低血鈣的鑒別診斷和治療

1、低血鈣的鑒別診斷與治療,2010-5-14,目錄,鈣磷代謝的調(diào)節(jié)低血鈣的臨床表現(xiàn)低血鈣的病因鑒別診斷治療,鈣磷代謝的激素,PTH維生素D降鈣素,臨床表現(xiàn),急性 神經(jīng)肌肉：麻木感，抽搐，喉痙攣，癲癇發(fā)作 精神癥狀：焦慮，抑郁，記憶力下降，易激惹，精神病 心血管: 心悸，氣短，胸痛，頭暈,臨床表現(xiàn),慢性 基底節(jié)鈣化 皮膚毛發(fā)干燥，指甲易碎

2、 視乳頭水腫 白內(nèi)障 顱內(nèi)壓增加,體格檢查,評(píng)價(jià)神經(jīng)肌肉興奮性 (Chvostek‘s ，Trousseau's signs)心血管：心律失常，心動(dòng)過(guò)緩，低血壓，心衰 頸部手術(shù)瘢痕其他內(nèi)分泌異常 (如腎上腺功能不全)兒童生長(zhǎng)發(fā)育障礙，先天異常，聽(tīng)力障礙，智力障礙提示可能為遺傳病,病因,低白蛋白血癥甲旁低維生素D相關(guān)疾病包括腎功能不全鈣結(jié)合改變骨吸收抑制,甲旁低,PTH分泌減

3、少PTH抵抗（假性甲旁低） 分型1a （Albright's hereditary osteodystrophy), 1b, 1c, and 2,PTH分泌減少,甲狀腺、甲狀旁腺手術(shù)后 (最常見(jiàn)原因） 特發(fā)性(散發(fā))自身免疫性（單獨(dú)或自身免疫多內(nèi)分泌腺綜合癥1型） 甲狀旁腺發(fā)育不良 ( DiGeorge syndrome, hypoparathyroidism-deafness-renal dysplasia

4、, Kenney-Caffey syndrome)浸潤(rùn)性疾病 (地中海貧血，血色病， Wilson disease,腫瘤轉(zhuǎn)移)頸部放療可逆性 (低血鎂，高血鎂) 低血鎂原因：飲酒，藥物，腎臟疾病，代謝性酸中毒，糖尿病，腹瀉，吸收不良，營(yíng)養(yǎng)不良一過(guò)性 （新生兒）,維生素D相關(guān)疾?。?維生素D前體物質(zhì)缺乏: 攝入減少 紫外線照射不足 吸收不良 肝臟疾病 異常肝腸循環(huán) 藥物(phenytoin, phen

5、obarbital) 腎病綜合癥 活性代謝產(chǎn)物轉(zhuǎn)化下降 Vitamin D-dependent rickets type 1 (1 alpha-hydroxylase deficiency) 作用抵抗 Vitamin D-dependent rickets type 2,鈣結(jié)合改變,高血磷 枸櫞酸 呼吸性堿中毒 急性嚴(yán)重疾病（敗血癥，燒傷，胰腺炎，中毒性休克）,骨吸收抑制,降鈣素光輝霉素二磷酸鹽治療,

6、實(shí)驗(yàn)室檢查,血清鈣，游離鈣PTH血磷血鎂腎功能,輔助檢查,ECG：QT間期延長(zhǎng)，心律失常,進(jìn)一步實(shí)驗(yàn)室檢查,25(OH) vitamin D 1,25(OH)2 vitamin D 淀粉酶、脂肪酶ALP電解質(zhì)24小時(shí)尿尿cAMP排泄試驗(yàn),治 療,靜脈輸注葡萄糖酸鈣 ①威脅生命：癲癇發(fā)作，手足搐搦 ，低血壓，心律失常 ②急性低血鈣癥狀,靜脈輸注1,10%葡萄糖酸鈣10~20毫升（10分鐘以上）緩慢靜脈推注

7、（稀釋以后滴注：20毫升入100毫升5%葡萄糖10~15分鐘以上）之后持續(xù)靜脈滴注：0.5~2mg元素鈣/kg/小時(shí)4~6小時(shí)監(jiān)測(cè)血鈣（目標(biāo)血鈣7~9mg/dL）1毫升10%葡萄糖酸鈣含9mg元素鈣1毫升10%氯化鈣含27mg元素鈣,靜脈輸注2,單次短時(shí)間輸注離子鈣 1-1.12 mmol/L: 20ml 10%葡萄糖酸鈣入50-150mL （5% 葡萄糖或 0.9% 氯化鈉 ） 2 小時(shí)輸注.離子鈣<1 mmo

8、l/L: 40 ml 10%葡萄糖酸鈣入50-150mL 4 小時(shí)輸注.糾正電解質(zhì)紊亂（低血鉀，低血鎂）,口服補(bǔ)鈣,元素鈣1500~2000mg/日劑量更高（甲旁低）：起始元素鈣500~1000mg tid,多數(shù)終劑量1000~2000mg tid,目標(biāo)血鈣正常低限，24小時(shí)尿鈣<1mmol/kg (4 mg/kg），減少P攝入副反應(yīng)：胃腸道反應(yīng)（惡心，嘔吐，便秘）,甲旁低,X-linked recessive: Neon

9、atal onsetAutosomal-dominant and autosomal-recessive forms:Chromosome 3q13: Activating mutations in the calcium-sensing receptor (CaSR) geneChromosome 6p23-24: Homozygous loss of function of GCMB gene (transcription

10、factor required for parathyroid gland embryology)Chromosome 10p15: GATA3 gene mutations cause dominantly inherited familial hypoparathyroidism, sensorineural deafness and renal anomaly ([HDR] syndrome).Chromosome 11p:

11、Mutations in the PTH geneChromosome 22q11: DiGeorge syndromeChromosome 21q22 (AIRE gene): Type 1 polyglandular autoimmune diseaseChromosome 20q13: Albright hereditary osteodystrophy,甲旁低,Mitochondria diseases: Kearns-S

12、ayre syndrome (progressive external ophthalmoplegia before age 20 years and pigmentary retinal degeneration, frequently with other organ system involvement including cardiac, neurologic, and hypoparathyroidism),分類1,Trans

13、ientFetal parathyroid suppression: Maternal hypercalcemia, diabetic motherHypomagnesemia: Direct effects (suppressed PTH secretion, increased PTH resistance)Alcohol intoxication,分類2,CongenitalFamilial: X-linked reces

14、sive, autosomal dominant, autosomal recessiveSporadic and isolatedDiGeorge syndrome: Parathyroid gland hypoplasia, thymic hypoplasia/aplasia, facial abnormalities, aortic arch and cardiac defects,分類3,Acquired:Postsurg

15、icalPostirradiationFollowing severe burnsType 1 polyglandular autoimmune disease (Blizzard syndrome): Hypoparathyroidism associated with chronic mucocutaneous candidiasis and autoimmune adrenal insufficiency; can also

16、 have diabetes mellitus, lymphocytic thyroiditis, hypogonadism, pernicious anemia, chronic hepatitisIron deposition: Thalassemia, hemochromatosisCopper deposition: Wilson diseaseMetastatic carcinomaMiliary tuberculos

17、is,分類4,Pseudohypoparathyroidism: Resistance to PTH:Albright hereditary osteodystrophy: G protein mutation,病理生理,Diminished or absent PTH activity results in:Hypocalcemia and hyperphosphatemiaReduced vitamin D activatio

18、n to 1,25(OH)2-vitamin DHypocalcemia leads to increased neural excitability.,體格檢查,Chvostek sign: Facial nerve stimulation (tapping anterior of external auditory meatus) causes contraction of orbicularis oris, producing

19、upper lip or mouth twitch.Trousseau sign: Inflation of BP cuff reduces the blood flow to peripheral motor nerves and thereby can elicit carpopedal spasm in latent tetany.Carpopedal spasmLaryngeal stridorMental status

20、 changesIrritabilityPapilledemaCataractsBradycardia, hypotensionDry skin, coarse hair, brittle nailsAlbright hereditary osteodystrophy (pseudohypoparathyroidism type Ia): Short stature, round face, thick neck, barr

21、el chest, obesity, subcutaneous calcifications, brachydactyly (short 4th metacarpal bones),鑒別診斷,Hypocalcemia:Vitamin D deficiencyVitamin D–dependent rickets type I and IIHyperphosphatemiaPrematurityAcute pancreatiti

22、sMalignancy: Osteoblastic metastases, tumor lysis syndromeMedication: Citrated blood products, phenobarbital, dilantin, phosphate,維生素D治療,1,25(OH)2-vitamin D: 6 years and adults: 0.5–2 mcg/d,預(yù)后,long-term outcome: Develo

23、pment of nephrocalcinosis resulting in renal insufficiency,并發(fā)癥,Hypocalcemia can cause tetany, arrhythmias, seizures, and respiratory arrest.Long-standing untreated hypoparathyroidism and pseudohypoparathyroidism can lea

24、d to intracranial calcifications, especially in the basal ganglia. These may cause extrapyramidal signs (e.g., choreoathetosis, dystonic spasms, parkinsonism). Cognitive impairment and psychiatric disturbances can also b