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Background: Serotonin syndrome and Parkinson's disease (PD) are two diseases whose symptoms partially overlap; this poses challenges in distinguishing them in clinical practice. Early manifestations such as tremor, akathisia, diaphoresis, hypertonia and hyperreflexia are common in mild-to-moderate serotonin syndrome and can also occur in PD. Without prompt recognition and treatment, serotonin syndrome can rapidly progress, potentially leading to severe complications such as multiple organ failure within hours. Given their disparate treatment strategies, accurate clinical distinction is crucial for effective treatment. This case study explores a patient with serotonin syndrome triggered by escitalopram in the context of PD psychosis (PDP), providing insights into diagnosis and treatment planning., Case Presentation: A 75-year-old Asian woman with a one-year history of PD, a two-month history of PDP, and a six-year history of depression presented with symptoms including hyperreflexia, tremor, hypertonia, impaired level of consciousness, and inappropriate behavior following a recent one-month adjustment in medication. Initially suspected of being drug-induced parkinsonism or worsening PD, therapeutic drug monitoring revealed warning levels of escitalopram. Subsequent diagnoses confirmed serotonin syndrome. This syndrome may result from increased cortical serotonin activity at the serotonin2A receptor due to dopamine and serotonin imbalances in PDP, compounded by increased dopamine-mediated serotonin release. Additionally, being an intermediate metabolizer of cytochrome P450 enzyme 2C19, the patient experienced excessive escitalopram accumulation, exacerbating her condition., Conclusions: This case underscores the critical need to differentiate between symptoms of serotonin syndrome and PD, particularly in manifestations like tremor and hypertonia. Careful consideration of receptor profiles in patients with PDP is essential when selecting antidepressants to mitigate the risk of serotonin syndrome., (© 2024. The Author(s).)

Rationale: Serotonin syndrome is a potentially life-threatening condition resulting from the use of antidepressants, their interactions with other serotonergic medications, or poisoning. It presents with a triad of psychiatric, dysautonomic, and neurological symptoms and is sometimes fatal. While cyproheptadine is a specific treatment option, the optimal duration of its administration remains unclear. The purpose of this report is to quantitatively assess the endpoints of serotonin syndrome treatment. Based on the hypothesis that neurological pupil index (NPi) on a digital pupil recorder would correlate with the severity of the serotonin syndrome, we administered cyproheptadine using NPi as an indicator., Patient Concerns: A patient with a history of depression was brought to our hospital after he overdosed on 251 tablets of serotonin and noradrenaline reuptake inhibitors., Diagnoses: On day 3, the patient was diagnosed with serotonin syndrome., Interventions: Cyproheptadine syrup was administered at 4 mg every 4 hours. The NPi of the automated pupillometer was simultaneously measured. On day 5, the NPi exceeded 3.0 cyproheptadine was discontinued., Outcomes: The patient was discharged on day 7., Lessons: The lack of considerable improvement during the treatment period suggests that the patient may have improved on his own. In this case, the relationship between NPi and the severity of serotonin syndrome could not be determined., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Serotonin syndrome (SS) is a potentially fatal adverse drug reaction characterized by an exaggerated increase in serotonergic activity in the central and peripheral nervous systems. It presents a constellation of signs and symptoms related to behavioral changes, neuromuscular excitability, and autonomic instability. These symptoms can occur in both mild and severe forms. SS can be triggered by the therapeutic use of a drug that increases serotonin (5-HT) availability in the synaptic cleft or by the co-administration of two or more drugs that provide this increase. With the escalating use of antidepressants by the world's population, this adverse reaction may be more recurrent. However, SS is often overlooked by patients or not diagnosed by doctors. This review aims to improve awareness about SS and provide a pharmacological perspective to explain its occurrence. Evidence shows that other neurotransmitters may also be involved with the pathology of SS. Furthermore, SS and neuroleptic malignant syndrome (NMS) seem to be part of the same pathological spectrum, especially in atypical NMS cases. The emergence of the syndrome's symptoms may be closely related to pharmacokinetic and/or pharmacodynamic polymorphisms that lead to an increase in the 5-HT available to or 5-HT signaling by specific receptors, thus constituting an important area for future investigations., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Poian et al.)

BACKGROUND Serotonin toxicity, often referred to as 'serotonin syndrome,' is a drug-induced condition due to excess serotonin released from brain synapses, resulting in symptoms that may be autonomic, neuromuscular, and/or cognitive in nature. Most cases involve more than 1 of the following drug regimens: monoamine oxidase inhibitors (MAOIs), serotonin releasers, selective serotonin reuptake inhibitors (SSRIs), or serotonin-norepinephrine reuptake inhibitors (SNRIs). This report is of a 70-year-old woman who presented with confusion and muscle spasms due to serotonin toxicity associated with paroxetine and quetiapine treatment. CASE REPORT An elderly woman with dementia presented to the Emergency Department with fever, altered mental status, labile blood pressures, and inducible clonus. No known medication dosage increases had been made, nor had any new serotonergic agents been added to the patient's drug regimen. She underwent a thorough workup in the Emergency Department and later during her hospitalization. A presumptive diagnosis of serotonin toxicity was made early on during her stay, with the etiology attributed to use of paroxetine and quetiapine. Clinical improvement was observed after benzodiazepine administration, discontinuation of offending agents, and a brief cyproheptadine course. The patient survived her hospital stay and was ultimately discharged to hospice care with a return to her baseline level of functioning. CONCLUSIONS Diagnosing serotonin toxicity requires a high degree of clinical suspicion and can occur in the absence of increased dosage of existing, or initiation of new, serotonergic agents.

Background: Over-the-counter medication overdose is a difficult diagnostic challenge for many physicians as common drug screening assays cannot detect these substances. We present a case of acute psychosis, serotonin syndrome, and anticholinergic overdose-like properties in the setting of Coricidin HBP Cough & Cold tablets, known by their street name Triple-C. This is the first case report we are aware of involving a patient presenting with these symptoms and requiring critical-care-level support., Case Presentation: A 31-year-old African American female with a past medical history of anxiety, childhood asthma, previous methamphetamine abuse, and coronavirus disease 2019 infection in August 2020 was brought to the emergency department by the local police department with altered mental status. Initial blood work, including extended drug screens, were unremarkable for a definitive diagnosis. This patient required critical-care-level support and high sedation because of her symptoms. Collateral history revealed the patient regularly consumed Triple-C daily for the 6 weeks prior to admission. A trial off sedation was attempted after 24 hours with no complications. The patient admitted to regular Triple-C consumption and auditory hallucinations since adolescence. She was discharged safely after 48 hours back into the community. She was lost to follow-up with psychiatry and internal medicine; however, she was evaluated in the emergency room 1 month later with a similar psychiatric presentation., Conclusion: Overdose of Triple-C should be kept in the differential diagnosis of patients presenting with a triad of psychosis, serotonin syndrome, and anticholinergic overdose, in the setting of unknown substance ingestion., (© 2021. The Author(s).)

We report a 21-year-old man with bipolar disorder who was on a stable dose of escitalopram and risperidone. Tramadol and cough syrup (dextromethorphan) were added for his recent attack of upper respiratory tract infection. However, he developed various neurological symptoms. Haloperidol and ondansetron were added after hospitalisation. However, his condition deteriorated. A diagnosis of serotonin syndrome (SS) was made, and cyproheptadine was started. Cyproheptadine provided relief in most of the symptoms within 48 hours except for the presence of fever and rigidity. The addition of bromocriptine provided a complete resolution of the symptoms. We considered the presence of both SS and neuroleptic malignant syndrome (NMS) in this case. There are four similar cases in the literature. We discussed a diagnostic and therapeutic approach for patients who are on both serotonergic agents and neuroleptics and develop SS-like or NMS-like clinical features., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Awareness of rare differential diagnoses of common clinical presentations helps promote early detection and prompt management of serious conditions. A 54-year-old man, with an infected non-union following a high tibial osteotomy, presented with an acutely discharging abscess to his proximal tibia. He was generally unwell with a Staphylococcus aureus bacteraemia. The tibia was debrided, CERAMENT G used as dead space management and a spanning external fixator applied. Postoperatively, pregabalin and tapentadol were commenced in addition to amitriptyline and sertraline, which the patient was taking regularly. Overnight, the patient developed hyperthermia, inducible clonus, hyperreflexia, agitation, confusion and rigors. Prompt recognition of the possibility of serotonin syndrome resulted in early cessation of serotonergic medications and a positive outcome. From this case an important message is that fever in a patient taking serotonergic medications should prompt a screening neurological examination. Clinicians should also be wary when patients are commenced on multimodal analgesia, including tapentadol., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Serotonin syndrome is a state of increased central and peripheral serotonin (5-hydroxytryptamine) activity. Unless recognized and treated early, serotonin syndrome can lead to seizures, shock and death. Both substances with direct and indirect serotonergic activity can precipitate the syndrome. Serotonin syndrome can occur not only in psychiatric but also in non-psychiatric settings. Yet, clinicians may not be familiar with the condition. We explore some of the current controversies regarding serotonin syndrome. Specifically, we tested the following assumptions: (i) Despite being rare, serotonin syndrome is still clinically relevant; (ii) The Hunter criteria are the gold standard for diagnosing serotonin syndrome; (iii) Hyperthermia is common in cases of serotonin syndrome; (iv) Serotonin syndrome usually develops fast; (v) Severe serotonin syndrome usually or almost exclusively involves monoamine oxidase inhibitors. We found that (i) despite being rare, serotonin syndrome was clinically relevant, (ii) the Hunter criteria could not be regarded as the gold standard for the diagnosis of serotonin syndrome since they missed more cases than the other two diagnostic criteria systems (Sternbach and Radomski criteria), (iii) Serotonin syndrome could occur in the absence of an elevated temperature, (iv) fast onset could not be regarded as a reliable clinical sign of serotonin syndrome, and (v) absence of monoamine oxidase inhibitors treatment did not exclude a diagnosis of serotonin syndrome. Clinicians should bear in mind that in the context of relevant drug history, serotonin syndrome may still be possible in these circumstances., Competing Interests: The authors declare no conflict of interest., (© 2020 Werneke et al. Published by IMR Press.)

Introduction: Serotonin syndrome is caused by an accumulation of serotonin in the body from drug interactions or overdose of serotonergic medications, including commonly used antidepressants. Symptoms can be life-threatening and encompass both neurologic and cardiovascular toxicity, including agitation, seizure, tachycardia, rhabdomyolysis, and hyperthermia., Methods: This simulation case was developed for pediatric emergency medicine fellows and emergency medicine residents in the pediatric emergency department and can be altered to accommodate other learners. The case involved a 16-year-old male, represented by a low- or high-fidelity manikin, who presented with altered mental status/agitation after an overdose of antidepressant medication. The team of learners was required to perform a primary and a secondary assessment; manage airway, breathing, and circulation; and recognize and initiate treatment for serotonin syndrome. The patient had a seizure resulting in airway compromise requiring advanced airway support, as well as developed rhabdomyolysis requiring aggressive fluid hydration. We created a debriefing guide and a participant evaluation form., Results: Fifty-seven participants across five institutions completed this simulation, which included residents, fellows, faculty, and students. The scenario was rated by participants using a 5-point Likert scale and was generally well received. Participants rated the simulation case as effective in learning how to both recognize ( M = 4.9) and manage ( M = 4.8) serotonin syndrome., Discussion: This pediatric emergency simulation scenario can be tailored for a range of learner backgrounds and simulation environments. We used the participant evaluation form to improve future iterations of the simulation., (© 2020 Shubin et al.)

BACKGROUND Serotonin syndrome is a life-threatening condition that involves overstimulation serotonin receptors, which can be caused by medication overdose, drug-drug interactions, and regular doses of medications. It is often an overlooked diagnosis due to the presenting symptoms. CASE REPORT Our patient was a 79-year-old man with a past medical history significant for coronary artery disease status after coronary bypass surgery who presented to the Emergency Department with altered mental status. Vital signs were significant for hyperthermia. On initial assessment, he was only oriented to person and demonstrated shaking rigors. Lab test results were significant for leukocytosis, with troponins 2.94. A chest X-ray revealed left lower-lobe opacification. He was initially treated for community-acquired pneumonia and his elevated troponin required further work up. He was moved to the Intensive Care Unit (ICU) due to worsening respiratory distress, shaking tremors, and confusion. His troponins remained elevated. On his third day of hospitalization, his rigors had improved, but clonus was present. A medication review revealed the patient was on sertraline. He was started on cyproheptadine. The next morning, his mental status had improved to alert and oriented, and his condition returned to baseline. Upon discharge to a rehab facility, sertraline was discontinued. CONCLUSIONS Serotonin syndrome is a condition that is often not initially recognized. Our patient had multiple health problems and presented with altered mental status and tremors, and serotonin syndrome was not recognized until a full neurological exam and medication review had been done. It is important for physicians to be aware of serotonin syndrome as a differential diagnosis, as the symptoms can be masked by other presenting symptoms.

Introduction: Bupropion is the only Food and Drug Administration-approved synthetic cathinone. It increases the release of norepinephrine in the locus coeruleus and dorsal raphe nucleus, causing an increase in the frequency of serotonergic neuron firing. The diagnosis of serotonin toxicity (ST) from bupropion poisoning is controversial due to the lack of direct serotonergic activity. Nonetheless, there is one documented report of ST after single-agent bupropion overdose and multiple reports describing polypharmacy overdoses where bupropion may have contributed to ST., Methods: This is a retrospective analysis of data collected by the Toxicology Investigators Consortium (ToxIC), a prospective multi-center toxico-surveillance and research network registry, from 2014 to 2017. Cases were identified if ST was a clinical effect and bupropion was the single agent listed. Data is presented descriptively., Results: Of the 266 recorded single bupropion overdoses, the most common symptoms were seizures (47.1%), tachycardia (greater than 140 bpm) (33.9%), agitation (31.7%), toxic psychosis (20.4%), and myoclonus/tremor/hyperreflexia (19%). Benzodiazepines were the most common therapy (69.2%). Thirteen patients (5.9%) were diagnosed with ST by a medical toxicologist., Conclusion: Bupropion overdose is primarily associated with seizures, tachycardia, and agitation; bupropion may be an atypical cause of serotonin toxicity.

Thiscase report concerns a 34-year-old male with a hip prosthesis infection, under treatment with antidepressant and antihypertensive drugs, who presented with an increase in blood pressure after four days of treatment with oral tedizolid. Tedizolid was discontinued, and the dose of antihypertensive was increased. The patient progressively achieved the normalisation of blood pressure values, which allowed a reduction in the antihypertensive agent dose to its usual regimen. No cases of hypertension or serotonin toxicity are described in the initial tedizolid studies, where patients treated with other serotonergic drugs were excluded. However, this does not mean that these effects may not occur in clinical practice, especially in patients under concomitant treatment with this type of medication, because of the greater risk of drug interactions. The causality of this suspected drug reaction was analysed and it was considered as possible. The case has been reported to the pharmacovigilance system., Competing Interests: Competing interests: None declared., (© European Association of Hospital Pharmacists 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

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-HT 2A receptors, whilst methadone, meperidine, and more weakly tapentadol, bind to 5-HT 2A but not 5-HT 1A 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., (Copyright © 2019 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.)

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-HT 2A 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.

Rationale: As increasing frequency of serotonergic drug use, SS (serotonin syndrome) occurred more than ever. But clinicians have not enough knowledge and experience about SS as a potentially life-threatening condition. SS is usually caused by the increased serotonin activity in the central nervous system which may due to a serotonergic agent overdose or the concomitant use of 2 or more serotonergic antidepressants. We report a case of SS due to a normal dose of selective serotonin inhibitors (SSRIs) thus to remind clinicians to pay attention to such patients and make an early diagnosis and initiation of therapy in the clinical practice., Patient Concerns: We report here a 49-year-old man presented with lethargic, less communicative, and insomnia for 20 days while a diagnosis of depression was considered and he was treated with SSRIs., Diagnosis: The patient in our case fulfilled the 3 criteria existed now for diagnosing SS, including the Sternbach criteria, Radomski revised diagnostic criteria, and the Hunter serotonin toxicity criteria., Interventions: All the antidepressants were stopped and cyproheptadine with an initial dose of 12 mg a day was started along with supportive care. The patient was also admitted to emergency intensive care unit for further treatment. He was sedated and paralyzed by intravenous Midazolam and Clonazepam along with physical cooling and supportive care., Outcomes: All of the patient's symptoms abated gradually and he soon could get off the bed and be communicative. Finally, the patient made a full recovery and he was discharged from the hospital., Lessons: Our case suggests an atypical clinical course while the medicine the patient takes was not in so much dose. We assumed that there may have been some variation in metabolism of these agents, resulting in increased possibility that led to the subsequent syndrome. Thus, it is essential for clinicians to keep in mind when patients taking serotonergic agents who demonstrate acute change in their mental status. Besides, clinicians should be aware of such patients who seem to be sensitive to SSRIs, who may require a genetic testing before the initiation of SSRI therapy.

A 26-year-old cachectic man presented with an altered mental status. He was agitated, tremulous, hyperthermic and diaphoretic with largely dilated pupils. Collateral history revealed acute ingestion of 3,4-methylenedioxymethamphetamine on a background of chronic drug abuse. His condition deteriorated requiring sedation and intubation with transfer to the intensive care unit. A diagnosis of serotonin syndrome was made, based on his findings in keeping with the Hunter criteria, and he was treated with supportive management during a resultant and briefly sustained delirium. With gradual resolution of his agitated state, further questioning and blood work a concurrent, and potentially contributory, thyrotoxicosis was revealed. The patient was commenced on treatment for this with urgent outpatient follow-up with both a local otolaryngologist and endocrinologist for consideration of further treatment., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Competing Interests: None

We report a case of a hospitalised patient who developed probable serotonin toxicity shortly after the initiation of linezolid in whom the selective serotonin reuptake inhibitor (SSRI) escitalopram had been recently discontinued. On day 2 of linezolid administration, the patient reported severe anxiety and was observed to have full body jerking and twitching motions without mental status change. Notably, the patient was concomitantly receiving the antidepressant, trazodone and the benzodiazepine, clonazepam possibly affecting the severity and manifestations of serotonin toxicity. Linezolid was discontinued after 5 days and the patient's symptoms resolved. Serotonin toxicity can present with an array of symptoms and be life threatening if left unrecognised. This report highlights the clinical lessons that discontinuation of an SSRI upon initiation of linezolid does not eliminate the risk of serotonin toxicity and that other concomitant medications may worsen or improve some of the symptoms lending delay and uncertainty to the diagnosis., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2018. No commercial re-use. See rights and permissions. Published by BMJ.)

BACKGROUND Serotonin syndrome is a common yet potentially life-threatening condition caused by increased serotonergic activity, usually from serotonergic pharmaceutical agents. Primary features of serotonin syndrome include mental status changes, autonomic hyperactivity, and neuromuscular abnormalities. However, the presentation of serotonin syndrome is often quite variable, leading to its under-diagnosis. CASE REPORT A 50-year-old female with chronic kidney disease on peritoneal dialysis presented to the Emergency Department with severe, diffuse body pain. Over the course of her hospital stay, she developed severe nausea, vomiting, and diarrhea followed by hyperreflexia and inducible clonus. Laboratory studies were remarkable for elevated liver transaminases. Review of her medications revealed several serotonergic agents, including duloxetine, tramadol, and ondansetron. Given her symptoms and the multiple serotonergic agents she was taking, she was diagnosed with serotonin syndrome. Discontinuation of the serotonergic agents led to resolution of her symptoms over the course of 4 days. CONCLUSIONS Our patient's initial presentation of diffuse body pain highlights the variable presentation of serotonin syndrome. Our case also demonstrates the importance of recognizing serotonin syndrome, as the supportive ondansetron we gave to alleviate her nausea and vomiting likely exacerbated her serotonin syndrome.

A 14-year-old young adult took an overdose of 1.2 g of fluoxetine, a selective serotonin reuptake inhibitor (SSRI) that he had been prescribed for depression. He had a generalised tonic/clonic seizure at 6 hours postingestion.After the seizure, he developed signs consistent with serotonin syndrome: fine tremor, agitation, sweating and hyperreflexia. This was followed by severe muscle pain and rhabdomyolysis with peak creatine kinase (CK) of 33 941 at 74 hours. He was managed with intravenous fluids and analgesia and discharged after 4 days, having avoided renal injury. The use of SSRI's such as fluoxetine in teenagers has increased in recent years. While it is generally considered benign in overdose, this report illustrates the severe consequences of overdose at high quantities and discusses appropriate management in these cases. We note that in this case, there was a delayed onset of rhabdomyolysis with peak CK at 74 hours postingestion., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2018. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To review the symptoms of serotonin toxicity (commonly referred to as serotonin syndrome ) and the causative drugs and their mechanisms of action, and to equip primary care providers with practical strategies to prevent and identify serotonin toxicity., Quality of Evidence: PubMed and Google Scholar were searched for relevant articles on serotonin toxicity, the causes, and the differential diagnosis using search terms related to serotonin toxicity ( serotonin syndrome, serotonin toxicity, serotonin overdose ), causes (individual names of drug classes, individual drug names), and diagnosis ( differential diagnosis, neuroleptic malignant syndrome, anticholinergic toxicity, discontinuation syndrome, malignant hyperthermia, serotonin symptoms ). Experts in psychiatric medicine, psychiatric pharmacy, clinical pharmacology, and medical toxicology were consulted. Evidence is level II and III., Main Message: Serotonin toxicity is a drug-induced condition caused by too much serotonin in synapses in the brain. Cases requiring hospitalization are rare, and mild cases caused by serotonin-mediated side effects are unlikely to be fatal. Patients present with a combination of neuromuscular, autonomic, and mental status symptoms. Serotonin-elevating drugs include monoamine oxidase inhibitors, serotonin reuptake inhibitors, and serotonin releasers. Most cases involve 2 drugs that increase serotonin in different ways; the most concerning combination is a monoamine oxidase inhibitor with a selective serotonin reuptake inhibitor or a serotonin-norepinephrine reuptake inhibitor., Conclusion: Family physicians play a key role in identifying and preventing serotonin syndrome by teaching patients to recognize symptoms and monitoring patients throughout therapy., (Copyright© the College of Family Physicians of Canada.)

BACKGROUND Serotonin syndrome is a life-threatening condition that can lead to neurologic complications and is associated with the use of serotonergic medications. As the use of antidepressant medications has increased, the incidence of perioperative serotonin syndrome has transitioned from a rare diagnosis to one that should be considered as a differential diagnosis for any patient displaying signs of neuroexcitation. CASE REPORT A 70-year-old man (ASA 2) with a history of vestibular migraines (treated with venlafaxine), gastroesophageal reflux disease, and benign prostatic hyperplasia presented to our institution for photoselective vaporization of the prostate. Upon review of prior anesthetic records, his medical chart was found to list a propofol allergy. In discussion with the patient, he stated the reaction was rigidity. The anesthesiologist and patient agreed this was not an allergy. Thus, the patient was induced with propofol and given ketamine and fentanyl boluses throughout the procedure. During emergence, the patient exhibited myoclonic jerks in the upper and lower extremities. He was given intravenous meperidine for postoperative shivering; minutes after administration, the myoclonic jerks and rigidity worsened. The anesthesia team raised concern about serotonin syndrome. Intravenous midazolam improved the patient's myoclonic jerks and rigidity. CONCLUSIONS Patients with a history of rigidity/movement disorders during the perioperative period may have experienced serotonin toxicity. It is possible, as in our case, for this history to have been labelled as an allergy to a perioperative medication. Clinicians should remain vigilant for patients at risk of developing serotonin syndrome, such as those taking outpatient medications that increase neuronal serotonin.

As the number of patients receiving a left ventricular assist device increases, physicians must always keep in mind that several conditions can present with non-specific symptoms, such as fever, tachypnoea and confusion. We herein report the case of a left ventricular assist device patient who developed a life-threatening condition with acute hyperthermia, confusion and extremities' clonus and muscle spasms. The patient was diagnosed with serotonin syndrome, attributed to the coadministration of 2 commonly prescribed medications (citalopram and omeprazole). This case highlights that a significant proportion of left ventricular assist device patients is treated with serotonergic agents that may predispose them to the appearance of serotonin syndrome, a potentially life-threatening condition.

As the use of serotonergic agents to treat depression has increased, so too has the incidence of serotonin syndrome. We identify the common agents implicated in serotonin syndrome and the clinical tools to diagnose, manage, and prevent serotonergic toxicity., (Copyright © 2016 Cleveland Clinic.)

Background: Serotonin syndrome is a toxic state, caused by serotonin (5HT) excess in the central nervous system. Serotonin syndrome's main feature is neuro-muscular hyperexcitability, which in many cases is mild but in some cases can become life-threatening. The diagnosis of serotonin syndrome remains challenging since it can only be made on clinical grounds. Three diagnostic criteria systems, Sternbach, Radomski and Hunter classifications, are available. Here we test the validity of four assumptions that have become widely accepted: (1) The Hunter classification performs clinically better than the Sternbach and Radomski criteria; (2) in contrast to neuroleptic malignant syndrome, the onset of serotonin syndrome is usually rapid; (3) hyperthermia is a hallmark of severe serotonin syndrome; and (4) serotonin syndrome can readily be distinguished from neuroleptic malignant syndrome on clinical grounds and on the basis of medication history., Methods: Systematic review and meta-analysis of all cases of serotonin syndrome and toxicity published between 2004 and 2014, using PubMed and Web of Science., Results: Two of the four assumptions (1 and 2) are based on only one published study each and have not been independently validated. There is little agreement between current criteria systems for the diagnosis of serotonin syndrome. Although frequently thought to be the gold standard for the diagnosis of the serotonin syndrome, the Hunter criteria did not perform better than the Sternbach and Radomski criteria. Not all cases seem to be of rapid onset and only relatively few cases may present with hyperthermia. The 0 differential diagnosis between serotonin syndrome and neuroleptic malignant syndrome is not always clear-cut., Conclusions: Our findings challenge four commonly made assumptions about serotonin syndrome. We propose our meta-analysis of cases (MAC) method as a new way to systematically pool and interpret anecdotal but important clinical information concerning uncommon or emergent phenomena that cannot be captured in any other way but through case reports.

Background: Serotonin syndrome (SS) involves serotonergic hyperactivity caused by excessive activation of 5-HT2A receptors. As the use of antidepressants increases, so does the population of patients at risk for developing this complication. The diagnosis is made based on current serotonergic medication use in conjunction with certain clinical signs. The severity of the clinical presentation may vary, especially when the complication occurs while the patient is under general anesthesia. As a result, the incidence of SS is likely underreported and treatment may be delayed, leading to life-threatening complications., Case Report: A 67-year-old, American Society of Anesthesiologist physical status 3 male with multiple medical comorbidities, including anxiety/depression and chronic neck pain, presented for an elective laparoscopic total abdominal colectomy for colonic inertia. His intraoperative course was significant for SS likely triggered by the administration of methylene blue, which only became clinically apparent during anesthetic emergence. We considered and systematically ruled out other potential causes of his clinical condition. His management was primarily supportive, using hydration and benzodiazepine administration, and resulted in full neurologic recovery., Conclusions: SS is an underdiagnosed condition with limited treatment options beyond symptom management. Thus, vigilance, early diagnosis, and cessation of offending medications are of utmost importance. Anesthesiologists managing at-risk surgical patients must have a high clinical suspicion of perioperative SS if their patients exhibit tachycardia, hypertension, and hyperthermia together with clonus, agitation, diaphoresis, or hypertonia. These signs may be masked by general anesthesia and may only manifest themselves upon anesthetic emergence.

Serotonin syndrome (SS) is a potentially life-threatening condition resulting from excessive central and peripheral serotonergic activity. Clinically, it is a triad of mental-status changes, neuromuscular abnormalities, and autonomic disturbances. It can be caused by intentional self-poisoning, overdose, or inadvertent drug interactions. We report the case of a 58-year-old male with type 2 diabetes mellitus and obsessive compulsive disorder who developed pulmonary edema as a possible complication of SS. SS was caused by a combination of three specific serotonin re-uptake inhibitors (fluoxetine, fluvoxamine, and sertraline), linezolid, and fentanyl. The hospital course was further complicated by difficult weaning from the ventilator. SS was identified and successfully treated with cyproheptadine and lorazepam. The case highlights the importance of effective consultation-liaison and prompt recognition of SS as the presentation may be complex in the presence of co-morbid medical illness.

Background: Serotonin syndrome is a mild to potentially life-threatening syndrome associated with excessive serotonergic activity within the central nervous system. Serotonin syndrome is associated with medication use, drug interactions, and overdose. While serotonin syndrome is often associated with the use of selective serotonin inhibitors (SSRI), an increasing number of reports are being presented involving the use of tramadol., Methods: This review article contains an overview of serotonin syndrome while specifically looking at tramadol's pharmacology and risk factors for serotonin syndrome. With tramadol's increasing popularity, the goal of this article is to make physicians more alert and aware of this potential side effect associated with tramadol., Conclusions: In conclusion, with the increasing incidence of serotonin syndrome, prescribing physicians should be aware of and educate their patients on the potential side effects of tramadol. It is important that the prescribing physician reviews patient medications for concurrent serotonergic drugs and monitors for potential abuse.

Background: There has been a recent surge in the literature highlighting the association of fentanyl as precipitating serotonin syndrome in patients on a serotonergic agent., Objective: The purpose of our study was to understand the incidence of serotonin syndrome in patients who receive fentanyl while on serotonergic agents., Study Design: This retrospective analysis was conducted from 2012 to 2013 after approval from the Institutional Review Board. We searched for all patients that had received a serotonergic agent and were admitted to the hospital during the study period. Next, we split these patients into 2 groups by placing all patients who had received fentanyl and a serotonergic agent into one group. We then searched for any of the Hunter Serotonin Toxicity Criteria in the records of patients that had received both fentanyl and a serotonergic agent. Further, we searched for all patients with serotonin syndrome mentioned in their records., Setting: This study was conducted at a 900 bed tertiary care academic center., Results: Over the 2 year study period, 112,045 patients were on a serotonergic agent, and 4,538 of these patients were treated with both fentanyl and a serotonergic agent. A search for Hunter's Criteria through the records of the patients receiving both fentanyl and a serotonergic agent revealed 23 patients had been documented with some of these symptoms. On detailed chart review, only 4 [95% CI 1 - 10] of these patients truly met Hunter's Criteria for serotonin syndrome. We then searched all admissions for a diagnosis code of serotonin syndrome during the study period. Five additional cases of serotonin syndrome were found, but none of these patients were treated with fentanyl., Limitations: Some of the limitations of our study include that it represents a single institution, although it is a large academic center. An inherent limitation may be the under diagnosis of serotonin syndrome., Conclusion: The incidence of serotonin syndrome in patients who receive both fentanyl and a serotonergic agent is low.

Background: Serotonin syndrome is a potentially life-threatening adverse drug reaction that most commonly results from adverse interactions between drugs. Because serotonin syndrome can be fatal and is often difficult to diagnose, it is vital for health professionals to know about this reaction. We report a typical case of transient serotonin syndrome secondary to tramadol-Citalopram combination. This case report highlights the value of awareness of the early and subtle signs of serotonin syndrome., Case Report: A 44-year-old female with past medical history of chronic pancreatitis, back pain, and major depression was brought to the emergency room (ER) with altered mental status, jerky movements in extremities, generalized weakness, and vomiting., Conclusions: Most physicians are aware of serotonin syndrome secondary to antidepressants but do not think about other classes of medications such as analgesics. Clinicians should also be aware of the possibility of serotonin syndrome when encountering a patient taking serotonergic drugs who presents with characteristic symptoms of serotonin syndrome.

Serotonin syndrome results from an acute hyperserotonergic state. It is a rare and potentially fatal complication of drugs that affect the central nervous system serotonin levels. It is characterised by a triad of clinical features comprising altered sensorium, autonomic instability and neuromuscular hyperexcitability, in different combinations. We present an atypical case of serotonin syndrome related to levodopa use in a patient of probable Lewy body dementia. This case highlights the difficulty in diagnosis and management of cases with serotonin syndrome in the absence of history of a known serotonergic drug and the fact that levodopa can contribute to its occurrence., (2014 BMJ Publishing Group Ltd.)

Overview: Tramadol toxicity has not previously been reported in a cat., Case Summary: This report describes the clinical signs, diagnosis and treatment of tramadol toxicity, manifesting as serotonin syndrome, in a cat in Australia., Practical Relevance: For any cat with suspicion of serotonin syndrome, in particular secondary to tramadol overdose, it is recommended that decontamination, monitoring and supportive care are instituted as soon as clinical signs develop. Prolonged hospitalisation may be required in the event of a severe overdose., Literature Review: The literature relating to the pharmacology of tramadol and tramadol overdose, clinical manifestations of tramadol overdose, and serotonin syndrome in cats, humans and dogs is reviewed. Recommended treatment for tramadol overdose and serotonin syndrome is also discussed., (© ISFM and AAFP 2014.)

Serotonin syndrome and neuroleptic malignant syndrome are two drug toxidromes that have often overlapping and confusing clinical pictures. We report a case of a young man who presented with alteration of mental status, autonomic instability and neuromuscular hyperexcitability following ingestion of multiple psychiatric and antiepileptic medications. The patient satisfied criteria for serotonin syndrome and neuroleptic malignant syndrome, and based on the characteristic clinical features, laboratory findings and clinical course it was concluded that the patient had both toxidromes. The patient was managed with cyproheptadine and supportive measures, and recovered over the course of 3 weeks. A brief review of literature highlighting the diagnostic clues as well as the importance of recognising and distinguishing the often missed and confounding diagnoses follows., (2014 BMJ Publishing Group Ltd.)

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.

This case demonstrates an acute presentation of unwitnessed seizure causing typical injuries. Progress in hospital was complicated by worsening autonomic disturbance and agitation, typical for serotonin syndrome, suspected in light of recent selective serotonin reuptake inhibitor antidepressant initiation. Supportive care required treatment in the intensive care unit setting but full recovery ensued. This case not only reminds clinicians of the potential pitfalls in assessing postictal injured patients, but also that serotonin syndrome requires a high-index of diagnostic suspicion given the range of presenting features. Management ranges from simple withdrawal of the offending agent to specific therapies such as a cyproheptadine.

This article describes the sequence of acute clinical deterioration seen in a head and neck oncology patient who developed serotonin syndrome peri-operatively. It highlights the clinical dilemma that can be encountered when a septic picture masks the onset of serotonin syndrome and reinforces the importance of awareness of the potential interactions and side effects associated with drugs that surgeons prescribe. We discuss the pathophysiology, causal factors, clinical presentation and diagnosis of serotonin syndrome as well as highlighting some of the dilemmas that this condition presents in the surgical setting.