病理生理学第三章水和电解质代谢紊乱.ppt

(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),体内的水和溶解在其中的物质。,(Water and electrolytes balance),水与电解质平衡,Total body water(TBW)60%,Transcellular fluid(third space)1,影响体液容量的因素,年龄、性别、胖瘦,二、体液的电解质(Electrolyte in body fluid),ECF:Na+、Cl-、HCO3-,ICF:K+、Mg2+、HPO42-Pr-,血Na 140 mmol/L血Cl 104 mmol/L血HCO3 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、Ca2+等不能自由通过,2.血管内外水的运动(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,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),1.渴感(thirst),2.抗利尿激素(antidiuretic hormone,ADH),ECF渗透压,有效循环血量,3.醛固酮(aldosterone),有效循环血量,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：T 38.7C，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Na152mmol/L,Cl-108mmol/L,K+5.4mmol/L，尿比重1.038,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 testNa+=140 mmol/LK+=3.3 mmol/LCl-116 mmol/LUrine Na+=9 mmol/LBUN=40 mg/dLArterial pH=7.25HCO3-=12 mmol/L PaCO2=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 concentration150 mmol/L,一、脱水(Dehydration),体液容量减少(2%)。To describe water deficit,1.概念(concept),低容量性高钠血症(hypovolemic hypernatremia),(一)高渗性脱水(hypertonic dehydration),water losssodium loss serumNa+150 mmol/L plasma osmotic pressure 310 mmol/L,2.原因(causes),(1)入量不足(decrease of intake),(2)丢失过多(lost 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+,3.影响(effects),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,1.概念(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 280 mmol/L,2.原因(causes),钠平衡调节：多吃多排，少吃少排，不吃不排,丢失过多(lost from ECF),胃肠道丢失(gastrointestinal losses)肾性失钠(renal losses)皮肤丢失(skin losses)液体积聚在第三间隙(accumulate in third space),失Na+失水,水移入 细胞,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),1.概念(concept),(三)等渗性脱水(Isotonic dehydration),sodium loss water loss serumNa+130150 mmol/L plasma osmotic pressure 280310 mmol/L,2.原因(causes),丢失等渗液(lost isotonic fluid),胃肠道丢失(gastrointestinal losses)肾性失钠(renal losses)皮肤丢失(skin 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,(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：T 38.7C，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 1.038,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/dLArterial pH=7.25HCO3-=12 mmol/L PaCO2=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 NS 1.5L 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。,1.概念(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 280 mmol/L,2.原因(causes),(1)水排出减少(decrease of water excretion),(2)ADH分泌过多,急、慢性肾功能障碍,应激 ADH分泌异常增多综合症 syndrome of inappropriate ADH secretion,(3)入水过多,水潴留,3.影响(effects),细胞内外液量均，渗透压均,水潴留的主要部位是细胞内,对机体危害最大的是脑水肿,4防治的病理生理基础(pathophysiological basis of prevention and treatment),预防,限水,排泄：利尿,转移：小剂量高渗盐水(减轻细胞水肿),(二)水肿(Edema),1概念(concept)过多的液体积聚在组织间隙。Accumulation of excess fluid within the interstitial spaces.,过多的液体在体腔内积聚又称为积水(hydrops)。,1分类(Classification),(4)按水肿液存在状态,显性水肿（frank edema)又称凹陷性水肿(pitting edema),隐性水肿（recessive edema),粘液性水肿(myxedema),2.水肿的机制(mechanisms of edema),影响组织液生成回流的基本因素,(1)血管内外液体交换异常(imbalance of exchange between intra-and extra-vascular fluid),组织液生成回流,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,(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,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,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,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,(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 HCO3-34mmol/L BUN35mg/dl EKG:T波低平，ST段降低 抽出3升胃内容物,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+3.55.5mmol/L,4.排泄(excretion):肾（urine 80%90）肠(feces 10)皮肤(sweat),体内钾(50mmol/Kg体重),Distribution and content of potassium within body,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,二、低钾血症(Hypokalemia),概念(concept)Serum K+3.5mmol/L,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,3.钾向细胞内转移(K shifts 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+,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+,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),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Ca2+内流,心肌代谢障碍,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,3.对肾功能的影响(effect on renal function),4.对酸碱平衡的影响(effect on acid-base balance),(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+5.5mmol/L,(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),酸中毒(acidosis),H+,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+,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),心肌兴奋性先后,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,Ca2+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),(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 HCO3-34mmol/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,