Causes and risk factors
Serotonin is produced by nerve cells in the brain and spinal cord. In normal circumstances it helps to regulate attention, behaviour, and body temperature. Nerve cells from intestines and other organs also produce serotonin which helps in various processes such as regulating digestive process, blood flow, breathing etc. Excessive accumulation of serotonin is caused by consumption of 2 or more of drugs at a time. Drugs like anti depressants, analgesics, anti migraine medicines taken in combination with one another lead to rise in levels of serotonin. Overdose of one medication can also cause serotonin syndrome.
Clinical presentation
Patient presents with symptoms like agitation, restlessness, confusion and headache. There is rapid heart rate, high blood pressure, and dilated pupils. Patient experiences loss of muscle tone, muscle rigidity. Gastrointestinal symptoms like nausea , vomiting and diarrhoea are also observed. In advanced cases shivering, high fever, seizures, unconsciousness can be seen.
Investigation
Medical history of drug intake by the patient and Clinical examination by the doctor helps in diagnosis. Tests such as CBC, blood culture, urine analysis, serum electrolyte levels are recommended. Renal function test, liver function test, thyroid function test are done. An ECG is often advised. Imaging studies such as chest x ray, CT scan may be useful for further evaluation. Lumbar puncture, drug toxicology screening confirms the diagnosis.
Treatment
First line of treatment involves stopping of the ongoing medication. Further treatment consists of medicines such as muscle relaxants, serotonin production blocking agents, drugs that control heart rate and blood pressure. Oxygen supplement, IV fluids or even intubation may be required in some cases. Serotonin syndrome can be fatal if left untreated.
