Review Question - QID 213823

A 2-year-old boy presents to the emergency department for a fever. The patient’s parents state that the patient has had a gradually worsening fever for the past 5 days. Recently, he has been eating and drinking less and will not take acetaminophen. The patient was born at home and has not received his vaccinations. The child currently takes multiple vitamin and herbal supplements. His rectal temperature is 104.0°F (40.0°C), blood pressure is 86/50 mmHg, pulse is 148/min, respirations are 22/min, and oxygen saturation is 99% on room air. Physical exam is notable for conjunctivitis and tender cervical adenopathy. A desquamating rash is noted on the patient’s palms, as well as erythema and swelling of the tongue. The child is highly irritable and will not participate in a neurological exam. The physician states he wants to order a few blood tests, which the parents refuse since they believe taking their son's blood could make him sicker. They ultimately leave the hospital without the workup being completed. Which of the following preventable complications is the patient at risk for as a result of not being treated?