Case Presentation: A 52-year-old man with a history of hypertension and coronavirus disease 2019 (COVID-19) two months prior presented to the emergency department (ED) with five days of fever, malaise, vomiting, and diarrhea. He tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) three days prior and received monoclonal antibody infusion the day prior to presentation. He received two doses of the Moderna vaccine, the second about ten days prior (Figure 1). In the ED, his vital signs were 38.8°C, heart rate 132, blood pressure 80/48 mmHg, respiratory rate 24 on room air. The remainder of his physical examination was unremarkable. Laboratory studies revealed mild electrolyte abnormalities, lymphopenia, thrombocytopenia, and an acute kidney injury (AKI). Chest x-ray (CXR) was normal. He was given intravenous fluids and methylprednisolone with resolution of his hypotension and was admitted to the hospital service. Empiric antibiotics were stopped after chest computed tomography showed mild bibasilar ground glass opacities and blood cultures remained negative. Further workup revealed elevated inflammatory markers, d-dimer, ferritin, and positive SARS-CoV-2 IgG antibodies. With concern for multisystem inflammatory syndrome in adults (MIS-A), infectious disease and rheumatology consultants recommended intravenous immunoglobulin (IVIG) and dexamethasone. The patient improved until day three of hospitalization, when he developed new respiratory distress requiring oxygen supplementation and orthopnea. Troponin and brain natriuretic peptide were elevated, and CXR at this time was concerning for pulmonary edema. Anakinra was added. Cardiac magnetic resonance imaging showed newly depressed left ventricular ejection fraction of 40% concerning for stress-induced cardiomyopathy. The patient was started on lisinopril after resolution of his AKI, and he remained on prophylactic dosing of heparin and aspirin throughout his hospital stay. His respiratory distress resolved with diuresis, and hospital day nine his inflammatory markers trended down (Figure 2). He remained inpatient for a 12-day course of anakinra and was discharged with a six week prednisone taper. At his post discharge follow up he remained well.

Discussion: MIS-A was first described in June 2020(1) and was noted to occur weeks after infection with SARS-CoV-2. It is characterized by severe illness, positive SARS-CoV-2 testing, extrapulmonary organ dysfunction, inflammation, and absence of severe respiratory illness.(1) A recent publication identified only 221 cases of MIS-A after review of the literature.(2) This patient displayed the five most common findings of MIS-A found in more than half of patients, including fever, hypotension, cardiac dysfunction, shortness of breath, and diarrhea.(2) This patient was also male, which makes up 70% of MIS-A patients.(2) Workup for MIS-A includes testing for SARS-CoV-2, inflammation, and coagulopathy. Management of includes supportive measures, anticoagulants, corticosteroids, IVIG, and immune modulators as demonstrated by this case. The pathogenesis of MIS-A is not fully understood, but it is more common in children (MIS-C) and thought to be due to a delayed and dysregulated immune response when recovering from COVID-19.

Conclusions: MIS-A is a rare but a likely underrecognized disease in the time of a pandemic. It is important to distinguish it from the many comorbidities that adults can have and treat it appropriately as demonstrated by this case.

IMAGE 1: Figure 1: Timeline of patient’s vaccinations and illnesses

IMAGE 2: Figure 2: Select inflammatory markers over the course of the patient’s illness and recovery