10.其他 甲状旁腺功能亢进、多发性骨髓瘤、舍格伦综合征、[[淀粉]]样变、[[肾病综合征]]、肾移植排斥反应、高维生素D血症、慢性活动性肝炎。
<span> <span lang="EN-US">(</span>二<span lang="EN-US">)</span>发病机制<span lang="EN-US"></span></span> 混合型发病机制应与Ⅰ、Ⅱ型相似。
<span> 混合型<span lang="EN-US">RTA</span>发病机制应与Ⅰ、Ⅱ型<span lang="EN-US">RTA</span>相似。<span lang="EN-US"></span></span>1. H 梯度缺陷：+转运对管腔管腔[[细胞]]或管腔小管周围梯度的抑制作用异常敏感，其主动转运速度降低。
<span> <span lang="EN-US">1.</span></span><span lang="EN-US"> (2) H<sup>+</sup></span><span>[[主动转运]]致管腔速度降低<span lang="EN-US"></span></span>浓度的抑制后，+由细胞向管腔转运仍低于正常，分泌能力降低。
<span> <span lang="EN-US">2. H(1)</span>梯度缺陷：</span><span lang="EN-US">H<sup> +</sup></span><span>转运对管腔<span lang="EN-US">H+(</span>管腔<span lang="EN-US">-</span>[[细胞反流]]增加：小管[[上皮细胞]]腔[[面膜]]或[[紧密连接]]或管腔<span lang="EN-US">-</span>小管周围<span lang="EN-US">H对+通透性增加，使+</span>梯度<span lang="EN-US">)</span>的抑制作用异常敏感，其主动转运速度降低。<span lang="EN-US"></span></span>由管腔向细胞内反流。
<span> <span lang="EN-US">(2)</span></span><span lang="EN-US"> H<sup>+</sup></span><span>分泌缺陷：即使解除</span><span lang="EN转运缺陷：因管腔+吸收减少或-US">H<sup>[[重吸收]]增加，降低了管腔的负电荷，降低了+</sup></span><span>浓度的抑制后，</span><span lang="EN-US">H<sup>的分泌或增加了+</sup></span><span>由细胞向管腔转运仍低于正常，分泌能力降低。<span lang="EN-US"></span></span>的反流。
<span> <span lang="EN-US">2.</span></span><span lang="EN-US"> H<sup>+</sup></span><span>从管腔到细胞<span lang="EN-US">(</span>或到间质<span lang="EN-US">)</span>弥散速度增加<span lang="EN-US"></span></span> <span> <span lang="EN-US">(1)</span></span><span lang="EN-US"> H<sup>+</sup></span><span>[[反流]]增加：小管[[上皮细胞]]腔[[面膜]]或[[紧密连接]]对</span><span lang="EN-US">H<sup>+</sup></span><span>通透性增加，使</span><span lang="EN-US">H<sup>+</sup></span><span>由管腔向细胞内反流。<span lang="EN-US"></span></span> <span> <span lang="EN-US">(2)</span>依赖电压的</span><span lang="EN-US">H<sup>+</sup></span><span>转运缺陷：因管腔<span lang="EN-US">[[Na]]</span></span><sup><span lang="EN-US">+</span></sup><span>吸收减少或<span lang="EN-US">Cl</span></span><sup><span lang="EN-US">-</span></sup><span>[[重吸收]]增加，降低了管腔的负电荷，降低了</span><span lang="EN-US">H<sup>+</sup></span><span>的分泌或增加了</span><span lang="EN-US">H<sup>+</sup></span><span>的反流。<span lang="EN-US"></span></span> <span> <span lang="EN-US">3.</span>重吸收</span><span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span><span>的能力下降 正常人</span><span lang="EN-US">HCO<sub>3</sub><sup>-</sup><span>85%</span></span><span>在[[近曲小管]]被重吸收，近曲小管酸化功能受损害时，重吸收</span><span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span><span>的能力下降，过多的</span><span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span><span>从尿中排出，这种碳酸氢盐的耗失，使血中</span><span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span><span>含量下降，形成[[酸中毒]]和碱性尿。</span>33333
==混合型肾小管性酸中毒的症状==
混合型[[RTA]]典型者[[临床表现]]有：
===混合型肾小管性酸中毒的检查化验===
<span> <span lang="EN-US">1.</span>[[血液]]化验 主要表现血<span lang="EN-US">K<sup>+</sup></span>、<span lang="EN-US">[[Ca]]<sup>2</sup> <sup>+</sup> </span>、<span lang="EN-US"> [[Na]]<sup>+</sup></span>、<span lang="EN-US">PO<sub>4</sub><sup>3-</sup></span>偏低，血<span lang="EN-US">Cl-</span>增高，[[血浆]]<span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span>减少，<span lang="EN-US">CO2</span>结合力降低血氯升高，血<span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span>降低，血钾正常或降低。<span lang="EN-US"></span></span> <span> <span lang="EN-US">2.</span>尿液化验 尿中无细胞成分，<span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span>[[排泄]]分数多<span lang="ENPOCl-US">HCOCO2HCO 尿液化验 尿中无细胞成分，3<5%</span>，尿<span lang="EN-US">NH<sub>4</sub><sup>+</sup><500mmol/d</span>，<span lang="EN-US">24h</span>尿<span lang="ENd24hKCa NaPO-US">K<sup>+</sup></span>、<span lang="EN-US">Ca<sup>2</sup> <sup>+</sup> </span>、<span lang="EN-US">Na<sup>+</sup></span>、<span lang="EN-US">PO<sub>4</sub><sup>3-</sup>-</span>排出增多。尿<span lang="EN-US">pH>5.5</span>，尿钾排泄量增加。<span lang="EN-US"></span></span>5 负荷试验
<span> <span lang="EN-US">3(1)Ⅰ[[RTA]];0.<1g/span>负荷试验<span lang="EN-US"><(kg.d)3331pHHCOHCO20mmol/spanLpH><5.51mmol/span>(kg.d) 尿铵测定：正常人尿铵排泄量约为，型尿铵排泄量。
<span(3)PCO25%pH0.5h;pH> <span lang="EN-US"pHPCO2>(1)</spanPCO2 2.66kPaHCOPCO2>9.3kPaH+ 尿[[氯化铵胱氨酸]]试验：对可疑和不完全性<span lang="EN-US">Ⅰ</span>型<span lang="EN-US">检查：[[近曲小管]]疾患时常存在[[RTA胱氨酸尿]]</span>常用试验<span lang="EN-US">;</span>给受试者氯化铵<span lang="EN-US">0.1g/(kg.d)</span>，分<span lang="EN-US">3</span>次口服，连续<span lang="EN-US">3</span>天。第<span lang="EN-US">3</span>天每小时留尿<span lang="EN-US">1</span>次，测尿<span lang="EN-US">pH</span>及血<span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span>，当血<span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span>降至<span lang="EN-US">20mmol/L</span>以下时而尿<span lang="EN-US">pH>5.5</span>，有诊断价值。有，如阳性则有助于诊断氰化物硝基氢氰酸盐试验：取尿液加[[肝病浓氨水]]者改用滴，的氰化钠滴，呈紫红色反应为阳性。在[[氯化钙酸负荷试验]]<span lang="EN-US">1mmol/(kg.d)</span>，方法与阳性结果的判定同氯化铵负荷试验。<span lang="EN-US"></span></span>中，如尿或更低，则诊断型的亚型。
<span> <span lang(5) 口服碳酸氢钠法：从开始，逐天加量至，[[酸中毒]]被纠正后，测血、尿3HCOHCO="EN-US">HCO (2mmol/L)<×(ml/span>尿铵测定：正常人尿铵排泄量约为<span lang="EN-US">40mmolmin)/d<HCO (mmol/span>，<span lang="EN-US">Ⅰ</span>型<span lang="ENL)×GFRHCO3-US";ⅡRTA>RTA15%ⅠRTA</span3%5%[[静脉滴入]]碳酸氢钠法：以的速度滴入，持续。注入前测患者血、2HCOpHHCO;3090minpHPCOHCO;60120minpHHCOHCOHCO>尿铵排泄量<span lang15%HCOHCO="EN-US"><40mmol(HCO/d<HCO/span>。<span lang="EN-US"><(/span)HCOⅡRTA HCO>15%ⅠRTA</span>5%ⅠⅡRTA [[影像学]]检查平片或片中可发现鱼籽样[[肾结石]]。并可了解[[骨病]]情况。
<span> <span lang="EN-US">(3)</span>尿<span lang="EN-US">PCO2</span>测定：<span lang="EN-US">5%</span>[[碳酸氢钠]][[静脉滴注]]， 使血<span lang="EN-US">pH</span>维持在<span lang="EN-US">0.5h</span>以上<span lang="EN-US">;</span>当尿<span lang="EN-US">pH></span>血<span lang="EN-US">pH</span>时，尿<span lang="EN-US">PCO2></span>血<span lang="EN-US">PCO2 2.66kPa</span>或更多则有诊断意义。即一旦尿液呈碱性，无论血<span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span>浓度是否恢复正常，如尿<span lang="EN-US">PCO2>9.3kPa</span>可认为集合管<span lang="EN-US">H+</span>分泌能力无异常。<span lang="EN-US"></span></span> <span> <span lang="EN-US">(4)</span>尿[[胱氨酸]]检查：[[近曲小管]]疾患时常存在[[胱氨酸尿]]，如阳性则有助于诊断<span lang="EN-US">(</span>氰化物硝基氢氰酸盐试验：取尿液<span lang="EN-US">5ml</span>加[[浓氨水]]<span lang="EN-US">1</span>滴，<span lang="EN-US">5%</span>的氰化钠<span lang="EN-US">3</span>滴，呈紫红色反应为阳性<span lang="EN-US">)</span>。在[[酸负荷试验]]中，如尿<span lang="EN-US">pH<5.5</span>或更低，则诊断<span lang="EN-US">Ⅱ</span>型<span lang="EN-US">RTA</span>的亚型。<span lang="EN-US"></span></span> <span> <span lang="EN-US">(5)</span>碱负荷试验：<span lang="EN-US"></span></span> <span> <span lang="EN-US">①</span>口服碳酸氢钠法：从<span lang="EN-US">1mmol/(kg.d)</span>开始，逐天加量至<span lang="EN-US">10mmol/(kg.d)</span>，[[酸中毒]]被纠正后，测血、尿<span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span>浓度与[[肾小球滤过率]]，计算尿<span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span>的百分率：尿中<span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span>量<span lang="EN-US">=</span>尿<span lang="EN-US">HCO<sub>3</sub><sup>-</sup> (mmol/L)×</span>[[尿量]]<span lang="EN-US">(ml/min)/</span>血浆<span lang="EN-US">HCO<sub>3</sub><sup>-</sup> (mmol/L)×GFR</span>。正常人尿<span lang="EN-US">HCO3-</span>为零<span lang="EN-US">;Ⅱ</span>型、混合型<span lang="EN-US">RTA>15%</span>，<span lang="EN-US">Ⅰ</span>型<span lang="EN-US">RTA<3%</span>～<span lang="EN-US">5%</span>。<br /><br /><span lang="EN-US"> ②</span>[[静脉滴入]]碳酸氢钠法：以<span lang="EN-US">4ml/min</span>的速度滴入<span lang="EN-US">5%NaHC03</span>，持续<span lang="EN-US">2h</span>。注入前测患者血<span lang="EN-US">pH</span>、<span lang="EN-US">PCO<sub>2</sub></span>、<span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span>浓度和尿<span lang="EN-US">pH</span>、<span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span>浓度<span lang="EN-US">;</span>以后分别在注入<span lang="EN-US">30</span>，<span lang="EN-US">90min</span>后测血<span lang="EN-US">pH</span>、<span lang="EN-US">PCO<sub>2</sub></span>、<span lang="EN-US">HCO<sub>3</sub><sup>-</sup>;60</span>，<span lang="EN-US">120min</span>测尿<span lang="EN-US">pH</span>和<span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span>，在患者血<span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span>恢复正常时，尿中<span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span>排泄量<span lang="EN-US">></span>[[肾小球]]滤过量的<span lang="EN-US">15%</span>，提示近曲小管<span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span>[[吸收障碍]]。尿<span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span>排泄分数<span lang="EN-US">=(</span>尿<span lang="EN-US">HCO<sub>3</sub><sup>-</sup>/</span>血浆<span lang="EN-US">HCO<sub>3</sub><sup>-</sup>/(</span>尿[[肌酐]]<span lang="EN-US">/</span>血肌酐<span lang="EN-US">)</span>。血浆<span lang="EN-US">HCO<sub>3</sub><sup>-</sup></span>浓度正常时，<span lang="EN-US">Ⅱ</span>型<span lang="EN-US">RTA HCO<sub>3</sub><sup>-</sup></span>排泄分数<span lang="EN-US">>15%</span>，<span lang="EN-US">Ⅰ</span>型<span lang="EN-US">RTA<5%</span>。此法可鉴别<span lang="EN-US">Ⅰ</span>型、<span lang="EN-US">Ⅱ</span>型<span lang="EN-US">RTA</span>。<span lang="EN-US"></span></span> <span> <span lang="EN-US">4.</span>[[影像学]]检查<span lang="EN-US"> KUB</span>平片或<span lang="EN-US">IVP</span>片中可发现鱼籽样[[肾结石]]。并可了解[[骨病]]情况。<span lang="EN-US"></span></span> <span> <span lang="EN-US">5.</span>[[超声波]]检查 可了解[[肾脏]]有无[[钙化]]及[[结石]]。<span lang="EN-US"></span></span>
===混合型肾小管性酸中毒的鉴别诊断===
本病需与Ⅰ型、Ⅱ型[[RTA]]及[[肾小球]][[疾病]]所致[[代谢性酸中毒]]鉴别，后者常有[[肾小球滤过率下降]]，[[氮质血症]]的[[临床表现]]。也需与氮质[[潴留]]所致[[酸中毒]]的其他疾病和其他类型[[肾小管性酸中毒]]鉴别。如[[远端肾小管性酸中毒]]有时与[[尿毒症]]酸中毒可混淆，但尿毒症的代谢性酸中毒有氮质血症和血磷增高，鉴别不难。
==混合型肾小管性酸中毒的护理==
对已病患者要积极治疗，防止病情进展，争取预后良好。
==参看==
*[[肾内科疾病]]
[[分类:肾内科疾病]]
== 百科帮你涨知识 ==
