第八版病理生理学第三章水和电解质代谢紊乱

单击此处编辑母版标题样式,*,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,(Disturbances of water and electrolyte balance),第三章水和电解质代谢紊乱,病理生理教研室,吴立玲,(Normal metabolism of water and electrolyte),第一节,水与电解质的正常代谢,一、体液的容量和分布,(Volume and,distribution of body fluid),体液,(body fluid),体内的水和溶解在其中的物质。,(Water and electrolytes balance),水与电解质平衡,体液的容量,(volume),化学成分,(composition),渗透压,(osmotic pressure),分布,(distribution),相对恒定,Total body water (TBW) 60%,细胞内液,Intracellular fluid (ICF),40,细胞外液,Extracellular fluid (ECF),组织间隙,15,组织液,Interstitial fluid(ISF),血浆,5%,Plasma,Transcellular fluid(,third space,),1,影响体液容量的因素,Body fluid,TBW (%),Adult male,TBW(%),Adult female,TBW(%),Infant,Normal,60,50,70,Lean,70,60,80,Obese,50,42,60,年龄、性别、胖瘦,二、体液的电解质,(Electrolyte in body fluid),ECF:,Na,+,、Cl,-,、 HCO,3,-,ICF:,K,+,、 Mg,2 +,、,HPO,4,2-,Pr,-,血,Na,140,mmol/L,血,Cl,104,mmol/L,血,HCO,3,24,mmol/L,平均正常值,三、体液的渗透压 和水的交换,(Osmotic pressure of body fluid and water movement),(一)体液的渗透压,(Osmotic pressure of body fluid),280310 mmol/L (mOsm/L),血浆渗透压,(二) 水的交换,(Water movement ),1.细胞内外水的运动,(water movement between outside-inside of cell),水自由通过,蛋白质、Na,、K,、Ca,2+,等不能自由通过,(water movement between outside-inside of capillary),蛋白质等大分子物质受限,水和电解质自由交换,Daily intake,(ml/day),Daily output,(ml/day),Drinking,1300,Urine,1500,Water in food,900,Lungs,400,Water of oxidation,300,Skin,500,Stool,100,Total,2500,Total,2500,3.,体内外水的运动,(Water movement between outside-inside of body),每日最低尿量,500ml,呼吸道失水,皮肤不显性蒸发,生理需水量:,1500ml/day,(从尿排代谢废物35g/日 最大浓度68g）,三、,水和钠的生理功能,(Physiologic function of water and sodium),(一)水的生理功能,(Function of body water),促进物质代谢,调节体温,润滑,(二)钠的生理功能,(,Physiologic function of sodium),维持体液的渗透压和酸碱平衡,参与细胞动作电位的形成,四、水与钠平衡的调节,(Regulation of water,and sodium balance),(thirst),渴中枢,ECF,渗透压,血容量,(antidiuretic hormone , ADH),ECF渗透压,有效循环血量,渗透压感受器,ADH,肾,重吸收水,ECF量渗透压,容量感受器,(aldosterone),有效循环血量,醛固酮,肾重吸收,Na,+,H,2,O,ECF,量,低血Na,+,高血K,+,42岁男性，因恶心、呕吐、腹胀和腹部,绞痛3天入院。,既往史：20岁做过阑尾切除术。,体检：,C,，脉搏104 beat/min,BP 115/70 mmHg,腹胀，有压痛和反跳痛。,皮肤和舌干燥，尿量5ml/h,化验：血Na,152mmol/L,Cl,-,108mmol/L,K,+,，,尿比重,Case study,woman,38 ， 2-day history of weakness and postural dizziness（,直立性眩晕 ）,History：,laxative（,泻药）,abuse with multiple bowel movements each day,Physical examination：,BP 110/60,mmHg,falls to 80/50,mmHg,HR 100 beats/min and regular Skin turgor is poor The mucous membrane is dry,Case study,Laboratory test,Na,+, = 140 mmol/LK,+, = 3.3 mmol/LCl,-, 116 mmol/LUrine Na,+, = 9 mmol/LBUN = 40 mg/dL,Arterial pH = 7.25HCO,3,-, = 12 mmol/L PaCO,2,= 28 mmHg,(Disturbances of water and sodium balance),第二节 水、钠代谢紊乱,脱水,(dehydration),高渗性,低渗性,等渗性,水过多,(water excess),水中毒,水 肿,类型,（,Classification）,低钠血症,（,hyponatremia,) The serum sodium concentration,150,mmol,/L,一、脱水,(Dehydration),体液容量减少(2%)。,To describe water deficit,(concept),低容量性高钠血症,(hypovolemic hypernatremia),(一) 高渗性脱水,(hypertonic dehydration),water loss,sodium loss,serumNa,+, 150 mmol/L,plasma,osmotic pressure,310 mmol/L,(causes),(1)入量不足,(d,ecrease of intake),(2)丢失过多,(l,ost from ECF),水源断绝,丧失口渴感,进食困难,大量,出汗,尿崩症和渗透性利尿,呼吸道蒸发,失水失Na,+,渴中枢,口渴,血容量,脉速,BP,皮肤蒸发,脱水热,ECF,量,ECF,渗透压,3. 影响,(effects),细胞内脱水,CNS功能障碍,幻觉,躁动,ADH,肾重吸收水,尿少比重高,血,Na,+,血浆渗透压,脱水热,(dehydration fever),因,皮肤蒸发水减少引起的体温上升。,高渗性脱水的主要发病环节,ECF,高渗,主要脱水部位,ICF,减少,4防治的病理生理基础,(pathophysiological basis of prevention and treatment),及时补水,适当补钠,(concept),低容量性低钠血症,(,hypovolemic hyponatremia,),(二) 低渗性脱水,(Hypotonic dehydration),sodium loss,water loss,serumNa,+, 130 mmol/L,plasma,osmotic pressure 失水,水移入,细胞,ECF渗,透压,ECF量,组织液,脱水征,血容量,脉速、BP,、V萎陷,ADH,肾血流量,醛固酮,尿少、氮质血症,尿Na,+,脑细胞,肿胀,淡漠,嗜睡,ADH,肾重吸,收水,尿量正常,（早期）,血Na,+,血渗透压,3. 影响,(effects),脱水征：,因组织间液量减少，临床 上出现皮肤弹性减退、眼 窝下陷，婴幼儿囟门凹陷 等体征。,低渗性脱水的主要脱水部位,ECF,对病人的主要威胁,循环衰竭,4防治的病理生理基础,(pathophysiological basis of prevention and treatment),轻、中度补生理盐水,(,机体排水量大于排,Na,+,量,),重度补少量高渗盐水,(,减轻细胞水肿,),(concept),(三) 等渗性脱水,(Isotonic dehydration),sodium loss,water loss,serumNa,+, 130150 mmol/L,plasma,osmotic pressure 280,310 mmol/L,(causes),丢失,等渗液,(l,ost isotonic fluid),胃肠道丢失,(g,astrointestinal,losses),肾性失钠,(r,enal,losses),皮肤丢失,(s,kin losses),液体积聚在第三间隙,(accumulate,in third space),3. 影响,(effects),ECF渗透压正常，血Na,+,正常,醛固酮,、ADH,分泌, 尿量,ECF减少 血容量组织液量 ICF变化不明显,(1)血浆渗透压和血钠的变化？,(2)容量的变化？脱水的主要部位？,(3)激素水平的变化？,4防治的病理生理基础,(pathophysiological basis of prevention and treatment),补水量多于补,Na,+,量,42岁男性，因恶心、呕吐、腹胀和腹部,绞痛3天入院。,既往史：20岁做过阑尾切除术。,体检：,C,，脉搏104 beat/min,BP 115/70 mmHg,腹胀，有压痛和反跳痛。,皮肤和舌干燥，尿量5ml/h,化验：血Na, 152 Cl,-, 108,K,+, 5.4 尿比重,Case study,急性肠梗阻,，,hypertonic dehydration,woman,38 ， 2-day history of weakness and postural dizziness（,直立性眩晕 ）,History：,laxative（,泻药）,abuse with multiple bowel movements each day,Physical examination：,BP 110/60,mmHg,falls to 80/50,mmHg,HR 100 beats/min and regular Skin turgor is poor The mucous membrane is dry,Case study,Laboratory test：,Na,+, = 140 mmol/LK,+, = 3.3 mmol/LCl,-, 116 mmol/LUrine Na,+, = 9 mmol/LBUN = 40 mg/dL,Arterial pH = 7.25HCO,3,-, = 12 mmol/L PaCO,2,= 28 mmHg,Case study,病史：,62,岁男性，嵌顿性腹股沟疝入院。,体检：,消瘦、虚弱、舌干、组织充盈差,治疗：,术前,NS 1L,术中,术后,NS 1L,GS 2L,昏昏欲睡、躁动，血,Na,+,133 mmol/L,GS 1L,昏迷、抽搐、死亡,What happened in the patient?,二、水过多,(Water excess),体液容量增多。,(concept),高容量性低钠血症,(hypervolemic hyponatremia),(一)水中毒,(water intoxication),低渗性液体在体内潴留的病理过程,serumNa,+, 130 mmol/L,plasma osmotic pressure,回流,Alteration in capillary hemodynamics that favors the movement of fluid from the vascular space into interstitium.,毛细血管流体静压增高,(increased capillary hydrostatic pressure),血浆胶体渗透压降低,(decreased plasma colloid osmotic pressure),摄入,；,合成,；,丢,失,微血管壁通透性,(,increased capillary permeability),漏出液,(,transudate,),蛋白质含量低，比重低，细胞数少,渗出液,(,exudate,),蛋白质含量高，比重高， 白细胞多,淋巴回流障碍,(,lymphatic obstruction),(2) 体内外液体交换平衡失调,(imbalance of exchange between intra- and extra-body fluid),肾小球滤出钠、水,9999.5,肾小管重吸收,6570,近曲小管吸收,0.51,滤出液排出,钠水潴留,Na,+,and water are retained by the kidney.,(,decreased glomerular filtration rate,),滤过面积,有效循环血量,肾小球滤过率下降,肾小管重吸收增加,(,Increased tubular reabsorption),肾内血流重新分布,近曲小管重吸收,（球,-,管平衡失调）,远曲小管和集合管重吸收,(,醛固酮、,ADH,),肾小球滤过分数增高,(滤过分数肾小球滤过率/肾血浆流量),球-管平衡失调的机制,(net filtration pressure),肾小球有效滤过压,Blood hydrostatic pressure,(,BHP,),60 mmHg out,Colloid osmotic pressure,(,COP,),-32 mmHg in,Capsular pressure,(,CP,),-18 mmHg in,Net filtration pressure,(,NFP,),10 mmHg out,NFP,BHP,60 out,COP,32 in,CP,10 out,18 in,循环血量减少:,出球小动脉收缩入球小动脉收缩肾小球滤过率,/,肾血浆流量, ,滤过分数增加,因,血浆从肾小球滤出增多,管周血管中胶体渗透压相对增高,血流量减少，流体静压相对降低,近曲小管重吸收钠水增多,3.常见全身性水肿的 发病机制及特点,心性水肿,(cardiac edema),左心衰心源性肺水肿 右心衰心性水肿,特点:因重力作用先发于下垂部位,机制,右心功能,V淤血、V压,肾血流量,Cap,内压,水肿,胃肠肝淤血,蛋白吸收合成,血浆胶渗压,GFR,钠水潴留,肾小管重吸收,醛固酮ADH,心输出量,(Potassium homeostasis and its disorders),第三节 钾代谢及钾代谢障碍,病理生理教研室,吴立玲,病史：,男41岁，呕吐4天， 不能进食食物和水。,既往史：,胃溃疡，服用抗酸药治疗。,体检：,重病容。血压100/60mmHg 心率90 beats/min 皮肤干燥、弹性差， 腱反射减弱。,Case study,化验：,血Na,+,145mmol/L Cl,-,92mmol/L K,+,2.6mmol/L HCO,3,-,34mmol/L BUN35mg/dl EKG:T波低平，ST段降低 抽出3升胃内容物,诊断：,幽门梗阻,一、正常钾代谢,(Normal metabolism of potassium),1. 摄入,(intake)：,食物,2. 吸收,(absorption):,肠道,3. 分布,(distribution)： 98%,细胞内,(ICF) 2%,细胞外,(ECF) serum K,+,4. 排泄,(excretion) :,肾,（urine 80%90）,肠,(feces 10),皮肤,(sweat),体内钾,(,50mmol/Kg,体重,),细胞外,2%,血清钾,（3.55.5mmol/L）,Distribution and content of potassium within body,细胞内,98%,(150mmol/L),5. 功能,(function),参与细胞代谢,(Promoting the cell metabolism),维持细胞膜静息电位,(Maintenance of the resting membrane potential),调节渗透压和酸碱平衡,(Regulating the osmotic pressure and acid-base balance),6. 钾平衡的调节,(Regulation of potassium balance),跨细胞转移,肾调节,1.,激素：,胰岛素，儿茶酚胺,2.,细胞外液的,K,+,浓度,3.,酸碱平衡,影响钾在细胞内外转移的因素,醛固酮:,Na,-,K,+,泵活性,细胞外液的K,+,浓度,酸碱平衡:,H,使,Na,-K,泵活性,远曲小管液流速加快,影响肾排钾的因素,Na,+,K,+,K,+,Na,+,K,+,小管液,主 细 胞,血液,-70mV,0mV,-50mV,二、低钾血症,(Hypokalemia),概念,(concept),Serum K,+,缺钾,(potassium,deficit),体内钾缺失,(一)原因和机制,(Causes and mechanisms),1. 摄入不足,(,decreased K,+,intake),钾来源减少,不吃也排,Hypokalemia,2. 失钾过多,(,increased K,+,excretion),消化液丢失,肾失钾,排钾性,利尿剂,渗透性利尿,皮质激素、醛固酮 ,Cusings,disease,远曲小管腔内阴离子,(,K,s,hifts into the cells),胰岛素治疗,(insulin therapy),碱中毒,(alkalosis),低钾性家族性周期性麻痹,(hypokalemic familial periodic paralysis),碱中毒,(alkalosis),H,+,H,+,K,+,血K,+,K,+,酸中毒,(acidosis),H,+,H,+,血K,+,(二)对机体的影响,(Effects),对神经肌肉兴奋性的影响,(effects on neuromuscular excitability),神经肌肉兴奋性,血K,+,细胞内外K,+,差,静息电位(负值),静息电位与阈电位差,兴奋性,机制,(mechanism),超极化阻滞,(hyperpolarized blocking),因静息电位与阈电位距离增大而使神经肌肉兴奋性降低的现象。,表现,(manifestations),CNS,：,萎靡、倦怠、嗜睡,骨骼肌：,四肢无力软瘫，呼吸肌麻痹,胃肠道平滑肌：,食欲不振、腹胀、 麻痹性肠梗阻,2.对心脏的影响,(effects on the heart),心肌传导性,心肌兴奋性,心肌自律性,心肌收缩性先 后,血,K,+,膜对,K,+,通透性,K,+,外流,静息膜电位,0期Na,+,内流, 0期除极化,自动除极化, 2期Ca,2+,内流,心肌代谢障碍,收缩性,兴奋性,传导性,自律性,收缩性,复极延缓,T,波低平,出现,U,波,传导性,P-R,间期延长，,QRS,波增宽,自律性,房性、室性期前收缩,心电图的变化,低钾血症时心电图的改变,(effect on renal function),(effect on acid-base balance),集合管对,ADH,反应性降低,多尿,（polyuria),低血钾 碱中毒,(三) 防治的病理生理基础,(Pathophysiological basis of prevention and treatment),先口服后静脉,见尿补钾,控制量和速度,严禁静脉注射,三、高钾血症,(Hyperkalemia),概念,(Concept),Serum K,+,(一)原因和机制,(Causes and mechanisms),1. 排钾减少,(,decreased K,+,excretion),少尿,(,oliguria),潴钾性利尿剂,醛固酮,2. K,+,从细胞内逸出,(K,+,shifts out of cells),细胞损伤,(cell injury),酸中毒,(acidosis),高钾性周期性麻痹,(,hyperkalemic,periodic paralysis),3. 入钾过多,(,increased K,+,intake),碱中毒,(alkalosis),H,+,H,+,K,+,血,K,+,酸中毒,(acidosis),H,+,H,+,K,+,血,K,+,(二)对机体的影响,(Effects),1. 对神经肌肉兴奋性的影响,(effects on neuromuscular excitability),神经肌肉兴奋性先,后,血K,+,细胞内外 K,+,差,静息电位,阈电位,兴奋性,(重度）,静息电位,与阈电位距离,兴奋性(轻度）,机制,(mechanism),除极化阻滞,(hypopolarized blocking),静息电位等于或低于阈电,位使细胞兴奋性降低的现象。,2.对心脏的影响,(effects on the heart),心肌传导性,心肌兴奋性先,后,心肌自律性,心肌收缩性,血,K,+,细胞内外,K,+,差,静息电,位,与阈电位距离,兴奋性, 低于阈电位,兴奋性,0期Na,+,内流,0期除极化,传导性,膜对K,+,通 透性,4期K,+,外流, 自动除极化,自律性,Ca,2+,内流,收缩性,3,期,K,+,外流,复极加速,T,波高尖,传导性 ,P-R,间期延长,QRS,波增宽,传导阻滞及自律性 ,心律失常,心电图的变化,高钾血症时心电图的变化,3.对酸碱平衡的影响,(effects on,acid-base balance,),高血钾 酸中毒,(三) 防治的病理生理基础,(Pathophysiological basis,of prevention and treatment),减少血钾来源,促进钾移入细胞,对抗钾的毒性,排钾,病史：,男41岁，呕吐4天， 不能进食食物和水。,既往史：,胃溃疡，服用抗酸药治疗。,体检：,重病容。血压100/60mmHg 心率90 beat/min 皮肤干燥、弹性差， 腱反射减弱。,Case study,化验：,血Na,+,145mmol/L Cl,-,92mmol/L K,+,2.6mmol/L HCO,3,-,34mmol/L BUN35mg/dl EKG:T波低平，ST段降低 抽出3升胃内容物,诊断：,幽门梗阻,