Conundrums in neurology: diagnosing serotonin syndrome - a meta-analysis of cases

Serotonin syndrome controversies: A need for consensus

Serotonin syndrome (SS) is a drug-induced clinical syndrome resulting from increased serotonergic activity in the central nervous system. Although more than seven decades have passed since the first description of SS, it is still an enigma in terms of terminology, clinical features, etiology, pathophysiology, diagnostic criteria, and therapeutic measures. The majority of SS cases have previously been reported by toxicology or psychiatry centers, particularly in people with mental illness. However, serotonergic medications are used for a variety of conditions other than mental illness. Serotonergic properties have been discovered in several new drugs, including over-the-counter medications. These days, cases are reported in non-toxicology centers, such as perioperative settings, neurology clinics, cardiology settings, gynecology settings, and pediatric clinics. Overdoses or poisonings of serotonergic agents constituted the majority of the cases observed in toxicology or psychiatry centers. Overdose or poisoning of serotonergic drugs is uncommon in other clinical settings. Patients may develop SS at therapeutic dosages. Moreover, these patients may continue to use serotonergic medications even if they develop mild to moderate SS due to several reasons. Thus, the clinical presentation (onset, severity, and clinical features) in such instances may not exactly match what toxicologists or psychiatrists observe in their respective settings. They produce considerable diversity in many aspects of SS. However, other experts discount these new developments in SS. Since SS is a potentially lethal illness, consensus is required on several concerns related to SS.

Serotonin syndrome presenting as acute dizziness with supine hypertension and orthostatic hypotension

Serotonin syndrome (SS) is a drug-induced clinical syndrome characterised by a combination of cognitive, neuromuscular and autonomic dysfunctions. The symptoms may include mild non-specific symptoms such as tremors and diarrhoea to coma and sudden death. Herein, we describe a case of SS in which acute dizziness was associated with supine hypertension and orthostatic hypotension. A man in his mid-30s had a 10-month history of anxiety, depression and chronic tension-type headache. He had been on amitriptyline (25 mg daily) and sertraline (50 mg daily). Increment of sertraline (75 mg daily) and amitriptyline (75 mg daily) and the addition of tramadol led to the development of acute severe dizziness. Physical examinations demonstrate supine hypertension and orthostatic hypotension. He also met the diagnostic criteria of SS. The administration of cyproheptadine provided a complete response to dizziness, supine hypertension, orthostatic hypotension and other clinical features of SS.

Serious adverse drug events associated with psychotropic treatment of bipolar or schizoaffective disorder: a 17-year follow-up on the LiSIE retrospective cohort study

Introduction

Mood stabilisers and other psychotropic drugs can lead to serious adverse drug events (ADEs). However, the incidence remains unknown. We aimed to (a) determine the incidence of serious ADEs in patients with bipolar or schizoaffective disorders, (b) explore the role of lithium exposure, and (c) describe the aetiology.

Methods

This study is part of the LiSIE (Lithium-Study into Effects and Side Effects) retrospective cohort study. Between 2001 and 2017, patients in the Swedish region of Norrbotten, with a diagnosis of bipolar or schizoaffective disorder, were screened for serious ADEs to psychotropic drugs, having resulted in critical, post-anaesthesia, or intensive care. We determined the incidence rate of serious ADEs/1,000 person-years (PY).

Results

In 1,521 patients, we identified 41 serious ADEs, yielding an incidence rate of 1.9 events per 1,000 PY. The incidence rate ratio (IRR) between ADEs with lithium present and causally implicated and ADEs without lithium exposure was significant at 2.59 (95% CI 1.20-5.51; p = 0.0094). The IRR of ADEs in patients <65 and ≥65 years was significant at 3.36 (95% CI 1.63-6.63; p = 0.0007). The most common ADEs were chronic lithium intoxication, oversedation, and cardiac/blood pressure-related events.

Discussion

Serious ADEs related to treatment of bipolar (BD) or schizoaffective disorder (SZD) were uncommon but not rare. Older individuals were particularly at risk. The risk was higher in individuals exposed to lithium. Serum lithium concentration should always be checked when patients present with new or unclear somatic symptoms. However, severe ADEs also occurred with other mood stabilisers and other psychotropic drugs.

Neuroleptic Malignant Syndrome: An Intensive Care Unit Case of Exceptionally High Creatinine Kinase and Myoglobin Levels

Neuroleptic Malignant Syndrome (NMS) is a rare, life-threatening neurologic emergency known to be related to the administration or sudden withdrawal of dopaminergic medications. The clinical course, symptoms, and bloodwork are very heterogeneous, making this syndrome difficult to identify. Thus, NMS is a diagnosis of exclusion. We present a case of severe NMS with exceptionally high creatinine kinase (CK) and myoglobin levels with unclear etiology and a challenging differential diagnosis. Also, our case stands out because it was serious, unique, and had a favorable outcome, which could contribute to the management of future similar cases.

Prevalence and Correlates of Serotonin Syndrome in Real-World Inpatients

BACKGROUND

Serotonin syndrome (SS) is a potentially life-threatening adverse drug reaction due to an increased central and peripheral serotonin activity, which usually presents as a triad of behavioral changes, neuromuscular excitability, and autonomic instability. Probably SS is often misdiagnosed, and its symptoms are mistaken for psychiatric symptoms or general medical issues: the true incidence of SS is not clear, and literature concerning potential risk factors is scarce. Our aims were to examine the prevalence of SS in a naturalistic sample of hospitalized patients and to evaluate potential factors related to the risk of developing the condition.

METHODS

The sample included 133 patients being treated with serotonergic medications admitted to the psychiatric inpatient unit of the San Luigi Gonzaga Hospital. All patients received a medical examination (including a neurological examination) within 24 hours of admission. Serotonin syndrome was diagnosed according to Hunter Criteria.

RESULTS

Sixteen patients (12%) were diagnosed with SS. In the subgroup of subjects with SS, we found a higher rate of male patients when compared with subjects with no SS (62.5% vs 33.3%, P = 0.023).

CONCLUSIONS

SS probably is an underestimated condition, which should be carefully assessed in patients on serotonergic medications. Male gender was the only factor found to be significantly related to a higher risk of developing SS. Further studies on larger samples are needed, to gain more information on possible risk factors and to identify subjects more prone to developing SS, given the potential risk for patients' health.

Serotonin Syndrome Precipitated by Paxlovid Initiation

A female in her early 40s taking buspirone, quetiapine, and daily kratom presented to the emergency department two days after starting a course of Paxlovid for a mild COVID-19 infection with diffuse tremors, ocular clonus, diaphoresis, and confusion consistent with serotonin syndrome (SS). The patient was treated with oral lorazepam, and her symptoms significantly improved within one hour without the need for additional dosing. To our knowledge, this is the first reported case of SS in a COVID-19-positive patient who was prescribed Paxlovid. Clinicians should be mindful of the potential interactions of Paxlovid with serotonergic agents, and they should consider reducing the dose of these agents or selecting other therapeutics to treat COVID-19 infection in these patients.

Serotonin Syndrome: The Role of Pharmacology in Understanding Its Occurrence

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.

A Case of Neuroleptic Malignant Syndrome Presenting as Anxiety

Neuroleptic malignant syndrome (NMS) is a rare but potentially lethal complication of dopamine antagonist use. A 34-year-old male presented to the emergency department with a chief complaint of feeling anxious for the past several days. He presented with his family who helped provide history as he had become less communicative over the preceding two days. It was revealed that the patient had a recent psychiatric hospitalization for suspected new-onset psychosis and was discharged six days prior to his presentation. It was reported that the patient was discharged with unknown psychiatric medications but stopped taking them two days prior because he felt they were increasing his anxiety. On physical examination, the patient was found to have upper extremity rigidity and appeared tremulous. A review of records revealed that the patient was discharged from inpatient psychiatric treatment on dual antipsychotic therapy. With this information, the patient met the diagnostic criteria for NMS. He was hospitalized and his symptoms resolved following treatment. Without the knowledge of antipsychotic use, the diagnosis of a serious, life-threatening condition may have been missed. Our case highlights an important but occasionally overlooked aspect of evaluating a patient in the emergency department, namely, outside chart and documentation reviewing.

Recognition and Management of Serotonin Toxidrome in the Emergency Department-Case Based Review

Serotonin syndrome (SS) is a clinical toxidrome with high variability in clinical practice. It develops due to increased serotonin levels in the central nervous system. With an underestimated frequency, SS can develop following an overdose, a therapeutic dose increase, or drug to drug interaction of at least one serotonergic agent. It can present with autonomic signs, neuromuscular changes and an altered mental status. However, history and clinical examination are key features to formulate the diagnosis. Treatment options consist of supportive measures, discontinuation of the offending agent and certain therapeutic agents previously reported to improve outcomes. Physicians have limited experience with SS, partially due to the lack of its identification in clinical practice. Therefore, we have integrated, in a narrative review, the case of a young male with SS following an atypical antipsychotic overdose superimposed on chronic treatment with agents previously known to produce SS.

Chronic Serotonin Toxicity in the Older Patient With Polypharmacy

Clinical pharmacists with experience may identify prescribing patterns resulting in iatrogenic disease, which is commonly encountered in geriatric populations where polypharmacy is common. Serotonin toxicity is one toxidrome clinicians may identify, where specific medications are used in treatment. As a result of their pharmacology training, pharmacists may identify toxidromes caused by medications that other clinicians may overlook. Pharmacogenomic (PGx) testing can provide added insight into a potentially iatrogenic cause for serotonin toxicity, because testing can elucidate how well an individual patient may metabolize serotonergic medications. Using PGx as a resource in addition to clinical experience, pharmacists can better guide therapy in the geriatric, polypharmacy population to avoid serotonin toxicity.

Dexmethylphenidate-Induced Rhabdomyolysis by Interaction With Aromatase Inhibitor

Rhabdomyolysis secondary to prescription drug-drug interactions can be an overlooked life-threatening emergency. Amphetamines and similar substances have been associated with muscle lysis secondary to increased sympathetic activity that can cause myotoxicity, hyperthermia, and increased muscular activity. Anabolic steroids may also be a predisposing factor in developing rhabdomyolysis. A high index of suspicion for drug-induced rhabdomyolysis in a patient presenting with atraumatic extremity pain can facilitate rapid diagnosis and treatment. We present a case of drug-induced rhabdomyolysis likely secondary to a previously unreported medication interaction.

Real-time monitoring of serotonin with highly selective aptamer-functionalized conducting polymer nanohybrids

Adequate serotonin levels are pivotal to human well-being; thus, serotonin can be used as a biomarker because it regulates a wide range of physical and psychological functions. As an imbalance of serotonin is highly likely to initiate the pathogenesis of various disorders, monitoring serotonin levels in real time is in high demand for the early detection of disease. We fabricated a field-effect transistor (FET) biosensor based on aptamer-immobilized conducting polymer nanohybrids, which showed an instantaneous response toward serotonin in solution. The mechanism of serotonin detection was based on aptamer deformation after aptamer-ligand interaction and the consequential decrease in the charge carrier density of the FET template. Docking simulations with AutoDock/Vina and PyMOL were successfully used to investigate the binding site of serotonin in the loop structure of the aptamer. The fabricated FET template showed high sensitivity toward serotonin in the range of 10 fM to 100 nM, and the limit of detection (LOD) was exceptionally low at 10 fM. Moreover, the selectivity toward serotonin was confirmed by observing no signal after the injection of structural analogs, functional analogs and excess physiological biomolecules. The potential clinical application of this sensor was confirmed because it remained consistent when the buffer solution was exchanged for artificial serum or artificial cerebrospinal fluid (CSF). ^† S.G.L. and S.E.S. contributed equally to this work.

Antidepressant-induced serotonin syndrome in older patients: a cross-sectional study

BACKGROUND

Widespread prescription of antidepressants and their resulting role in serotonin syndrome (SS) are of great importance for clinical practice in the elderly. This study aims to investigate possible associations of antidepressant drug-induced SS with related variables in these patients.

METHODS

A total of 238 older adults using antidepressants were included. Patients who fulfilled the Hunter Serotonin Toxicity Criteria (HSTC) for SS were considered as the clinical groups (mild, moderate, or severe), and those who did not as the control group. We recorded all patients' demographic and clinical characteristics, including age, gender, comorbidity index, number of medications, daily equivalent dose of the relevant antidepressant according to fluoxetine per day, electrocardiogram test results, laboratory results, and management.

RESULTS

The mean age of all patients was 75.4 ± 7.6 years and 63.4% were female. Sixty patients had SS, while 178 patients did not. There was a significant difference between those with and without SS in terms of gender, frequency of combination antidepressant therapy, and daily equivalent antidepressant dose (P < 0.05). The most common diagnostic findings in SS patients were tremor and hyperreflexia and 31.7% was mild, and moderate in 68.3% with higher median age and number of medications (P < 0.041). Antidepressants were discontinued in all patients regardless of severity, of whom 71.7% were treated with benzodiazepines and 36.7% with cyproheptadine. After adjusting for age and sex, association with use of SSRI + SNRI, use of any combination therapy, and daily equivalent dose remained significant.

CONCLUSIONS

The widespread single or combined use of antidepressants in older adults represents an increased clinical concern for SS and physicians should be aware of this drug-related complication in older patients.

Too much of a good thing? Diagnosis and management of patients with serotonin syndrome

Serotonin syndrome is a rare but potentially life-threatening condition caused by excess serotonin in the central and peripheral nervous systems. Patients with serotonin syndrome present with a range of mild to severe autonomic, neuromuscular and mental state signs and symptoms. A variety of drugs affect the serotonin pathways by modifying serotonin release and reuptake mechanisms, or reducing metabolism. There are also several genetic polymorphisms and clinical risk factors that affect the development and course of serotonin syndrome. This article describes the pathophysiology of serotonin syndrome and discusses diagnosis and treatment with reference to a case study of a patient who attended an emergency department (ED) with signs and symptoms of the condition following an increase in antidepressant medicines. The article aims to increase clinicians' awareness of serotonin syndrome to improve identification and treatment of patients who present to EDs with the condition.

The serotonin toxidrome: shortfalls of current diagnostic criteria for related syndromes

INTRODUCTION

Serotonin syndrome (toxicity) describes adverse drug effects from toxic amounts of intra-synaptic central nervous system serotonin. A wide range of drugs have been implicated to cause serotonin toxicity, not all justifiably. The plausible agents all have a final common pathway resulting in a substantial increase in central nervous system serotonergic neurotransmission. Serotonin toxicity is characterized by neuromuscular excitation, mental status changes, and autonomic dysregulation. Signs and symptoms represent a spectrum of toxicity (mild to life-threatening) related to increasing serotonin concentrations. As there is no consensus on the threshold for "toxicity" or diagnostic criteria, the true incidence of serotonin toxicity is unknown. The incidence in overdose is easier to quantify and is reasonably common in serotonergic antidepressant overdoses. In a large case series of overdoses, moderate serotonin toxicity occurred in 14% of poisonings with a selective serotonin reuptake inhibitor. While half those ingesting a monoamine oxidase inhibitor in combination with a serotonergic agent in overdose exhibit at least moderately severe serotonin toxicity. In contrast, the incidence of serotonin toxicity in those on therapeutic serotonergic agents appears to be very low.

OBJECTIVES

To provide a narrative review of the current diagnostic criteria, utilizing case reports of fatalities to evaluate how many meet the various diagnostic criteria and propose practical solutions to resolve controversies in diagnosis.

METHODS

A review of serotonin toxicity diagnostic criteria in the English literature was completed by searching Embase and PubMed from January 1990 to July 2021 for the keywords "serotonin syndrome/toxicity" paired with "diagnostic criteria" or "diagnosis." Also, fatal cases of serotonin toxicity identified from a recent systematic review were independently examined to determine what diagnostic criteria were met and whether serotonin toxicity or another cause was most likely.

REVIEW OF DIAGNOSIS CRITERIA

Serotonin toxicity is a clinical diagnosis, four diagnostic criteria (Sternbach, Serotonin Syndrome Scale, Radomski, and Hunter) have been proposed. However, the Serotonin Syndrome Scale has not been validated in patients with serotonin toxicity and only utilized in those on a serotonergic agent. The remaining three criteria are utilized more widely but have undergone little refinement or validation.

REVIEW OF FATAL CASES

Shortfalls with diagnostic criteria can be illustrated by examining case fatalities. Of 55 fatal cases reviewed, 12 (22%) were unlikely to be serotonin toxicity. Sternbach and Radomski criteria were met by 25 (45%), 20 (36%) had insufficient data reported and 10 (18%) met an exclusion criterion. Few had sufficient information reported to determine whether Hunter Criteria were met, with only 13 (24%) documented as meeting the criteria, the remaining 42 (76%) had insufficient data.

RESOLVING SHORTFALLS IN CURRENT DIAGNOSTIC CRITERIA

As serotonin toxicity is a clinical diagnosis, issues arise when basing the diagnosis on symptom criteria alone, without considering whether the drug/s ingested increase central nervous system serotonin or whether there is an alternative diagnosis. This has resulted in case reports and government warnings for drugs that cannot plausibly cause significant serotonin toxicity (e.g., ondansetron and antipsychotics). We propose when assessing for a serotonin toxidrome, both the causative agent(s) and clinical scenario is considered to determine the likelihood of serotonin toxicity. Then the clinical features assessed, those with a moderate to high prior probability (e.g., serotonergic drug-drug interaction, overdose, recent initiation or increase in dose of serotonergic agent/s) could be diagnosed based on the Hunter criteria. However, those with a low probability (e.g., stable therapeutic doses of a serotonergic agent) require more specific and stringent criteria. Finally, we propose a minimum dataset for case reports/series of serotonin toxicity.

CONCLUSIONS

More complete and accurate reporting of serotonin toxicity cases is required in the future, to avoid further misleading associations that are physiologically implausible.

New Serotonin-Norepinephrine Reuptake Inhibitors and Their Anesthetic and Analgesic Considerations

Serotonin-norepinephrine reuptake inhibitors (SNRIs) inhibit the presynaptic neuronal uptake of serotonin and norepinephrine and prolong the effects of the monoamines in the synaptic cleft within the central nervous system, leading to increased postsynaptic receptor activation and neuronal activities. Serotonin-norepinephrine reuptake inhibitors can have multiple clinical indications, including as the first-line agents for the management of depression and anxiety, and as analgesics in the treatment of chronic pain. The effects of reuptake inhibition of norepinephrine and serotonin are often dose-dependent and agent-dependent. There are five FDA-approved serotonin-norepinephrine reuptake inhibitors (desvenlafaxine, duloxetine, levomilnacipran, milnacipran and sibutramine) currently being marketed in the United States. As the COVID-19 pandemic significantly increased the incidence and prevalence of anxiety and depression across the country, there are significantly increased prescriptions of these medications perioperatively. Thus, anesthesiologists are more likely than ever to have patients administered with these agents and scheduled for elective or emergency surgical procedures. A thorough understanding of these commonly prescribed serotonin-norepinephrine reuptake inhibitors and their interactions with commonly utilized anesthetic agents is paramount. There are two potentially increased risks related to the continuation of SNRIs through the perioperative period: intraoperative bleeding and serotonin syndrome. SNRIs have some off-label uses, more new indications, and ever-increasing new applications in perioperative practice. This article aims to review the commonly prescribed serotonin-norepinephrine reuptake inhibitors and the current clinical evidence regarding their considerations in perioperative anesthesia and analgesia.

Serotonin Toxicity in Children and Adolescents: A Systematic Review and Meta-Analysis of Cases

Objectives: Serotonin toxicity is a state of central nervous system (CNS) excitation classically featuring altered mental status, neuromuscular excitation, and autonomic instability. While retrospective studies and reviews have characterized serotonin toxicity in adults, there have been no systematic reviews of serotonin toxicity in pediatric populations. The goal of this review was to use published case reports to describe serotonin toxicity in pediatric patients and to consider the impact of age on clinical presentation. Methods: A search for case reports of serotonin toxicity in patients younger than 18 years was conducted. Cases were systematically screened for inclusion using serotonin toxicity diagnostic tools, and a meta-analysis of case characteristics was conducted. Results: Sixty-six cases of serotonin toxicity in pediatric patients were reviewed. Only 56.1% met diagnostic criteria for serotonin toxicity on all three of the most commonly used diagnostic tools. Antidepressants were found to be the most common trigger of toxicity, implicated in 78.8% of cases. While onset of toxicity was rapid following overdose, toxicity was more likely to be delayed in the setting of medication titration (71.8% vs. 0%, p < 0.0001). Signs of neuromuscular excitation were prevalent, occurring in 92.4% of cases with 81.8% showing the full triad of neuromuscular symptoms, altered mental status, and autonomic instability. The only age-related differences occurred in relation to activation symptoms (more likely to be reported in children than in adolescents) and seizures (less likely to be reported in children than in adolescents or toddlers). Treatment was primarily supportive in nature, although 25.8% of patients received cyproheptadine. In all but one reviewed case, the patient survived. Conclusions: The presentation of serotonin toxicity in the pediatric population is similar to that seen in adults. Treatment is supportive with most patients achieving full recovery. Further exploration of the age-related differences in serotonin activity within the CNS is needed.

Multimodal Analgesic Management for Cervical Spine Surgery in the Ambulatory Setting

BACKGROUND

Patient selection and analgesic techniques, such as the multimodal analgesic (MMA) protocol, aid in ambulatory surgical center (ASC) cervical spine surgery. The purpose of this case series is to characterize patients undergoing anterior cervical discectomy and fusion (ACDF) and total cervical disc replacement (CDR) in an ASC with an enhanced MMA protocol.

METHODS

A prospectively maintained registry was retrospectively reviewed for cervical surgeries between May 2013 and August 2019. Inclusion criteria included ASC patients who underwent single-level or multilevel CDR or ACDF using an MMA protocol. Baseline, intraoperative, and postoperative characteristics were recorded, including length of stay, visual analog scale pain scores, neck disability index, complications, and narcotics administered.

RESULTS

A total of 178 patients met inclusion criteria with 125 single-level, 52 two-level, and 1 three-level procedure. Of those patients, 127 underwent ACDF and 51 underwent CDR. The longest procedure was 95 minutes and the mean length of stay was 6.1 hours, with 2 patients requiring hospital admission. All other patients were discharged within 10 hours. One of the admitted patients experienced a postoperative seizure that was later determined to be secondary to drug use and serotonin syndrome. The second patient developed an anterior cervical hematoma 5 hours postoperatively, which was immediately evacuated. The patient was admitted for observation and discharged the next day.

CONCLUSION

In our study, patients experienced considerable improvement in disability scores, with a low likelihood of postoperative complications. A safe and effective MMA protocol may help facilitate anterior cervical surgery in the outpatient setting.

LEVEL OF EVIDENCE

3.

CLINICAL RELEVANCE

Transitioning anterior cervical discectomy and fusions to the ASC requires an appropriate MMA protocol. Our findings reveal that an enhanced MMA protocol will help improve disability scores while keeping the likelihood of postoperative complications low. This supports the ASC setting for cervical spine procedures in appropriate patient populations.

Movement Disorder Emergencies

Acute presentation of new movement disorders and acute decompensation of chronic movement disorders are uncommon but potentially life-threatening. Inadvertent or purposeful overdose of many psychiatric medications can result in acute life-threatening movement disorders including serotonin syndrome, neuroleptic malignant syndrome, and malignant catatonia. Early withdrawal of potentiating medications, treatment with benzodiazepines and other diagnosis-specific drugs, and providing appropriate supportive care including airway and breathing management, hemodynamic stabilization, fluid resuscitation, and renal support including possible hemodialysis are the mainstays of acute management. Many of these conditions require admission to the neurologic intensive care unit.

Chronic Serotonergic Overstimulation Mimicking Panic Attacks in a Patient with Parkinson's Disease Receiving Additional Antidepressant Treatment with Moclobemide

Background

The pharmacological treatment options of Parkinson's disease (PD) have considerably evolved during the last decades. However, therapeutic regimes are complicated due to individual differences in disease progression as well as the occurrence of complex nonmotor impairments such as mood and anxiety disorders. Antidepressants in particular are commonly prescribed for the treatment of depressive symptoms and anxiety in PD. Case Presentation. In this case report, we describe a case of a 62-year-old female patient with PD and history of depressive symptoms for which she had been treated with moclobemide concurrent with anti-Parkinson medications pramipexole, rasagiline, and L-DOPA+benserazide retard. An increase in the dosage of moclobemide 12 months prior to admission progressively led to serotonergic overstimulation and psychovegetative exacerbations mimicking the clinical picture of an anxiety spectrum disorder. After moclobemide and rasagiline were discontinued based on the hypothesis of serotonergic overstimulation, the patient's psychovegetative symptoms subsided.

Conclusions

The specific pharmacological regime in this case probably caused drug-drug interactions resulting in a plethora of psychovegetative symptoms. Likely due to the delayed onset of adverse effects, physicians had difficulties in determining the pharmacologically induced serotonin toxicity. This case report emphasizes the complexity of pharmacological treatments and the importance of drug-drug interaction awareness in the treatment of PD patients with complicating nonmotor dysfunctions such as depression.

Recognition and Treatment of Psychiatric Emergencies for Health Care Providers in the Emergency Department: Panic Attack, Panic Disorder, and Adverse Drug Reactions

Mental health disorders are common in the United States and may cause significant disturbances in all aspects of a person's life. Individuals with mental health disorders often present to emergency departments for health care. Recognizing and managing common psychiatric emergencies may be challenging for non-mental health providers. The Diagnostic Statistical Manual-5 diagnostic criteria will be discussed and reviewed for panic attack and panic disorder. Both pharmacologic and nonpharmacologic treatment strategies will also be addressed. Adverse drug reactions associated with antipsychotics and selective serotonin reuptake inhibitors are another common psychiatric emergency that will be examined, offering potential management strategies. The objective of this clinical manuscript is to educate emergency health care providers about specific psychiatric emergencies, including panic attack, panic disorder, and adverse drug reactions associated with mental health treatment medications.

Fever in a patient with osteomyelitis: the diagnosis could be serotonin syndrome

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.

Insidious Onset of Serotonin Syndrome in a 6-Year-Old Boy

Serotonin syndrome, characterized by autonomic, neuromuscular, and mental status changes, is an uncommon but well-established risk of psychotropic medications. The presentation can be highly variable, especially when triggered by agents with effects on additional neurotransmitters.¹ The presence of a nonspecific prodrome has been reported but poorly characterized and can lead to misattribution of symptoms.² We describe a case of serotonin syndrome with insidious onset in a boy treated with multiple medications for behavioral dysregulation.

The prevalence of serotonin syndrome in an intensive care unit: A prospective observational study

PURPOSE

In spite of life-threatening nature of serotonin syndrome (SS), it remains an under-diagnosed condition. The availability of epidemiological data about SS, especially in the ICU setting, may help physicians make early diagnoses and interventions.

MATERIALS AND METHODS

This was a 6-month prospective study in a medical ICU of a tertiary hospital to find out the prevalence of SS. All consecutive adult patients admitted to the medical ICU were evaluated to see if they fulfilled the Hunter criteria of SS. Patients who met the Hunter criteria were evaluated further for other details.

RESULTS

Overall, 309 patients were identified of which 24 (7.8%) met the Hunter criteria. The mean age was 52.4 years, and 75% were male. Most patients received two or more serotonergic drugs. Ondansetron was the most common serotonergic drug (58%), followed by tramadol (38%), and cough syrup (dextromethorphan or chlorpheniramine, 21%). None of the patients received a diagnosis of SS by the treating physicians. Chronic obstructive pulmonary disease exacerbation with respiratory failure and metabolic encephalopathy were the two most common admission diagnoses (17% each). Twenty-two patients received cyproheptadine. There were no fatalities.

CONCLUSION

SS is not uncommon in the ICU setting. There is a need to increase awareness among physicians.

Posterior reversible encephalopathy syndrome in a patient with serotonin syndrome

Serotonin syndrome (SS) is a drug-induced clinical syndrome, characterised by a triad of cognitive impairment, autonomic hyperactivity and neuromuscular abnormalities. Hypertension, one of the common autonomic manifestations in SS, may lead to lead to several life-threatening conditions. Herein, we report a case of SS who had posterior reversible encephalopathy syndrome (PRES) because of high blood pressure.A young male with a 5-month history of chronic tension-type headache and depression had been receiving amitriptyline and paroxetine. Increment of paroxetine led to the development of various new clinical features, fulfilling the Hunter criteria of SS. MRI brain revealed high-signal intensity lesions on T2 fluid-attenuated inversion recovery, and T2-weighted imaging in the posterior regions of the occipital, parietal, temporal and cerebellum lobes, suggestive of PRES. The patient responded to cyproheptadine. Autonomic hyperactivity, due to SS, is the most likely explanation of this association.

Fatal serotonin syndrome: a systematic review of 56 cases in the literature

INTRODUCTION

Serotonin syndrome (SS) is a drug-induced potentially life-threatening clinical condition. There is a paucity of data on the risk factors, clinical course, and complications associated with fatal SS.

OBJECTIVE

To characterize the epidemiological profile, clinical features, and risk factors associated with fatal SS through a systematic review.

METHODS

We performed a systematic review of MEDLINE and Google Scholar for case reports, case series, or cohort studies of fatal SS.

RESULTS

Initial database search identified 2326 articles of which 46 (56 patients) were included in the final analysis. The mean age was 42.3 years (range 18-87 years) with female predominance (57%). North America and Europe constitute 80% of the reported fatal SS. The symptoms evolved very rapidly, within 24 h after the administration of serotonergic drugs in 59% of the cases. Fever (61%) was the most common symptom, followed by seizure (36%) and tremors (30%). The mean temperature in the reported cases (25 patients) was 41.6 ± 1.3 °C (range 38.3-43.5 °C). SS was reported to occur with the maintenance dosage of serotonergic agents, after initiation of the drug for the first time, and addition of the drugs for the development of another unrelated illness. Creatine kinase (CK) activities were elevated (>3 times of the upper limit of normal) in eighteen patients, and it was very high (>25,000 IU/L) in four patients. Presence of high grade fever, seizures, and high CK activities may be associated with severe SS. Nine patients (16%) received 5-HT2A antagonists as a therapy. About 50% of patients died within 24 h of the onset of symptoms.

CONCLUSIONS

While fatal SS is rare, frequently observed features include hyperthermia, seizures, and high CK activities. Cyproheptadine use appears infrequent for these patients.

Risk assessment of ayahuasca use in a religious context: self-reported risk factors and adverse effects

Objective:

Whether for spiritual, recreational, or potential therapeutic use, interest in ayahuasca has grown remarkably. Ayahuasca’s main active substances are N,N‐dimethyltryptamine and certain monoamine oxidase inhibitor β-carbolines. Possible drug interactions are a major concern, and research is lacking in this area. The objective of this study was to evaluate the safety of ritual ayahuasca use regarding adverse effects and risk factors.

Methods:

In this cross-sectional study, ayahuasca users from a religious institution answered an online questionnaire about its safety. Adverse effects, safety measures, and possible risk factors (psychiatric diagnosis and medications) were investigated.

Results:

The most frequent adverse effects among the 614 participants were transient gastrointestinal effects (nausea and vomiting). Fifty participants self-reported a psychiatric diagnosis (depression and anxiety were the most prevalent), and these participants experienced adverse effects more frequently. Psychiatric medication use was reported by 31 participants. No indication of increased adverse effects due to drug-drug interactions was found.

Conclusion:

A minority of participants reported being very negatively affected by persistent adverse effects. Psychiatric medication use while participating in ayahuasca rituals was not associated with increased adverse effects. For the most part, the institution’s practices seem sufficient to prevent exacerbated reactions. Future studies may focus on negatively affected users.

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.

Perioperative Considerations for Patients With Major Depressive Disorder Undergoing Surgery

In the United States, approximately 15% of adults suffer from major depressive disorder (MDD), which results in an annual cost of over $200 billion per year. In the perioperative setting, MDD is associated with increased morbidity and mortality. The exact causes of the increase in adverse outcomes are unknown. Major depression affects virtually all major systems in the human body, and most antidepressants affect dopamine, norepinephrine, and serotonin levels or alter their target receptors. Unfortunately, anesthesia and medications used in the perioperative period affect the same neurotransmitters. As a result, patients with MDD are at an increased risk for cardiovascular effects, altered thermoregulation, and postoperative cognitive dysfunction. To determine when to continue or hold antidepressants preoperatively and avoid potential drug interactions, perioperative providers must understand the pharmacological action of antidepressants. This article reviews the pathophysiology of MDD, mechanism of action of antidepressants, and perioperative considerations for patients on antidepressant medications.

Serotonin Syndrome Mimicking Intrathecal Baclofen Withdrawal in a Patient with Hereditary Spastic Paraparesis

Context

Serotonin syndrome is a drug-induced condition related to an increased level of serotonin in the brain, which may induce neuromuscular, autonomic and mental symptoms.

Case report

A 40-year-old woman with hereditary spastic paraparesis (Strumpell-Lorrain disease) with an implanted intrathecal baclofen pump for severe spasticity. Two days after starting a medication known to inhibit serotonin re-uptake (paroxetine), she developed a sudden increase in lower limb spasticity with continuous spasms, fever, tachycardia and hypertension. Intrathecal baclofen withdrawal was excluded, confirming serotonin syndrome.

Conclusion

Medications that inhibit serotonin reuptake may induce serotonin syndrome, resulting in increased spasticity in patients with spinal cord lesions, and should be prescribed with caution.

Serotonin Syndrome in the Emergency Department

With the widespread use of serotonergic agents including many antidepressants, antiemetics, illicit drugs, and even some herbal supplements, serotonin syndrome is a condition seen more frequently. It can appear abruptly and, if untreated, can progress to a life-threatening state. Prompt recognition and treatment is imperative to avoid complications. The presentation is variable and can be confused with other conditions. The authors present a case of serotonin syndrome that was recognized early and treated promptly in the emergency department.

Triptan and ergotamine overdoses in the United States

Objective

To examine the clinical outcomes of intentional overdoses involving triptans and ergotamines with a retrospective review of the National Poison Data System (NPDS).

Methods

This was a 5-year retrospective cross-sectional study (2014–2018) using the NPDS. Demographics, exposure characteristics, and outcomes were described. Univariate logistic regression was used to estimate the odds ratio (OR) for major effect or death. A multivariable logistic regression model with inclusion criteria ofp< 0.1 in univariate analysis was implemented with backwards selection.

Results

In this population (n = 1,489), multiple exposure was most common (n = 1,145). The mean age was 31.2 years and 1,197 (80.4%) participants were female. Major effects from a single exposure were seen in <1% with no recorded deaths. Triptan ingestion (n = 328) resulted in hypertension (14%), tachycardia (10.7%), drowsiness (11%), nausea (6.4%), vomiting (4.6%), vertigo (4%), chest pain (3.7%), and diaphoresis (2.4%). Ergotamine ingestion (n = 16) resulted in abdominal pain (16%), vomiting (12.5%), numbness (12.5%), nausea (6.3%), diarrhea (6.3%), and vertigo (6.3%). No clinical effect was seen in 90 (26.2%). No cases met Hunter criteria for serotonin syndrome. There is risk of major event or death due to age (OR 1.02; 95% confidence interval [CI] 1.01–1.04;p= 0.004), multiple product exposure (OR 9.50; 95% CI 2.29–39.48;p= 0.002), and concomitant overdose with benzodiazepines (OR 1.71; 95% CI 1.05–2.78;p= 0.032) or tricyclic antidepressants (OR 3.16; 95% CI 1.88–5.31;p< 0.001).

Conclusion

The risk of major effect or death was low and predicted by age, multiple product exposure, and concomitant benzodiazepine or tricyclic antidepressant. The triptan toxidrome consists of hypertension, tachycardia, and drowsiness. The toxic effects of ergotamine are acute gastrointestinal syndrome with vertigo and numbness. No cases of serotonin syndrome were seen.

Serotonin Syndrome: Pathophysiology, Clinical Features, Management, and Potential Future Directions

Serotonin syndrome (SS) (also referred to as serotonin toxicity) is a potentially life-threatening drug-induced toxidrome associated with increased serotonergic activity in both the peripheral (PNS) and central nervous systems (CNS). It is characterised by a dose-relevant spectrum of clinical findings related to the level of free serotonin (5-hydroxytryptamine [5-HT]), or 5-HT receptor activation (predominantly the 5-HT_1A and 5-HT_2A subtypes), which include neuromuscular abnormalities, autonomic hyperactivity, and mental state changes. Severe SS is only usually precipitated by the simultaneous initiation of 2 or more serotonergic drugs, but the syndrome can also occur after the initiation of a single serotonergic drug in a susceptible individual, the addition of a second or third agent to long-standing doses of a maintenance serotonergic drug, or after an overdose. The combination of a monoamine oxidase inhibitor (MAOI), in particular MAO-A inhibitors that preferentially inhibit the metabolism of 5-HT, with serotonergic drugs is especially dangerous, and may lead to the most severe form of the syndrome, and occasionally death. This review describes our current understanding of the pathophysiology, clinical presentation and management of SS, and summarises some of the drugs and interactions that may precipitate the condition. We also discuss the newer novel psychoactive substances (NPSs), a growing public health concern due to their increased availability and use, and their potential risk to evoke the syndrome. Finally, we discuss whether the inhibition of tryptophan hydroxylase (TPH), in particular the neuronal isoform (TPH2), may provide an opportunity to pharmacologically target central 5-HT synthesis, and so develop new treatments for severe, life-threatening SS.

Recent developments in drug-induced movement disorders: a mixed picture

A large and ever-growing number of medications can induce various movement disorders. Drug-induced movement disorders are disabling but are often under-recognised and inappropriately managed. In particular, second generation antipsychotics, like first generation agents, are associated with potentially debilitating side-effects, most notably tardive syndromes and parkinsonism, as well as potentially fatal acute syndromes. Appropriate, evidence-based management is essential as these drugs are being prescribed to a growing population vulnerable to these side-effects, including children and elderly people. Prevention of the development of drug-induced movement disorders is an important consideration when prescribing medications that can induce movement disorders. Recent developments in diagnosis, such as the use of dopamine transporter imaging for drug-induced parkinsonism, and treatment, with the approval of valbenazine and deutetrabenazine, the first drugs indicated for tardive syndromes, have improved outcomes for many patients with drug-induced movement disorders. Future research should focus on development of safer antipsychotics and specific therapies for the different tardive syndromes and the treatment of drug-induced parkinsonism.

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.

Use of a Bioinformatics-Based Toxicity Scoring System to Assess Serotonin Burden and Predict Population-Level Adverse Drug Events from Concomitant Serotonergic Drug Therapy

STUDY OBJECTIVE

Numerous medications interact at serotonin (5-hydroxytryptamine [5-HT]) receptors directly or through off-target interactions, causing mild to severe serotonergic adverse drug events (ADEs), particularly among older adults. Our objective was to develop a novel molecular-based toxicity scoring system to assess serotonergic burden resulting from concurrently administered drugs. Quantitative methods to assess serotonergic burden may provide a useful clinical tool for improving pharmacotherapy.

DESIGN

Retrospective cohort study.

DATA SOURCES

PharMetrics Legacy health claims database (January 2001-December 2013) and ChEMBL bioactivity database.

PATIENTS

A 2-serotonergic drug exposure cohort (78,172 patients) and a 3-serotonergic drug exposure cohort (19,900 patients) were generated, and population-level statistics were collected. Nonexposure cohorts were created for each drug exposure cohort and matched in a 4:1 ratio for age, sex, and length of enrollment.

MEASUREMENTS AND MAIN RESULTS

Eight 5-HT medications were screened against multiple bioactivity databases to identify their off-target interactions at 5-HT receptors and serotonin reuptake transporter protein. A computational serotonin burden score (SBS) was derived from the receptor-specific interaction propensities reported from the comprehensive bioactivity screen. Linear regression was used to characterize associations between SBSs and combined total ADE incidence rate detected by International Classification of Diseases, Ninth Revision, Clinical Modification, diagnosis codes. A significantly greater incidence of 17 potential 5-HT-related ADEs was seen in exposed serotonergic drug cohorts (p<0.05). A positive correlation between SBS and overall ADE incidence rate in the 2-serotonergic drug exposure cohort (R²  = 0.69, p<0.34) and 3-drug cohort (R²  = 0.85, p<0.01) was observed. When both drug cohorts were combined, total drug SBSs strongly correlated with the composite 5-HT adverse event rate (R²  = 0.92, p<0.0001). Despite an increasing burden of illness, these data suggest that drug combinations with higher SBSs are associated with a higher rate of potential serotonergic ADEs.

CONCLUSION

In this test of concept, positive associations between SBSs and serotonin-related ADEs suggest that it may offer a pharmacologic-based foundation for developing risk assessment tools to assist in optimizing pharmacotherapy.

Refining the Clinical Features of Serotonin Syndrome: A Prospective Observational Study of 45 Patients

Introduction:

Serotonin syndrome (SS) is a drug-induced clinical syndrome that results from the excess intrasynaptic concentration of serotonin. Prospective observations are limited for SS.

Methods:

We prospectively recruited 45 consecutive adult patients (>18 years) fulfilling the Hunter's criteria for SS. All patients were subjected to a detailed clinical history and examinations. Patients were subjected to appropriate investigations to find out the other causes. The causation of SS to serotonergic drugs was assessed according to Naranjo adverse drug reaction probability scale.

Results:

The mean age was 37.3 years (range: 18–59 years). Sixty-two percent of patients were male. There were 15 different underlying clinical syndromes for which serotonergic drugs were started. Psychiatry conditions (36%) and cough/respiratory tract infection (16%) were the two most common clinical conditions for starting serotonergic drugs. We noted 49 different symptoms and physical signs. Overall, tremor (78%) and dizziness (47%) were the two most common symptoms. Headache (16%) and dizziness (16%) were the two most common initial (or first) symptoms. However, gait difficulty and febrile encephalopathy were the two most common reasons to visit the hospital. We noted 18 different drugs causing SS. Thirty-eight percent of patients received single serotonergic agent antidepressants, pain medicines and cough syrups were other important drugs causing SS.

Conclusions:

This study represents the largest clinic-based study on SS. SS is not rare in clinical practice. However, various aspects of this syndrome are still to be determined. All patients on serotonergic drugs should be physically examined for the presence of SS on the development of any new symptom.

Preoperative Management of Medications

Increasingly complex medication regimens for many comorbidities in patients for planned surgical and procedural interventions necessitate detailed preoperative evaluation of the pharmacologic therapy, including the indications, the specific drugs, and dosing amount and interval. The implications of continuing or withholding these agents in the perioperative period need to be elucidated, as well as the risks of interactions and side effects. A comprehensive plan of the management of the therapeutic agents should be devised during the preoperative visit, with input from all relevant specialists, and clearly communicated to the patients in a format that ensures their comprehension and consistent compliance.

Serotonin Syndrome with Atypical Hypernatremia

The incidence of serotonin syndrome in the United States is rising yearly. Providers should be aware of the useful diagnostic criteria and have a low threshold for utilizing such criteria to prevent increased morbidity and mortality. In this case, a 64-year-old female with a complex past medical history presented to the emergency department with an altered mental status after being found poorly responsive by her husband. Many of her symptoms aligned with the commonly used criteria for serotonin syndrome; yet, her complex past medical history and uncommonly elevated sodium levels veered her providers from arriving at this diagnosis earlier. This unique case illustrates that despite having specific criteria for diagnosis, serotonin syndrome can be a complicated diagnosis to make, particularly in the setting of multiple co-morbidities and polypharmacy. In addition, it is important to keep medication toxicities high on a differential diagnosis list and be aware of the criteria used for diagnosis. One of the easiest and most cost-effective methods to diagnosis is to start with a thorough history, physical exam, and medication reconciliation to address easily preventable medication adverse effects.