#25: Contemporaneous Evaluation of Kawasaki Disease and Multisystem Inflammatory Syndrome in Children Cases in Northern Virginia

Background Multisystem inflammatory syndrome in children (MIS-C) has a temporal association with SARS-coronavirus 2 (SARS-CoV-2) infection and can present similarly to Kawasaki disease (KD). After the Centers for Disease Control and Prevention issued a MIS-C case definition in May 2020, we implemented local diagnostic and management strategies to standardize the care for patients with MIS-C encouraging limited laboratory evaluation of non-toxic patients presenting with a febrile illness. We then sought to re-evaluate our diagnostic and management recommendations to ensure appropriate resource utilization for children with MIS-C and KD. Methods Patients with MIS-C and KD were identified via convenience sampling of Pediatric Infectious Diseases clinical records at Inova Children’s Hospital from May 1, 2020 to August 28, 2020. Manual chart review was done to extract clinical points of interest and the two cohorts were compared with descriptive statistics. Abdominal symptoms included pain, emesis, and diarrhea. Respiratory symptoms included shortness of breath, tachypnea, cough, and need for mechanical ventilation. Musculoskeletal symptoms included pain and edema. Neurologic symptoms included headache, dizziness, altered mental status, and irritability. Results 7 patients with KD and 14 patients with MIS-C were identified. No patients with KD had presenting hypotension and 9 patients with MIS-C had presenting hypotension (p < 0.01). Oral changes were seen in 5 patients with KD and 3 patients with MIS-C (p = 0.05). Conjunctival injection, rash, abdominal symptoms, musculoskeletal symptoms, and neurologic symptoms were seen in some patients with KD and MIS-C with no statistically significant occurrence of these symptoms between the two cohorts. The median initial absolute lymphocyte count was 2,860/µL in KD cases whereas it was 1,325/µL in MIS-C cases (p < 0.01). The median platelet count was 367,000/ µL in KD cases versus 193,000 in MIS-C cases (p = 0.03). The median initial C-reactive protein was 11.2 mg/dL in KD cases versus 23.2 mg/dL in MIS-C cases (p < 0.01). There was no statistically significant difference in the white blood cell count, erythrocyte sedimentation rate, alanine transaminase, B-natriuretic peptide, troponin I, or ferritin values between KD and MIS-C patients. Coronary artery dilation or prominence was seen in 4 patients with KD and in 8 patients with MIS-C (p > 0.99). There were no deaths. Conclusions Following national recognition of MIS-C we saw approximately 1 MIS-C case per week. Presenting hypotension, an absolute lymphocyte count less than 1400/µL, a platelet count less than 200,000/µL, and a CRP greater than 20 mg/dL best predicted MIS-C versus KD. The initial white blood cell count, alanine transaminase, erythrocyte sedimentation rate, B-natriuretic peptide, troponin I, ferritin, and initial coronary artery dilation did not readily distinguish KD from MIS-C. Thus, our diagnostic management recommending limited laboratory evaluation for non-toxic patients presenting with a febrile rash illness, fever and abdominal symptoms, or fever with conjunctival injection is reasonable.