The neuroleptic malignant syndrome: a logical approach to the patient with temperature and rigidity

Atypical Neuroleptic Malignant Syndrome With Type 2 Respiratory Failure Treated With Non-invasive Ventilation

Neuroleptic malignant syndrome (NMS) is characterized by hyperthermia, severe rigidity, and autonomic instability that is life-threatening if not treated promptly by intensive supportive care. However, there have been numerous reports of "atypical NMS" where the diagnostic criteria of NMS are only partially satisfied. We present a case of an elderly male who presented with atypical NMS secondary to antidopaminergic drug administration which precipitated acute respiratory failure. Our patient exhibited features of severe rigidity and autonomic instability, without hyperthermia. He developed tachypneic hypoventilation with type 2 hypercapneic respiratory failure which was treated with non-invasive ventilation (NIV). The patient recovered after three days with resolution of rigidity and was transferred to a normal medical ward on oxygen via a facemask, where he gradually improved. This study highlights that non-invasive ventilation may have a role in treating respiratory failure in mild to moderate cases of atypical NMS, avoiding the need for intubation.

Dexmedetomidine Infusion as a Novel Supportive Therapy for Fluphenazine-Induced Neuroleptic Malignant Syndrome in a 10-Year-Old Boy: A Case Report and Review of Literature

A 10-year-old male child patient developed symptoms of neuroleptic malignant syndrome (NMS) 1 month following initiation of fluphenazine for behavioral therapeutic management. Dexmedetomidine infusion was able to adequately control the symptoms of NMS with resolution of encephalopathy. This was the first report of novel dexmedetomidine utilization for the treatment of NMS. We suggest using dexmedetomidine as an adjunctive agent to control NMS symptomatology without attendant risk of respiratory depression.

Neuroleptic malignant syndrome and serotonin syndrome

The clinical manifestation of drug-induced abnormalities in thermoregulation occurs across a variety of drug mechanisms. The aim of this chapter is to review two of the most common drug-induced hyperthermic states, serotonin syndrome and neuroleptic malignant syndrome. Clinical features, pathophysiology, and treatment strategies will be discussed, in addition to differentiating between these two syndromes and differentiating them from other hyperthermic or febrile syndromes. Our goal is to both review the current literature and to provide a practical guide to identification and treatment of these potentially life-threatening illnesses. The diagnostic and treatment recommendations made by us, and by other authors, are likely to change with a better understanding of the pathophysiology of these syndromes.

Fluphenazine-Induced Neuroleptic Malignant Syndrome in a Schizophrenic Patient

OBJECTIVE:

To report a case of neuroleptic malignant syndrome (NMS) associated with fluphenazine in a schizophrenic patient and review the literature related to this condition.

CASE SUMMARY:

A 21-year-old African American male with schizophrenia came to our medical intensive care unit from the crisis intervention unit (CIU). He was hyperthermic (oral temperature 40.6 °C), diaphoretic, tachycardic (heart rate 140 beats/min), and tachypneic (respiratory rate 22 breaths/min), with severe muscle rigidity and shaking tremors. He had an extensive psychiatric history significant for schizophrenia and multiple past hospital admissions, starting at age 14 years. Two days prior to admission to the CIU, he had been given 25 mg of fluphenazine decanoate injection intramuscularly in addition to his regular psychotropic regimen of thioridazine and haloperidol after reportedly making several verbal threats and displaying aggressive behavior toward the personnel at the group home where he resided. Laboratory studies showed elevated creatine kinase, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase levels, as well as azotemia, hyperphosphatemia, hypocalcemia, and leukocytosis.

DISCUSSION:

NMS is a rare but potentially fatal reaction associated with neuroleptic drugs. It occurs in approximately 0.07–2.2% of patients treated with neuroleptics. Risk factors include previous episodes, dehydration, agitation, polypharmacy, and the rate and route of neuroleptic administration.

CONCLUSIONS:

An objective causality assessment revealed that fluphenazine was the probable cause of NMS in this patient. There was no reaction associated with thioridazine and/or haloperidol. Clinicians need to be aware of this drug-induced condition and the potential increased risk associated with concurrent use of multiple psychotropics.

Diagnostic uncertainty in a case of neuroleptic malignant syndrome

Neuroleptic malignant syndrome (NMS) is a potentially life-threatening condition that has been associated with antipsychotic use. Most diagnostic criteria include fever and muscle rigidity, although NMS may present without either. Diagnostic uncertainty in such cases may result in delays in diagnosis and management, leading to adverse consequences for these patients. The differential diagnosis of NMS is broad and includes a number of neurological, medical and psychiatric conditions as well as substance and medication-induced disorders. A case is described that illustrates an atypical presentation of NMS and demonstrates some of the challenges in its diagnosis. Limitations of current NMS criteria are also examined, and suggestions for future criteria are presented.

Neuroleptic malignant syndrome complicating antipsychotic treatment of delirium or agitation in medical and surgical patients: case reports and a review of the literature

BACKGROUND

Neuroleptic malignant syndrome (NMS) is a potentially fatal adverse event associated with the use of antipsychotics.

OBJECTIVE

The authors provide information on the development and outcome of NMS during antipsychotic treatment of delirium or agitation in medically ill patients.

METHOD

The authors present case reports and a literature review of NMS arising during antipsychotic treatment of delirium.

RESULTS

A total of 25 cases of NMS occurring in patients with delirium or agitation were identified. Most cases involved men with agitated delirium who received relatively high doses of parenteral haloperidol. The signs and symptoms of NMS episodes were similar to those reported in other settings, and most patients had a complete recovery.

CONCLUSION

Clinicians utilizing antipsychotics in managing delirium or agitation are advised to be vigilant for NMS. Further study is required to determine whether certain patient characteristics or medications present greater risk for this serious adverse event.

Hyperthermic Syndromes Induced by Toxins

Normal thermogenesis requires a complex interaction between systems that generate and dissipate heat. Serving as director of thermogenesis, the hypothalamus activates the sympathetic nervous system along with the thyroid and adrenal glands to respond to changes in body temperature. Working in concert, these systems result in heat generation by uncoupling of oxidative phosphorylation, combined with impaired heat dissipation through vasoconstriction. In this article, the authors discuss serotonin and sympathomimetic syndromes, neuroleptic malignant syndrome,and malignant hyperthermia and how these syndromes affect the hypothalamic and sympathetic nervous systems, resulting at times in severe hyperthermia. Current treatment recommendations and future trends in treatment are also discussed.

Toxin-induced hyperthermic syndromes

Toxin-induced hyperthermic syndromes are important to consider in the differential diagnosis of patients presenting with fever and muscle rigidity. If untreated, toxin-induced hyperthermia may result in fatal hyperthermia with multisystem organ failure. All of these syndromes have at their center the disruption of normal thermogenic mechanisms, resulting in the activation of the hypothalamus and sympathetic nervous systems.The result of this thermogenic dysregulation is excess heat generation combined with impaired heat dissipation. Although many similarities exist among the clinical presentations and pathophysiologies of toxin-induced hyperthermic syndromes, important differences exist among their triggers and treatments. Serotonin syndrome typically occurs within hours of the addition ofa new serotonergic agent or the abuse of stimulants such as MDMA or methamphetamine. Treatment involves discontinuing the offending agent and administering either a central serotonergic antagonist, such as cyproheptadine or chlorpromazine, a benzodiazepine, or a combination of the two. NMS typically occurs over hours to days in a patient taking a neuroleptic agent; its recommended treatment is generally the combination of a central dopamine agonist, bromocriptine or L-dopa, and dantrolene. In those patients in whom it is difficult to differentiate between serotonin and neuroleptic malignant syndromes, the physical examination may be helpful:clonus and hyperreflexia are more suggestive of serotonin syndrome,whereas lead-pipe rigidity is suggestive of NMS. In patients in whom serotonin syndrome and NMS cannot be differentiated, benzodiazepines represent the safest therapeutic option. MH presents rapidly with jaw rigidity, hyperthermia, and hypercarbia. Although it almost always occurs in the setting of surgical anesthesia, cases have occurred in susceptible individuals during exertion. The treatment of MH involves the use of dantrolene. Future improvements in understanding the pathophysiology and clinical presentations of these syndromes will undoubtedly result in earlier recognition and better treatment strategies.

Drug-induced movement disorders in children and adolescents

The use of psychotropic medication among children and adolescents is increasing with a concomitant increase in the incidence of drug-related movement disorders. This class of adverse reactions to medications can be divided into those that are acute in onset, others that are continuous as long as the offending drug is administered, and a final category consisting of symptoms that are persistent, even after the causative agent has been discontinued. Within these three categories, this review discusses the epidemiology, risk factors, clinical features and treatment of acute dystonic reactions, drug-induced parkinsonism, neuroleptic malignant syndrome, serotonin syndrome, acute akathisia, and the tardive syndromes. In addition, drugs that commonly cause tremor, chorea, or myoclonus are included.

Drug-induced movement disorders in children

The increased use of stimulants, antipsychotic agents, and antidepressant drugs in children by primary care physicians, psychiatrists, and neurologists has inevitably led to increased numbers of pediatric patients manifesting the side effects of these agents, many of which are movement disorders. Unlike the isolated abnormal involuntary movements associated with drugs prescribed for epilepsy or asthma, movement syndromes (eg, acute dystonic reaction, neuroleptic malignant syndrome, serotonin syndrome, tardive dyskinesia) associated with psychotropic drugs are complex, difficult to recognize, and potentially seriously disabling. Accurate clinical identification of these drug-induced syndromes is critical to engaging the proper therapeutic intervention for them.

Neuroleptic malignant syndrome induced by atypical antipsychotics

A review of the English literature confirms that neuroleptic malignant syndrome (NMS) occurs with both traditional and atypical antipsychotic medications. Published reports of NMS induced by the traditional antipsychotics have given the practitioner valuable information on the prevention and treatment of this adverse effect. Case reports have also been published concerning NMS and clozapine, risperidone, olanzapine and quetiapine. By evaluating the case reports of atypical antipsychotic-induced NMS, valuable information may be obtained concerning similarities or differences from that induced by the traditional antipsychotics. The case reports of NMS with atypical antipsychotics were evaluated for diagnosis, age/sex of patient, risk factors, antipsychotic doses and duration of use, symptoms of NMS, and clinical course.

Effects of intrathecal injection of diatrizoate on dopamine receptors

RATIONALE AND OBJECTIVES

The authors performed this study to determine whether adverse reactions similar to those that occur in patients receiving antipsychotic medication may occur after inadvertent intrathecal injections of some contrast material.

MATERIALS AND METHODS

Recombinant human dopamine-2 (D-2) receptors were incubated together with tritiated (hydrogen 3) spiperone, a D-2 receptor agonist commonly used in binding studies, and three types of contrast material (sodium/meglumine diatrizoate; meglumine iothalamate; and iohexol) in different concentrations to determine competitive binding potentials. Nonspecific binding was also assessed. Membranes were washed, filtered, and counted in a scintillation counter.

RESULTS

At several different concentrations, diatrizoate demonstrated a potential to displace the binding of spiperone to the D-2 receptors, whereas the other two contrast materials tested (iothalamate meglumine and iohexol) showed only weak binding potentials.

CONCLUSION

Diatrizoate, which has been incriminated in most adverse reactions resulting from the inadvertent intrathecal injection of a contrast material, may produce symptoms similar to those of the neuroleptic malignant syndrome by blocking neurotransmission through dopamine receptors. Although antipsychotic drugs produce this parkinsonism-like effect only after prolonged use, it is probable that diatrizoate produces the effect immediately by virtue of the high concentrations that may accumulate at the base of the brain after myelography. Also worthy of note is the fact that the two other contrast materials that have produced a number of reported adverse reactions share a molecular similarity to diatrizoate that is not found with other contrast materials.

Olanzapine overdose with serum concentrations

Olanzapine, a new atypical antipsychotic drug, has been prescribed in the treatment of schizophrenia and psychotic mood disorders for approximately 2.3 million patients worldwide. Considering the increase in olanzapine prescriptions and the increased risk of suicide in this patient population, the number of reported cases of olanzapine overdose may be expected to increase. This report describes the clinical course and serum concentrations in a patient who consumed an olanzapine overdose (800 mg). Profound central nervous system depression and tachycardia without arrhythmia occurred within 2 hours after the ingestion. Additional clinical findings (ie, fever, mutism, agitation, dystonia, akathisia, elevated creatine kinase, and increased leukocyte count) were similar to those of neuroleptic malignant syndrome. After intubation, gut decontamination, and supportive care, the patient recovered and was discharged.

A veteran with acute mental changes years after combat

A 49-year-old man presented with a five-week history of worsening confusion, agitation, and bizarre behavior. According to his mother and sister, who live with him, he had inexplicably jumped out of bed one day and complained of injuring his back. The pain apparently resolved within several days. Two weeks later, again just after awakening, he had experienced a period of confusion, lasting about 15 min. The latest episode occurred three days previously and included vivid hallucinations--at various times, he seemed to believe that he was talking to his brother on the telephone, drinking a glass of water, emptying the refrigerator, jumping into a foxhole, and stomping on rattlesnakes. He was disoriented to time as well as environment.