Exertional rhabdomyolysis and heat stroke: Beware of volatile anesthetic sedation

Usefulness of sequential organ failure assessment score on admission to predict the 90-day mortality in patients with exertional heatstroke: An over 10-year intensive care survey

BACKGROUND AND OBJECTIVES

Despite a growing understanding of exertional heatstroke (EHS), there is a paucity of clinical evidence for risk-stratification of patients with EHS. The objective of this study was to identify an appropriate scoring system for prognostic assessment of EHS.

METHODS

This was a retrospective cohort study of all patients with EHS admitted to intensive care unit (ICU) of the General Hospital of Southern Theatre Command of PLA between October 2008 and May 2019. Inflammatory indices and organ function parameters at admission, the Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, Sequential Organ Failure Assessment (SOFA) scores, and Glasgow Coma Scale (GCS) score were collected. Risk factors for 90-day mortality were identified using multivariate Cox proportional hazard risk regression model.

RESULTS

189 patients (all male) were finally included, with a median age of 21.0 years (IQR 19.0-27.0), median APACHE II score of 11.0 (IQR 8.0-16.0), median SOFA score of 3.0 (IQR 2.0-6.0), and median GCS score of 12.0 (IQR 7.0-14.0). There were 166 survivors (87.8%) and 23 non-survivors (12.2%). Compared with survivor group, non-survivors had higher incidence of severe organ damage, including rhabdomyolysis (46.1% vs 63.6%), disseminated intravascular coagulation (25.6% vs 90.0%), acute liver injury (69.4% vs 95.7%), and acute kidney injury (36.6% vs 95.7%). Multivariate Cox risk regression model showed that SOFA score was an independent risk factor for 90-day mortality, with an optimal cutoff score of 7.5.

CONCLUSIONS

SOFA score may be a clinically useful predictor of death in EHS. Prospective studies are required to confirm the effectiveness of SOFA score and the optimal cutoff level.

RYR1-related rhabdomyolysis: a spectrum of hypermetabolic states due to ryanodine receptor dysfunction

Variants in the ryanodine receptor-1 gene (RYR1) have been associated with a wide range of neuromuscular conditions, including various congenital myopathies and malignant hyperthermia (MH). More recently, a number of RYR1 variants, mostly MH-associated, have been demonstrated to contribute to rhabdomyolysis events not directly related to anesthesia in otherwise healthy individuals. This review focuses on RYR1-related rhabdomyolysis, in the context of several clinical presentations (i.e., exertional rhabdomyolysis, exertional heat illnesses and MH), and conditions involving a similar hypermetabolic state, in which RYR1 variants may be present (i.e., neuroleptic malignant syndrome and serotonin syndrome). The variety of triggers that can evoke rhabdomyolysis, on their own or in combination, as well as the number of potentially associated complications, illustrates that this is a condition relevant to several medical disciplines. External triggers include but are not limited to strenuous physical exercise, especially if unaccustomed or performed under challenging environmental conditions (e.g., high ambient temperature or humidity), alcohol/illicit drugs, prescription medication (in particular statins, other anti-lipid agents, antipsychotics and antidepressants) infection, or heat. Amongst all patients presenting with rhabdomyolysis, a genetic susceptibility is present in a proportion, with RYR1 being one of the most common genetic causes. Clinical clues for a genetic susceptibility include recurrent rhabdomyolysis, creatine kinase (CK) levels above 50 times the upper limit of normal, hyperCKemia lasting for 8 weeks or longer, drug/medication doses insufficient to explain the rhabdomyolysis event, and a positive family history. For the treatment or prevention of RYR1-related rhabdomyolysis, the RYR1 antagonist dantrolene can be administered, both in the acute phase, or prophylactically in patients with a history of muscle cramps and/or recurrent rhabdomyolysis events. Aside from dantrolene, several other drugs are being investigated for their potential therapeutic use in RYR1-related disorders. These findings offer further therapeutic perspectives for humans, suggesting an important area for future research.

The relationship between 24-hour indicators and mortality in patients with exertional heat stroke

BACKGROUND

Exertional heat stroke (EHS) is a life-threatening illness that can lead to multiple organ damage in the early stage.

OBJECTIVE

This study aimed to investigate the relationship between 24-hour indicators and mortality in patients with EHS.

METHODS

The records of EHS patients hospitalized were collected and divided into the death group and the survival group. We then analyzed the demographic characteristics and APACHE II scores and laboratory results of the participants in the blood within the first 24 h after hospitalization, and assessed whether these candidate indicators differed between the death group and the survival group. Cox regression analysis of the survival data was performed to explore the relationship between early indicators and prognosis.

RESULTS

The levels of plasma PT, APTT, TT, and INR were significantly higher in the death group than in the survival group. The blood PLT count and the levels of PTA and Fb were significantly lower in the death group than in the survival group, while the levels of BU, SCr, ALT, AST, TBil, and DBil were significantly higher in the death group than in the survival group. Furthermore, the levels of Mb, LDH, TNI, and NT-proBNP were significantly higher in the death group than in the survival group, while there was no significant difference in CK levels between the two groups.

CONCLUSION

Patients with EHS often had multiple organ injuries in the early stage (within 24 h), while those cases in the death group were more severe.

Repetitive Bouts of Exhaustive Exercise Induces a Systemic Inflammatory Response and Multi-Organ Damage in Rats

Multiple organ dysfunction syndrome can follow severe infection or injury, but its relationship to exercise is not well understood. Previous studies have observed that prolonged strenuous exercise can lead to transiently increased level and/or activity of markers for systemic inflammatory response and multiple organ damage. However, few studies have analyzed the pathogenesis of the inflammatory response and subsequent multi-organ injury in exhaustive exercise conditions. In this study, we established a rat model of repetitive bouts of exhaustive running (RBER) and investigated its effects on multiple organ damage. Rats were subjected to RBER in either uphill or downhill running modes daily for a period of 7 days. Morphologically, RBER causes tissue structural destruction and infiltration of inflammatory cells in the skeletal muscles and many visceral organs. RBER also causes sustained quantitative changes in leukocytes, erythrocytes, and platelets, and changes in the concentration of blood inflammatory factors. These inflammatory alterations are accompanied by increases in serum enzyme levels/activities which serve as functional markers of organ damage. In general, RBER in the downhill mode seemed to cause more damage evaluated by the above-mentioned measures than that produced in the uphill mode. A period of rest could recover some degree of damage, especially for organs such as the heart and kidneys with strong compensatory capacities. Together, our data suggest that, as a result of multi-organ interactions, RBER could cause a sustained inflammatory response for at least 24 h, resulting in tissue lesion and ultimately multiple organ dysfunction.

Exertional rhabdomyolysis: Relevance of clinical and laboratory findings, and clues for investigation

Some degree of exertional rhabdomyolysis (ER), striated muscle breakdown associated with strenuous exercise, is a well-known phenomenon associated with endurance sports. However in rare cases, severe and/or recurrent ER is a manifestation of an underlying condition, which puts patients at risk for significant morbidity and mortality. Selecting the patients that need a diagnostic work up of an acute rhabdomyolysis episode is an important task.

Based on the diagnostic work up of three illustrative patients treated in our hospital, retrospectively using the ‘RHABDO’ screening tool, we discuss the clinical and biochemical clues that should trigger further investigation for an underlying condition. Finally, we describe the most common genetic causes of this clinical syndrome.