Case Presentation: A 15-year-old female with history of migraines presented to the emergency department with six days of headache, fatigue, and fever to 105F. Three days prior, she developed diffuse body aches and severe neck pain. On the day of presentation, the patient developed a nonpruritic rash on her face, trunk, and extremities. She had no known COVID-positive contacts, but her sister did have an unexplained fever one month prior. On admission, she was febrile to 104F and tachycardic to 120. She had bilateral non-exudative conjunctival injection, full active range of motion of the neck with reported discomfort, non-pitting edema of her hands, diminished extremity strength against resistance but intact reflexes, and a diffuse, blanching, erythematous, macular serpiginous rash involving her face, arms, legs, and trunk. Electrolytes and kidney function were normal. Liver enzymes were mildly elevated, and creatinine kinase on presentation was 5,612 with peak at 11,295 units/L (reference range 21-232 units/L) on hospital day four. She had evidence of systemic inflammation with hypoalbuminemia, elevated C-reactive protein, erythrocyte sedimentation rate, procalcitonin, D-dimer, and ferritin. Cerebrospinal fluid studies were negative for pleocytosis with normal protein and glucose. MRI/MRV brain was obtained for persistent headache and revealed focal restricted diffusion in the splenium of the corpus callosum.This patient met diagnostic criteria for atypical Kawasaki disease and was treated with intravenous immunoglobulin (IVIG) and medium-dose aspirin . Intravenous fluids were administered for rhabdomyolysis. On hospital day 4, COVID-19 antibody testing returned as positive, and the patient met criteria for multisystem inflammatory syndrome in children associated with SARS-CoV-2 (MIS-C) based on fever, multisystem involvement, systemic inflammation, and history of SARS-CoV-2 infection. As her symptoms gradually improved, she did not require treatment with corticosteroids. Repeat brain imaging three months later showed interval resolution of prior abnormality. She recovered fully without long-term sequalae.

Discussion: MIS-C is a newly described condition occurring in children up to 4 weeks after infection with the SARS-CoV-2 virus[1-4]. The most common presenting symptoms are fever and gastrointestinal symptoms such as abdominal pain, vomiting, or diarrhea[1]. Symptoms similar to those seen in Kawasaki disease, such as conjunctivitis, rash, mucositis, and extremity edema are also common[1]. This patient’s presenting symptoms of headache and body aches are less often cited as presenting symptoms in the literature and, although there are reports of rhabdomyolysis as a complication of active COVID-19 in children[5], there have been no previous reports of rhabdomyolysis in MIS-C. Brain MRI findings in this case are also notable, as diffusion restricted lesions in the splenium of the corpus collosum were also noted in three adult patients in a retrospective case series evaluating brain MRI findings two to four weeks after active SARS-CoV-2 infection[6].

Conclusions: This case illustrates that pediatricians should have a high index for suspicion of MIS-C in patients with evidence of systemic inflammation, even in cases without typical presenting signs and symptoms. MIS-C is a rapidly emerging condition with significant risk of morbidity and mortality. Though this patient had atypical symptoms, she was quickly diagnosed and treated for MIS-C and subsequently made a complete recovery.