From the Guidelines
Serotonin syndrome is a life-threatening condition that can cause irritability and aggression, and its symptoms include altered mental status, autonomic instability, and neuromuscular abnormalities. The classic triad of symptoms includes confusion, agitation, anxiety, irritability, and potentially aggression, as well as high fever, sweating, rapid heart rate, high blood pressure, dilated pupils, muscle rigidity, tremors, clonus, and hyperreflexia 1. Other common symptoms include restlessness, diarrhea, headache, shivering, and in severe cases, seizures and loss of consciousness. According to the Hunter criteria, the diagnosis of serotonin syndrome can be made if the patient has taken a serotonergic drug and has any of the following symptoms: tremor and hyperreflexia, spontaneous clonus, muscle rigidity, temperature >38°C, and either ocular clonus or inducible clonus 1.
Key Symptoms
- Altered mental status: confusion, agitation, anxiety, irritability, and potentially aggression
- Autonomic instability: high fever, sweating, rapid heart rate, high blood pressure, dilated pupils
- Neuromuscular abnormalities: muscle rigidity, tremors, clonus, hyperreflexia
- Other symptoms: restlessness, diarrhea, headache, shivering, seizures, and loss of consciousness in severe cases
Causes and Treatment
Serotonin syndrome is most commonly caused by combining multiple serotonergic medications such as SSRIs, SNRIs, MAOIs, triptans, certain opioids like tramadol, and some over-the-counter supplements like St. John's Wort 1. Treatment often involves discontinuing the precipitating agent and providing supportive care, which may include treatment of agitation with benzodiazepines, amelioration of hyperthermia, and management of autonomic instability with IV fluids and other agents to address abnormal vital signs 1. In severe cases, emergency sedation, neuromuscular paralysis, and intubation may be considered. It is essential to seek immediate medical attention if serotonin syndrome is suspected, as it can progress rapidly and become life-threatening if not treated promptly.
From the Research
Symptoms of Serotonin Syndrome
- Alteration of mental status, such as agitation, confusion, and altered consciousness 2, 3
- Abnormalities of neuromuscular tone, including muscle rigidity, tremors, and hyperreflexia 2, 3, 4
- Autonomic hyperactivity, characterized by rapid heart rate, high blood pressure, dilated pupils, sweating, and diarrhea 2, 3
- Other symptoms may include fever, lower leg clonus, and agitation 5
Irritability and Aggression
- Serotonin syndrome can cause agitation, which may manifest as irritability and aggression 3, 5
- The condition can lead to altered mental status, which may result in aggressive behavior 2, 3
- However, it is essential to note that serotonin syndrome is a complex condition, and its symptoms can vary widely from person to person 2, 3, 4, 5, 6
Severity and Management
- Serotonin syndrome can range in severity from mild to life-threatening 2, 3
- Management of the condition typically involves discontinuing the use of the substance that caused the excess serotonin levels and providing supportive care, such as intravenous fluids and electrolytes 2, 3
- In severe cases, benzodiazepines may be used to control agitation and muscle rigidity, while serotonin antagonists, such as cyproheptadine, may be used to reduce serotonin levels 3, 4, 5