TEACHING MEDICAL STUDENTS DIAGNOSTIC ERROR USING THE PROBLEM BASED LEARNING (PBL) METHOD: A CASE OF CELLULITIS MISDIAGNOSIS

Learning objectives:

1. Understand the Problem Based Learning approach to medical student education
2. Identify the cognitive reasons for cellulitis diagnostic error
3. Describe the teaching of diagnostic error within the context of the PBL method of medical education

Case information: This is a case of a 68 yo woman presenting to the emergency department with a swollen, erythematous, leg.  The emergency department diagnosed her with cellulitis and admitted her for intravenous antibiotics.  On the third morning the patient developed a rash.  A dermatology consult resulted in the diagnosis of a antibiotic medication reaction and the dermatologist diagnosed stasis dermatitis, rather than cellulitis. 

Discussion: Many medical schools have adopted the Problem-Based Learning (PBL) educational method.  PBL is a methodology used to encourage self-directed group learning and to practice differential diagnosis.  PBL is student directed, involves critical analysis of the literature, teamwork, group interaction and cooperation.  We developed a PBL around a case of presumed cellulitis as a method to introduce first year medical students to diagnostic error.  The new PBL was piloted in 2010, and then run successfully as part of the curriculum in 2011.    Students generally were positive in the evaluation of the PBL. The subsection of the class that was asked to evaluate the PBL and accompanying lecture rated it 4.4 out of 5 points.  PBL is a logical place to introduce diagnostic error because it is where students first learn to generate a differential diagnosis. This PBL case was well received and taught students about a common specific diagnostic error in addition to diagnostic error theory.