Objective: To highlight the severity of Serotonin syndrome precipitated in a Psychiatric patient on two unique serotonergic medications leading to a comatose state.

Background: Serotonin syndrome is a common life-threatening movement disorder emergency(1). It is caused by an excess of serotonin in the peripheral and central nervous system leading to altered mental status, neuromuscular hyperactivity, and autonomic dysfunction. It is commonly triggered by serotonergic drugs or their inadvertent interactions. It is important to differentiate it from Neuromuscular Malignant syndrome (NMS) for better clinical outcomes.

Method: We report a case of a 51-year-old male patient with Long-standing Diabetes mellitus, Hypertension, Chronic kidney disease, and Bipolar Mood disorder who presented to us as acute Febrile encephalopathy of 4 days duration. He was well maintained on 600 mg lithium per day but was recently added 600 mg valproic acid for his exaggerated mood symptoms. Physical examination on admission revealed tachycardia, and tachypnoea with autonomic instability with GCS E1V1M1 requiring urgent endotracheal intubation. His initial evaluation for metabolic, infective, and structural causes of encephalopathy in form of Basic Blood investigations, MRI Brain, EEG, and CSF analysis was negative and hence treated as Lithium toxicity vs SILENT syndrome(2) vs NMS.

Results: He was started on empirical hemodialysis and 2 cycles were completed. His serum lithium levels decreased from 2.18 mmol/L to 0.56 mmol/L on day 4 of admission without any significant change in his GCS. On day 5 of admission, he was empirically started on a loading dose of 12mg of Tablet Cyproheptadine followed by 2 mg every 2 hourly. The next day patient’s sensorium improved dramatically to E4V4M6 with unmasked generalized tremulousness and was extubated succesfully. The patient improved to a baseline state by the 10th day of the illness and was discharged with MRS 1.

Conclusion: This is one of the few cases of serotonin syndrome presenting as a severe comatose state(3,4) not presenting as a usual hyperexcitable state. However, the dramatic response to Cyproheptadine in a background of exposure to two serotonergic drugs namely Lithium and Valproate should make us think about this rare differential.

References: 1.Rajan S, Kaas B, Moukheiber E. Movement Disorders Emergencies. Semin Neurol. 2019 Feb;39(1):125-136

2.Miguela Marie Señga, Gemmalynn Sarapuddin, Edmundo Saniel, “A Case Report on an Atypical Presentation of the Syndrome of Irreversible Lithium-Effectuated Neurotoxicity (SILENT) in a War Veteran with Bipolar Disorder and PTSD”, Case Reports in Psychiatry, vol. 2020, Article ID 5369297, 4 pages, 2020

3.Chechani V. Serotonin syndrome presenting as hypotonic coma and apnea: potentially fatal complications of selective serotonin receptor inhibitor therapy. Critical Care Medicine. 2002 Feb;30(2):473-476

4.Pape, Kate; Romanowski, Kathleen. 1622: SEROTONIN SYNDROME PRESENTING AS COMA IN A PATIENT WITH SEVERE THERMAL INJURY. Critical Care Medicine 46(1):p 795, January 2018

« Back to 2023 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/serotonin-coma-an-antipodal-emergency/