Serotonin syndrome

Serotonin syndrome is the clinical manifestation of excess serotonin in the central nervous system, resulting from the therapeutic use or overdose of serotonergic drugs.

Characterised by a triad of clinical features: neuromuscular excitation, autonomic effects, and altered mental status.

Better described as a spectrum of toxicity, ranging from mild to severe, rather than a 'syndrome'.

Diagnosis is clinical and should be based on the Hunter Serotonin Toxicity Criteria (HSTC), of which clonus is a key diagnostic feature.

Treatment is guided by the severity of toxicity and involves cessation of the drug(s), supportive care, and anti-serotonergic drugs in select patients.

An excess of synaptic serotonin in the central nervous system that clinically manifests as the triad of neuromuscular excitation, autonomic effects, and altered mental status.[1]Boyer EW, Shannon M. The serotonin syndrome. N Engl J Med. 2005;352:1112-1120. http://www.ncbi.nlm.nih.gov/pubmed/15784664?tool=bestpractice.com Can result from therapeutic use of medications, drug overdose, or specific drug-drug interactions. It is better described as a spectrum of toxicity rather than a specific syndrome.[2]Buckley NA, Dawson AH, Isbister GK. Serotonin syndrome. BMJ. 2014;348:g1626 http://www.ncbi.nlm.nih.gov/pubmed/24554467?tool=bestpractice.com [3]Isbister GK, Buckley NA. The pathophysiology of serotonin toxicity in animals and humans: implications for diagnosis and treatment. Clin Neuropharmacol. 2005;28:205-214. http://www.ncbi.nlm.nih.gov/pubmed/16239759?tool=bestpractice.com Commonly known as serotonin toxicity.