Type 1-Distal RTA
Distal RTA (dRTA) is the classical form of RTA, being the first described. Distal RTA is characterized by a failure of acid secretion by the alpha intercalated cells of the cortical collecting duct of the distal nephron. This failure of acid secretion may be due to a number of causes, and it leads to an inability to acidify the urine to a pH of less than 5.3. Because renal excretion is the primary means of eliminating acid from the body, there is consequently a tendency towards acidemia. There is an inability to excrete H+ while K+ cannot be reabsorbed, leading to acidemia (as H+ builds up in the body) and hypokalemia (as K+ cannot be reabsorbed). This leads to the clinical features of dRTA; In other words, the intercalated cells' apical H+/K+ antiporter is non-functional, resulting in potassium-wasting and proton retention. Since calcium stones demonstrate a proclivity for deposition at higher pHs (alkaline), the substance of the kidney develops stones bilaterally; this does not occur in the other RTA types.
- Normal anion gap metabolic acidosis/acidemia
- Hypokalemia
- Urinary stone formation (related to alkaline urine, hypercalciuria, and low urinary citrate).
- Nephrocalcinosis (deposition of calcium in the substance of the kidney)
- Bone demineralisation (causing rickets in children and osteomalacia in adults)
Read more about this topic: Renal Tubular Acidosis
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