P0888 - Incomplete Kawasaki Disease with Evidence of Prior COVID-19 Infection

Introduction:
Currently the United States is the most affected country worldwide with COVID-19. Initial data found the majority of pediatric cases to be mild or asymptomatic, with decreased hospitalizations compared to adults. Recently there are reports demonstrating systematic inflammatory illnesses in children with COVID-19, including toxic shock syndrome and Kawasaki Disease (KD). The following case describes a pediatric patient with incomplete KD and evidence of previous COVID-19 infection.

Case:
A healthy 2-year-old female presented with 5 days of fever, polymorphous rash, and conjunctivitis. She was found to have elevated CRP 19.2mg/dL and ESR 115mm/hr. Echocardiogram noted mild dilation of the right coronary artery (z-score +2.1). She received IVIG and aspirin. Repeat echocardiogram showed a small fusiform RCA aneurysm (z-score +3.1) and LAD aneurysm (z-score +5.0). An S3 gallop was appreciated on exam. BNP was elevated (max 2,100pg/mL) and CXR showed a right sided pleural effusion. She received infliximab for refractory KD with resolution of fever and rash. BNP remained elevated warranting continued Lasix with improvement.

Initial infectious workup on admission was negative, including SARS-CoV-2 RT-PCR testing from nasopharyngeal swab. Anti-SARS-CoV-2 serum IgG Antibody testing was sent and resulted positive.

A repeat echocardiogram demonstrated a small, stable RCA aneurysm with normal function. She was discharged home on low dose aspirin and Lasix.

Discussion:
Kawasaki Disease is a systemic, inflammatory illness that affects medium-sized arteries and causes coronary artery aneurysms if untreated. The etiology remains unknown, despite decades of investigation. An infectious trigger leading to a systemic inflammatory response has been theorized however data is inconsistent. There is some evidence that infection with a novel RNA virus may be linked to a KD agent.

Diagnosis requires fever >5 days and 4 of the following: conjunctivitis, mucositis, polymorphous exanthem, peripheral extremities swelling, cervical lymphadenopathy. Incomplete KD can be considered in patients with prolonged fevers, 2-3 exam findings, supporting laboratory evidence or echocardiogram abnormalities. Our patient met criteria for incomplete KD with prolonged fevers, conjunctivitis, polymorphous rash, elevations in CRP/ESR and positive echocardiogram findings.

The clinical significance of IgG antibodies to COVID-19 remains unknown. Our patient initially tested negative with RT-PCR suggesting no active infection during symptom onset. The family denied antecedent illness or known contacts infected with COVID-19. Positive antibodies suggest our patient may have been an asymptomatic carrier, however a false positive (received IVIG prior to testing or reaction from another coronavirus) cannot be ruled out.

Conclusion:
The effects of COVID-19 on children is not well understood. Children appear to be less affected than adults, and symptoms tend to be very mild. There is increasing evidence that a post-viral inflammatory response may contribute to systemic illness in children and more information is needed for clinicians to approach affected patients moving forward.