Serotonin syndrome
| Serotonin syndrome | |
|---|---|
| Other names | Serotonin toxicity, serotonin toxidrome, serotonin sickness, serotonin storm, serotonin poisoning, hyperserotonemia, serotonergic syndrome, serotonin shock |
| Serotonin | |
| Specialty | Critical care medicine, psychiatry |
| Symptoms | High body temperature, agitation, increased reflexes, tremor, sweating, dilated pupils, diarrhea |
| Usual onset | Within a day |
| Causes | Selective serotonin reuptake inhibitor (SSRI), serotonin norepinephrine reuptake inhibitor (SNRI), monoamine oxidase inhibitor (MAOI), tricyclic antidepressants (TCAs), amphetamine, methylene blue, pethidine (meperidine), tramadol, dextromethorphan, ondansetron, cocaine |
| Diagnostic method | Based on symptoms and medication use |
| Differential diagnosis | Neuroleptic malignant syndrome, malignant hyperthermia, anticholinergic toxicity, heat stroke, meningitis |
| Treatment | Active cooling |
| Medication | Benzodiazepines, cyproheptadine |
| Frequency | Unknown |
Serotonin syndrome (SS) consists of a group of symptoms that may occur with the use of certain serotonergic medications or drugs. The symptoms can range from mild to severe, and are potentially fatal. Symptoms in mild cases include high blood pressure and a fast heart rate, usually without a fever. Symptoms in moderate cases include high body temperature, agitation, overactive reflexes, tremor, sweating, dilated pupils, and diarrhea. In severe cases, body temperature can increase to greater than 41.1 °C (106.0 °F). Complications may include seizures and extensive muscle breakdown.
Serotonin syndrome is typically caused by the use of two or more serotonergic medications or drugs. These may include selective serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs), monoamine oxidase inhibitors (MAOIs), tricyclic antidepressants (TCAs), amphetamines, pethidine (meperidine), tramadol, dextromethorphan, buspirone, L-tryptophan, 5-hydroxytryptophan, St. John's wort, triptans, MDMA, metoclopramide, or cocaine. It occurs in about 15% of SSRI overdoses. It is a predictable consequence of excess serotonin on the central nervous system. Onset of symptoms is typically within a day of the extra serotonin.
Diagnosis is based on a person's symptoms and history of medication use. Other conditions that can produce similar symptoms such as neuroleptic malignant syndrome, malignant hyperthermia, anticholinergic toxicity, heat stroke, and meningitis should be ruled out. As of 2013, no laboratory tests exist that can confirm the diagnosis.
Initial treatment consists of discontinuing medications which may be contributing. In those who are agitated, benzodiazepines may be used. If this is not sufficient, a serotonin antagonist such as cyproheptadine may be used. In those with a high body temperature, active cooling measures may be needed. The number of cases of serotonin syndrome that occur each year is unclear. With appropriate medical intervention the risk of death is low, likely less than 1%. The high-profile case of Libby Zion, who is generally accepted to have died from serotonin syndrome, resulted in changes to graduate medical school education in New York State.