Atypical Neuroleptic Malignant Syndrome Associated with Use of Clozapine

Sospecha fallida de síndrome neuroléptico maligno en una paciente con esquizofrenia

El estado mental alterado es un término general que se utiliza para describir varios trastornos del funcionamiento mental, que pueden variar desde una ligera confusión hasta el coma. Este término en general no es un diagnóstico, por el contrario, hace referencia a un grupo de síntomas neurológicos variables e inespecíficos que requieren una mayor especificación de la causa. Dentro de las múltiples causas a considerar en el paciente adulto mayor se encuentran los efectos adversos e interacciones medicamentos. Paciente con antecedentes de esquizofrenia requiere tratamiento de por vida, incluso si los síntomas desaparecen. Los medicamentos antipsicóticos deben ser tenidos en cuenta dado sus potenciales efectos asociados. El síndrome neuroléptico maligno (SNM) es uno de los efectos adversos a tener en cuenta por su riesgo de mortalidad. Se presenta el caso de una paciente de 78 años que ingresó al servicio de urgencias de un hospital de tercer nivel por alteración del estado de conciencia, con antecedentes de esquizofrenia y múltiples comorbilidades, que representan un reto en el abordaje inicial en el servicio de urgencias; los paraclínicos tomados mostraron elevación de la CPK.

Office-based General Anesthesia for a Patient With a History of Neuroleptic Malignant Syndrome

First described in 1956 subsequent to a reaction reported to the newly introduced antipsychotic drug chlorpromazine, neuroleptic malignant syndrome (NMS) is a rare, potentially life-threatening reaction to antipsychotic drugs characterized by high fever, muscle rigidity, altered mental status, and autonomic instability. All neuroleptics, including newer antipsychotics, have been linked to this condition. Due to similar symptoms, it is debatable if individuals with NMS can be susceptible to malignant hyperthermia (MH). This case report presents the anesthetic care of a 30-year-old male undergoing general anesthesia in the office-based dental environment. The rationale behind the selected total intravenous anesthesia technique without NMS or MH triggering agents is outlined as well as other agents that may still be questionable regarding their trigger effect for NMS.

Atypical Neuroleptic Malignant Syndrome: Case Reports and Diagnostic Challenges

Neuroleptic malignant syndrome caused by atypical antipsychotic drugs may present in an atypical manner without symptoms such as hyperthermia and/or muscle rigidity. A detailed description of atypical neuroleptic malignant syndrome induced by atypical antipsychotic drugs, practical information to distinguish neuroleptic malignant syndrome from other related conditions, and the diagnostic criteria that may be used to settle the diagnosis of atypical neuroleptic malignant syndrome are highlighted in this paper. This study was conducted searching PubMed and Science Direct, resulting in 525 articles. 26 case reports that met inclusion criteria were identified. Atypical neuroleptic malignant syndrome was found to develop mainly in male patients suffering from schizophrenia (14 cases) and bipolar disorder (2), and was induced by clozapine (6 cases), olanzapine (5 cases), aripiprazole and quetiapine (4 cases). Muscle rigidity did not develop in patients treated with clozapine and quetiapine, whereas a lack of hyperthermia was common with aripiprazole and clozapine treatment. Atypical neuroleptic malignant syndrome is a difficult matter, especially when symptoms of hyperthermia or muscle rigidity is lacking, but using Levenson's or Adityanjee and Aderibigbe's criteria may increase it detectability, can permit earlier intervention and prevent development of life-threatening typical neuroleptic malignant syndrome.

Neuroleptic Malignant Syndrome (NMS) on Clozapine with a Potential Atypical Interaction with Paliperidone

Neuroleptic Malignant Syndrome (NMS) associated with the use of first-generation antipsychotics is a widely known phenomenon. This idiosyncratic reaction is less significant with the use of second-generation antipsychotics, and only a few cases in the literature exist, describing this reaction with clozapine use. While being titrated on clozapine, the patient developed major and minor criteria features of NMS as per the Diagnostic and Statistical Manual of Mental Disorders, Fifth edition (DSM-5) criteria except for fever, a core symptom which created diagnostic uncertainty. Initially, clozapine was temporarily discontinued due to his deteriorating mental and physical state. A rechallenge was considered at a much lower dose, but due to a rapid increase in his creatinine kinase (CK) levels within a 12-hour timeframe, clozapine was permanently stopped. The evidence further suggests that the presentation of NMS for patients on this medication may be different to the classical presentation, and other criteria for diagnosis are suggested, which may lower the threshold for investigating NMS for patients on clozapine.

Atypical Neuroleptic Malignant Syndrome in the Setting of Quetiapine Overdose: A Case Report and Review of the Literature

Neuroleptic malignant syndrome (NMS) is a rare and life-threatening emergency. The condition is largely iatrogenic and is often precipitated by medications such as antipsychotics. First-generation antipsychotics are more likely to cause NMS than second-generation antipsychotics. The literature lacks an objective measure for NMS diagnosis. Instead, the diagnosis relies largely on the recognition of characteristic symptoms in the presence of an inciting medication. Additional challenges exist with concomitant disease processes and toxicities that may distort the clinical picture. Here, we report a case of a 44-year-old Caucasian man who presented with atypical NMS in the setting of quetiapine overdose. The patient remained uncharacteristically afebrile throughout his admission. Although the patient recovered, extended delays in identification and management can contribute to an increased risk of morbidity and mortality.

Investigation of Clozapine and Olanzapine Reactive Metabolite Formation and Protein Binding by Liquid Chromatography-Tandem Mass Spectrometry

Drug-induced toxicity has, in many cases, been linked to oxidative metabolism resulting in the formation of reactive metabolites and subsequent covalent binding to biomolecules. Two structurally related antipsychotic drugs, clozapine (CLZ) and olanzapine (OLZ), are known to form similar nitrenium ion reactive metabolites. CLZ-derived reactive metabolites have been linked to agranulocytosis and hepatotoxicity. We have studied the oxidative metabolism of CLZ and OLZ as well as two known metabolites of CLZ, desmethyl-CLZ (DCLZ), and CLZ-N-oxide (CLZ-NO), using in vitro rat liver microsomal (RLM) incubations with glutathione (GSH) trapping of reactive metabolites and liquid chromatography-high resolution tandem mass spectrometry (LC-HRMS/MS). Reactive metabolite binding to selected standard peptides and recombinant purified human proteins was also evaluated. Bottom-up proteomics was performed using two complementary proteases, prefractionation of peptides followed by LC-HRMS/MS for elucidating modifications of target proteins. Induced RLM was selected to form reactive metabolites enzymatically to assess the complex profile of reactive metabolite structures and their binding potential to standard human proteins. Multiple oxidative metabolites and several different GSH adducts were found for CLZ and OLZ. Modification sites were characterized on human glutathione S-transferase (hGST) alpha 1 (OLZ-modified at Cys112), hGST mu 2 (OLZ at Cys115), and hGST pi (CLZ, DCLZ, CLZ-NO and OLZ at Cys170), human microsomal GST 1 (hMGST1, CLZ and OLZ at Cys50), and human serum albumin (hSA, CLZ at Cys34). Furthermore, two modified rat proteins, microsomal GST 1 (CLZ and OLZ at Cys50) and one CYP (OLZ-modified, multiple possible isoforms), from RLM background were also characterized. In addition, direct effects of the reactive metabolite modifications on proteins were observed, including differences in protease cleavage specificity, chromatographic behavior, and charge-state distributions.

A Look at Genetic Linkage between Clozapine-induced Agranulocytosis, Malignant Hyperthermia, Neuroleptic Malignant Syndrome, and Statin-induced Myopathy

Clozapine-induced agranulocytosis, malignant hyperthermia (MH), statin-induced myopathy, and neuroleptic malignant syndrome (NMS) are all serious drug reactions with significant overlap in terms of clinical symptomatology. The use of clozapine can lead to neutropenia, as well as the development of NMS; thus, it seemed logical to explore a possible common genetic background for the development of these two adverse effects. Furthermore, due to the overwhelming clinical resemblance between NMS, MH, and statin-induced myopathy, we decided specifically to search for a common genetic background in the development of these conditions. Methods: We searched the PubMed, OMIM, WikiGenes, Medline, and Google Scholar databases to identify articles pertinent to our subject published over the last 30 years. Articles were reviewed according to our inclusion/exclusion criteria, and irrelevant articles were excluded. Results and Conclusions: In our exploration for a common genetic background between clozapine-induced agranulocytosis, MH, NMS, and statin-induced myopathy, we identified the SLCO1B1 gene, which was common to three of these four conditions (MH, statin-induced myopathy, and clozapine-induced agranulocytosis). Although we did not find a gene common among NMS and the other conditions, the overlap of clinical symptoms between NMS, MH, and statin-induced myopathy did not allow us to rule out the possibility of a common factor, in terms of genetic predisposition, between these conditions. Future studies can aid to fill in the gaps of knowledge in terms of any genetic linkage between these three conditions and the mechanism of their associations.

Safety of antipsychotics for the treatment of schizophrenia: a focus on the adverse effects of clozapine

Clozapine, a dibenzodiazepine developed in 1961, is a multireceptorial atypical antipsychotic approved for the treatment of resistant schizophrenia. Since its introduction, it has remained the drug of choice in treatment-resistant schizophrenia, despite a wide range of adverse effects, as it is a very effective drug in everyday clinical practice. However, clozapine is not considered as a top-of-the-line treatment because it may often be difficult for some patients to tolerate as some adverse effects can be particularly bothersome (i.e. sedation, weight gain, sialorrhea etc.) and it has some other potentially dangerous and life-threatening side effects (i.e. myocarditis, seizures, agranulocytosis or granulocytopenia, gastrointestinal hypomotility etc.). As poor treatment adherence in patients with resistant schizophrenia may increase the risk of a psychotic relapse, which may further lead to impaired social and cognitive functioning, psychiatric hospitalizations and increased treatment costs, clozapine adverse effects are a common reason for discontinuing this medication. Therefore, every effort should be made to monitor and minimize these adverse effects in order to improve their early detection and management. The aim of this paper is to briefly summarize and provide an update on major clozapine adverse effects, especially focusing on those that are severe and potentially life threatening, even if most of the latter are relatively uncommon.

[Neuroleptic malignant syndrome]

BACKGROUND

Neuroleptic malignant syndrome (NMS) is a rare but severe undesired complication of psychopharmacological treatment. The mortality has shown a significant decrease since its first description. Knowledge of NMS is important for every clinician because of the need for rapid diagnosis and treatment.

OBJECTIVE

This article presents a review and critical appraisal of the current study situation for NMS. Recommendations for diagnostics, differential diagnostics and treatment are presented particularly from a clinical perspective.

MATERIAL AND METHODS

A literature review with the keywords "neuroleptic malignant syndrome", "Malignes neuroleptisches Syndrom" and various psychotropic drugs was performed in PubMed. The database of the Working Group for Pharmaceutical Treatment of Psychiatric Diseases (Arbeitsgemeinschaft für Arzneimitteltherapie bei psychiatrischen Erkrankungen, AGATE) was analyzed with respect to registered cases of the undesired side effect NMS.

RESULTS

In contrast to the first description, which also led to the name, there are now case reports of clinical conditions similar to NMS, which were obviously triggered by several groups of psychotropic drugs not just antipsychotic agents (German: Neuroleptika). Treatment recommendations exist whereby the effectiveness cannot always be scientifically substantiated; however, it is still undisputed that a rapid initiation of treatment is of great importance.

DISCUSSION

The psychiatrist must be familiar with the symptoms of NMS, its differential diagnosis and the therapeutic options for a rapid and effective treatment. Further studies are urgently needed for scientific substantiation of the pathophysiology of NMS and to develop evidence-based guidelines for treatment.