Not Out of the Woods Yet: A Case of Multisystem Inflammatory Syndrome Due to COVID-19 in an Adult

Introduction Multisystem inflammatory syndrome (MIS) is a hyperinflammatory disorder seen in patients with history of COVID-19 infection. It is most commonly seen in children (MIS-C) and is rare in adults (MIS-A). We report a case of MIS-A with multiorgan failure in a previously healthy patient who had recently recovered from COVID-19. Case Presentation A 29-year-old Caucasian male with no medical history presented with fever to 103 degrees Fahrenheit, headache, syncope, and vomiting for 3 days. He had been diagnosed with COVID-19 five weeks prior and recovered without complication. Patient was seen in the ED the previous day for fever and neck stiffness, at which time he had a negative repeat COVID-19 test and unremarkable lumbar puncture. Physical exam was normal. Labs revealed WBC 13.4, platelets 90, AST 92, ALT 120, total bilirubin 1.7, ferritin 1,033, CRP 312, and procalcitonin 1.35. Initial imaging revealed gallbladder sludge and inflammation of the mesentery and distal ileum with adenopathy. Patient was started on broad-spectrum antibiotics. However, over the next 3 days, he developed an oxygen requirement up to 6 liters, tachycardia, increasing liver function tests, and acute kidney injury. Procalcitonin trended up to 16.03. Infectious workup was negative. CTA chest revealed right upper lobe pulmonary emboli, bilateral pleural effusions, and pulmonary edema. Pro-BNP was 24,554. Echocardiogram showed ejection fraction (EF) 45-50%, enlarged right ventricle, and small pericardial effusion. Patient was started on a heparin drip, without improvement. Diuresis was attempted but limited by hypotension. He was ultimately treated with dexamethasone, resulting in rapid improvement. Discussion The pathophysiology of MIS-A is poorly understood but is thought to be due to immune dysregulation. This may be a post-infectious process or could be due to persistent infection outside of the upper respiratory system, as SARS-CoV-2, the virus that causes COVID-19, is known to affect other organs, such as the heart, liver, kidneys, and gastrointestinal system. MIS-A usually occurs 2-5 weeks after the patient has COVID-19. It disproportionately affects minority groups. Common presenting symptoms include fever, chest pain, dyspnea, myalgias, and gastrointestinal and dermatologic symptoms. Inflammatory markers (e.g., CRP, ferritin, D-dimer) are elevated. Severe dysfunction of at least one extrapulmonary organ system (e.g., cardiac dysfunction, hypotension, acute kidney or liver injury, thromboembolism) must be present. The mainstay of treatment is corticosteroids;intensive care admission, mechanical ventilation, vasopressor or inotrope support, and hemodialysis may also be required. The majority of patients with MIS-A survive. The long-term effects are unknown.