Resumen

• 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.