AbstractPatients withnonexertional heat stroke often have a poor prognosis and suffer neurologicalsequelae. We report a rare case of full neurological recovery in a 77-year-oldwoman who fell into a coma with an initial Glasgow Coma Scale of 3 while takinga bedrock bath. Severe nonexertional heat stroke was quickly diagnosed, and intensivetreatment including a blood transfusion and body temperature management was immediatelyprovided. Laboratory data showed multi-organ failure, and herelectroencephalogram showed very low amplitude on hospitalization day 6, indicatinga poor prognosis; however, she gradually recovered consciousness, and herelectroencephalogram normalized, showing a Glasgow Coma Scale of 15 atdischarge. This case demonstrated that intensivists should not withhold treatmentfrom a patient with severe heat stroke on the basis of a poor initialelectroencephalogram result and laboratory data.
132 words Nonexertional heat stroke is defined as acore body temperature exceeding 40 degrees Celsius causing central nervoussystem dysfunction. 1 In general, the deeper the coma, the greater thelikelihood of mortality becomes. 2 Few studies were reported regarding heatstroke caused by bedrock bath compared to sauna. We experienced report here a rarecase of severe nonexertional heat stroke that initially showed an electroencephalogram(EEG) with very low amplitude (< 10 uV) indicating a poor prognosis, but eventuatedin a full recovery.A 77-year-old woman was brought to theemergency department by ambulance after being found with severe disturbance ofconsciousness and fecal incontinence while taking a bedrock bath. On physicalexamination, she was in a deep coma with a Glasgow Coma Scale of 3, bloodpressure of 93/67 mmHg, heart rate of 175 beats per minute, regular respiratoryrate of 24 breaths per minute, and a tympanic temperature of 40.
1 degreesCelsius. She had a history of untreated hypertension. A laboratory testrevealed increased serum creatinine and creatine kinase at 1.38mg/dL and 1545IU/L, respectively. A head CT and MRI scan showed no significant lesion. Allother examinations including abdominal ultrasonography, transthoracicechocardiography, lumbar puncture, and EEG disclosed no specific abnormalities.The possibility of epilepsy or encephalitis was negligible.After detailed examination, we initiated immediatecooling and intensive care including a blood transfusion and mechanicalventilation in the intensive care unit for the treatment of severe heat stroke.
Tracheal intubation and a sedative and analgesic were also administered. Despiteintensive medical care, her clinical course was severe as shown in Figure.1.
Herinitial SOFA score at hospitalization was 8 and reached a peak of 16 onhospital day 4. On hospital day 4, autonomic nervousabnormalities of uncertain origin were found. Hypertensive crisis withoutcounter-regulation of the heart rate followed by consecutive circulatorycollapse every 2 hours occurred as shown in Figure 2. The presentation wassimilar to the “autonomic storm” found in amyotrophic lateral sclerosis,suggesting involvement of the limbic system.
3 This central sympathetichyperactivity ceased on hospital day 5 without further life-threatening events.On hospital day 5, sedation using midazolamwas discontinued. Despite the discontinuation, she remained unconscious for thefollowing 2 days, and her EEG on the day 6 showed verylow amplitude (< 10 uV), suggesting an unfavorableneurological prognosis even if death were prevented (Figure 3).As per her family's wishes, treatment was withheld and further attempts atresuscitation were discontinued.However, contrary to our expectations, thepatient responded to intensive supportive care.
She gradually recovered consciousnessfrom hospital day 8, and was extubated on hospital day 11 with a Glasgow ComaScale of 15. Her EEG eventually normalized and she was discharged. She had nosignificant neurological sequelae. Her Mini–Mental State Examination scorewas 29 at 2 years after discharge. A bedrock bath is similar to a sauna butdiffers in the way it heats the body. The bedrock bath does not use water; instead,the bather lies on a flat stone which is heated to around 50 degrees Celsius.The room temperature is maintained at 40-45 degrees Celsius and the humidity ismaintained at about 40%, creating what is believed to be a more comfortable environmentthan a sauna.
During a bedrock bath the heated stone emits far infrared rays,which warm the body without steam or water. Although Hannuksela et al. have reportedthe risks of sauna bathing 4, only one case report in Japanese on nonexertionalheat stroke during a bedrock bath exists.
5 Our case demonstrated that fallingasleep in a bedrock bath might cause central sympathetic hyperactivity, whichsometimes results in sudden death due to circulatory collapse 3 or disseminatedintravascular coagulation (DIC).Furthermore, there are few studies focusingon the relationship between heat stroke and EEG. In this case, the duration ofthe sedation-free time was almost 36 h on hospital day 6. We could have usedflumazenil to reverse the sedation, discontinuation period of midazolaminjection was sufficient not to affect EEG regardless of the liver dysfunction.6 Although further studies are needed, our case demonstrated that theprognosis of patients with heat stroke may be unrelated to poor EEG findings,laboratory data, unknown causes of sympathetic hyperactivity, or poor state of consciousness.Careful judgement should therefore be exercised before withholding treatment.AcknowledgementsWe thank Dr.
Toshio Shimizu and Dr. Yasufumi Miyake for their constructive commentsand all the staff for their care of the patient and their contributions to thisstudy. Figure LegendsFigure 1.Clinical course from admission to hospital day 11Despite immediate cooling and intensive care,the patient’s clinical course was severe. The initial SOFA score athospitalization was 8 and reached a peak of 16 on hospital day 4.
The patient’sconsciousness gradually recovered after hospital day 8. The patient was successfullyextubated on hospital day 11 with a Glasgow Coma Scale of 15. CK, creatinekinase IU/L, left axis; ALT, alanine aminotransferase IU/L, left axis;T-bil, total bilirubin mg/dL, right axis, SOFA score (right axis). Figure 2. Autonomicnervous abnormalities on hospital day 4.Hypertensivecrisis without counter-regulation of heart rate followed by consecutivecirculatory collapse every two hours was observed. sBP, systolicblood pressure mmHg; dBP, diastolic blood pressure mmHg; HR, heart rate/min Figure 3.
Electroencephalogram(EEG) on days 6 (A), 9 (B), 21 (C), and 156 (D)Follow-up EEGs normalized in theclinical course. (A) The amplitudeof the EEG was lower than 10 microvolts. Note the prominent ECG artifacts.(B) Slight revivalof neuronal activity.
(C) Backgroundactivity showed a diffuse alpha rhythm (not dominant in the occipital region). (D) Alphaattenuation was fully conserved (Arrow head, eye opening).All EEGs used the samescale and were filtered by a time constant of 0.1 sec and high cut filter of 70Hz.
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