Renal tubular acidosis

2,056 views
1,676 views

Published on

Published in: Health & Medicine
0 Comments
2 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
2,056
On SlideShare
0
From Embeds
0
Number of Embeds
2
Actions
Shares
0
Downloads
177
Comments
0
Likes
2
Embeds 0
No embeds

No notes for slide

Renal tubular acidosis

  1. 1. RENAL TUBULAR ACIDOSIS
  2. 2.  First described clinically in  Refers to disorders 1935 affecting the overall ability Confirmed as a renal of the renal tubules either tubular disorder in 1946 to secrete hydrogen Designated as RTA in 1951 ions or to retain bicarbonate ions  All types produce hyperchloremic metabolic acidosis with a normal anion gap.
  3. 3. PROXIMAL RENAL TUBULAR ACIDOSIS MAIN DEFECT  Carbonic Anhydrase deficiency
  4. 4. Proximal RTA (Type 2) Caused by an impairment of HCO3- reabsorption in the proximal tubules Most cases occur in the context of Fanconi’s syndrome Isolated proximal RTA is rare.
  5. 5. HCO3 100% HCO3 HCO380% reabsorbed 15% reabsorbed HCO3 5% excreted Normal renal tubular function
  6. 6. HCO3 100% HCO 3 HCO3 60% reabsorbed 15% reabsorbedDecreased proximal tubuleefficiency Cl- 25% HCO3- K+Proximal RTA or RTA type 2
  7. 7. Proximal RTA Massive loss of bicarbonate – metabolic acidosis Absorption of chloride - hyperchloremia Loss of potassium – hypokalemia Kidneys tries to compensate for the acidosis – urine ph is low - < 5.5
  8. 8. Distal RTA Decreased excretion of titratable acids = Acidification defect
  9. 9. DISTAL RTA Impairment of distal acidification Inability to lower urine pH maximally below 6.0 under acid load Pathomechanism is inability to secrete H+ adequately (secretory defect or classic distal RTA) Gradient defect Voltage dependent defect In children mainly a genetic defect of the H+ pump
  10. 10. Cl-Distal RTAor RTA type 1 Acidification defect H+ HCO3- K+ excreted
  11. 11. Distal RTA Loss of bicarbonate less than type 2 – metabolic acidosis Absorption of chloride – hyperchloremia Loss of potassium – hypokalemia Decreased excretion of titratable acids – high urinary ph >5.5
  12. 12. RTA Type IV Hypoaldosteronism or Deficiency of aldosterone Pseudohypoaldosteronism or end organ target failure
  13. 13. Na Adolsterone H20RTA IV: K+ Cl-Hypoaldosteronism orpseudohypoaldosteronism H+ Water Na+
  14. 14. RTA IV End organ target failure or low aldosterone:  Lost of sodium – hyponatremia  Retention or decreased excretion of potassium - hyperkalemia Absorption of chloride – hyperchloremia Decreased excretion of acids – metabolic acidosis Loss of fluid - dehydration
  15. 15. Proximal RTA Distal RTA RTA IVType of Hyperchloremic Hyperchloremic HyperchloremicAcidosis metabolic metabolic metabolic acidosis acidosis acidosisSerum low low highPotassiumUrine pH < 5.5 >5.5 < 5.5Urinebicarbonateloss
  16. 16. Features of the RTA Syndromes Feature Type 1 Type 2 Type 4 Nephro- present absent Absent lithiasis Nephro- present absent Absent calcinosis Osteo- present present Absent malacia Growth +++ ++ +++ failure Hypokalemic ++ + - muscle weakness Alkali Low dose (2 High dose ( Low dose ( 2- therapy –4 meq/kg) 2-14 meq/kg) 3 meq/kg) Response to good fair fair therapy
  17. 17. Features of the RTA SyndromesFeature Type 1 Type 2 Type IVPlasma HCO3 Variable, 14- 18 meq/L 15-29 meq/L may be <10 meq/LPlasma Cl- increased Increased IncreasedPlasma K+ Mildly to Mildly Mildly to severely decreased severely decreased decreasedPlasma anion Normal Normal NormalgapGFR Normal or Normal of Normal to slightly slightly moderately decreased decreased decreasedFractional <5% > 15% <5%Excretion ofHCO3Urine pH >6.0 </= 5.5 </= 5.5duringacidosis

×