AudienceThis scenario was developed to educate emergency medicine residents on the diagnosis and management of blast crisis.IntroductionChronic myeloid leukemia (CML) makes up 15% of diagnosed adult leukemias with the median age of diagnosis being 67 years old. Chronic myeloid leukemia consists of three phases: chronic, accelerated, and blast phases. Most patients are initially diagnosed while in the chronic phase.1Of those diagnosed in the chronic phase and being treated with a tyrosine kinase inhibitor (TKI), about 1% –1.5% of CML patients per year will subsequently transform into an advanced phase or blast crisis.2While rare, blast crisis is considered an oncologic emergency, with increased mortality occurring primarily from subsequent infections or bleeding. Therefore, emergency physicians must be familiar with its clinical presentation and subsequent management.Educational ObjectivesBy the end of this simulation, the participant will be able to: 1) create a thorough differential for the undifferentiated febrile, altered patient, 2) identify the signs and symptoms of blast crisis, 3) describe proper resuscitation of a patient in blast crisis, and 4) describe the indications, steps, and contraindications of performing a lumbar puncture.Educational MethodsThis session was conducted using high-fidelity simulation, followed by a debriefing session and lecture on the diagnosis, differential diagnosis, and management of blast crisis. Debriefing methods may be left to the discretion of participants, but the authors have used advocacy-inquiry techniques. This scenario may also be run as an oral boards case.Research MethodsOur simulation center’s feedback form is based on the Center of Medical Simulation’s Debriefing Assessment for Simulation in Healthcare (DASH) Student Version Short Form, with the inclusion of required qualitative feedback if an element was scored less than a 6 or 7.ResultsThis session received all 6 or 7 scores (consistently effective/very good or extremely effective/outstanding). During the debriefing session, feedback from the residents was largely positive. They appreciated reviewing the broad differential of altered mental status and oncologic emergencies. While many groups anchored on the diagnosis of encephalitis, they also expressed that after this experience, blast crisis would be added to their differential for patients with CML.DiscussionThis is a cost-effective method for reviewing blast crisis. Learners were able to identify more common causes of altered mental status in their differentials, but without further prompting, they were unable to ultimately come up with the diagnosis of blast crisis. Our main take-away is to continue reviewing oncologic emergencies as a part of our residency curriculum.TopicsMedical simulation, chronic myeloid leukemia, blast crisis, leukostasis, emergency medicine, oncologic emergencies, hematologic emergencies.