Incipient neuroleptic malignant syndrome with quetiapine/paroxetine combination treatment: atypical presentation and early, successful rechallenge with olanzapine

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.

Case reports of neuroleptic malignant syndrome in context of quetiapine use

A retrospective analysis was followed on 20 case reports covering the possible correlation between the atypical antipsychotic, quetiapine, and neuroleptic malignant syndrome (NMS), determined by the study of 7 different NMS criteria guidelines. A great majority (19) of the case studies did not meet the requirements of all 7 guidelines, frequently due to unreported information. Nor was quetiapine proven to be the sole cause of the possible NMS in the two age groups investigated. Only one case was found to have no other medication or medical conditions confounding the relationship of quetiapine and NMS symptoms, and that case was in the context of a significant quetiapine overdose. The other 19 cases demonstrated the difficulty of identifying the cause of NMS when polypharmacy and other medical conditions are involved. The authors note the need for caution in deciding both the presence of NMS and the causal factors of the symptoms.

Neuroleptic malignant syndrome associated with atypical antipsychotic drugs

Neuroleptic malignant syndrome (NMS) is a rare but potentially severe idiosyncratic adverse reaction usually seen in the context of treatment with antipsychotic drugs. Although NMS is historically associated with the classic or 'typical' antipsychotic drugs, it is also a potential adverse effect of atypical antipsychotic drugs. The widespread use of atypical antipsychotic drugs highlights the need to examine the data relating to the symptomatology, diagnosis, classification and management of NMS with these newer agents. We used MEDLINE and EMBASE to identify NMS case reports and systematic reviews published to June 2008 related to the atypical antipsychotic drugs clozapine, olanzapine, risperidone, paliperidone, aripiprazole, ziprasidone, amisulpride and quetiapine. Case reports and reviews were systematically examined. Our review suggests that, in general, NMS associated with atypical antipsychotic drugs manifests in a typical manner. One notable exception is clozapine-induced NMS, which appears less likely to manifest with extrapyramidal features, including rigidity and tremor. The available literature highlights the divergence of opinion relating to the core diagnostic features of NMS and its conceptualization as a categorical versus dimensional disorder. Both these issues have relevance for the identification of atypical or milder forms of NMS, which are sometimes seen with atypical antipsychotic drugs.

Neuroleptic Malignant Syndrome Secondary to Quetiapine

Objective:

To report a case of neuroleptic malignant syndrome (NMS) secondary to quetiapine in which the patient developed extrapyramidal symptoms (EPS).

Case Summary:

A 34-year-old male with a history of severe brain damage, mental retardation, and seizures was admitted to the hospital with changes in mental status, development of tremors, and a temperature of 39.9 °C. Initial differentia) diagnoses included seizure, aspiration, stroke, and infection. Once these were excluded, NMS was considered. The patient exhibited other characteristics of NMS during hospitalization, including lead pipe rigidity, tachycardia, and high creatine kinase level (up to 12,654 IU/L). Drug therapy on presentation included quetiapine 200 mg 3 times per day, guanfacine 2 mg/day. carbamazepine 400 mg every 12 hours, valproic acid 500 mg twice daily, and lorazepam 2 mg (unknown schedule). He reportedly had received these medications for at least a month before admission. On hospital day 2, quetiapine was discontinued. The patient received traditional treatment (or NMS, which included bromocriptine, dantrolene, intravenous fluids, and supportive care. The NMS resolved in 7 days.

Discussion:

In cases of NMS, clinicians previously believed that the risk for developing severe adverse effects such as EPS was lower with atypical versus typical antipsychotics. We identified 13 cases of NMS secondary to quetiapine in the literature via a search of MEDLINE/PubMed (1950–2008), and Iowa Drug Information Service (1966–2008). Seventy-five percent of previous reports of NMS secondary to quetiapine had reactions that included EPS, Common patient characteristics in our report and others included male sex, history of mental retardation, and treatment modalities used in NMS. Unique characteristics in this case included length of therapy without dosage change or titration and no known history of drug-related EPS. The Naranjo probability scale indicated a probable relationship between the development of NMS and quetiapine.

Conclusions:

NMS with associated EPS has been previously associated with quetiapine. Clinicians should be aware that NMS with EPS can occur with quetiapine at steady state doses without recent dosage adjustments or titration.