Recognition and management of perioperative serotonin syndrome

Non-convulsive status epilepticus in the immediate postoperative period following spine surgery

Background

Non-convulsive status epilepticus (NCSE), in which continuous epileptiform discharges occur without seizure-like movement, is rare and unfamiliar to anesthesiologists, both of which make this condition overlooked in patients with decreased levels of consciousness following general anesthesia.

Case

We report on an elderly female patient who developed NCSE in the immediate postoperative period after the spine surgery. Initially, delayed emergence from anesthesia was suspected, but the electroencephalogram confirmed NCSE, and anticonvulsant therapy was initiated.

Conclusions

Delayed emergence is commonly attributed to cerebrovascular events or residual anesthetic effects, but NCSE must be included in the differential diagnosis, especially in elderly patients. Anticonvulsant therapy should be initiated as soon as possible for a better prognosis.

Perioperative Serotonin Syndrome Manifesting as Gastrocnemius Myofasciculations: A Case Report

In perioperative settings where a patient under general anesthesia, presentation of serotonin syndrome might be far from the "classical" description of this potentially fatal condition. A patient who manifested signs of serotonin toxicity during an intravenous anesthetic, remifentanil, is presented. At the time of surgery, the patient was being treated with tramadol for pain management. The patient displayed myofasciculations on both gastrocnemius muscles confirmed electromyographically. All other conventional signs of serotonin syndrome were absent except hypotension and nystagmus. A presumptive diagnosis of serotonin syndrome was made intraoperatively. The symptoms resolved once remifentanil infusion was discontinued in the operating room without incident. Mild-to-moderate perioperative serotonin syndrome may manifest with myofasciculations in gastrocnemius muscles in the settings of no neuromuscular blockade. In spinal surgeries involving intraoperative EMG monitoring, the neuromonitoring team should be aware of this presentation and include serotonin syndrome in the differential diagnosis of unexplained EMG activity.

Management of severe arterial hypertension associated with serotonin syndrome: a case report analysis based on systematic review techniques

Serotonin syndrome is thought to arise from serotonin excess. In many cases, symptoms are mild and self-limiting. But serotonin syndrome can become life threatening, when neuromuscular hyperexcitability spins out of control. Uncontainable neuromuscular hyperexcitability may lead to cardiovascular complications, linked to extreme changes in blood pressure. Currently, there is little guidance on how to control blood pressure in hyperserotonergic states. We report a case with treatment-resistant arterial hypertension, followed by a clinical review (using systematic review principles and techniques) of the available evidence from case reports published between 2004 and 2016 to identify measures to control arterial hypertension associated with serotonin syndrome. We conclude that classic antihypertensives may not be effective for the treatment of severe hypertension associated with serotonin syndrome. Benzodiazepines may lower blood pressure. Patients with severe hypertension not responding to benzodiazepines may benefit from cyproheptadine, propofol or both. In severe cases, higher cyproheptadine doses than currently recommended may be necessary.

Serotonin Syndrome in Pregnancy

Millions of people take selective serotonin reuptake inhibitors (SSRIs) for depression and anxiety, so nurses and other clinicians need to be aware of the potential for serotonin toxicity and serotonin syndrome. These conditions can occur when women taking SSRIs are given additional medications in the labor and birth or postpartum settings. Symptoms can have an acute onset and can include delirium, fever and hypertension. Understanding the mechanism and symptoms of serotonin syndrome can lead to timely treatment of this unusual condition.

Delayed emergence after anesthesia

In most instances, delayed emergence from anesthesia is attributed to residual anesthetic or analgesic medications. However, delayed emergence can be secondary to unusual causes and present diagnostic dilemmas. Data from clinical studies is scarce and most available published material is comprised of case reports. In this review, we summarize and discuss less common and difficult to diagnose reasons for delayed emergence and present cases from our own experience or reference published case reports/case series. The goal is to draw attention to less common reasons for delayed emergence, identify patient populations that are potentially at risk and to help anesthesiologists identifying a possible cause why their patient is slow to wake up.

Pharmacogenetic workup of perioperative serotonin syndrome

Serotonin syndrome is gaining attention in perioperative and chronic pain settings due to the growing prevalence of multimodal therapies that increase serotonin levels and thereby heighten patient risk. A patient's genetic make-up may further increase the risk of serotonin syndrome. A case of serotonin syndrome on emergence after general anesthesia is presented. A subsequent cytochrome P4502D6 genetic test result suggested a potential alteration in metabolism. For this patient, who was taking combination antidepressant medications and receiving common perioperative medicines, additive pharmacodynamic effects converged with a pharmacogenetic predisposition, resulting in serotonin syndrome.