Abstract
A 45-year-old man was admitted to the emergency department because of twitching of the head. The patient took a tablet of sumatriptan every 3–4 h because of increasing head pain after a car accident. Owing to depression, the patient was on long-term treatment with venlafaxine. The patient presented as hypertensive, tachycardic, with dyskinesia and spontaneous myoclonic movements of the right sternocleidomastoid muscle. In a CT scan of the head and cervical spine any fractures, bleeding or damage of the vessels after the accident could be ruled out. After discontinuation of all serotonergic agents, administration of lorazepam symptoms resolved 24 h after the last intake of sumatriptan. Serotonin syndrome is a clinical diagnosis, which requires a high-index of diagnostic suspicion. Clinical features include a broad spectrum of symptoms ranging from mild to life-threatening manifestations. Management is based on removal of precipitating drugs and symptomatic care including benzodiazepines.
Background
Serotonin syndrome is a clinical diagnosis, which requires a high-index of diagnostic suspicion. Clinical features include a broad spectrum of symptoms ranging from mild to life-threatening manifestations.
Case presentation
A 45-year-old man was admitted to the emergency department with the symptom of head twitching. He reported that he had been suffering from muscle clonus of the neck since the morning of the previous day. The patient had a car accident 4 days before, which resulted in contusion of the ribs of the left chest wall. For pain management, the patient received 30 mg codeine, 500 mg paracetamol (acetaminophen) and 500 mg metamizole. Long-term medications included venlafaxine 75 mg once daily for 5 years for depression, zolpidem 10 mg as needed for sleeping disorders and sumatriptan 50 mg as needed for known migraine. The patient interrupted zolpidem intake after the car accident because of the ‘drug burden’. The patient took a tablet of sumatriptan every 3–4 h because of increasing head pain after the accident. Moreover, he reported a panic attack the day before and insomnia for two nights.
In the emergency department, the patient was hypertensive, with a blood pressure 170/100 mm Hg, tachycardic with a pulse rate around 100 bpm, 15/15 points on the Glasgow Coma Scale with dyskinesia and spontaneous myoclonic movements of the right sternocleidomastoid muscle (video 1). Hyperreflexia, hyperthermia, inducible clonus and diaphoresis were all absent.
Investigations
Laboratory values showed slight hypercalcaemia, increases in alanine aminotransferase and γ-glutamyl transpeptidase, but normal creatine kinase and creatine. A CT scan of the head and cervical spine ruled out any fractures, bleeding or damage to the vessels.
Treatment
All serotonergic agents were immediately stopped and lorazepam was administered for sedation. The patient was admitted to the hospital for further observation and symptomatic treatment.
Outcome and follow-up
The patient’s blood pressure and heart rate subsequently normalised. The myoclonic movements resolved within 24 h of the last intake of sumatriptan.
Spontaneous muscle clonus of the head resulting in head twitching.
Discussion
The serotonin syndrome is a potentially life-threatening adverse effect of serotonergic drugs.1 It is a clinical diagnosis based on the intake of specific drugs and certain clinical findings. Different classes of drugs possess the ability to enhance serotonin activity and are used in a variety of diseases, such as in depression, against emesis, migraine, bacterial infections or other conditions.
The clinical findings of the serotonin syndrome include a broad and variable spectrum of symptoms, such as hyperkinetics, autonomic instability or agitation. The Hunter criteria are fulfilled if clinical symptoms occur in a patient on a serotonergic drug.2 Our patient used two serotonergic agents concomitantly. Venlafaxine is a potent inhibitor of serotonin uptake.3 Sumatriptan is a selective agonist for serotonin receptors.4 The concomitant use of these agents may increase the risk of toxic effects due to central serotonergic overstimulation. Therefore, therapy may have to be modified. Moreover our patient unintentionally overdosed with sumatriptan, which has the potential for serotonin syndrome as monotherapy.4 On the other hand, the patient discontinued zolpidem, which has a sedating effect similar to benzodiazepines.
Management is primarily based on the removal of the precipitating drugs, as well as supportive and symptomatic care including benzodiazepines. The administration of 5-HT2a antagonists was not necessary in our patient, as he only suffered mild symptoms, without signs of severe autonomic instability such as hyperthermia. The serotonin syndrome can be prevented by cautious use of potential drugs and by paying attention to possible drug interactions. Overdosage and combination therapy in our patient resulted in a shaking head—an easily recognised sign of rejection.
Learning points.
The serotonin syndrome is a potentially life-threatening adverse effect of serotonergic drugs.
The serotonin syndrome is a clinical diagnosis, where clinical findings include a broad and variable spectrum of symptoms.
Management is primarily based on removal of precipitating drugs, supportive and symptomatic care including benzodiazepines.
Footnotes
Contributors: SW, AO and AKE had substantial contribution to the article. SW and AO were involved in the acquisition of the data. SW, AO and AKE interpreted the data. SW drafted the article, AO and AKE revised it critically for important intellectual content. SW, AO and AKE finally approved the submitted version of the article.
Competing interests: None.
Patient consent: Obtained.
Provenance and peer review: Not commissioned; externally peer reviewed.
References
- 1.Boyer EW, Shannon M. The serotonin syndrome. N Engl J Med 2005;2013:1112–20 [DOI] [PubMed] [Google Scholar]
- 2.Dunkley EJ, Isbister GK, Sibbritt D, et al. The Hunter serotonin toxicity criteria: simple and accurate diagnostic decision rules for serotonin toxicity. QJM 2003;2013:635. [DOI] [PubMed] [Google Scholar]
- 3.Claassen JA, Gelissen HP. The serotonin syndrome. N Engl J Med 2005;2013:2454–6 [PubMed] [Google Scholar]
- 4.Soldin OP, Tonning JM. Serotonin syndrome associated with triptan monotherapy. N Engl J Med 2008;2013:2185–6 [DOI] [PubMed] [Google Scholar]
Associated Data
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Supplementary Materials
Spontaneous muscle clonus of the head resulting in head twitching.