低血钙鉴别诊断与治疗

目录钙磷代谢的调节低血钙的临床表现低血钙的病因鉴别诊断治疗第1页/共37页钙磷代谢的激素PTH维生素D降钙素第2页/共37页第3页/共37页第4页/共37页临床表现急性神经肌肉：麻木感，抽搐，喉痉挛，癫痫发作精神症状：焦虑，抑郁，记忆力下降，易激惹，精神病心血管:心悸，气短，胸痛，头晕第5页/共37页临床表现慢性基底节钙化皮肤毛发干燥，指甲易碎视乳头水肿白内障颅内压增加第6页/共37页体格检查评价神经肌肉兴奋性(Chvostek‘s，Trousseau'ssigns)心血管：心律失常，心动过缓，低血压，心衰颈部手术瘢痕其他内分泌异常(如肾上腺功能不全)儿童生长发育障碍，先天异常，听力障碍，智力障碍提示可能为遗传病第7页/共37页病因低白蛋白血症甲旁低维生素D相关疾病包括肾功能不全钙结合改变骨吸收抑制第8页/共37页甲旁低PTH分泌减少PTH抵抗（假性甲旁低）分型1a（Albright'shereditaryosteodystrophy),1b,1c,and2

第9页/共37页PTH分泌减少甲状腺、甲状旁腺手术后(最常见原因）特发性(散发)自身免疫性（单独或自身免疫多内分泌腺综合症1型）甲状旁腺发育不良(DiGeorgesyndrome,hypoparathyroidism-deafness-renaldysplasia,Kenney-Caffeysyndrome)浸润性疾病(地中海贫血，血色病，Wilsondisease,肿瘤转移)颈部放疗可逆性(低血镁，高血镁)

低血镁原因：饮酒，药物，肾脏疾病，代谢性酸中毒，糖尿病，腹泻，吸收不良，营养不良一过性（新生儿）

第10页/共37页维生素D相关疾病：维生素D前体物质缺乏:

摄入减少紫外线照射不足吸收不良肝脏疾病异常肝肠循环药物(phenytoin,phenobarbital)

肾病综合症活性代谢产物转化下降VitaminD-dependentricketstype1(1alpha-hydroxylasedeficiency)作用抵抗

VitaminD-dependentricketstype2第11页/共37页钙结合改变高血磷

枸橼酸

呼吸性碱中毒急性严重疾病（败血症，烧伤，胰腺炎，中毒性休克）第12页/共37页骨吸收抑制降钙素光辉霉素二磷酸盐治疗第13页/共37页实验室检查血清钙，游离钙PTH血磷血镁肾功能第14页/共37页辅助检查ECG：QT间期延长，心律失常第15页/共37页进一步实验室检查25(OH)vitaminD1,25(OH)2vitaminD

淀粉酶、脂肪酶ALP电解质24小时尿尿cAMP排泄试验第16页/共37页第17页/共37页第18页/共37页治疗静脉输注葡萄糖酸钙①威胁生命：癫痫发作，手足搐搦，低血压，心律失常②急性低血钙症状第19页/共37页静脉输注110%葡萄糖酸钙10~20毫升（10分钟以上）缓慢静脉推注（稀释以后滴注：20毫升入100毫升5%葡萄糖10~15分钟以上）之后持续静脉滴注：0.5~2mg元素钙/kg/小时4~6小时监测血钙（目标血钙7~9mg/dL）1毫升10%葡萄糖酸钙含9mg元素钙1毫升10%氯化钙含27mg元素钙第20页/共37页静脉输注2单次短时间输注离子钙1-1.12mmol/L:20ml10%葡萄糖酸钙入50-150mL（5%葡萄糖或0.9%

氯化钠）2小时输注.离子钙<1mmol/L:40ml10%葡萄糖酸钙入50-150mL4小时输注.纠正电解质紊乱（低血钾，低血镁）第21页/共37页口服补钙元素钙1500~2000mg/日剂量更高（甲旁低）：起始元素钙500~1000mgtid,多数终剂量1000~2000mgtid,目标血钙正常低限，24小时尿钙<1mmol/kg(4mg/kg），减少P摄入副反应：胃肠道反应（恶心，呕吐，便秘）第22页/共37页第23页/共37页第24页/共37页第25页/共37页甲旁低X-linkedrecessive:NeonatalonsetAutosomal-dominantandautosomal-recessiveforms:Chromosome3q13:Activatingmutationsinthecalcium-sensingreceptor(CaSR)geneChromosome6p23-24:HomozygouslossoffunctionofGCMBgene(transcriptionfactorrequiredforparathyroidglandembryology)Chromosome10p15:GATA3genemutationscausedominantlyinheritedfamilialhypoparathyroidism,sensorineuraldeafnessandrenalanomaly([HDR]syndrome).Chromosome11p:MutationsinthePTHgeneChromosome22q11:DiGeorgesyndromeChromosome21q22(AIREgene):Type1polyglandularautoimmunediseaseChromosome20q13:Albrighthereditaryosteodystrophy第26页/共37页甲旁低Mitochondriadiseases:Kearns-Sayresyndrome(progressiveexternalophthalmoplegiabeforeage20yearsandpigmentaryretinaldegeneration,frequentlywithotherorgansysteminvolvementincludingcardiac,neurologic,andhypoparathyroidism)第27页/共37页分类1TransientFetalparathyroidsuppression:Maternalhypercalcemia,diabeticmotherHypomagnesemia:Directeffects(suppressedPTHsecretion,increasedPTHresistance)Alcoholintoxication第28页/共37页分类2CongenitalFamilial:X-linkedrecessive,autosomaldominant,autosomalrecessiveSporadicandisolatedDiGeorgesyndrome:Parathyroidglandhypoplasia,thymichypoplasia/aplasia,facialabnormalities,aorticarchandcardiacdefects第29页/共37页分类3Acquired:PostsurgicalPostirradiationFollowingsevereburnsType1polyglandularautoimmunedisease(Blizzardsyndrome):Hypoparathyroidismassociatedwithchronicmucocutaneouscandidiasisandautoimmuneadrenalinsufficiency;canalsohavediabetesmellitus,lymphocyticthyroiditis,hypogonadism,perniciousanemia,chronichepatitisIrondeposition:Thalassemia,hemochromatosisCopperdeposition:WilsondiseaseMetastaticcarcinomaMiliarytuberculosis第30页/共37页分类4Pseudohypoparathyroidism:ResistancetoPTH:Albrighthereditaryosteodystrophy:Gproteinmutation第31页/共37页病理生理DiminishedorabsentPTHactivityresultsin:HypocalcemiaandhyperphosphatemiaReducedvitaminDactivationto1,25(OH)2-vitaminDHypocalcemialeadstoincreasedneuralexcitability.第32页/共37页体格检查Chvosteksign:Facialnervestimulation(tappinganteriorofexternalauditorymeatus)causescontractionoforbicularisoris,producingupperlipormouthtwitch.Trousseausign:InflationofBPcuffreducesthebloodflowtoperipheralmotornervesandtherebycanelicitcarpopedalspasminlatenttetany.CarpopedalspasmLaryngealstridorMentalstatuschangesIrritabilityPapilledemaCataractsBradycardia,hypotensionDryskin,coarsehair,brittlenailsAlbrighthereditaryosteodystrophy(pseudohypoparathyroidismtypeIa):Shortstature,roundface,thickneck,barrelchest,obesity,subcutaneouscalcifications,brachydactyly(short4thmetacarpalbones)第33页/共37页鉴别诊断Hypocalcemia:VitaminDdeficiencyVitaminD–dependentricketstypeIandIIHyperphosphatemiaPrematurityAcutepancreatitisMalignancy:Osteoblasticmetastases,tumorlysissyndromeMedication:Citratedbloodproducts,phenobarbital,dilantin,phosphate第34页/共37页维生素D治疗1,25(OH)2-vitaminD:<1year:0.04–0.08mcg/kg/d;1–5years:0.25–0.75mcg/d;>6yearsandadults:0.5–2mcg/d第35页/共37页预后long-termou