Primary Measles Encephalitis.

Abstract

This scenario was developed to educate emergency medicine residents on the diagnosis and management of primary measles encephalitis. Measles is a highly infectious ribonucleic acid (RNA) virus whose prevalence in the United States has continued to increase despite being declared eliminated in 2000,1 and larger outbreaks have been noted among those who elect not to vaccinate.2 The recommended live-attenuated measles, mumps, and rubella (MMR) vaccine schedule for pediatrics includes one routine dose at 12-15 months of age and a second dose between 4-6 years of age with at least 28 days in between dose administration.1-2 Measles-associated complications include otitis media, pneumonia, laryngotracheobronchitis, diarrhea, and corneal ulceration.2 Patients may also develop central nervous system complications, including primary measles encephalitis, acute post-infectious measles encephalomyelitis, measles inclusion body encephalitis, and subacute sclerosing panencephalitis. Primary measles encephalitis and measles inclusion body encephalitis involve an active ongoing measles infection.3 We will focus on primary measles encephalitis for this case scenario. One out of every 1000 measles patients will develop primary measles encephalitis,1 with onset typically occurring within seven days of the measles prodrome. Treatment is largely supportive. Mortality from primary measles encephalitis is 10%-15%, with an additional 25% developing permanent neurodevelopmental sequalae.3 It is critical to maintain a high index of suspicion for this diagnosis, to place the patient in airborne precautions to protect other immunocompromised individuals, and to transfer to a pediatric intensive care unit (PICU). At the conclusion of the simulation session, learners will be able to: 1) Obtain a relevant focused history, including immunization status, associated symptoms, sick contacts, and travel history. 2) Develop a differential for fever, rash, and altered mental status in a pediatric patient. 3) Discuss management of primary measles encephalitis, including empiric broad spectrum antibiotics and antiviral treatment. 4) Discuss appropriate disposition of the patient from pediatric emergency departments, community hospitals, and freestanding emergency departments, including appropriate time to call for transfer and the appropriate time to transfer this patient during emergency department (ED) workup. 5) Review types of isolation and indications for each. This session was conducted using high-fidelity simulation, followed by a debriefing session and lecture on the diagnosis, differential diagnosis, and management of primary measles encephalitis. Debriefing methods may be left to the discretion of participants, but the authors have utilized advocacy-inquiry techniques. This scenario may also be run as an oral board case. Our residents are provided a survey at the completion of the debriefing session so they may rate different aspects of the simulation, as well as provide qualitative feedback on the scenario. Feedback from the residents was overwhelmingly positive with an average score of 7 (consistently effective/very good or extremely effective/outstanding) across all categories. The subsequent debriefings allowed for multiple areas of discussion, including differential diagnoses of fever and rash, the clinical presentation of measles, empiric treatment of meningitis/encephalitis, types and indications of isolation, when to call for transfer to a pediatric center, and when a child is deemed stable enough for transfer. This is a cost-effective method for reviewing primary measles encephalitis. There are multiple measles complications that may be reviewed via simulation, including pneumonia and dehydration from diarrhea. We encourage readers to utilize clinical photos of measles rashes, because this was difficult to capture via standard moulage techniques. Medical simulation, measles, primary measles encephalitis, encephalitis, infectious disease, emergency medicine, pediatric emergency medicine.