關於熱急症. 搞懂每個名詞的定義固然重要. 但了解每一種情況的成因, 針對各種不同成因做處置更重要. 名詞正確有助於與其他人溝通. 即使名詞記錯, 遇到狀況能正確處置才是重點.
人體的體溫調節中樞在下視丘. 我們能維持恆定的體溫, 取決於下視丘的溫度設定. 這個溫度設定會受到各種細胞激素或致熱因子影響. 通常是37度上下. 在炙熱的環境, 當身體溫度高於設定溫度. 身體會藉由各種機制降溫, 例如流汗, 體表血管擴張. 藉由增加皮膚血流增加, 提高散熱效率. 當身體散熱機制啟動, 大量流汗會造成脫水. 大量補充水分沒有補充電解質, 會造成電解質失調, 例如嚴重的低血鈉, 皮膚血管擴張. 會造成血液滯留在周邊. 造成重要器官(腦部.心臟)供血不足. 引起昏厥. 當散熱機制無法抵銷外界帶來的溫度上升. 會影響到腦部的正常運作. 造成意識改變或昏迷.
輕微低血鈉可能造成頭暈. 嚴重低血鈉可能引起癲癇或昏迷
當體溫設定點溫度為37度. 而身體溫度為35度. 此時人體會感覺寒冷. 收縮皮膚表面血管. 保存體溫避免散失到外界.
當體溫設定點溫度為37度. 身體溫度因外來熱源而升高到39度. 此時會感覺熱. 皮膚血管擴張. 流向皮膚的血量增加. 藉由皮膚流汗將熱排出.
各種感染(細菌.病毒)或藥物(擬交感神經作用類), 會調升下視丘的體溫設定點. 此時靠退燒藥物可將體溫設定點的溫度下調.
退燒藥物是作用在下視丘的體溫設定點. 藥物本身無法幫身體降溫. 藥物作用是將體溫設定點的溫度調低. 但體溫下降仍須透過排汗等等物理機制. 當身體機能無法代償外界進入身體的熱量. 體溫就開始節節攀升.
1. 通用處置, 協助患者脫離高溫環境. 移到陰涼處
2. 神智清醒, 大量流失水分及電解質, 應適當補水補電解質
3. 神智不清. 不建議讓患者直接喝水. 避免嗆到造成更嚴重問題
4. 大量流失水分及電解質. 若意識不良, 無法從口補充水分電解質. 應送醫
5. 單純因高溫造成血管擴張. 造成血壓下降, 會導致昏厥(例如小學生開朝會.久站而暈厥). 此時不需要補充水分電解質, 盡快移到陰涼處. 維持復甦姿勢或躺平時頭部稍微墊高. 通常能很快恢復.
6.老人或無法正常行動的人. 因高溫引起大量流汗脫水散熱. 仍無法降低體溫.之後因脫水無法繼續排汗. 皮膚從流汗變成無汗. 當體溫超過40.5度(不同文獻的體溫數值有差異.有些寫40度C) , 會造成意識不清或昏迷. 此時處理應盡快將體溫降低到39度C以下(冰浴,毛巾沾水擦拭全身,吹電風扇.移到冷氣房).
** 此時使用退燒藥物降低下視丘體溫設定點. 無效. 因為這不是體溫設定點的異常.
參考資料:
2. Nonexertional (classic) heat stroke in adults(uptodate)
下面是舊的筆記
2018-12-16 edit. from uptodate
Heat syncope and exercise associated collapse
名詞定義. Heat syncope 不是很好的說法. 因為 heat syncope 並非因為核心體溫過高造成的暈厥. 在運動員發生暈厥. 更好的說法是 EAC (運動相關暈厥). EAC 通常發生於結束比賽或完成工作之後. 常見於耐力賽, 例如馬拉松. 機轉是靜脈回血突然減少. 長時間運動會造成血管擴張. 而運動的時候, 肌肉會在血管施加壓力. 當肌肉突然放鬆. 血管壓力突然降低. 導致靜脈流向心臟的血量突然下降. 造成運動員暈厥.
Definitions, clinical presentation, and pathophysiology — Heat syncope is among the more confusing diagnoses identified by the International Classification of Diseases. Like heat cramps, heat syncope is a misnomer as heat does not directly cause the syncopal event (ie, core body temperature is not significantly elevated). The treatment of heat-related syncope is discussed separately.
The syncopal event that occurs in the exercising athlete is more appropriately termed "exercise associated collapse" (EAC) [15]. EAC occurs when an athlete is unable to stand or walk as a result of lightheadedness or syncope. EAC usually occurs immediately after completing a race or workout and is commonly observed at endurance events (eg, marathon). The mechanism for collapse is an abrupt decrease in venous return once that athlete completes the event. Given the typical degree of vasodilatation seen with prolonged exertion, the sudden loss of the pressure exerted by the skeletal muscles on the vasculature leads to a precipitous decline in venous return, as well as postural tone, causing the athlete to collapse.
典型的EAC. 病患核心體溫可能正常或稍微上升. 而且經過適當處置之後神智狀態很快恢復正常 (約15-20分鐘). 藉此可與熱中暑(HEAT STROKE)區別
Heat is an indirect contributor to EAC as the body is dually tasked to provide blood to exercising muscle and the periphery, to assist in thermoregulation. In typical EAC, the athlete's core temperature is either normal or only marginally elevated and any alterations in mental status quickly resolve (within approximately 15 to 20 minutes) with appropriate treatment. These features help to distinguish EAC from heat stroke.
非運動造成的熱暈厥. 可由高溫環境間接影響導致. 通常是發生在環境變熱的前幾天. 身體尚未適應. 有兩種常見型態.
1. 久站於熱環境. 身體缺乏活動.
2. 在熱的環境突然站起來.
這類的熱暈厥症狀包括. 頭重腳輕. 隧道性視野. 臉色蒼白. 皮膚發汗. 脈搏變慢. 通常核心體溫是正常或輕微上升. 病患通常在適當治療之後很快恢復.
Heat syncope in those who are not exercising can be described as a transient loss or near-loss of consciousness due to the indirect effects of high ambient temperature. Heat syncope occurs most often during the first few days that someone is exposed to high environmental temperatures, before acclimatization is complete. Two common scenarios for heat syncope are:
●Prolonged standing in the heat with little movement
●Sudden standing after prolonged sitting in the heat
The signs and symptoms associated with these forms of heat syncope include light-headedness, tunnel vision, pale and sweaty skin, and decreased pulse rate. Most often the core temperature is normal or only mildly elevated. Patients generally recover rapidly with appropriate treatment.
非運動性熱暈厥的病生理反應與身體對於熱調節和維持直立姿勢的血壓調節機轉有關. 熱調節需要藉由血管擴張增加周邊血流, 增加排汗. 而周邊血管擴張可導致血液滯留在周邊組織. 造成姿勢性低血壓. 身體的適應最後會讓循環血量增加. 有利於在熱的環境排汗與活動. 在這些不同情境. 熱急症的嚴重度與身體體溫上升和脫水程度成正比.
The pathophysiology for each of these nonexertional events is related to the body's competing needs for thermoregulation and maintaining adequate blood pressure for an upright posture [41,57]. Thermoregulation requires increasing blood flow to the periphery through vasodilation in order to facilitate sweating. This increase in peripheral vasodilation can lead to peripheral pooling of blood, causing postural hypotension. Acclimatization eventually results in an increased circulating blood volume capable of accommodating both sweating and activity in the heat. In each scenario, the severity of illness is proportional to the rise in body temperature and the degree of dehydration.
2016-04-21 修改
中暑定義：體溫超過 40 度C 以上，合併下列症狀
無汗
皮膚乾熱
中樞神經異常（反應遲鈍、失憶、瞻妄、抽搐、神智不清、昏迷、癲癇）
沒有治療的中暑，死亡率高達 50％, 退燒藥物沒有作用.
Heat stroke is diagnosed by an elevated core body temperature (40°C or higher) accompanied by anhidrosis, hot dry skin, and central nervous system abnormalities such as attention deficit, impaired memory, drowsiness, delirium, convulsions, and coma.[4-6] It is sometimes fatal even if the body temperature is adequately reduced because the exaggerated acute-phase response, the altered expression of heat-shock protein released when cells are exposed to high temperatures, and immune system dysfunction often lead to inflammatory responses, intravascular coagulation, and multiorgan injury
http://www.medscape.com/viewarticle/444158
熱急症
最輕微的是 heat cramps, 中度是 heat exhaustion, 最嚴重的是 heat stroke.
Definition By Mayo Clinic Staff
熱衰竭 heat exhaustion 是因過熱造成大量流失體液及電解質引起，症狀會出現虛弱，體溫略高或正常，脈搏淺快
誘發原因主要是暴露在過熱環境，尤其是加上高濕度和高強度活動更易造成，如果沒有積極處理，可能惡化成中暑
Heat exhaustion is a condition whose symptoms may include heavy sweating and a rapid pulse, a result of your body overheating. It's one of three heat-related syndromes, with heat cramps being the mildest and heatstroke being the most severe.
Causes of heat exhaustion include exposure to high temperatures, particularly when combined with high humidity, and strenuous physical activity. Without prompt treatment, heat exhaustion can lead to heatstroke, a life-threatening condition. Fortunately, heat exhaustion is preventable.
http://www.mayoclinic.org/diseases-conditions/heat-exhaustion/basics/definition/con-20033366
http://www.cdc.gov/niosh/topics/heatstress/
熱衰竭, 身體因為高溫造成水分電解質大量流失. 通常是流太多汗, 在高熱環境工作的人還有老人容易發生
Heat Exhaustion
Heat exhaustion is the body's response to an excessive loss of the water and salt, usually through excessive sweating. Workers most prone to heat exhaustion are those that are elderly, have high blood pressure, and those working in a hot environment.
Symptoms
Symptoms of heat exhaustion include:
Heavy sweating 大量流汗
Extreme weakness or fatigue 極度疲憊
Dizziness, confusion 頭暈 神智混亂
Nausea 噁心
Clammy, moist skin 皮膚濕冷
Pale or flushed complexion 臉色發白或潮紅
Muscle cramps 肌肉抽筋
Slightly elevated body temperature 體溫輕微上升
Fast and shallow breathing 呼吸淺快
First Aid
Treat a worker suffering from heat exhaustion with the following:
Have them rest in a cool, shaded or air-conditioned area. 在陰涼處休息
Have them drink plenty of water or other cool, nonalcoholic beverages. 補充大量水分或其他不含酒精的飲料
Have them take a cool shower, bath, or sponge bath. 沖冷水澡，泡澡或用海綿擦澡
熱暈厥. 或熱昏厥. 有運動性和非運動性的. 運動性的機轉在上面有描述了. 非運動性的可能是站太久, 或久坐(躺著)突然站起, 造成昏厥. 脫水和身體不適應可能會增加發生機率
Heat Syncope
Heat syncope is a fainting (syncope) episode or dizziness that usually occurs with prolonged standing or sudden rising from a sitting or lying position. Factors that may contribute to heat syncope include dehydration and lack of acclimatization.
Symptoms
Symptoms of heat syncope include:
Light-headedness 頭重腳輕
Dizziness 頭暈
Fainting 昏厥
First Aid
Workers with heat syncope should: 非大量脫水，補水不需太快
Sit or lie down in a cool place when they begin to feel symptoms. 在陰涼處坐下或躺下休息，以病患舒服為原則
Slowly drink water, clear juice, or a sports beverage. 慢慢補充水分，包括果汁或運動飲料
2018-12-16 edit. from uptodate
Heat syncope and exercise associated collapse
名詞定義. Heat syncope 不是很好的說法. 因為 heat syncope 並非因為核心體溫過高造成的暈厥. 在運動員發生暈厥. 更好的說法是 EAC (運動相關暈厥). EAC 通常發生於結束比賽或完成工作之後. 常見於耐力賽, 例如馬拉松. 機轉是靜脈回血突然減少. 長時間運動會造成血管擴張. 而運動的時候, 肌肉會在血管施加壓力. 當肌肉突然放鬆. 血管壓力突然降低. 導致靜脈流向心臟的血量突然下降. 造成運動員暈厥.
Definitions, clinical presentation, and pathophysiology — Heat syncope is among the more confusing diagnoses identified by the International Classification of Diseases. Like heat cramps, heat syncope is a misnomer as heat does not directly cause the syncopal event (ie, core body temperature is not significantly elevated). The treatment of heat-related syncope is discussed separately.
The syncopal event that occurs in the exercising athlete is more appropriately termed "exercise associated collapse" (EAC) [15]. EAC occurs when an athlete is unable to stand or walk as a result of lightheadedness or syncope. EAC usually occurs immediately after completing a race or workout and is commonly observed at endurance events (eg, marathon). The mechanism for collapse is an abrupt decrease in venous return once that athlete completes the event. Given the typical degree of vasodilatation seen with prolonged exertion, the sudden loss of the pressure exerted by the skeletal muscles on the vasculature leads to a precipitous decline in venous return, as well as postural tone, causing the athlete to collapse.
典型的EAC. 病患核心體溫可能正常或稍微上升. 而且經過適當處置之後神智狀態很快恢復正常 (約15-20分鐘). 藉此可與熱中暑(HEAT STROKE)區別
Heat is an indirect contributor to EAC as the body is dually tasked to provide blood to exercising muscle and the periphery, to assist in thermoregulation. In typical EAC, the athlete's core temperature is either normal or only marginally elevated and any alterations in mental status quickly resolve (within approximately 15 to 20 minutes) with appropriate treatment. These features help to distinguish EAC from heat stroke.
非運動造成的熱暈厥. 可由高溫環境間接影響導致. 通常是發生在環境變熱的前幾天. 身體尚未適應. 有兩種常見型態.
1. 久站於熱環境. 身體缺乏活動.
2. 在熱的環境突然站起來.
這類的熱暈厥症狀包括. 頭重腳輕. 隧道性視野. 臉色蒼白. 皮膚發汗. 脈搏變慢. 通常核心體溫是正常或輕微上升. 病患通常在適當治療之後很快恢復.
Heat syncope in those who are not exercising can be described as a transient loss or near-loss of consciousness due to the indirect effects of high ambient temperature. Heat syncope occurs most often during the first few days that someone is exposed to high environmental temperatures, before acclimatization is complete. Two common scenarios for heat syncope are:
●Prolonged standing in the heat with little movement
●Sudden standing after prolonged sitting in the heat
The signs and symptoms associated with these forms of heat syncope include light-headedness, tunnel vision, pale and sweaty skin, and decreased pulse rate. Most often the core temperature is normal or only mildly elevated. Patients generally recover rapidly with appropriate treatment.
非運動性熱暈厥的病生理反應與身體對於熱調節和維持直立姿勢的血壓調節機轉有關. 熱調節需要藉由血管擴張增加周邊血流, 增加排汗. 而周邊血管擴張可導致血液滯留在周邊組織. 造成姿勢性低血壓. 身體的適應最後會讓循環血量增加. 有利於在熱的環境排汗與活動. 在這些不同情境. 熱急症的嚴重度與身體體溫上升和脫水程度成正比.
The pathophysiology for each of these nonexertional events is related to the body's competing needs for thermoregulation and maintaining adequate blood pressure for an upright posture [41,57]. Thermoregulation requires increasing blood flow to the periphery through vasodilation in order to facilitate sweating. This increase in peripheral vasodilation can lead to peripheral pooling of blood, causing postural hypotension. Acclimatization eventually results in an increased circulating blood volume capable of accommodating both sweating and activity in the heat. In each scenario, the severity of illness is proportional to the rise in body temperature and the degree of dehydration.
2016-04-21 修改
中暑定義：體溫超過 40 度C 以上，合併下列症狀
無汗
皮膚乾熱
中樞神經異常（反應遲鈍、失憶、瞻妄、抽搐、神智不清、昏迷、癲癇）
沒有治療的中暑，死亡率高達 50％, 退燒藥物沒有作用.
Heat stroke is diagnosed by an elevated core body temperature (40°C or higher) accompanied by anhidrosis, hot dry skin, and central nervous system abnormalities such as attention deficit, impaired memory, drowsiness, delirium, convulsions, and coma.[4-6] It is sometimes fatal even if the body temperature is adequately reduced because the exaggerated acute-phase response, the altered expression of heat-shock protein released when cells are exposed to high temperatures, and immune system dysfunction often lead to inflammatory responses, intravascular coagulation, and multiorgan injury
http://www.medscape.com/viewarticle/444158
熱急症
最輕微的是 heat cramps, 中度是 heat exhaustion, 最嚴重的是 heat stroke.
Definition By Mayo Clinic Staff
熱衰竭 heat exhaustion 是因過熱造成大量流失體液及電解質引起，症狀會出現虛弱，體溫略高或正常，脈搏淺快
誘發原因主要是暴露在過熱環境，尤其是加上高濕度和高強度活動更易造成，如果沒有積極處理，可能惡化成中暑
Heat exhaustion is a condition whose symptoms may include heavy sweating and a rapid pulse, a result of your body overheating. It's one of three heat-related syndromes, with heat cramps being the mildest and heatstroke being the most severe.
Causes of heat exhaustion include exposure to high temperatures, particularly when combined with high humidity, and strenuous physical activity. Without prompt treatment, heat exhaustion can lead to heatstroke, a life-threatening condition. Fortunately, heat exhaustion is preventable.
http://www.mayoclinic.org/diseases-conditions/heat-exhaustion/basics/definition/con-20033366
http://www.cdc.gov/niosh/topics/heatstress/
熱衰竭, 身體因為高溫造成水分電解質大量流失. 通常是流太多汗, 在高熱環境工作的人還有老人容易發生
Heat Exhaustion
Heat exhaustion is the body's response to an excessive loss of the water and salt, usually through excessive sweating. Workers most prone to heat exhaustion are those that are elderly, have high blood pressure, and those working in a hot environment.
Symptoms
Symptoms of heat exhaustion include:
Heavy sweating 大量流汗
Extreme weakness or fatigue 極度疲憊
Dizziness, confusion 頭暈 神智混亂
Nausea 噁心
Clammy, moist skin 皮膚濕冷
Pale or flushed complexion 臉色發白或潮紅
Muscle cramps 肌肉抽筋
Slightly elevated body temperature 體溫輕微上升
Fast and shallow breathing 呼吸淺快
First Aid
Treat a worker suffering from heat exhaustion with the following:
Have them rest in a cool, shaded or air-conditioned area. 在陰涼處休息
Have them drink plenty of water or other cool, nonalcoholic beverages. 補充大量水分或其他不含酒精的飲料
Have them take a cool shower, bath, or sponge bath. 沖冷水澡，泡澡或用海綿擦澡
熱暈厥. 或熱昏厥. 有運動性和非運動性的. 運動性的機轉在上面有描述了. 非運動性的可能是站太久, 或久坐(躺著)突然站起, 造成昏厥. 脫水和身體不適應可能會增加發生機率
Heat Syncope
Heat syncope is a fainting (syncope) episode or dizziness that usually occurs with prolonged standing or sudden rising from a sitting or lying position. Factors that may contribute to heat syncope include dehydration and lack of acclimatization.
Symptoms
Symptoms of heat syncope include:
Light-headedness 頭重腳輕
Dizziness 頭暈
Fainting 昏厥
First Aid
Workers with heat syncope should: 非大量脫水，補水不需太快
Sit or lie down in a cool place when they begin to feel symptoms. 在陰涼處坐下或躺下休息，以病患舒服為原則
Slowly drink water, clear juice, or a sports beverage. 慢慢補充水分，包括果汁或運動飲料
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