Clinical Scenario:
A 12-year-old previously healthy boy is brought to the emergency department with a 6-day history of high-grade fever, abdominal pain, vomiting, and diarrhea. His parents report that he had a mild respiratory illness 5 weeks ago after several family members tested positive for COVID-19. On examination, he is febrile (39.5°C), tachycardic, hypotensive, and has bilateral non-purulent conjunctivitis, cracked lips, and a generalized erythematous rash. Laboratory investigations reveal markedly elevated CRP, ferritin, D-dimer, and troponin levels. Echocardiography demonstrates mild left ventricular dysfunction.
Which of the following is the most likely diagnosis?
A. Acute COVID-19 pneumonia
B. Kawasaki disease
C. Multisystem Inflammatory Syndrome in Children (MIS-C)
D. Septic shock due to bacterial infection
E. Toxic shock syndrome
Correct Answer & Explanation:
The correct answer is C.
The most discriminating clues are the recent COVID-19 exposure, persistent high fever, prominent gastrointestinal symptoms, mucocutaneous inflammation, shock, markedly elevated inflammatory markers, and myocardial dysfunction. This combination strongly supports MIS-C rather than uncomplicated acute COVID-19 or isolated Kawasaki disease.
Explanation: Multisystem Inflammatory Syndrome in Children (MIS-C)
It a serious inflammatory condition associated with SARS-CoV-2 infection. It typically develops several weeks after the initial infection, rather than presenting solely as acute viral respiratory disease. It can affect multiple organ systems, including the cardiovascular, gastrointestinal, dermatological, hematological, and neurological systems.
In this case, the mild respiratory illness occurred five weeks before the current presentation, which fits the characteristic delayed timing of MIS-C.
Interpreting the clinical findings
Persistent high-grade fever: A central feature of MIS-C and other significant inflammatory or infectious illnesses.
Abdominal pain, vomiting, and diarrhea: Gastrointestinal involvement is common in MIS-C and may dominate the initial presentation.
Bilateral non-purulent conjunctivitis, cracked lips, and generalized rash: These mucocutaneous findings reflect systemic inflammation and can resemble Kawasaki disease.
Hypotension and tachycardia: Suggest cardiovascular compromise and possible shock.
Elevated CRP and ferritin: Indicate substantial systemic inflammation.
Elevated D-dimer: Supports associated coagulation activation and inflammation.
Elevated troponin and reduced left ventricular function: Suggest myocardial injury and cardiac involvement, which are important features of severe MIS-C.
The combination of gastrointestinal, mucocutaneous, cardiovascular, and laboratory abnormalities is much more informative than any individual finding.
Why are the other options less likely?
A. Acute COVID-19 pneumonia
Acute COVID-19 may cause fever and respiratory symptoms, but this child has a delayed post-infectious presentation dominated by gastrointestinal symptoms, shock, mucocutaneous inflammation, and myocardial dysfunction. The absence of prominent current respiratory features makes acute COVID-19 pneumonia less likely.
B. Kawasaki disease
Kawasaki disease can cause prolonged fever, conjunctivitis, oral changes, and rash. However, prominent gastrointestinal symptoms, hypotension, markedly elevated D-dimer and ferritin, elevated troponin, and left ventricular dysfunction—particularly after recent SARS-CoV-2 infection—favour MIS-C. There is clinical overlap, and some children with MIS-C have Kawasaki-like features.
D. Septic shock due to bacterial infection
Bacterial sepsis can cause fever, hypotension, raised inflammatory markers, and myocardial dysfunction. It must nevertheless be investigated urgently because it is potentially life-threatening. The recent COVID-19 illness and characteristic multisystem inflammatory presentation make MIS-C the most likely diagnosis in this examination scenario. A possible diagnosis of MIS-C does not exclude concurrent infection.
E. Toxic shock syndrome
Toxic shock syndrome may produce fever, rash, hypotension, and multiorgan dysfunction, usually in association with toxin-producing Staphylococcus aureus or Streptococcus pyogenes. However, the delayed relationship to COVID-19, gastrointestinal involvement, elevated cardiac biomarkers, and left ventricular dysfunction collectively favour MIS-C. Microbiological investigations are still needed when clinically indicated.
Clinical pearl
In a child with persistent fever several weeks after COVID-19, remember the combination:
Fever + gastrointestinal symptoms + mucocutaneous findings + shock or cardiac dysfunction + markedly elevated inflammatory markers = suspect MIS-C.
MIS-C is a potentially life-threatening condition. A child presenting with hypotension and ventricular dysfunction needs urgent hospital-level care, cardiovascular stabilisation, and assessment for alternative diagnoses, including bacterial sepsis.
Find More High-Yield Clinical Scenario Based MCQs with Answer on Pediatric Emergencies.
References
Centers for Disease Control and Prevention. Clinical overview of multisystem inflammatory syndrome in children (MIS-C). CDC.
World Health Organization. Multisystem inflammatory syndrome in children and adolescents with COVID-19. WHO.
Henderson LA, Canna SW, Friedman KG, Gorelik M, Lapidus SK, Bassiri H, et al. American College of Rheumatology clinical guidance for multisystem inflammatory syndrome in children associated with SARS-CoV-2 and hyperinflammation in pediatric COVID-19: Version 3. Arthritis Rheumatol. 2022;74(4)–e20. https://doi.org/10.1002/art.42062.
