High risk and low prevalence diseases: Serotonin syndrome.

INTRODUCTION: Serotonin syndrome is a rare, frequently misdiagnosed, serious condition with high morbidity. OBJECTIVE: This review highlights the pearls and pitfalls of serotonin syndrome, including diagnosis, initial resuscitation, and management in the emergency department (ED) based on current evidence. DISCUSSION: Serotonin syndrome is a potentially deadly toxidrome marked by excess serotonin receptor activity or neurotransmission. Features of serotonin syndrome include 1) neuromuscular excitation such as tremor, hyperreflexia, and clonus; 2) autonomic dysfunction such as tachycardia, hypertension/hypotension, and hyperthermia; and 3) altered mental status such as agitation, delirium, and coma. Although serotonin syndrome may be more obvious in patients who have overdosed on serotonergic agents such as serotonin reuptake inhibitors (SSRIs), multiple other medications may also cause serotonin syndrome. Alternative diagnoses such as sepsis, neuroleptic malignant syndrome, and decompensated hyperthyroidism should be considered. The primary components of therapy include stopping the offending agent and supportive care, which focuses on agitation control, monitoring for and treating hyperthermia, and managing autonomic instability. CONCLUSIONS: An understanding of serotonin syndrome can assist emergency clinicians in diagnosing and managing this disease.

Deep brain stimulation as a possible treatment of hyperthermia in patients with serotonin syndrome.

Maintaining a body temperature within a narrow range is vital for the survival of all mammals, including humans. With the help of optogenetics, a better understanding of the thermoregulatory organs and pathways is achieved. Optogenetic activation of the GABAergic neurons in the ventral part of the lateral preoptic nucleus (VLPO) leads to decrease in the body temperature. On the other hand, number of drugs could alter the thermoregulatory balance, leading to a hyperthermic state, such as serotonin syndrome (SS). SS is a potentially life-threatening clinical condition that occurs as a result of a drug-induced increase in the intrasynaptic serotonin (5-hydroxytryptamine, 5-HT) levels due to overdose of a single drug or due to interaction between two or more drugs with serotonergic mechanism of action. In this hypothesis, we propose a novel method for the treatment of hyperthermia, a core clinical sign of serotonin syndrome, through deep brain stimulation (DBS). An electrode is stereotactically placed in the VLPO, which may lead to reduction of the core body temperature. If proven effective, this technique should be left as a salvage method for reduction of hyperthermia, where the drug treatment is insufficient or ineffective. This technique could be used for the treatment of other syndromes, where hyperthermia takes a central place, including malignant hyperthermia, neuroleptic malignant syndrome, etc. DBS, on the other hand, could be used alone to induce hyperthermia in patients with malignant diseases. Hyperthermia improves the immune response, improves the drug penetration and stop the repair of already damaged tumor cells after chemotherapy or radiotherapy.

The anaesthetist, opioid analgesic drugs, and serotonin toxicity: a mechanistic and clinical review.

Most cases of serotonin toxicity are provoked by therapeutic doses of a combination of two or more serotonergic drugs, defined as drugs affecting the serotonin neurotransmitter system. Common serotonergic drugs include many antidepressants, antipsychotics, and opioid analgesics, particularly fentanyl, tramadol, meperidine (pethidine), and methadone, but rarely morphine and other related phenanthrenes. Symptoms of serotonin toxicity are attributable to an effect on monoaminergic transmission caused by an increased synaptic concentration of serotonin. The serotonin transporter (SERT) maintains low serotonin concentrations and is important for the reuptake of the neurotransmitter into the presynaptic nerve terminals. Some opioids inhibit the reuptake of serotonin by inhibiting SERT, thus increasing the plasma and synaptic cleft serotonin concentrations that activate the serotonin receptors. Opioids that are good inhibitors of SERT (tramadol, dextromethorphan, methadone, and meperidine) are most frequently associated with serotonin toxicity. Tramadol also has a direct serotonin-releasing action. Fentanyl produces an efflux of serotonin, and binds to 5-hydroxytryptamine (5-HT)1A and 5-HT2A receptors, whilst methadone, meperidine, and more weakly tapentadol, bind to 5-HT2A but not 5-HT1A receptors. The perioperative period is a time where opioids and other serotonergic drugs are frequently administered in rapid succession, sometimes to patients with other serotonergic drugs in their system. This makes the perioperative period a relatively risky time for serotonin toxicity to occur. The intraoperative recognition of serotonin toxicity is challenging as it can mimic other serious syndromes, such as malignant hyperthermia, sepsis, thyroid storm, and neuroleptic malignant syndrome. Anaesthetists must maintain a heightened awareness of its possible occurrence and a readiness to engage in early treatment to avoid poor outcomes.

The Serotonin Syndrome: From Molecular Mechanisms to Clinical Practice.

The serotonin syndrome is a medication-induced condition resulting from serotonergic hyperactivity, usually involving antidepressant medications. As the number of patients experiencing medically-treated major depressive disorder increases, so does the population at risk for experiencing serotonin syndrome. Excessive synaptic stimulation of 5-HT2A receptors results in autonomic and neuromuscular aberrations with potentially life-threatening consequences. In this review, we will outline the molecular basis of the disease and describe how pharmacologic agents that are in common clinical use can interfere with normal serotonergic pathways to result in a potentially fatal outcome. Given that serotonin syndrome can imitate other clinical conditions, an understanding of the molecular context of this condition is essential for its detection and in order to prevent rapid clinical deterioration.

Neuroleptic malignant syndrome and serotonin syndrome.

The clinical manifestation of drug-induced abnormalities in thermoregulation occurs across a variety of drug mechanisms. The aim of this chapter is to review two of the most common drug-induced hyperthermic states, serotonin syndrome and neuroleptic malignant syndrome. Clinical features, pathophysiology, and treatment strategies will be discussed, in addition to differentiating between these two syndromes and differentiating them from other hyperthermic or febrile syndromes. Our goal is to both review the current literature and to provide a practical guide to identification and treatment of these potentially life-threatening illnesses. The diagnostic and treatment recommendations made by us, and by other authors, are likely to change with a better understanding of the pathophysiology of these syndromes.

Common toxidromes in movement disorder neurology.

BACKGROUND: Physicians can come across patients who are exposed to certain prescription drugs or toxins that can result in adverse effects and complications which have high rates of morbidity and mortality. OBJECTIVE: To summarise the key clinical features and management of the common movement disorder toxidromes relevant to physicians (with an interest in neurology). METHODS: We searched PUBMED from 1946 to 2016 for papers relating to movement toxidromes and their treatment. The findings from those studies were then summarised and are presented here. RESULTS: The key features of 6 of the common movement disorder toxidromes and their treatment are tabulated and highlighted. The management of toxidromes with the highest mortality like neuroleptic malignant syndrome and serotonin syndrome are discussed in detail. CONCLUSION: There are several toxidromes that have the potential to become a serious life-threatening emergency if there is a delay in recognition of key clinical features and instituting the appropriate treatment at the earliest is crucial.

[Malignant hyperthermia syndrome in the intensive care unit : Differential diagnosis and acute measures]. / Maligne hypertherme Syndrome auf der Intensivstation : Differenzialdiagnostik und Akutmaßnamen.

Malignant hyperthermia is a life-threatening disease caused by derangement of the autonomic nerve system and hypermetabolism of the peripheral musculature. Commonly body core temperatures of more than 40 °C will be found in this disease which is caused mostly by psychopharmacological drugs like antidepressants, neuroleptics but also antibiotics, pain killers, anti-Parkinson drugs, and volatile anesthetics. The inducers of malignant hyperthermia interact with postsynaptic receptors (serotonin, anticholinergics) or muscular intracellular structures responsible for calcium utilization (volatile anesthetics, succinylcholine). Rarely malignant hyperthermia is a consequence of mental stress or vigorous exercise and or heat. Malignant hyperthermic syndromes lead to a severe dysbalance of the autonomic nerve system accompanied by rhabdomyolysis, disseminated intravascular coagulopathy, and finally multi-organ failure. Accordingly, medical management is primarily directed to stabilize vital functions, withdrawal of the causing drug, and if possible antagonizing toxic substances. The leading symptom hyperthermia needs to be treated physically with available cooling systems.

Serotonin Syndrome: The Potential for a Severe Reaction Between Common Perioperative Medications and Selective Serotonin Reuptake Inhibitors.

Selective serotonin reuptake inhibitors (SSRIs) are widely prescribed to patients of all ages. Although generally considered safe, therapy with SSRIs can be complicated by serotonin syndrome (SS), a life-threatening condition. We present a case of SS that developed in a young man who was receiving a stable dose of fluoxetine and then received several commonly used medications during an emergent appendectomy. Because polypharmacy in the perioperative setting may trigger SS, it is important for anesthesiologists to be cognizant of the interactions between SSRIs and common perioperative medications to formulate anesthetic plans that optimize patient safety.

Serotonin syndrome overlapping with neuroleptic malignant syndrome: A case report and approaches for differentially diagnosing the two syndromes.

Serotonin syndrome (SS) and neuroleptic malignant syndrome (NMS) are life-threatening adverse reactions caused by serotonergic antidepressants and neuroleptics, respectively. SS and NMS have overlapping clinical features, and thus differentially diagnosing the syndromes can be difficult in patients who are taking both types of drugs. Here, the author reports a unique case of a patient who developed SS that overlapped with NMS after taking imipramine and lithium carbonate with the subsequent addition of metoclopramide. This is the first case report of SS that overlapped with NMS. The author also briefly summarizes the clinical symptoms of each syndrome and describes the approaches that were used to differentially diagnose the two syndromes.

Serotonin syndrome: a concise review of a toxic state.

The serotonin syndrome is a toxic state caused by increased intrasynaptic serotonin and characterized by a triad of altered mental status, autonomic instability and neuromuscular abnormalities. It can result from exposure to a single serotonergic agent but is more likely to be due to polypharmacy, often with drugs from multiple classes. It develops over a short period of time and resolves just as quickly once identified and treated. Diagnostic criteria have been developed to assist in clinical practice. Treatment is largely supportive and prognosis is generally very favorable. Pharmacologic vigilance and prevention are key.

Persistent fever in the ICU.

Disorders of elevated body temperature may be classified as either fever or hyperthermia. Fever is caused by a pyrogen-mediated upward adjustment of the hypothalamic thermostat; hyperthermia results from a loss of physiologic control of temperature regulation. Fever in the ICU can be due to infectious or noninfectious causes. The initial approach to a febrile, critically ill patient should involve a thoughtful review of the clinical data to elicit the likely source of fever prior to the ordering of cultures, imaging studies, and broad-spectrum antibiotics. Both high fever and prolonged fever have been associated with increased mortality; however, a causal role for fever as a mediator of adverse outcomes during non-neurologic critical illness has not been established. Outside the realm of acute brain injury, the practice of treating fever remains controversial. To generate high-quality, evidence-based guidelines for the management of fever, large, prospective, multicenter trials are needed.

Serotonin syndrome: fentanyl and selective serotonin reuptake inhibitor interactions.

Serotonin syndrome is a rare but potentially fatal adverse drug reaction associated with increased serotonergic activity in the central nervous system. It is characterized by a triad of symptoms, which include altered mental status, neuromuscular hyperactivity, and autonomic instability or hyperactivity. Due to the potential of rapid onset, it is important for clinicians to recognize the signs and symptoms of serotonin syndrome. Serotonin syndrome symptoms may resemble other conditions. Although this article focuses on serotonin syndrome as a result of an adverse interaction of selective serotonin reuptake inhibitors (SSRI) and fentanyl, it is important for not only anesthesia professionals, but all clinicians--such as those in emergency medicine and critical care--to be aware of this syndrome and its management. This article discusses the clinical manifestations of the serotonin syndrome and highlights reported cases of serotonin syndrome specifically related to an interaction between SSRIs and fentanyl, a commonly used opioid in anesthesia practice.

Diagnosis and treatment of drug-induced hyperthermia.

PURPOSE: The etiology, pathophysiology, clinical presentation, and management of drug-induced hyperthermia (DIH) syndromes are reviewed. SUMMARY: DIH syndromes are a rare and often overlooked cause of body temperature elevation and can be fatal if not recognized promptly and managed appropriately. There are five major DIH syndromes: (1) neuroleptic malignant syndrome, (2) serotonin syndrome, (3) anticholinergic poisoning, (4) sympathomimetic poisoning, and (5) malignant hyperthermia. The differential diagnosis of DIH syndromes can be challenging because symptoms are generally nonspecific, ranging from blood pressure changes and excessive sweating to altered mental status, muscle rigidity, convulsions, and metabolic acidosis. Evidence from the professional literature (per a MEDLINE search for articles published through November 2011) indicates that few currently available treatment options can reduce the duration of hyperthermia; therefore, prompt identification of the provoking agent based on the patient's medication history, the clinical presentation, and the timing of symptom onset is essential to determine the appropriate treatment and mitigate potentially life-threatening sequelae. For all DIH syndromes, appropriate management includes the immediate discontinuation of the suspected offending agent(s) and supportive care (external cooling, volume resuscitation as needed); in some cases, pharmacologic therapy (e.g., a benzodiazepine, bromocriptine, dantrolene) may be appropriate, with the selection of a specific agent primarily determined by the medication history and suspected DIH syndrome. CONCLUSION: DIH is a hypermetabolic state caused by medications and other agents that alter neurotransmitter levels. The treatment of DIH syndromes includes supportive care and pharmacotherapy as appropriate.

Recognizing serotonin toxicity in the pediatric emergency department.

The use of selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors in treating depression, mood disorders, and behavioral disorders has escalated dramatically in the last 20 years, resulting in increased risk and clinical presentation of serotonin toxicity. Health care providers must also be aware of other medications and substances with proserotonergic activity that can cause serotonin toxicity when used in combination with these medications. There are many adverse effects of selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors, although their toxicity profile compared to older antidepressants seems to be safer. Serotonin syndrome is described as a clinical triad of mental status changes, autonomic hyperactivity, and neuromuscular abnormalities. It encompasses a spectrum of clinical findings ranging from a few nonspecific symptoms to significant clinical toxicity that can result in death. The objectives of this article are to review specific serotonergic medications including their adverse effects and toxicity in overdose, to describe other medications/substances that have proserotonergic effects, which could result in serotonin excess in combination with traditional serotonergic agents, and to define the criteria for serotonin syndrome/toxicity and its treatment.

Treatment of four psychiatric emergencies in the intensive care unit.

OBJECTIVES: To review the diagnosis and management of four selected psychiatric emergencies in the intensive care unit: agitated delirium, neuroleptic malignant syndrome, serotonin syndrome, and psychiatric medication overdose. DATA SOURCES: Review of relevant medical literature. DATA SYNTHESIS: Standardized screening for delirium should be routine. Agitated delirium should be managed with an antipsychotic and, possibly, dexmedetomidine in treatment-refractory cases. Delirium management should also include ensuring a calming environment and adequate pain control, minimizing benzodiazepines and anticholinergics, normalizing the sleep-wake cycle, providing sensory aids as required, and providing early physical and occupational therapy. Neuroleptic malignant syndrome should be treated by discontinuing dopamine blockers, providing supportive therapy, and possibly administering medications (benzodiazepines, dopamine agonists, and/or dantrolene) or electroconvulsive therapy, if indicated. Serotonin syndrome should be treated by discontinuing all serotonergic agents, providing supportive therapy, controlling agitation with benzodiazepines, and possibly administering serotonin2A antagonists. It is often unnecessary to restart psychiatric medications upon which a patient has overdosed in the intensive care unit, though withdrawal syndromes should be prevented, and communication with outpatient prescribers is vital. CONCLUSIONS: Understanding the diagnosis and appropriate management of these four psychiatric emergencies is important to provide safe and effective care in the intensive care unit.