◐General Nephrology

Type I and II RTA (also normal urine FeCa/FeP/FeUA; FeCa<0.02, FeP 0.05-0.20, FeUA 0.04-0.12)

Electrolyte約 25 分鐘8 個章節

1.RTA features#

    • 註:NaHCO3 loading test:0.5-1mEq/kg/hr(或 100mEq/hr), check UpH Q0.5-1H, 關鍵前提為須持續補鹼直至血中 HCO3- 正常化(>20-22 mmol/L)且 UpH 連續三次 >7.5:
      • 正常人當UpH>7.5, UPCO2(因為distal tubules幾乎沒有type IV CA, 所以Urine CO2可代表distal tubules排酸能力)應>70mmHg and U-B(urine-blood) PCO2應>20mmHg; 正常人與 type I(distal) RTA 之 FeHCO3 <3-5%; type II(proximal) RTA 在補鹼至血中正常濃度(>20-22)時 FeHCO3 >15-20%; type IV RTA 之 FeHCO3 <5-10%
      • Classical type I RTA:UPCO2<50mmHg, U-B(urine-blood) PCO2<10mmHg, FeHCO3<5%
      • Gradient classical type I RTA(Backleak(=gradient) distal RTA(ampho B...)):UPCO2>70mmHg; 原始UpH>5.1
        • 若Basolateral Cl-bicarbonate exchanger (SLC4A1 gene, encoding AE1) mutation且AE1由basolateral跑到apical membrane則因為會將HCO3-交換入lumen中(distal HCO3-secretion(雖然表現和backleak一樣, 但不叫此名字)), 所以一樣UPCO2>70mmHg; 原始UpH>5.1
      • Low NH3 available:UPCO2>70mmHg; 原始UpH<5.1 (=normal response?)
        • Due to PCT problems(so some type II RTA?) or hyperkalemia or CKD(eGFR 20-50ml/min) or IN/medullary interstitial disease(因為↓NH3 accumulation in the interstitium, 可能合併classical type I RTA而使UpH~6)
      • Type II RTA:當Serum HCO3>18-20時, UpH>7.5 with FeHCO3>15-20%
      • type IV RTA:normal results, FeHCO3 5-10% (=normal response?)
      • 其實UpH沒有分得那麼明確, 互有overlap
      • 見下述UpH limitations
  • Type I RTA pathophysiology
    • Decreased H-ATPase activity in collecting tubules(most common type)
      • Medullary collecting duct若lumen中的pH太高, 也會使NH3無法放出(why?身體覺得不需要?)而更使H+無法排出
        • 所以Type I RTA其urine NH3也↓ !!
          • 但見下述3.Etiology of type I RTA(CTIN類的可type I and IV RTA)-D/D-小心incomplete form type I RTA
            • 似乎NH3也可以代償性↑
    • Or increased luminal membrane permeability(導致K, Mg流出, H流入cells) Ampho B mechanism（gradient classical type I RTA）
    • For K+ losing mechanism in type I RTA
      • Metabolic acidosis本身會抑制NaCl被proximal tubules再吸收(why??, 雖然NaHCO3再吸收↑, 猜測是因為metabolic acidosis-->NHE3↑, Na多由NHE3 resorption而少由Na-A.A. or SGLT...被吸收, 導致luminal potential less negative而影響Cl-的再吸收?)-->(1)↑distal delivery of Na-->↑ K excretion (2)Na↓/volume contraction-->RAAS↑-->↑ K excretion
        • 或許是身體保護自己的機制? 因為metabolic acidosis會hyperkalemia by transcellular shifting
      • Na在collecting tubules是和Cl-(註:吸收較快) or HCO3-(註:吸收較慢)一起吸收 or 是和H+ or K+ exchange; 所以不排H+, 就會1.多排K+(Na-H exchange↓-->Na-K exchange↑)
      • H+-K+ exchanger of collecting ducts也可能有問題, 導致K+ reabsorption↓
      • 所以若補NaHCO3
        • 1.矯正metabolic acidosis使↑Na被proximal tubules再吸收-->↓distal delivery of Na-->↓ K excretion
        • 2.↓RAAS by volume expansion
        • 3.Increase luminal pH-->collecting ducts可排H+(=H+ATPase作用↑?)-->Na-H exchange↑-->Na-K exchange↓
        • 上述結果會可使hypokalemia改善!
    • 會hypercalciuria
      • 因為metabolic acidosis-->1. bone放出Ca, P, Mg由kidney排出(acidosis也抑制renal再吸收Ca and Mg(by ↓TRPV5(Transient receptor potential cation channel subfamily V member 5, 和distal nephrons吸收Ca有關) and ↓TRPM6(見hypomagnesiumhypomagnesium) and P)(回思milk-alkali syndrome, metabolic alkalosis會↑Ca resorption), 2.hypocitraturia(metabolic acidosis本身會使p. tubules再吸收Citrate↑(感覺是一種代償?, 因為citrate在體內會變成HCO3, 部分也因為dehydration?, 因為metabolic acidosis會使p. tubules intracellular acidosis-->citrate metabolic rate↑-->更易吸收; 也會使p. tubules intraluminal acidosis使citrate由3價變成2價而容易被p. tubules的sodium-citrate cotransporter再吸收)
      • 因為hypercalciuria+urine alkalization-->nephrocalcinosis(60-80%)
        • type II比較不會Ca-P沉積(nephrocalcinosis, stones), 因為1. 有可能p tubules dysfunction無法再吸收citrate(所以看urine citrate(normal:~400mg/d)也可以分辨type I or type II RTA) 2.[UpH可較低(可同正常人) 且bone不再需要釋放Ca-P to buffer unexcreted acid ]if under steady state
  • Type II RTA pathophysiology
    • For K+ losing mechanism in type II RTA
      • Metabolic acidosis本身會抑制Na被proximal tubules再吸收(also proximal tubule dysfunction而loss Na+)-->↑distal delivery of Na-->↑ K excretion
      • 可能proximal tubules dysfunction而loss K+
      • Loss Na/volume contraction-->RAAS↑
      • 若給Soda for metabolic acidosis-->Na+ and HCO3- distal delivery↑(因為proximal tubules dysfunction, 就算改善acidosis, 給的Soda反而使distal Na+ delivery↑)-->反而↑ K excretion(vs. type I RTA)(即使dehydration改善->RAAS↓?)
  • Volume contraction會↑Cl-resorption-->hyperchloremic metabolic acidosis

2.Bicarbonate physiology#

    • 正常proximal tubules每天約再吸收4000mEq的Bicarbonate(if GFR:125==>1251440/100024*0.9=3888mEq), 藉由Na-K pump, 使cell內Na濃度低, lumen中Na濃度約同serum(因為GFR出來的嘛...)-->drive apical Na-H exchanger(NHE3)-->H+和lumen中的HCO3變成CO2 by CA IV-->CO2入cell-->CO2+H2O變成-->H+ and HCO3-->H+再被丟出去, HCO3和Na被吸收(by basolateral NBC1)

3.Etiology of type I RTA(基本上若機制是因為disease影響distal tubules/collecting ducts, 則可type I, IV RTA)#

  • I
    • HIV(因為TIN?)(可type I, IV RTA)
  • I
    • M Sjogren's syndrome(可type II但多type I), SLE(type I, II, IV RTA), RA, AIH/PBC...
      • 研究發現Sjogren's syndrome的病人可complete absence of H+-ATPase activity in collecting tubules; 也可以Ab to CA II
      • Renal transplantation rejection(可type I, II, IV)
  • M
    • C Amyloidosis(可type I, II, IV RTA)
  • H
    • O hypercalciuria/hyperoxaluria status(uncommon)
      • 回思hypercalcemia可type I RTA
    • D/D Hyperparathyroidism(可type I + type II RTA)
      • 原發性副甲亢直接抑制近曲小管 NHE3 與 Na-Pi 吸收 → 呈現 type II RTA;長期高尿鈣與腎鈣化損害遠端小管後, 可續發 type I RTA
    • Drugs
      • Ifosfamide(可type I, II RTA)
      • Ampho B(gradient classical type I RTA)
        • Increased luminal membrane permeability(導致K, Mg流出, H流入cells)
        • Also increase ADH resistance-->NDI
      • Lithium(可type I, IV RTA)
      • Ibuprofen(long term use)(type I, IV)
        • Mechanism unknown; 停藥之後多數天內回復
        • 其他NSAID好像不會type I(但可以type IV RTA by NSAID, 因為↓renin...)
    • Tubular defect
      • Basolateral Cl-bicarbonate exchanger (SLC4A1 gene, encoding AE1) mutation(多AD, 可AR)
        • 症狀和backleakage distal RTA類似(見上述1.RTA features)
        • Without sensorineural hearing impairment
        • 因為RBC membrane上也有此exchanger, 可cause hereditary spherocytosis(會true hemolysis), pseudohyperkalemia(exchanger變得可通過Na, K+而由RBC內跑出來)而實際上是hypokalemia due to type I RTA) and Southeast Asian ovalocytosis(SAO)
          • AR form比較嚴重
      • Apical H+-ATPase (ATP6V0A4 and ATP6V1B1 genes) mutation)(AR)
        • (ATP6V1B1 mutation)With sensorineural hearing impairment(因為requirement for active H+ secretion to maintain proper endolymph pH)
          • ATP6V0A4不太會deafness
        • Endemic(Northeastern Thailand)
          • Possible abnormality in H+-K+- ATPase
    • Wilson's disease(type I, II RTA, 註:也可以hypoparathyroidism due to Cu depositions)
    • ADTKD(因為cTIN?)
  • H
    • Sickle cell anemia nephropathy(可type I, IV RTA)
      • 因為medullary ischemia?
  • O
    • Obstructive uropathy/chronic PN(可type I, IV)
    • Medullary sponge kidney(可type I, IV, nephrocalcinosis, renal stones)
    • CKD本身(when EGFR 20-50ml/min, 尤其CKD原因是TIN者)(原因是p. tubules製造NH3↓, 而OMCD分泌NH3也↓)(serum K+ level基本上是正常的)
      • 其實好像不應該歸類成type I RTA, 因為剩下的nephrons都有好好工作, 只是buffer不夠身體所需導致無法排出daily產生的酸
  • D/D
    • High AG metabolic acidosis later changed to non-AG metabolic acidosis者(DKA, D-lactic acidosis, toluene ingestion(註:chronic acetaminophen ingestion是high AG metabolic acidosis with (Na- unmeasured anions excretions or NH4-unmeasured anions excretion)-但好像不太會漸漸變成non-AG metabolic acidosis? why?); 因為有可能non-AG MA+high UAG+(high UpH?); 此時可看UOG來D/D)
    • 小心incomplete form type I RTA
      • 可normal HCO3 level with persistent UpH>5.3(net acid excretion is normal and achieved by increased NH4+ excretion); 不過HCO3 loading後U-P CO2會<30mmHg and NH4Cl loading後UpH也不會<5.3; 另外會有persistent hypocitraturia(due to chronic metabolic acidosis(可能在incomplete type I RTA是intermittent metabolic acidosis) or other unknown causes)-->nephrocalcinosis
        • Metabolic acidosis本身會使proximal tubule↑citrate reabsorption(因為metabolic acidosis會使p. tubules intracellular acidosis-->citrate metabolic rate↑-->更易吸收; 也會使p. tubules intraluminal acidosis使citrate由3價變成2價而容易被p. tubules的sodium-citrate cotransporter再吸收)
      • 會漸漸變成complete form, 因為NH3導致的IN and nephrocalcinosis導致的tubular injury

4.Etiology of type II RTA#

  • I
    • Sjogren's syndrome(大多type I +/- II)
      • 會Fanconi syndrome
    • Renal transplantation(type I, II, IV)
      • 會Fanconi syndrome
    • Other AIR diseases:除 Sjögren 與 SLE 外, 類風濕性關節炎(RA)與橋本氏甲狀腺炎亦有自體免疫性近端 RTA/Fanconi 之報告
  • M
    • MM, amyloidosis(可type I, II, IV RTA), LCDD(應該也是type I, II, IV RTA?; type II RTA主要原因是light chains堆積在proximal tubules內, 又不能被lysosomal proteases消化, 導致proximal tubules dysfunction)
      • 會Fanconi syndrome(light chain proximal tubulopathy)
    • PNH(因為hemoglobin傷tubules?)
  • M
    • Alcoholism
      • 會Fanconi syndrome
    • Vitamin D deficiency(可以Fanconi, 因為hypocalcemia造成iPTH上升而造成RTA I+II+hypophosphatemia(hypophosphatemia也可↑kidney loss Ca, Mg), 本身RTA and hypovolemia induced RAAS再造成hypokalemia(hypokalemia也可↑kidney loss Ca, Mg)); 但似乎無法完全解釋, 詳細病理機轉未明)
      • 會Fanconi syndrome
        • 話說, Fanconi syndrome本身應該也會↓25-OH vitamin D的resorption?
    • Hyperparathyroidism(可type I + type II RTA)
      • Serum Cl-(mM)/P(mg/dL) ratio多>33 (vs. other hypercalcemia etiologies)
    • Toxins(鉛鎘汞銅)
      • Lead
        • 會cTIN/hyperuricemia/Fanconi syndrome
      • Cadmium
        • 會cTIN/Fanconi syndrome
      • Mercury
        • 會Fanconi syndrome
      • Copper(回思Wilson's syndrome會type I+II RTA, nephrocalcinosis)
        • 會Fanconi syndrome
  • Drugs
    • Tenofovir
      • 會Fanconi syndrome
    • Ifosfamide(type I, II RTA)
      • 會Fanconi syndrome
      • 可持續很久, even many years
    • Aminoglycoside
      • 會Fanconi syndrome
      • 也會Bartter's syndrome type V
    • Cisplatin(會傷害所有nephrons區域, 所以TMA, type II RTA/Fanconi, Bartter's syndrome, Gitelman's syndrome, type I RTA, NDI, SIADH...都可以), Alimta
      • 會Fanconi syndrome
    • Azol(acetazolamide), Topamax(topiramate; 20%Pts會non-AG MA)(也抑制carbonic anhydrase II) [此二者只影響bicarbonate; 不過Azol也會hypophosphatemia(因為Increased proximal tubules PTH sensitivity)]
      • Azol使用後會↓proximal tubules吸收Na, water, HCO3==>natriuresis會↑K+ excretion, 如前述也會↑Pi excretion; 且會↑UCa(抑制近端小管Ca再吸收)＋↓urine citrate==>碳酸酐酶抑制劑(acetazolamide/topiramate/zonisamide)是Ca-P結石的經典藥物
        • 雖然↑K+ excretion, 但因為同時伴隨metabolic acidosis, 所以少有hypokalemia
      • Type II為主, 但其實也有type I RTA(因為CA II distal nephrons也有)
    • Valproic acid
      • 會Fanconi syndrome
    • Deferasirox
      • 會Fanconi syndrome(也可GN, IN, TN)
  • C
    • Proximal tubule Na bicarbonate co-transporter (NBCe1) defect(SLC4A4 gene)(AR)
      • Associated with ocular abnormalities and short stature
      • 比較常見(雖然是AR...)
    • Proximal tubule sodium-hydrogen exchanger(NHE3) mutation(AD)
      • Associated with short stature
      • 少見
    • Wilson's disease(type I, II RTA, nephrocalcinosis)
      • 會Fanconi syndrome
    • Cystinosis(AR)
      • CTNS(cystinosis) gene mutation
      • 是一種lysosomal storage disease, 在細胞內堆積cystine消化不掉
      • 會Fanconi syndrome; 也會hypothyroidism, distal vacuolar myopathy, cystine crystal deposition in cornea(fusiform crystals involving the anterior third of the central cornea and the full thickness of the peripheral cornea), CNS disease, type I DM(20-40 y/o~)
        • most frequent cause of inherited renal Fanconi's syndrome
        • Diagnosis:Measuring the cystine content of peripheral leukocytes or characteristic corneal crystals on slit-lamp examination
        • Tx:cysteamine(by forming the mixed disulfide cysteine-cysteamine and exiting the lysosome via the lysine transporter)
    • Tyrosinemia type I(AR)
      • 會Fanconi syndrome
    • Hereditary fructose intolerance
      • 這些病患僅能將fructose代謝成fructose 1-phosphate(by fructokinase), 無法繼續代謝下去, 會導致intracellular phosphate depletion, 導致ATP↓而↓Na-K+ pump function-->Fanconi syndrome(在腎臟中因為僅p. tubules有fructokinase, 所以僅影響p. tubules)
    • Galactosemia
      • 會Fanconi syndrome
    • Glycogen storage disease (type I)(AR)
    • Lowe's syndrome(Oculocerebrorenal syndrome)
      • X-linked
      • 會Fanconi syndrome
    • Dent's disease
      • X-linked, 會Fanconi syndrome-->nephrocalcinosis
      • CLCN5 gene mutation
    • Mitochondrial disease
      • 會Fanconi syndrome, 也會FSGS
  • O
    • Nephrotic syndrome(因為p. tubules吸收太多proteins導致dysfunction?)

5.Etiology of type III RTA#

  • I
    • Sjogren's syndrome(大多type I +/- II)
    • Renal transplantation(type I, II, IV RTA)
  • M
    • Hyperparathyroidism(Type I(due to hypercalciuria?)+type II)
    • Drugs
      • Ifosfamide(type I, II RTA)
  • C
    • Carbonic anhydrase II mutation(AR)(是狹義的type III RTA)(又叫Guibaud-Vainsel syndrome or marble brain disease)
      • 多也有osteopetrosis, mental retardation, cerebral calcification, ocular abnormalities
    • Wilson's disease(type I, II RTA, nephrocalcinosis)

5-1.RTA 核心鑑別總表(必背)#

特徵 Type I(distal) Type II(proximal) Type IV(hypoaldo)
血鉀 低血鉀 低血鉀(補鹼後更低) 高血鉀(主病因)
酸中毒時尿 pH >5.3-5.5(無法酸化) <5.3(穩態時可排酸) <5.3(可排酸但 NH3 不足)
NaHCO3 負荷 FeHCO3 <3-5% FeHCO3 >15-20% FeHCO3 <5-10%
Urine AG 陽性(>0) 變動/陽性 陽性(>0，典型高)
Urine osmolal gap <100(排 NH4+ 障礙) >150-200(正常) <100(NH3 製造受抑)
腎鈣化/結石 常見(60-80%) 罕見(以骨軟化/佝僂為主) 極罕見
尿檸檬酸 顯著低下 正常或偏低 正常
治療 補鹼 1-2 mEq/kg/d(K-citrate) 補鹼 10-30 mEq/kg/d ± thiazide 降鉀、fludrocortisone、利尿劑
  • UAG vs UOG 判讀
    • UAG = UNa + UK − UCl: 腹瀉等腸胃道流失 UAG < −20(NH4Cl 排泄正常增加); RTA 則 UAG > 0
    • 有非氯陰離子時(DKA、D-lactate、toluene、補鹼中)UAG 會失真, 一律改看 UOG
      • UOG = Uosm − [2(UNa+UK) + UGLU/18 + UUN/2.8]; 估 U_NH4+ ≈ UOG/2
      • 代酸下 U_NH4+ < 40 mmol/L(UOG < 100) 代表腎臟排酸不足(RTA)

6.Approaching#

  • 確定non-AG metabolic acidosis
  • Check UpH, UAG, UOG
    • UpH limitations
      • Acidosis原則上UpH應<5.3(註:UpH下限約4.5-5.0(見Metabolic acidosisMetabolic acidosis)), 但下述情況UpH可>5.5
        • 1.RTA(不過type II RTA在steady state時可UpH<5.3; type IV RTA也可以UpH<5.3)
        • 2.Hypokalemia(因為會製造許多NH3-->NH4+-->↑UpH, 不過UAG, UOG應該仍是準的)
        • 3.UTI(Urea-->NH4+ and bicarbonate; 此時UOG and UpH不準, UAG應該不影響)
        • 4.Severe dehydration(因為↓distal Na delivery會↓H+ secretion by cortical collecting ducts)
          • UNa應>25才能reliably判斷UpH(回思TTKG也一樣需要UNa>25)
      • UpH並非很好的marker, 因為acute acidosis和chronic acidosis時, NH3產生的量不一樣(如上圖)
      • 在chronic acidosis時, UpH=6 urine排出最多NH4+, 此時若UpH<5多代表PCT NH3產生不夠, 此時若UpH>7多代表distal nephron排酸有問題, 此時若UpH=6也可能是NH3不足+distal nephron排酸有問題(如:medullary interstitial disease(因為↓NH3 accumulation in the interstitium+type I RTA))
    • UAG limitations
      • 細節見Metabolic acidosis-UAG limitations(主檔, 不在此重複); 要點: 排 NH4-非Cl anions(DKA、D-lactic、toluene、type II RTA 給 soda、chronic acetaminophen)時 UAG 會假性偏高, high AG 代酸幾乎不能用 UAG 看排酸能力; Brenner(p1076): 建議改用 UOG
    • UOG limitations
      • 若有其他osmos(如醇類, mannitol...)會假性偏高(可測Sosm, serum osmo gap評估)
      • 理論上有其他(non-Na, non-K, non-NH4+的陽離子)+anions也會影響
      • if UTI with urease(會由urea產生NH4+ and HCO3)-->↑UOG but 並非kidney排NH4+
    • D/D by UpH(U/A), UNa(需>25才能看UpH), UAG, UOG, U/A, U/C(以免UTI時UOG不準), Ucitrate, Sosm, Serum osmo gap(以免血中有其他osmos, UOG不準), bicarbonate loading with UpH and FeHCO3(D/D type I and II), SCa(hypercalcemia會type I RTA), iPTH, other urine data(for FeNa, FeK, FeCa, FeP, FeUA, FeMg, glycosuria, proteinuria for potential Fanconi syndrome), one touch(for DKA and 評估是否有glycosuria but no DM), Lactate(for lactic acidosis and D-Lactate(但不是所有實驗室都可驗出D-lactate)), drugs/toxins screen/review(小心重金屬), FH, MM surveillance, AIR surveillance, Vitamin D, renal echo(obstructive uropathy)
      • Normal FeCa : ~0.5-2%(至多4%; FHH<1%, primary hyperparathyroidism>2%), normal UCa 100-250mg/d(若吃low calcium diet可50-150mg/d, 若吃calcium free diet可5-40mg/d)
      • Normal FeP: 5-20%, 所以TRP normal:0.80-0.95, normal urine P:400-1000mg/d; TmP/GFR(mg/dL) normal:2.5-4.5
        • If TRP<0.86(此時表示loss P很多, 表示tubules再吸收達上限, 表示(再吸收 and P excretion)和Serum P成正比)
          • 則TmP/GFR(maximal tubular phosphate reabsorption to GFR) = TRP*serum P
            • 因為磷最大吸收量(TmP)=GFRserum PTRP (when TRP<0.86)
        • If TRP>0.86
          • 則TmP/GFR=[(0.3TRP)/(1-0.8TRP)]*serum P
        • Normal TmP/GFR if >=18y/o : 2.5-4.5 (單位為P的單位(mg/dL))
          • 不過Brenner(p812)的公式是
            • TmP/GFR (mg/dL)=Serum Pi(mg/dL)-[Urine Pi(mg/dL)*(Scre/Ucre)]
            • Normal range一樣是2.5-4.5mg/dL(不受Age影響)
      • Normal FeUA : 4-12%; UUA/Ucre>0.8
        • ↓in pre-renal AKI(因為proximal tubules resorption↑?); ↑in SIADH(V1 effect使排UA↑), intrinsic AKI
        • Normal values in healthy adults are 8±3% in males and 13±3% in females; The normal FEUA in healthy children is even higher (18±5%)

7.Tx#

  • Tx of underlying diseases
  • Type I RTA
    • Correction of metabolic acidosis to ↓K loss and ↓hypercalciuria and other metabolic acidosis S/E
      • Soda and Na-citrate 1~2mEq/kg/d(小孩需要多一點, 因為酸產生較多)
        • Goal bicarbonate level:22-24mM(=in normal range)
          • ERKNet dRTA Registry (Nephrol Dial Transplant 2026; PMID 41790493)：遠端 RTA 歐洲 5 年前瞻登記世代(n=214)，病童身高發育(Height SDS)隨血清重碳酸鹽達標改善，支持治療目標維持 24 mmol/L｜身高 SDS 在 HCO3 達 22-24 mmol/L 時達最佳改善，SLC4A1 變異者具有較低 eGFR 與較高 CKD 風險〔PMID 41790493〕
        • 若hypokalemia persists after metabolic acidosis corrected-->改用K-citrate
          • 不過Na-citrate因為有Na, 會加重Ca excretion而加重Ca-P deposit(回思Ca在loop吸收是based on NKCC2導致的電位差), K-citrate則相反(見CKD-Urinalysis and renal stones-renal stones), 所以若nephrocalcinosis/nephrolithiasis則用K-citrate較好
  • Type II RTA
    • Supplement of lost electrolytes; also Tx of vitamin D deficiency
    • May need 10-30mEq/kg/d(是type I RTA的10倍耶...; 所以可補到>3瓶Rolikan/d!!) bicarbonate to correct metabolic acidosis; 但是這樣補會因為bicarbonaturia而increase distal Na delivery-->increase K loss
      • 所以應用K-citrate較好, 也可以搭配K+ sparing diuretics
      • Goal
        • 小孩因為chronic metabolic acidosis會osteomalacia, ↓growth, 所以希望補到正常
        • 大人雖然也會長期也會osteopenia..., 但不用補到正常(也很難補到正常就是了...)
      • If large dosage of alkali is ineffective or not tolerated-->可用thiazide(!)-->mild volume depletion-->increase proximal reabsorption of Na, bicarbonate(by Na-H+ exchanger)(可是不是proximal tubule dysfunction?這樣還會↑resorption嗎?); Cl depletion and potassium depletion可能也有影響
    • 比type I需要more monitoring

反向連結

General Nephrology · 腎專考試筆記 · 僅供學習參考