Physician Fellow University of Michigan Health System PM&R Program Ann Arbor, Michigan
Case Diagnosis: A 17-year-old male with history of Trisomy 21 presenting with suspected serotonin syndrome.
Case Description or Program Description: The patient was admitted for volvulus complicated by ischemic bowel requiring resection and prolonged stay in the pediatric intensive care unit. While in the PICU he was observed to have sustained ankle clonus initially attributed to medication withdrawal. On admission to IPR the patient continued to demonstrate clonus in addition to lower extremity hyperreflexia with recurrent fevers of unknown origin having undergone repeat negative infectious workups. Differential diagnoses included metabolic/toxic versus hypoxic injury to the central nervous system, spinal cord pathology, medication withdrawal, and serotonergic toxicity. Magnetic resonance imaging of the brain, cervical and thoracic spine noted a midline pons lesion of unclear chronicity without acute infarct and congenitally shortened pedicles with mild narrowing of the thoracic spinal canal without cord signal abnormality. Review of the patient’s medications identified several serotonergic agents that have been associated with serotonin syndrome in the literature: Fentanyl, Methadone, Olanzapine, Quetiapine, and Ondansetron.
Setting: Tertiary care pediatric hospital.
Assessment/Results: Given the patient’s constellation of signs meeting Hunter criteria and otherwise inconclusive workup suggestive of an alternative etiology for his presentation, there remained a high suspicion for serotonin syndrome. This was further substantiated by improvement of the patient’s hyperreflexia and ankle clonus with complete resolution of his recurrent fevers upon discontinuation of all the serotonergic medications. At outpatient follow up he continued to do well with only 2-3 beats of ankle clonus reported on exam.
Discussion (relevance): This was an interesting case in that the timeline of symptom onset was unclear with multiple confounding variables making a definitive diagnosis of serotonin toxicity difficult.
Conclusions: Maintaining a broad differential and thorough review of medications, especially in the context of prolonged hospitalization, can be critical in identifying potentially life-threatening conditions such as serotonin syndrome.