Serotonin syndrome and neuroleptic malignant syndrome: A case report of intersecting symptomatology.

Introduction: Serotonin syndrome and neuroleptic malignant syndrome are caused by 2 distinct pathologies; however, the clinical presentation associated with both syndromes share many features. Methods: We describe a 56-year-old male patient who presented to our facility with seizures, leukocytosis, fevers, extremity hyperreflexia, and signs of autonomic dysfunction as evidenced by cardiovascular instability. The patient was noted to be taking vortioxetine, trazodone, lamotrigine, lurasidone, and carbidopa-levodopa as outpatient medications for his depression, an unspecified mood disorder, and Parkinson disease. Following a robust workup and failure of other therapies, all serotonergic and dopaminergic medications were held, and the patient was tried on cyproheptadine for serotonin syndrome, which led to the cessation of fevers. Bromocriptine was added to the regimen, which led to the resolution of the remainder of the patient's symptoms. Results: The overlapping symptomatology of several key diagnostic criteria for both serotonin syndrome and neuroleptic malignant syndrome as well as their nature as diagnoses of exclusion require an evaluation of the patient's aggregate improvement following targeted pharmacologic strategies for both syndromes. The efficacy of both cyproheptadine and bromocriptine when administered concomitantly support the concurrent pathologies. Discussion: Clinicians at the bedside must be cognizant of the potential for clinically relevant drug-drug interactions that may present with overlapping pathologies.