The treatment of neuroleptic malignant syndrome using dantrolene sodium

Toxicological Emergencies

Poisoning, drug overdose, and adverse drug effects continue to be a common encounter, especially in the intensive care unit (ICU). Patients are often critically ill or have a potential to rapidly deteriorate and warrant ICU admission. Adults suffering from overdoses rarely give a complete and accurate description of the quantity or type of medications ingested. In most adult cases, multiple substances are involved. A tentative diagnosis in most overdose and poisoning cases can be made by physical examination and simple laboratory tests (electrolyte panel, creatinine, serum osmolarity, urinalysis, etc). Supportive care, with particular attention to airway management, oxygenation, and circulation, is the mainstay of treatment. Basic treatment principles include limiting the amount of toxin absorbed, enhancing the elimination of ingested toxin, and preventing the conversion of non-toxic compounds to toxic metabolites. Drugs or poisons, where specific antidotes or effective therapies exist (especially acetaminophen, salicylates, methanol, ethylene glycol, and digitalis), should be aggressively sought and treated after initial stabilization has been accomplished. For those drugs or poisons where specific quantitative tests are available, levels should be obtained before treatment and may be repeated as clinically indicated.

Intravenous dantrolene in hypermetabolic syndromes: a survey of the U.S. Veterans Health Administration database

BACKGROUND

Intravenous dantrolene is often prescribed for hypermetabolic syndromes other than the approved indication of malignant hyperthermia (MH). To clarify the extent of and indications for dantrolene use in conditions other than MH, we sought to document current practices in the frequency, diagnoses, clinical characteristics and outcomes associated with dantrolene treatment in critical care settings.

METHODS

Inpatients receiving intravenous dantrolene from October 1, 2004 to September 30, 2014 were identified retrospectively in the U.S. Veterans Health Administration national database. Extracted data included; diagnoses of hypermetabolic syndromes; triggering drugs; dantrolene dosages; demographics; vital signs; laboratory values; in-hospital mortality; complications; and lengths of stay. Frequency and mortality of patients who did not receive dantrolene were obtained in selected diagnoses for exploratory comparisons.

RESULTS

Dantrolene was administered to 304 inpatients. The most frequent diagnoses associated with dantrolene treatment were neuroleptic malignant syndrome (NMS; N = 108, 35.53%) and sepsis (N = 47, 15.46%), with MH accounting for only 13 (4.28%) cases. Over half the patients had psychiatric comorbidities and received psychotropic drugs before dantrolene treatment. Common clinical findings in patients receiving dantrolene included elevated temperature (mean ± SD; 38.7 ± 1.3 °C), pulse (116.33 ± 22.80/bpm), respirations (27.75 ± 9.58/min), creatine kinase levels (2,859.37 ± 6,646.88 IU/L) and low pO₂ (74.93 ± 40.16 mmHg). Respiratory, renal or cardiac failure were common complications. Mortality rates in-hospital were 24.01% overall, 7.69% in MH, 20.37% in NMS and 42.55% in sepsis, compared with mortality rates in larger and possibly less severe groups of unmatched patients with MH (5.26%), NMS (6.66%), or sepsis (41.91%) who did not receive dantrolene.

CONCLUSIONS

In over 95% of cases, dantrolene administration was associated with diagnoses other than MH in critically-ill patients with hypermetabolic symptoms and medical and psychiatric comorbidities. Exploratory survey data suggested that the efficacy and safety of dantrolene in preventing mortality in hypermetabolic syndromes other than MH remain uncertain. However, randomized and controlled studies using standardized criteria between groups matched for severity are essential to guide practice in using dantrolene.

Neuroleptic malignant syndrome in a postoperative patient: A case report

Neuroleptic malignant syndrome is a rare medical emergency associated with the use of antipsychotics and other antidopaminergic drugs. There is no specific test, and diagnosis is based on high clinical suspicion and good differential diagnosis. A clinical picture consistent with hyperthermia, muscle rigidity, altered level of consciousness, together with signs of rhabdomyolysis in analytical studies and a history of taking neuroleptic drugs are the key elements in the detection of this entity. Due to its low incidence and potential mortality, it is essential to publish case reports of neuroleptic malignant syndrome in order to raise awareness of this entity and facilitate diagnostic suspicion when encountering a patient with compatible symptoms. The following is the case of a 79 year old patient with chronic alcohol consumption as the only history of interest, who was given a single dose of haloperidol after an episode of delirium in the postoperative period of conventional trauma surgery. She subsequently developed a picture of progressive deterioration of the level of consciousness, diaphoresis, generalized muscle rigidity, hyperthermia, together with severe metabolic acidosis, hyperlacticaemia, rhabdomyolysis, hypertransaminasemia and hypocalcemia. After ruling out other entities compatible with the clinical picture, neuroleptic malignant syndrome was given as the main diagnostic hypothesis. Diagnosis was confirmed after clinical and analytical improvement following treatment with dantrolene. The patient was discharged from hospital with no sequelae a few days after onset of the condition.

Neuroleptic malignant syndrome in a postoperative patient: a case report

Neuroleptic malignant syndrome is a rare medical emergency associated with the use of antipsychotics and other antidopaminergic drugs. There is no specific test, and diagnosis is based on high clinical suspicion and good differential diagnosis. A clinical picture consistent with hyperthermia, muscle rigidity, altered level of consciousness, together with signs of rhabdomyolysis in analytical studies and a history of taking neuroleptic drugs are the key elements in the detection of this entity. Due to its low incidence and potential mortality, it is essential to publish case reports of neuroleptic malignant syndrome in order to raise awareness of this entity and facilitate diagnostic suspicion when encountering a patient with compatible symptoms. The following is the case of a 79 year old patient with chronic alcohol consumption as the only history of interest, who was given a single dose of haloperidol after an episode of delirium in the postoperative period of conventional trauma surgery. She subsequently developed a picture of progressive deterioration of the level of consciousness, diaphoresis, generalized muscle rigidity, hyperthermia, together with severe metabolic acidosis, hyperlacticaemia, rhabdomyolysis, hypertransaminasemia and hypocalcemia. After ruling out other entities compatible with the clinical picture, neuroleptic malignant syndrome was given as the main diagnostic hypothesis. Diagnosis was confirmed after clinical and analytical improvement following treatment with dantrolene. The patient was discharged from hospital with no sequelae a few days after onset of the condition.

Neuroleptic malignant syndrome: a guide for psychiatrists

Neuroleptic malignant syndrome (NMS) is a rare and potentially fatal adverse reaction to drugs. In psychiatric practice, it is mainly associated with antipsychotics. The classic presentation is that of hyperpyrexia, muscle rigidity, mental state changes and autonomic instability. Subtle forms are difficult to recognise owing to symptom overlap with other conditions. This article discusses the clinical presentation of the syndrome, its differential diagnosis and use of supportive care, medication and electroconvulsive therapy in its treatment. It also explores prevention of NMS and reinstatement of treatment after an episode. It is stressed that all but the mildest forms of NMS should be considered a medical emergency that is properly managed in an acute hospital.

The neuroleptic malignant syndrome-a systematic case series analysis focusing on therapy regimes and outcome

INTRODUCTION

Neuroleptic malignant syndrome (NMS) is a rare, potentially life-threatening antipsychotic-associated disorder that requires an efficient and timely therapy. The aim of the study was to compare the effectiveness of different NMS therapies and to analyze its outcome depending on NMS severity.

METHOD

Systematic search for NMS cases in biomedical databases. The focus of the analysis was on therapy with dantrolene, bromocriptine, and electroconvulsive therapy (ECT) when each was compared with symptomatic therapy. Primary outcomes were the survival rate and the duration of treatment.

RESULT

405 case reports were included. Overall, no statistically significant differences regarding mortality rate or duration of treatment were found between dantrolene, bromocriptine, or ECT compared to supportive care. A subgroup analysis regarding NMS severity showed that the mortality under specific NMS pharmacotherapy (dantrolene, bromocriptine) and under ECT was significantly lower than under purely symptomatic therapy in severe NMS (P = 0.018). The difference was not significant in mild and moderate cases.

DISCUSSION

An overall superiority of the specific NMS therapy (dantrolene, bromocriptine, and ECT) was not found in this study. When regarding severity classification, specific therapies were superior but only in severe cases, and ECT showed the lowest mortality rate. In previous case series, an effect on survival or the duration of the disease could only be observed in part for specific therapies, but the evidence available is inconsistent. The results of this study support our hypothesis that NMS treatment with dantrolene, bromocriptine, and ECT is advantageous over purely symptomatic therapy in severe NMS cases.

Electroconvulsive Therapy for Neuroleptic Malignant Syndrome: A Case Series

OBJECTIVES

Neuroleptic malignant syndrome (NMS) is an uncommon condition associated with significant morbidity and mortality. Data on treatment interventions are limited. In this case series, we sought to describe all NMS cases requiring ECT from a large academic institution over a nearly 2-decade period.

METHODS

We retrospectively identified all patients with NMS who were treated with ECT over a 17-year period. Patients were included in the study based on chart review using the International Consensus Diagnostic Criteria for NMS. Data were collected related to clinical findings, treatment course, and response to ECT.

RESULTS

We identified 15 patients meeting the inclusion criteria. Most patients had neurocognitive or schizophrenia spectrum disorders and developed NMS after exposure to multiple antipsychotic drugs. All patients received bitemporal ECT after failed pharmacotherapy for NMS. Electroconvulsive therapy was well tolerated and resulted in a remission rate of 73.3% (n = 11). Patients showed early initial response to ECT (mean of 4.2 treatments), but an average of 17.7 treatments was necessary to minimize recurrence of catatonic signs. One patient died after interruption of the index course of ECT because of severe infection, and another was discharged to hospice care after limited response. These cases highlight the lethality of NMS and its complications despite aggressive treatment measures.

CONCLUSIONS

Bitemporal ECT was well tolerated and effective in treating NMS refractory to pharmacotherapy. We suggest that ECT be considered early in cases of NMS that are refractory to pharmacological interventions, especially if the underlying condition is also responsive to ECT.

Acute Dystonic Reaction and the Neuroleptic Malignant Syndrome

Up to 90% of patients on chronic antipsychotic therapy will experience adverse neurologic side effects, with many of these effects attributable to the dopamine-blocking properties of these drugs. Even the newer, “atypical” antipsychotics are increasingly associated with neurologic complications. In the acute care setting, these medications have broad application beyond the management of psychiatric illness. Given the extent of their use, clinicians should be familiar with the spectrum of neurological syndromes that can develop. Some are common, such as akathisia, acute dystonic reaction, tardive dyskinesia, and drug-induced parkinsonism. Others, such as the life-threatening neuroleptic malignant syndrome, are rare yet must be recognized early to affect survival and improve outcome. This discussion highlights 2 idiosyncratic syndromes, acute dystonic reaction and neuroleptic malignant syndrome. The differential diagnosis for both syndromes and their management is discussed.

Malignant hyperthermia and the clinical significance of type-1 ryanodine receptor gene (RYR1) variants: proceedings of the 2013 MHAUS Scientific Conference

The Malignant Hyperthermia Association of the United States and the Department of Anesthesia at the University of Toronto sponsored a Scientific Conference on November 1-2, 2013 in Toronto, ON, Canada. The multidisciplinary group of experts, including clinicians, geneticists, and physiologists involved in research related to malignant hyperthermia (MH), shared new insights into the pathophysiology of diseases linked to the type-1 ryanodine receptor gene (RYR1) as well as the relationship between MH and "awake MH" conditions, such as exertional rhabdomyolysis and exertional heat illness. In addition, the molecular genetics of MH and clinical issues related to the diagnosis and management of disorders linked to RYR1 were presented. The conference also honoured Dr. David H. MacLennan for his contributions to our understanding of the genetics, pathogenesis, and treatment of MH and other RYR1-related myopathies. This report represents a summary of the proceedings of this conference.

Fatal neuroleptic malignant syndrome in a previously long-term user of clozapine following its reintroduction in combination with paroxetine

A 77-year-old patient with initial behavioral and psychological symptoms of dementia was treated with clozapine (50 mg/daily). Since no clinical benefit was apparent, clozapine was discontinued after six weeks and the patient started on paroxetine (20 mg/daily). After three weeks on paroxetine, he was given another trial of clozapine at a starting dosage of 25 mg/daily. While clozapine had previously been well tolerated, this time he rapidly developed fever, mental confusion, lethargy, muscle spasms and rigidity. The diagnosis of neuroleptic malignant syndrome was delayed, because there was no leukocytosis and serum creatine phosphokinase was initially not elevated. Subcutaneous apomorphine was then given but, after an initial improvement, the patient developed a multiple organ failure syndrome and died.

Efficacy of methylprednisolone pulse therapy on neuroleptic malignant syndrome in Parkinson's disease

BACKGROUND

Neuroleptic malignant syndrome (NMS) is a dangerous complication in patients with Parkinson's disease (PD).

AIMS

To evaluate the efficacy of methylprednisolone pulse therapy compared to placebo in PD patients with NMS.

METHODS

In a double blind, placebo controlled study, 20 PD patients with NMS received steroid pulse therapy for three days, and 20 PD patients received placebo. Both groups received levodopa, bromocriptine, and dantrolene.

RESULTS

NMS in the steroid group healed within 10 days in 17 patients; median value of duration of illness of NMS in this group was 7 days (range 4-20). NMS in the placebo group healed within 10 days in five patients; in the remaining 15, it persisted for 12-27 days after the onset of NMS; median value of duration illness of NMS in this group was 18 days. Hyperthermia, rigidity, and consciousness improved within 10 days in many patients in the steroid group; these signs persisted more than 10 days in many patients in the placebo group.

CONCLUSIONS

Steroid pulse therapy is useful in NMS for reducing the illness duration and improving symptoms.

Treatment of neuroleptic malignant syndrome with subcutaneous apomorphine monotherapy

A 20-year-old psychiatric patient receiving haloperidol treatment developed acute-onset fever, rigidity, and mental changes. Subcutaneous apomorphine was given alone for treatment. The patient had rapid clinical improvement after the treatment. Serial blood examinations showed decline and subsequent normalization of the creatine phosphokinase levels.

The neuroleptic malignant and serotonin syndromes

The neuroleptic malignant syndrome and the serotonin syndrome share many clinical features and may exist on a spectrum of the same disorder. The neuroleptic malignant syndrome, however, is an idiosyncratic drug reaction, whereas the serotonin syndrome is an effect of drug toxicity. Both syndromes present with varying degrees of mental status changes and autonomic instability. In general, patients with the neuroleptic malignant syndrome have higher fevers and pronounced extrapyramidal signs with muscle rigidity, whereas patients with the serotonin syndrome have lower fevers, more gastrointestinal dysfunction, and myoclonus. Treatment for both syndromes consists of removing the offending agent and providing intensive supportive care. Syndrome-specific therapies are controversial.