of mononuclear cells and normal cerebrospinal fluid protein and glucose levels
Echocardiogram
- Should be performed in all patients with a definitive or suspected diagnosis of Kawasaki disease.
- Goals is to perform on the day of diagnosis
- It is both highly sensitive and specific for detecting coronary artery lesions. Most commonly affected vessel is proximal segment of the LAD.
- Myocarditis is common during the acute phase of the illness
- It should be noted that a normal initial echocardiogram should not be used to exclude the diagnosis of Kawasaki disease
How do we treat it?
IVIG
- Associated with a significant reduction in coronary artery aneurysm development in children receiving IVIG plus aspirin compared to aspirin alone
- 2 g/kg given over a period of 10 to 12 hours
- Significantly reduces the risk of coronary artery aneurysms at 30 days
Aspirin
- Despite the lack of evidence to support the use of aspirin, the AHA and the AAP continue to recommend its use in combination with IVIG
- Started at high doses (80-100 mg/kg/day) and divided into 4 doses.
- The dose is then decreased to 3 to 5mg/kg/day after defervescence
- Low-dose aspirin is then continued for 6 to 8 weeks until follow-up echocardiography is normal.
- For children who develop coronary artery lesions, low-dose aspirin may be continued indefinitely for its anti-platelet effects.
Resources
Kawasaki disease: A Comprehensive Review. Kamleshun Ramphul, Stephanie Mejias. Archives of Medical Science - Atherosclerotic Diseases . 2018
Evidence-Based Management of KawasakiDisease in the Emergency Department. Kara K. Seaton, Anupam Kharbanda. PediatricEmergency Medicine Practice, Volume 12. January 2015.
Children'sHospital. “Kawasaki Disease or Incomplete Kawasaki Disease Clinical Pathway -Emergency and Inpatient.” Kawasaki Disease or Incomplete KawasakiDisease Clinical Pathway - Emergency and Inpatient, The Children's Hospital of Philadelphia, 5 Jan. 2018,www.chop.edu/clinical-pathway/kawasaki-disease-incomplete-kawasaki-disease-clinical-pathway.
