《泌尿病生习题.doc》由会员分享，可在线阅读，更多相关《泌尿病生习题.doc（5页珍藏版）》请在金锄头文库上搜索。
1、病理生理学思考题（泌尿系统）1.（1）大海中的航行者如果缺乏淡水供应会如何？ 答：*水摄入量减少血浆晶体渗透压升高渴感中枢兴奋，产生渴觉。 *水摄入量减少血容量降低，动脉血压降低近球细胞分泌肾素增多，继而血管紧张素增多刺激肾上腺皮质球状带分泌醛固酮促进肾脏钠、水的重吸收和钾、氢的排出尿量减少 *水摄入量减少血浆晶体渗透压升高，血容量降低下丘脑渗透压感受器以及心房等容量感受器刺激神经垂体释放ADH增加远端小管、集合管对水的重吸收尿量减少，尿钾、钠增高 *水摄入量减少血容量降低动脉血压下降 *缺水船员处于应激状态交感神经兴奋肾上腺素、去甲肾上腺素增多肾素分泌增加，刺激醛固酮分泌 *应激状态下丘脑-
2、腺垂体-肾上腺皮质轴兴奋肾上腺皮质激素增加 轻度的排钾保钠，促进醛固酮的分泌 *尿量减少肾脏排酸保碱作用降低，可出现酸中毒 *水源断绝导致饮水不足，造成高血钠性体液容量减少，对机体的影响主要有口渴感，尿少，细胞内液向细胞外转移造成细胞脱水，中枢神经功能紊乱，早期或轻症患者尿钠浓度正常或略有升高，晚期或重症病例尿钠含量减少，由于皮肤蒸发水分减少而导致脱水热。 *航行者因缺水时间不同以及体液容量减少程度不同，而有不同的临床表现 轻度：失水量为体重的2-4% 粘膜干燥，汗少，皮肤弹性降低，口渴，尿量少，尿渗量高，尿比重高，可发生酸中毒，但不发生休克 中度：失水量为体重的4-6% 有严重的口渴，恶心，
3、心动过速，体位性低血压，中心静脉压下降，表情淡漠，肾功能低下，少尿，血浆肌酐和尿素氮水平增高，尿渗量800，尿比重1.025，发生酸中毒 重度：失水量为体重6%以上 常发生休克，临床主要表现为有少尿或无尿，血压下降，肾功能严重损害，血浆肌酐和尿素氮水平上升，血清钾浓度升高，代谢性酸中毒严重。 （2）若此时大量饮用海水，会造成什么反应和后果？答：海水的主要成分：计算可得，海水中钠浓度434mmol/L/钾浓度12.8mmol/L，远高于血浆中钠钾的浓度。因缺乏淡水，航行者细胞外液渗透压升高，此时如补充海水，可使细胞外液的渗透压进一步升高，细胞脱水更为严重，造成更为严重的中枢神经系统功能紊乱。尿量
4、减少，体内钠水潴留，导致高血钠性体液容量增加，且口渴感因血浆晶体渗透压的进一步升高非但没有缓解，反而加重。同时，海水中含有砷、汞等有害元素，若大量饮用，可对机体产生一定的危害。然而，在淡水短缺的情况下，可采用淡水海水混合饮用的方法，短期内并无明显危害。2.短时间内摄入大量钾，如何维持血钾水平稳定。 答：明确诊断高血钾后，立即注射胰岛素、葡萄糖、速尿，促进钾向细胞内的转运以及钾离子经尿排出。若心肌出现明显抑制情况，可使用葡萄糖酸钙，以兴奋和增强心肌收缩力。输入碳酸氢钠纠正酸中毒。如有条件，可进行血液透析。以下为高血钾治疗指南：TREATMENT OF HYPERKALAEMIAStop furt
5、her potassium accumulationStop all potentially offending medicines immediately. These include ACE inhibitors,angiotensin receptor blockers, potassium retaining diuretics e.g. spironolactone,amiloride (in co-amilofruse), NSAIDs and potassium containing laxatives(Movicol, Klean-Prep, Fybogel). Beta-bl
6、ockers and digoxin should also bestopped as they prevent intracellular buffering of potassium and reduce theeffectiveness of insulin-glucose and beta-2 agonists.Place the patient on a low potassium diet. It is imperative that whilst waiting for thisdiet that the patient does not consume fruit juice,
7、 fruits, chocolate, fruit gums,biscuits, coffee or potatoes.Use the Hyperkalaemia KitInformation on how to use the kit is contained in Appendix 1. The kit contains: 10 x 10ml calcium gluconate 10% ampoules 2 x 50ml glucose 50% Minijet 1 x 50ml glucose 50% vial 20 x salbutamol 2.5mg nebules 2 x insul
8、in syringesNB Actrapid insulin is stored in the pharmaceutical refrigerator.Protect the cardiac membraneGive 10ml of calcium gluconate 10% intravenously over 2 minutes (Thehyperkalaemia kit contains a box of 10 x 10ml calcium gluconate 10% ampoules) This intervention will not lower the potassium, bu
9、t if ECG changes are present,there should be improvement seen within 1 to 3 minutesShift the potassium from the blood into the cell Withdraw 10 units of Actrapid insulin using an INSULIN syringe. There are twoinsulin syringes in the hyperkalaemia kit. Always obtain a check of volume from a senior nu
10、rse before proceeding. Add to 50ml glucose 50% Minijet as shown in the Standard OperatingProcedure (SOP) in the hyperkalaemia kit (Appendix 1). Use of a Minijet is thepreferred method. If there are any difficulties using a Minijet, use the 50mlglucose 50% vial in the kit. Administer by slow IV injec
11、tion over 5 minutes The onset of the hypokalaemic action occurs within 15 minutes and lasts at least60 minutes. The reduction in potassium observed ranges from 0.6 to 1.0mmol/L Monitor urea and electrolytes (U&Es) 30 minutes after each administration ofinsulin/glucose. If there is a good response, c
12、heck U&Es 1-2 hours after lastintervention.REMOVAL OF POTASSIUM FROM THE BODYHaemodialysisIf despite the above measures the potassium remains greater than 7mmol/L or ifpathological ECG changes/symptoms persist, the renal team should be contacted toarrange urgent dialysis if appropriate.Use the gut C
13、alcium polystyrene sulphonate resin (Calcium Resonium) 15g orally 4 timesdaily with regular lactulose will increase gut losses of potassium. The onset of action is slow (2 hours) and other measures should be employed inthe interim to lower potassium levels. Do not add Calcium Resonium to fruitjuice
14、which has a high potassium content Each gram of Calcium Resonium removes approximately 1mmol/L potassiumfrom the gutMedicines administered for the treatment of hyperkalaemia must be prescribed onthe Kardex. The term units must not be abbreviated when prescribing insulin.3水肿和水中毒的区别。答：液体积聚部位不同：水肿为过多的液
15、体在组织间隙或体腔中积聚 水中毒为细胞内或组织间液中液体含量过多，但轻度水中毒大部分潴留的水分积聚在细胞内，组织间隙中的水潴留不足以引起水肿。 液体的渗透压不同：水肿积聚的液体为等渗性液体，与血浆成分相近，一般不引起细胞水肿。 水中毒细胞外液渗透压降低，可引起细胞水肿 发生时血钠浓度不同：水肿血钠浓度在正常范围内 水中毒血钠浓度降低。 发生原因不同：水肿可归结为两种原因：组织液总量过多和组织液生成大于回流 水中毒原因为肾功能不全导致排水障碍，ADH分泌失调或各种应激状态下ADH分泌增加，低渗性脱水晚期输入大量水分机体症状不同： 水肿的症状：尿量减少，体重增加。不同原因所致水肿，分布部位有差别。右心功能不全所致心性水肿，最先出现于身体低垂部位。立位
