Are neuroleptic malignant syndrome and serotonin syndrome the same syndrome?

HyperCKemia and rhabdomyolysis in the neuroleptic malignant and serotonin syndromes: A literature review

Neuroleptic malignant syndrome and serotonin syndrome are two syndromes whose molecular bases remain poorly understood. The phenotypes of both syndromes overlap with other syndromes that have a clear genetic background, in particular RYR1-related malignant hyperthermia. Through a literature review, performed according to the PRISMA guidelines, we aimed to report the clinical features of both syndromes, and the results of genetic testing performed. 10 case series and 99 case reports were included, comprising 134 patients. A male predominance of 58% was found. The median age was 35 (range 4-84) years. Eight patients experienced recurrent episodes of rhabdomyolysis. Genetic analysis was performed in eleven patients (8%), revealing four RYR1 variants, three likely benign (p.Asp849Asn, p.Arg4645Gln, p.Arg4645Gln) and one variant of uncertain significance (p.Ala612Thr). This review underlines that a subset of patients with neuroleptic malignant syndrome and serotonin syndrome develop recurrent episodes of rhabdomyolysis. This recurrent pattern suggests a possible underlying (genetic) susceptibility. However, the genetic background of neuroleptic malignant syndrome and serotonin syndrome has only been investigated to a very limited degree so far. The increasing availability of next generation sequencing offers an opportunity to identify potentially associated genetic backgrounds, especially in patients with recurrent episodes or a positive family history.

Serotonin syndrome: a spectrum of toxicity

Serotonin syndrome (serotonin toxicity or serotonin toxidrome) is a potentially serious and theoretically predictable reaction that appears to be rarely diagnosed in practice in the UK. Some symptoms of serotonin syndrome overlap with features of other presentations in psychiatry and thus may be misattributed to mental illness (‘diagnostic overshadowing’). Further, there may be diagnostic dilemmas in patients on combinations of drugs, those receiving drugs with previously unknown serotonergic properties or where there are drug interactions. Prescriber vigilance and holistic review of the patient, including the pharmacotherapy, may be helpful in avoiding progression of serotonin syndrome to more serious outcomes.

Malignant Syndrome and Serotonin Syndrome in a General Hospital Setting: Clinical Features, Frequency and Prognosis

Objective The differences in the frequency and clinical features of malignant syndrome (MS) and serotonin syndrome (SS) in same population have only rarely been reported. To report the frequency and clinical features of MS and SS in a general hospital setting. Methods The clinical and laboratory features of patients with MS and those with SS, who were consecutively admitted to Chiba Rosai Hospital, during the past 4.5 years were reviewed. Results Of the 2005 patients admitted, MS was observed in 16 patients (0.8%) and SS in 2 (0.1%). In the 16 patients with MS, the underlying disorder included depression (n = 5), and dementia or parkinsonism (n = 11). The underlying etiology of the 2 patients with SS was depression. In 5 patients, MS was difficult to distinguish from SS because of overlapping symptoms and signs and/or treatments with both neuroleptic and serotoninergic drugs. Of the 16 patients with MS, 1 died, 1 remained wheelchair-bound, 4 were able to walk with assistance, and 10 regained their ability to ambulate independently. The 2 patients with SS recovered after cyproheptadine therapy and were discharged on foot. Conclusion MS occurs more frequently than SS in the general hospital setting. Underlying aetiologies in patients with MS were more common due to dementia or parkinsonism than in patients with psychiatric disorders. The differential diagnosis of MS and SS is often difficult and the diagnostic sensitivities largely differ for each of the diagnostic criteria. As a result, the establishment of new diagnostic criteria that specifically focus on distinguishing MS from SS is therefore required.

Improving Psychiatric Nurses' Detection of Neuroleptic Malignant Syndrome

Patients with psychiatric disorders receive nursing care in psychiatric units, medical units and long-term care facilities. Like other patients, their well-being is reliant upon knowledgeable caregivers. The pharmacological interventions that patients are dependent on can have catastrophic effects; of particular concern is Neuroleptic Malignant Syndrome (NMS). This article affords a succinct review of the literature related to NMS and provides suggestions for psychiatric nurse educators to facilitate early recognition, thereby reducing mortality and morbidity. Emphasis is placed on educational tools to help reduce under-detection. A case study illustrates how under-detection can lead to a near fatal outcome.

Second-generation antipsychotics and neuroleptic malignant syndrome: systematic review and case report analysis

BACKGROUND

Neuroleptic malignant syndrome (NMS) is a rare, severe, idiosyncratic adverse reaction to antipsychotics. Second-generation antipsychotics (SGAs) were originally assumed to be free from the risk of causing NMS, however several cases of NMS induced by SGAs (SGA-NMS) have been reported.

OBJECTIVES

The aim of this study was to systematically review available studies and case reports on SGA-NMS and compare the presentation of NMS induced by different SGAs.

DATA SOURCES

Citations were retrieved from PubMed up to November 2013, and from reference lists of relevant citations.

STUDY ELIGIBILITY CRITERIA

Eligibility criteria included (a) primary studies reporting data on NMS, with at least 50 % of the sample receiving SGAs; or (b) case reports and case reviews reporting on NMS induced by SGA monotherapy, excluding those due to antipsychotic withdrawal.

STUDY APPRAISAL AND SYNTHESIS METHODS

A standardized method for data extraction and coding was developed for the analysis of eligible case reports.

RESULTS

Six primary studies and 186 individual cases of NMS induced by SGAs were included. Primary studies suggest that SGA-NMS is characterized by lower incidence, lower clinical severity, and less frequent lethal outcome than NMS induced by first-generation antipsychotics. Systematic analysis of case reports suggests that even the most recently marketed antipsychotics are not free from the risk of inducing NMS. Furthermore, clozapine-, aripiprazole- and amisulpride-induced NMS can present with atypical features more frequently than other SGA-NMS, i.e. displaying less intense extrapyramidal symptoms or high fever.

LIMITATIONS

Case reports report non-systematic data, therefore analyses may be subject to bias.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

Clinicians should be aware that NMS is virtually associated with all antipsychotics, including those most recently marketed. Although apparently less severe than NMS induced by older antipsychotics, SGA-NMS still represent a relevant clinical issue.

Neurotoxic syndrome induced by clomipramine plus risperidone in a patient with autistic spectrum disorder: serotonin or neuroleptic malignant syndrome?

To the best of our knowledge, there are no case studies of serotonin syndrome (SS) in patients with autism spectrum disorder. We report the case of a 33-year-old male who presented SS under the combined use of clomipramine and risperidone. More specifically, within 2 days after clomipramine (10 mg/BID-two times a day) was added to risperidone (4 mg/OD-once a day), mirtazapine 45 mg/OD and alprazolam (0,5 mg/TID-three times a day) he began to present mental, neurological and autonomic symptoms. All his psychopathological manifestations and laboratory findings normalized after the above-mentioned drugs' discontinuation, and the administration of supportive medical care and lorazepam 2,5 mg/TID. The diagnosis of serotonin syndrome was challenging due to the relatively low dose of clomipramine, an increase of risperidone which had taken place before clomipramine administration and clinical symptoms which could be attributed to both serotonin and neuroleptic malignant syndrome.

Neuroleptic malignant syndrome and closed head injury: A case report and review

Neuroleptic malignant syndrome (NMS) is a rare, but potentially lethal neurological emergency. Fifty percent of traumatic brain injury (TBI) patients will have emotional disorders and post-traumatic agitations. Haloperidol is a neuroleptic antipsychotic medication commonly used in the traumatic brain injury patients due to its advantage of no effect on respiration and conscious level. But it is one of the common medications causing NMS. A 19-year-old male driver involved in the road traffic accident had an acute subdural hematoma, which was immediately evacuated. Postoperatively, he was awake. He was weaned from ventilator and extubated. He received 20 mg of intravenous haloperidol in divided doses with in 24 hours to control his agitation. Next day, he became drowsy, spastic, febrile, and tachycardic with labile blood pressure. He was diagnosed to have NMS, needed intubation, aggressive hydration and pharmacological treatment with dentrolene sodium and bromocriptin. He was weaned from ventilator and extubated on day 17. He was transferred to the ward and then discharged to be followed in out-patient clinic. NMS in head injury patient is rare and difficult to diagnose. Diagnosis of NMS should be suspected if two of the four cardinal signs and symptoms are developed following the use of neuroleptic or dopamine agonist medication withdrawal.