Why was this previously healthy 14-year-old so sick? | Medical Mystery

A previously healthy 14-year-old male was brought to the emergency department after experiencing fatigue, fevers, and decreased appetite for four days. Two days earlier, he’d been seen in an urgent care center, where doctors prescribed a course of amoxicillin for suspected middle ear infection. Now, he was feeling worse and complaining of abdominal pain.

When examined in the ED, the patient had a fever, an increased heart rate, and low blood pressure requiring IV fluids. He was admitted to the pediatric intensive care unit for close monitoring. His doctors were worried about sepsis, which is the body’s extreme response to infection and is a life-threatening medical emergency.

But what was the underlying cause of his illness? Initially, doctors were concerned about pancreatitis, as his pancreatic enzymes (amylase and lipase) were elevated in his blood. However, the patient developed new symptoms including neck pain and limited neck motion, as well as reddening of his eyes, which is not consistent with this diagnosis.

Further laboratory testing revealed elevated heart enzyme levels, indicating damage to his myocardium, or heart muscle, as well as very high levels of c-reactive protein, which indicates generalized inflammation. Due to the evidence of inflammation in multiple organ systems, his doctors now suspected a condition called multisystem inflammatory syndrome in children, or MIS-C.

MIS-C is a rare but serious complication of COVID-19 that can occur in susceptible patients, usually presenting around 2-6 weeks after initial COVID infection. This patient was not aware of having had COVID recently, but an asymptomatic COVID infection can still spur MIS-C. MIS-C can present with persistent fever, multiorgan dysfunction, and elevated inflammatory markers, which were all present in our patient. This condition was much more prevalent at the heights of the COVID-19 pandemic. Cases dropped rapidly after distribution of the COVID vaccine. This particular patient presented before the creation of the COVID vaccine.

Since this patient’s inflammatory symptoms were progressing and tests showed signs of heart involvement, treatment for MIS-C was started. Specific treatment courses can vary but all include intravenous immunoglobulin (IVIG), steroids, and aspirin. The patient’s symptoms improved quickly; he was soon able to move his neck without pain, and the redness in his eyes abated. COVID-19 antibody testing eventually came back positive, further supporting the diagnosis.

As we get further into life with COVID-19 as a part of our overall medical picture, it’s important to take a step back and look at all we have already learned about the disease. MIS-C is a well documented complication of a COVID infection; however, it may no longer be foremost in physicians’ minds. COVID vaccination has proven highly effective in preventing this frightening condition; a CDC study from 2021 reported 91% effectiveness of these vaccines in preventing MIS-C, as well as more severe disease in MIS-C patients who were unvaccinated. For this patient, there was a full recovery thanks to doctors who quickly recognized the signs and symptoms of MIS-C and started treatment rapidly. Moving forward, it’s important for parents to understand that vaccination can help prevent COVID-related complications, and for our primary care teams to continue communicating everything we have learned over the past six years.

Jordan Priess is a third-year pediatric resident and Hayley Goldner is a pediatrician in the adolescent medicine department at Nemours Children’s Hospital, Delaware.