Multisystem inflammatory syndrome in children masquerading as retropharyngeal infection

ABSTRACT

Case Report Multisystem inflammatory syndrome in children (MIS-C) typically presents with fever and multisystem dysfunction following infection with SARS-CoV-2. Per CDC guidelines, MIS-C can be diagnosed when an individual less than 21 years of age presents with fever, laboratory evidence of inflammation, and multisystem organ involvement requiring hospitalization with no alternative diagnosis and evidence of current or prior COVID-19 infection. Systems are categorized as either cardiac, renal, respiratory, hematologic, gastrointestinal, dermatologic, or neurological. Otolaryngologic is not a designated system. However, atypical presentations of MIS-C involving the deep neck have been reported. Specifically, cases of children with retropharyngeal pathology, including edema and phlegmon, have been described. Our report highlights a case of deep neck infection as the initial presentation of MIS-C. A 12-year-old male was admitted to the pediatric hospital medicine service for medical management of a moderately large retropharyngeal phlegmon/ abscess confirmed by computed tomography (CT) scan. Otolaryngology team was consulted, and surgical intervention was not recommended. The patient was started on empiric intravenous (IV) antibiotic treatment with ceftriaxone and vancomycin. After two days of antibiotics, he showed minimal improvement. On physical exam, he continued to have neck pain, tenderness to palpation on the left neck inferior/posterior to the left ear, mild edema, and limited lateral range of motion due to pain. Repeat CT scan of his neck also showed minimal improvement of phlegmon. During admission, he developed bilateral non-exudative conjunctivitis, erythematous lips, mild erythema over his palms, abdominal pain, and cough, with a worsening fever curve while on broad spectrum antibiotics. At this time, differential diagnosis was broadened to include viral syndrome, MIS-C, and atypical Kawasaki Disease. Respiratory viral panel (including COVID-19) was negative. Inflammatory markers were elevated, including CRP of 26.6 mg/dL, ESR of 64 mm/hr, and Pro-BNP of 1,908 pg/mL. Ultimately, the patient met criteria for MIS-C less than 21 years old, presence of fever, elevated inflammatory markers, multisystem involvement, and positive COVID-19 antibody. Treatment was initiated for moderate-severe MIS-C with IV immunoglobulin (IVIG) infusion, aspirin, IV methylprednisolone, and omeprazole prophylaxis. The patient clinically improved after IVIG infusion, and antibiotics were de-escalated to oral Augmentin for a total duration of 14 days of antibiotic therapy. He was discharged on aspirin, a prednisone wean, and omeprazole with Cardiology outpatient follow-up established. MIS-C is a novel syndrome that can have unique presentations. Clinicians should consider MIS-C when a febrile patient being treated for infection does not improve with standard therapies and have a low threshold to initiate MIS-C evaluation if new symptoms involving other organ systems develop.