MSFinals-4228

MSFinals-4228

A 4-year-old boy is brought to his pediatrician by his father. He has been experiencing a dry cough and runny nose for the past 7 days, along with a 6-day history of fevers up to 38.7ºC that have not responded to paracetamol and ibuprofen.

During the examination, the boy appears generally unwell and unhappy. His tongue is bright red, and there is a maculopapular rash on his trunk. Bilateral conjunctival injection is present, but there is no apparent discharge. Additionally, palpable submandibular lymphadenopathy is observed.

What investigation should be utilized to screen for long-term complications, given the probable diagnosis?