Hypothermia as a Possible Symptom of Serotonin Toxicity: A Case Report

Background There are three commonly used sets of criteria to diagnose serotonin syndrome and all three diagnostic tools have all been shown to have shortcomings that do not fully encompass the possible symptoms of serotonin toxicity. Objective To describe a case of an atypical presentation of possible drug-induced serotonin syndrome, characterized by hypothermia, night sweats, muscle tremors, and confusion. Setting A rural and medically underserved area in eastern Washington State. Practice Description This patient case was identified as a part of a project to identify and intervene with complex and high-risk patients from local rural and underserved populations. The pharmacist identified the symptoms of possible drug-induced serotonin syndrome during a comprehensive medication review with the patient. Results The pharmacist identified a possible case of drug-induced serotonin syndrome and made a recommendation to the patient's physician that led to discontinuation of both fluoxetine and trazodone. At the follow-up visit, the patient reported that his symptoms had resolved completely. Discussion The three sets of diagnostic criteria for serotonin syndrome all include fever as a symptom, but do not list hypothermia. Effects at various 5-HT receptors and receptor subtypes have been linked to symptoms often seen in serotonin syndrome, but there are gaps in the currently used diagnostic criteria. Conclusion Pharmacists' comprehensive review of medications can allow identification of symptoms, such as hypothermia to identify possible serotonin syndrome.