Atypical neuroleptic malignant syndrome (NMS)

Uvais, N. A.

doi:10.1016/j.ajp.2017.08.020

Cited by 5 publications

(3 citation statements)

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“…Given all these similarities and difficulties in differentiating these two syndromes, some authors consider them part of the same pathological spectrum [ 5 , 99 ]. Interestingly, some case reports reported a different presentation of NMS (atypical NMS), which does not necessarily present rigidity or hyperthermia as primary symptoms [ 100 , 101 ]. These cases always occur in the presence of atypical antipsychotics.…”

Section: Reviewmentioning

confidence: 99%

“…One of the most widely accepted hypotheses about this "atypical" NMS pathophysiology is that, due to the action of these drugs on the serotonergic system, in addition to the lower degree of dopaminergic receptors antagonism, the motor symptoms could be attenuated. In addition, adrenergic and muscarinic receptor activity disruption can lead to autonomic dysfunction [100][101][102]. Therefore, SS and NMS may be part of the same pathological spectrum since the atypical NMS seems to occur due to an augmented serotonergic action.…”

Section: Serotonin Syndrome Versus Neuroleptic Malignant Syndromementioning

confidence: 99%

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Serotonin Syndrome: The Role of Pharmacology in Understanding Its Occurrence

Poian,

Chiavegatto

2023

Cureus

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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.

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Section: Reviewmentioning

confidence: 99%

Section: Serotonin Syndrome Versus Neuroleptic Malignant Syndromementioning

confidence: 99%

Serotonin Syndrome: The Role of Pharmacology in Understanding Its Occurrence

Poian,

Chiavegatto

2023

Cureus

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“…The DSM5 diagnosis of NMS is more pragmatic and descriptive compared to its predecessors as it facilitates the identification of typical cases of NMS. However, clinicians who treat hundreds of psychotic patients encounter NMS presentations with atypical symptom patterns that seem clinically somewhat similar, but do not necessarily meet all the criteria described in the DSM5 system [6]. It is noteworthy that [7] concluded, "hyperthermia and/or muscle rigidity may be absent or develop slowly over several days, leading to impairment or a significant delay in diagnosis and treatment.…”

Section: Introductionmentioning

confidence: 99%

Symptom Frequencies and Correlations with Temperature Variations in Suspected Cases of Neuroleptic Malignant Syndrome (NMS)

Velamoor

Mann²,

Woodbury

et al. 2021

EJMED

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Background: The incidence of NMS is rare. Relative frequencies of symptoms that are most valuable in making a diagnosis of NMS can be assessed statistically only if a large sample of suspected NMS cases is available. Similarly, the relationship of such NMS symptoms to temperature (a cardinal symptom of NMS) can be meaningfully evaluated only by studying large samples. Method: De-identified archival data on 212 suspected NMS cases were obtained from professionals across the USA and Canada or were extracted from studies published in medical journals. We recorded the symptoms frequencies. The patients’ temperature ranged from 37.20C to 43.00C, with the mean at 39.50 (SD=1.3). All cases were caused by older first-generation antipsychotics (FGAs). We evaluated the frequencies of symptoms reported in these cases. These included symptoms in the realm of mental status, rigidity, and autonomic symptoms. We calculated the frequency of abnormal blood pressure, respiration and heart rate, symptoms such as Dysarthria, Dysphagia, Rigidity, Focal Dystonia, Waxy Flexibility, Myoclonus, Masked Facies, Bradykinesia, Akinesia, Cogwheeling, Stupor, Coma, Obtundation, Mutism, Decrease in Consciousness, Disorientation, Diaphoresis, Sialorrhea, and Seizures. We also calculated their correlations with temperature elevations, the most spectacular symptom of this dangerous syndrome. Results: The highest symptom frequencies (those > 10%) were found for Rigidity (91.0% of patients), Autonomic Instability (66.5%), Diaphoresis (45.8%), Mutism (34.4%), Tremor (31.6%), Stupor (20.3%), Confusion (15.6%), Incontinence (15.6%), Sialorrhea (14.6%), Coma (13.2%), and Dysphagia (11.3%). Other symptoms were too rare within the sample of the 212 suspected NMS cases to calculate the statistical significances of their relationships to temperature. The only significant correlations found of temperature were to increased heart rate and to the severe cases of coma. Discussion and Conclusion: Besides the elevated temperature, the most frequently reported symptoms in this sample of suspected NMS caused by FGAs were Rigidity, Autonomic Instability, Diaphoresis, Mutism, and Tremor. Higher temperature was associated with tachycardia as well as profound impairment of consciousness or coma. Reviews and database studies of second generation antipsychotics (SGAs), also referred to as atypical antipsychotics, suggest a lower incidence of NMS and milder severity of symptoms such as hyperthermia and rigidity. It would be of clinical interest to generate similar de-identified files of archival data for suspected cases of NMS in patients treated with SGAs. Furthermore, a similar profile derived from archival data on milder or prodromal NMS cases could enhance our understanding of this syndrome from a spectrum perspective.

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