Drug-induced hyperthermia and muscle rigidity: a practical approach

Neuroleptic malignant syndrome and serotonin syndrome: a comparative bibliometric analysis

OBJECTIVE

This study aimed to analyze and map scientific literature on Neuroleptic Malignant Syndrome (NMS) and Serotonin Syndrome (SS) from prestigious, internationally indexed journals. The objective was to identify key topics, impactful articles, prominent journals, research output, growth patterns, hotspots, and leading countries in the field, providing valuable insights for scholars, medical students, and international funding agencies.

METHODS

A systematic search strategy was implemented in the PubMed MeSH database using specific keywords for NMS and SS. The search was conducted in the Scopus database, renowned for its extensive coverage of scholarly publications. Inclusion criteria comprised articles published from 1950 to December 31st, 2022, restricted to journal research and review articles written in English. Data were analyzed using Microsoft Excel for descriptive analysis, and VOSviewer was employed for bibliometric mapping.

RESULTS

The search yielded 1150 articles on NMS and 587 on SS, with the majority being case reports. Growth patterns revealed a surge in NMS research between 1981 and 1991, while SS research increased notably between 1993 and 1997. Active countries and journals differed between NMS and SS, with psychiatry journals predominating for NMS and pharmacology/toxicology journals for SS. Authorship analysis indicated higher multi-authored articles for NMS. Top impactful articles focused on review articles and pathogenic mechanisms. Research hotspots included antipsychotics and catatonia for NMS, while SS highlighted drug interactions and specific medications like linezolid and tramadol.

CONCLUSIONS

NMS and SS represent rare but life-threatening conditions, requiring detailed clinical and scientific understanding. Differential diagnosis and management necessitate caution in prescribing medications affecting central serotonin or dopamine systems, with awareness of potential drug interactions. International diagnostic tools and genetic screening tests may aid in safe diagnosis and prevention. Reporting rare cases and utilizing bibliometric analysis enhance knowledge dissemination and research exploration in the field of rare drug-induced medical conditions.

Drug-associated hyperthermia: A longitudinal analysis of hospital presentations

WHAT IS KNOWN AND OBJECTIVE

Hyperthermia occurs when heat accumulation surpasses the body's ability for heat dissipation. Many drugs can affect thermoregulation through mechanisms including altering the neurotransmitters that cause increased heat production or decreased heat loss and may, therefore, be associated with hyperthermia. This study aimed to examine hospitalizations and emergency department (ED) presentations due to hyperthermia and to investigate the potential association with drug therapy.

METHODS

A retrospective analysis of ED presentations and hospitalizations due to hyperthermia in all four major hospitals in Tasmania, Australia, between July 2010 and December 2018 was performed. Data of patients aged ≥18 years were extracted from the hospital digital medical records and analysed for the prevalence, trends and various potential risk factors for hyperthermia, such as age, environmental temperature and drug therapy.

RESULTS

This study included 224 patients. The data illustrated a trend with time, albeit not statistically significant, towards increasing hospital presentations due to hyperthermia. Antiepileptics (P = .03) and furosemide (P = .04) were the most frequently used drugs in patients with primary hyperthermia. The high use of levothyroxine in the study population (6.7%) stood out compared with the estimated national average (2.1%). Various drug classes associated with hyperthermia were used significantly more in the age group ≥60 years, suggesting polypharmacy in the elderly as a contributing factor for hyperthermia.

WHAT IS NEW AND CONCLUSION

This study reports a possible association of some drugs, particularly diuretics (furosemide), antiepileptics and levothyroxine, with hyperthermia. Healthcare professionals should be aware of the increasing prevalence of hyperthermia and the possible involvement of drugs.

The hot patient: acute drug-induced hyperthermia

Drugs can cause dysregulation of the hypothalamic–pituitary–adrenal axis which can result in a rise in core temperature This type of hyperthermia is unresponsive to antipyretics and can be complicated by rhabdomyolysis multi-organ failure and disseminated intravascular coagulation

Organic causes of fever such as infection must be ruled out Syndromes associated with drug-induced fever include neuroleptic malignant syndrome and anticholinergic sympathomimetic and serotonin toxicity

The class of offending drugs as well as the temporal relationship to starting or stopping them assists in differentiating between neuroleptic malignant syndrome and serotonin toxicity

Immediate inpatient management is needed The mainstay of management is stopping the drug and supportive care often in the intensive care unit

Pure distraction injury of T1-2 with quad fever

INTRODUCTION

We report a pure distraction injury of the upper thoracic spine and uncontrolled hyperthermia without an infectious cause. Quad fever appears in the first several weeks to months after a cervical or upper thoracic SCI and is characterized by an extreme elevation in body core temperature beyond 40 °C without an infectious cause. Discriminating between infectious and noninfectious causes is important, and a thorough clinical assessment is required.

MATERIALS AND METHODS

A 52-year-old male visited the emergency room complaining of back pain with complete paralysis [American Spinal Injury Association (ASIA) A] of both lower extremities after a pedestrian-motor vehicle accident. He had trouble breathing due to a hemothorax and flail chest caused by fractures of the right second to eleventh and left fourth to seventh ribs. A computed tomography scan revealed severe distraction of the T1-2 intervertebral space. A magnetic resonance image showed signal changes in the spinal cord and a clean-cut margin between the T1-2 disc and T2 body. The neurological level of injury was C8 upon the initial neurological assessment. Emergency surgery was performed. C6-T3 posterior instrumentation and an autologous iliac bone graft were performed.

RESULTS

After surgery, the core temperature increased gradually to above 38.0 °C on post-trauma day 4 and increased to 40.8 °C on post-trauma day 7. None of the repeated aerobic, anaerobic, or fungal cultures of the blood, tracheal aspirate, line tips, urine, or stool was positive until post-trauma day 21, when Candida tropicalis was identified in the urine culture. On post-trauma day 63, the blood pressure, pulse, and body temperature stabilized and the patient was transferred to the general ward. At post-trauma year 6, the injury state was still complete and the neurological level of injury was changed to C4.

CONCLUSIONS

Based on the Grand Round case and relevant literature, we discuss the case of pure distraction injury of T1-2 with quad fever. Spinal surgeons should be knowledgeable regarding quad fever as well as the differential diagnoses and treatment strategies.

Neuroleptic Malignant Syndrome/Malignant Catatonia in Child Psychiatry: Literature Review and a Case Series

OBJECTIVE

To describe the presentation of neuroleptic malignant syndrome (NMS) and malignant catatonia (MC) in children and adolescents.

BACKGROUND

NMS and MC are life-threatening, neuropsychiatric syndromes, associated with considerable morbidity and mortality. NMS is diagnosed when there is a recent history of treatment with an antipsychotic (AP) medication, while MC is diagnosed when the symptoms resemble NMS but without a history of exposure to an AP agent. Some authorities believe that apart from the history of exposure to an AP medication, the two conditions are identical. The symptoms of NMS/MC include severe agitation, behavior disregulation, motor and speech changes, self-injury and aggression, autonomic instability, and a range of psychiatric symptoms (affective, anxiety, or psychotic symptoms). Patients may be misdiagnosed with another disorder leading to extensive tests and a delay in treatment. Untreated, the condition may be fatal in 10%-20% of patients, with death sometimes occurring within days of disease onset.

METHOD

We describe the presentation and management of five children and adolescents with NMS/MC.

CONCLUSION

MC and NMS are life-threatening medical emergencies, which if diagnosed promptly, can be successfully treated with known effective treatments (benzodiazepines and/or electroconvulsive therapy).

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.

Diagnosis and treatment of drug-induced hyperthermia

PURPOSE

The etiology, pathophysiology, clinical presentation, and management of drug-induced hyperthermia (DIH) syndromes are reviewed.

SUMMARY

DIH syndromes are a rare and often overlooked cause of body temperature elevation and can be fatal if not recognized promptly and managed appropriately. There are five major DIH syndromes: (1) neuroleptic malignant syndrome, (2) serotonin syndrome, (3) anticholinergic poisoning, (4) sympathomimetic poisoning, and (5) malignant hyperthermia. The differential diagnosis of DIH syndromes can be challenging because symptoms are generally nonspecific, ranging from blood pressure changes and excessive sweating to altered mental status, muscle rigidity, convulsions, and metabolic acidosis. Evidence from the professional literature (per a MEDLINE search for articles published through November 2011) indicates that few currently available treatment options can reduce the duration of hyperthermia; therefore, prompt identification of the provoking agent based on the patient's medication history, the clinical presentation, and the timing of symptom onset is essential to determine the appropriate treatment and mitigate potentially life-threatening sequelae. For all DIH syndromes, appropriate management includes the immediate discontinuation of the suspected offending agent(s) and supportive care (external cooling, volume resuscitation as needed); in some cases, pharmacologic therapy (e.g., a benzodiazepine, bromocriptine, dantrolene) may be appropriate, with the selection of a specific agent primarily determined by the medication history and suspected DIH syndrome.

CONCLUSION

DIH is a hypermetabolic state caused by medications and other agents that alter neurotransmitter levels. The treatment of DIH syndromes includes supportive care and pharmacotherapy as appropriate.

Incidence, etiology, and outcomes of rhabdomyolysis in a single tertiary referral center

We have encountered numerous cases of rhabdomyolysis associated with acute pesticide intoxication; however, the cause, incidence, and treatment outcomes of rhabdomyolysis have not been studied. The current study involved 2,125 patients hospitalized with acute chemical poisoning. Based on clinical and laboratory parameters and treatment outcomes, we found that overall incidence of rhabdomyolysis in our hospital was 0.06% (93 of 143,830 patients admitted), but the incidence associated with acute pesticide intoxication was 1.8% (33 of 1,793 cases). The incidence of rhabdomyolysis after pesticide intoxication was significantly higher in men than in women (P = 0.010). The amount of pesticide ingested was significantly higher in rhabdomyolysis patients than that in those who did not develop rhabdomyolysis (mean ± SD, 114.1 ± 79.5 mL vs 74.1 ± 94.2 mL, P = 0.010). Our results show that pesticide intoxication is a frequent cause of rhabdomyolysis and is more common among men than women. The volume of pesticide ingested, and not the degree of human toxicity, is the main factor influencing the incidence of rhabdomyolysis.

[Pharmacologically-induced neurocatastrophes]

Drug-induced adverse reactions represent a significant health problem in developed countries. These events cause 5% of hospital admissions and are one of the main causes of mortality. Neurological manifestations are among the most frequent. This article reviews catastrophic cerebrovascular situations and confusional syndromes, as well as epilepsy, structural encephalopathy, neuromuscular disorders, catastrophic movement disorders and infections, all of which can be drug-induced.

Neuroleptic Malignant Syndrome: Severe Hyperthermia Treated with Endovascular Cooling

We report a patient with neuroleptic malignant syndrome who presented with the characteristic features of altered mental state, hyperthermia, haemodynamic dysregulation, elevated creatine kinase and subsequently increased muscle rigidity. The hyperthermia was refractory to standard cooling techniques and dantrolene but was rapidly corrected using an endovascular cooling device. He recovered from this life-threatening condition but required ongoing renal replacement support following discharge from the intensive care unit.

Zuclopenthixol-induced neuroleptic malignant syndrome presenting as fever of unknown origin, hyperglycaemia and acute myocardial infarction in a 60-year-old man

Neuroleptic malignant syndrome (NMS) is a rare clinical condition and potentially life-threatening complication of antipsychotic medications. We report a patient with an atypical presentation of NMS. A 60-year-old man with schizophrenia was admitted to our hospital with disturbed consciousness, fever and marked extrapyramidal rigidity both in the upper and lower extremities. He had been given i.m. zuclopenthixol 200 mg/month but had not taken the last dose. Laboratory investigations showed that creatinine phosphokinase 428 IU/l (normal up to 130), lactate dehydrogenase 772 IU/l (normal up to 450), blood glucose 256 mg/dl (65-110). Urine analyses revealed ketonuria. White blood cell (WBC) count was 6100 cells/mm(3). Therefore, the patient was diagnosed as having NMS and antipsychotic medications were stopped. Adequate hydration was provided and bromocryptine 5 mg was started three times a day. Despite treatment, the patient died due to acute myocardial infarction after 3 days of hospitalization.

Fatal fever of unknown origin in acute cervical spinal cord injury: five cases

BACKGROUND/OBJECTIVE

Patients with traumatic upper thoracic and cervical spinal cord injuries are at increased risk for the development of autonomic dysfunction, including thermodysregulation. Thermoregulation is identified as an autonomic function, although the exact mechanisms of thermodysregulation have not been completely recognized. Quad fever is a hyperthermic thermoregulatory disorder that occurs in people with acute cervical and upper thoracic spinal cord injuries. First described in 1982, it has not been widely discussed in the literature.

METHODS

Case reports of 5 patients with cervical spinal cord injury (SCI).

RESULTS

Five of 18 patients (28%) with acute cervical SCI who were admitted during a 1-year period had fatal complications caused by persistent hyperthermia of unknown origin.

CONCLUSIONS

Patients with acute traumatic cervical and upper thoracic SCI are at risk for thermoregulatory dysfunction. Changes in the hypothalamic axis may be implicated, especially in the light of modification in hypothalamic afferent nerves, but this hypothesis has not yet been explored. Thermodysregulation may be an early sign of autonomic dysfunction. A comprehensive guideline is needed for the management of elevated body temperature in critically ill patients with cervical SCI, because this condition may be fatal.

Hyperthermia increases the cytotoxicity of many exogenous compounds

Cytotoxicity testing of extracts from medical device materials is typically conducted at 37 degrees C. It may be more relevant to screen extracts from device materials for in vitro cytotoxicity at temperatures found in febrile patients. To address this, the cytotoxicity of selected chemicals, drugs, and medical device extracts was evaluated in vitro following incubation at normothermic (37 degrees C) and hyperthermic (39 degrees C) conditions. In L929 cells, the percentage of cell death increased from 2-fold to more than 4-fold after chemical exposure when cells were maintained at 39 degrees C. Extracts of some medical devices and materials showed a 10-fold increase in cytotoxicity when cells were maintained at 39 degrees C as compared to 37 degrees C. For many of the substances in this study, exogenous compounds that are toxic at normothermic conditions (37 degrees C) are more cytotoxic under hyperthermic conditions (39 degrees C). The toxicity of compounds was more readily discernable at the higher incubation temperature, even at lower concentrations. In vitro cytotoxicity testing of chemicals and extracts at febrile temperatures can provide more sensitive and relevant biocompatibility tests than under normothermic conditions alone.

Bench-to-bedside review: mechanisms and management of hyperthermia due to toxicity

Body temperature can be severely disturbed by drugs capable of altering the balance between heat production and dissipation. If not treated aggressively, these events may become rapidly fatal. Several toxins can induce such non-infection-based temperature disturbances through different underlying mechanisms. The drugs involved in the eruption of these syndromes include sympathomimetics and monoamine oxidase inhibitors, antidopaminergic agents, anticholinergic compounds, serotonergic agents, medicaments with the capability of uncoupling oxidative phosphorylation, inhalation anesthetics, and unspecific agents causing drug fever. Besides centrally disturbed regulation disorders, hyperthermia often results as a consequence of intense skeletal muscle hypermetabolic reaction. This leads mostly to rapidly evolving muscle rigidity, extensive rhabdomyolysis, electrolyte disorders, and renal failure and may be fatal. The goal of treatment is to reduce body core temperature with both symptomatic supportive care, including active cooling, and specific treatment options.

Endovascular cooling in a patient with neuroleptic malignant syndrome

We report a case of severe neuroleptic malignant syndrome with hyperthermia, rhabdomyolysis and hepatic failure where we applied endovascular cooling in order to reverse hyperthermia. After rapid normalization of core temperature at 37.5 degrees C, the patient's condition improved and CK levels dropped. However, upon withdrawl of endovascular temperature control there was a relapse. This is the first case where endovascular cooling was applied successfully in neuroleptic malignant syndrome.

Methods to produce hyperthermia-induced brain dysfunction

The recent increase in the frequency and intensity of killer heat waves across the globe has aroused worldwide medical attention to exploring therapeutic strategies to attenuate heat-related morbidity and/or mortality. Death due to heat-related illnesses often exceeds >50% of heat victims. Those who survive are crippled with lifetime disabilities and exhibit profound cognitive, sensory, and motor dysfunction akin to premature neurodegeneration. Although more than 50% of the world populations are exposed to summer heat waves; our understanding of detailed underlying mechanisms and the suitable therapeutic strategies have still not been worked out. One of the basic reasons behind this is the lack of a reliable experimental model to simulate clinical hyperthermia. This chapter describes a suitable animal model to induce hyperthermia in rats (or mice) comparable to the clinical situation. The model appears to be useful for studying the effects of heat-related illnesses on changes in various organs and systems, including the central nervous system (CNS). Since hyperthermia is often associated with profound brain dysfunction, additional methods to examine some crucial parameters of brain injury, e.g., blood-brain barrier (BBB) breakdown and brain edema formation, are also described.

[Medically induced myopathia]

Muscular side effects of various anesthetics, analgetics, antibiotics, antihistaminic drugs, antiretrovirals, cardiotropics, immunosuppressants, lipid-lowering drugs, psychotropic drugs, anticancer drugs, and other substances are more frequent than assumed and are easily overlooked. Clinically, muscular side effects manifest as fatigue, myalgias, persistent or transient weakness, stiffness, intolerance to exercise, psychomotor slowing, muscle cramps, wasting, dyspnea, dysphagia, fasciculations, reduced tendon reflexes, impaired consciousness, myoglobinuria, renal failure, or hyperthermia. Diagnosis of these drug-induced myopathies is based on history, clinical neurologic examination, blood work, urine analysis, repetitive stimulation, electromyography, and muscle biopsy. A drug which induces muscular side effects should never be given again. Particularly in patients suffering from primary myopathy, myotoxic drugs should be applied with caution. The drugs which most frequently induce muscular side effects are steroids, statins, fibrates, antiretrovirals, immunosuppressants, colchicine, amiodarone, and anticancer drugs. Many drugs exhibit their myotoxic potential only in combination with other drugs or premorbid pathologic myogenic conditions.

UCP3 and thyroid hormone involvement in methamphetamine-induced hyperthermia

Here, we determined the extent of hypothalamic-pituitary-thyroid (HPT) axis and uncoupling protein-3 (UCP3) involvement in methamphetamine (METH)-induced hyperthermia. Sprague-Dawley rats treated with METH (40mg/kg, s.c.) responded with a hyperthermic response that peaked 1h post-treatment and was sustained through 2h. After METH treatment, thyroparathyroidectomized (TX) animals developed hypothermia that was sustained for the 3h monitoring period. In TX animals supplemented for 5 days with levothyroxine (100microg/kg, s.c.), METH-induced hypothermia was eliminated and the hyperthermic response was restored. Thyroid hormone levels (T3 and T4), measured in euthyroid animals 1h after METH, remained unchanged. As seen in rats, 1h post-METH (20mg/kg, i.p.) treatment, wild-type (WT) mice developed profound hyperthermia that was sustained for 2h. In marked contrast, UCP3-/- animals developed a markedly blunted hyperthermic response at 1h compared to WT animals. Furthermore, UCP3-/- mice could not sustain this slight elevation in temperature. Two hours post-METH treatment, UCP3-/- animal temperature returned to baseline temperatures. UCP3-/- mice were also completely protected against the lethal effects of METH, whereas 40% of WT mice succumbed to the hyperthermia. These findings suggest that thyroid hormone plays a permissive role in the thermogenic effects induced by METH. Furthermore, the findings indicate that UCP3 plays a major role in the development and maintenance of the hyperthermia induced by METH. The relationship of these results to the hyperthermia induced by 3,4-methylenedioxymethamphetamine (MDMA) is also discussed.