Improved Detection of Heat Stroke-Induced Brain Injury by High B-Value Diffusion-Weighted Imaging:

Risk factors for brain injury in patients with exertional heatstroke: A 5-year experience

PURPOSE

Minimal data exist on brain injury in patients with exertional heatstroke (EHS) in developing country. In this study, we explored the risk factors for brain injury induced by EHS 90-day after onset.

METHODS

A retrospective cohort study of patients with EHS was conducted in the intensive care unit of the General Hospital of Southern Theater Command of PLA in China from April 2014 to June 2019. Patients were divided into non-brain injury (fully recovered) and brain injury groups (comprising deceased patients or those with neurological sequelae). The brain injury group was further subdivided into a death group and a sequela group for detailed analysis. General information, neurological performance and information on important organ injuries in the acute stage were recorded and analysed. Multivariable logistic regression was used to identify risk factors for brain injury after EHS and mortality risk factors for brain injury, and Kaplan-Meier survival curve was used to evaluate the effect of the neurological dysfunction on survival.

RESULTS

Out of the 147 EHS patients, 117 were enrolled, of which 96 (82.1%) recovered, 13 (11.1%) died, and 8 (6.8%) experienced neurological sequelae. Statistically significant differences were found between non-brain injury and brain injury groups in age, hypotension, duration of consciousness disorders, time to drop core body temperature below 38.5°C, lymphocyte counts, platelet counts, procalcitonin, alanine aminotransferase, aspartate aminotransferase, creatinine, cystatin C, coagulation parameters, international normalized ratio, acute physiology and chronic health evaluation II scores, sequential organ failure assessment (SOFA) scores, and Glasgow coma scale scores (all p < 0.05). Multivariate logistic regression showed that age (OR = 1.090, 95% CI: 1.02 - 1.17, p = 0.008), time to drop core temperature (OR = 8.223, 95% CI: 2.30 - 29.40, p = 0.001), and SOFA scores (OR = 1.676, 95% CI: 1.29 - 2.18, p < 0.001) are independent risk factors for brain injury induced by EHS. The Kaplan-Meier curves suggest significantly prolonged survival (p < 0.001) in patients with early Glasgow coma scale score > 8 and duration of consciousness disorders ≤ 24 h.

CONCLUSIONS

Advanced age, delayed cooling, and higher SOFA scores significantly increase the risk of brain injury post-EHS. These findings underscore the importance of rapid cooling and early assessment of organ failure to improve outcomes in EHS patients.

Evolution of MRI characteristics of heatstroke in a patient with schizophrenia maintained with antipsychotic drugs

Although heatstroke commonly occurs in summer, herein, we present a case of heatstroke that occurred in March. The patient has been schizophrenic for over 20 years and has been receiving long-term medications, such as lithium carbonate, clozapine, and lorazepam. We analyzed the evolution of her cerebellar magnetic resonance imaging characteristics to determine the association of heatstroke in schizophrenia. Patients with schizophrenia are at high risk for developing heatstroke, possibly due to the use of antipsychotic drugs.

Analysis of Clinical Symptoms and Brain MRI of Heat Stroke: 2 Case Reports and a Literature Review

INTRODUCTION

Heat stroke is defined as high body temperature causing multiple organ failure, psychological change, seizure, and consciousness disturbance, which lead to its high mortality rate. However, the involvement of brain injury is rare, and heat-stroke has only been reported in a few case reports or case series. The purpose of this case study was to evaluate the clinical symptoms and radiological features of heat stroke.

METHODS

We reviewed our hospital records and previously published reports to find cases of heat stroke. We excluded those with unknown clinical features or radiological findings.

RESULTS

We retrieved 2 cases of heat stroke from our hospital, which presented as extensive lesions on brain imaging that led to disseminated intravascular coagulation and death within a few days. In 21 previously reported cases of heat stroke, similar brain lesions were noted. These were classified as infarction/posterior reversible encephalopathy syndrome (PRES)-like lesions. The patients who developed PRES-like lesions and survived often developed cerebellar sequelae.

CONCLUSION

The mechanism of heat stroke is presumed to be multifactorial. Ischemic-like lesions result from hypovolemia and unusual coagulation, whereas PRES-like lesions are caused by direct heat and vasogenic edema due to hypercytokinemia. We need to consider the above mentioned conditions when evaluating heat stroke.

Magnetic resonance imaging and magnetic resonance venography features in heat stroke: a case report

Background

Heat stroke (HS) is a critical illness that can cause multiple organ dysfunction, including damage to the central nervous system (CNS), which can be life-threatening in severe cases. Brain lesions in patients with HS who present with CNS damage have been rarely reported before, and they usually vary in different cases, hence, patients with such lesions may present a clinical challenge in terms of diagnosis and management. Cerebral venous thrombosis (CVT) is a rare cause of stroke that mostly affects young individuals and children. The pathogenesis of brain damage caused by HS is complex, and CVT may be involved in the pathogenesis of HS with CNS damage. In this manuscript, we have reported a case of a patient with HS having CVT with symmetrical lesions in the bilateral putamen, posterior limb of the internal capsule, external capsule, insular lobe, and subcortical white matter in the brain.

Case presentation

We encountered a 48-year-old man who presented with HS in the summer season. During admission, he had a high body temperature and was in coma and shock. Then, he developed rhabdomyolysis syndrome, acute kidney and liver damage, electrolyte imbalance, and acid–base balance disorders, and his D-dimer level was elevated. After several days of anti-shock treatment, the patient’s level of consciousness improved. However, he experienced a decline in vision. Cerebral magnetic resonance imaging (MRI) showed symmetrical lesions in the bilateral posterior limb of the internal capsule, putamen, external capsule, insula, and subcortical white matter, and cerebral magnetic resonance venography (MRV) showed the development of CVT. Therefore, anti-coagulation treatment was provided. After timely clinical intervention, the symptoms of the patient gradually improved.

Conclusions

This case showed that HS can cause CVT. Therefore, cerebral MRI findings in HS must be assessed; in addition, early MRV can help in the diagnosis of the disease, which can effectively improve prognosis.

Heatstroke

Heatstroke is an acute medical emergency that is always fatal if left untreated. The diagnosis of heatstroke should be considered in any hyperthermic patient with altered mental status during a heat wave or following vigorous muscle exertion. Heat can damage the structure and function of essential macromolecules, including proteins, membrane lipids, and nucleic acids, and thereby lead to multiple-organ failure, culminating in death. The cytotoxic effect of heat is a function of degree and duration of hyperthermia; thus, an early diagnosis and prompt initiation of cooling are paramount to halt progression to tissue damage and death.

Effect of respiratory and cardiac gating on the major diffusion-imaging metrics

The effect of respiratory gating on the major diffusion-imaging metrics and that of cardiac gating on mean kurtosis (MK) are not known. For evaluation of whether the major diffusion-imaging metrics-MK, fractional anisotropy (FA), and mean diffusivity (MD) of the brain-varied between gated and non-gated acquisitions, respiratory-gated, cardiac-gated, and non-gated diffusion-imaging of the brain were performed in 10 healthy volunteers. MK, FA, and MD maps were constructed for all acquisitions, and the histograms were constructed. The normalized peak height and location of the histograms were compared among the acquisitions by use of Friedman and post hoc Wilcoxon tests. The effect of the repetition time (TR) on the diffusion-imaging metrics was also tested, and we corrected for its variation among acquisitions, if necessary. The results showed a shift in the peak location of the MK and MD histograms to the right with an increase in TR (p ≤ 0.01). The corrected peak location of the MK histograms, the normalized peak height of the FA histograms, the normalized peak height and the corrected peak location of the MD histograms varied significantly between the gated and non-gated acquisitions (p < 0.05). These results imply an influence of respiration and cardiac pulsation on the major diffusion-imaging metrics. The gating conditions must be kept identical if reproducible results are to be achieved.