Proximal (type II) renal tubular acidosis

Proximal renal tubular acidosis (PRTA), also known as type Ⅱ renal tubular acidosis, is characterized by: ① most of the glomerular filtered HCO-3 is excreted when the blood bicarbonate (HCO-3) concentration is normal , HCO-3 reabsorption is reduced. ② When the HCO-3 concentration in the blood drops below the patient's HCO-3 renal threshold, there is little HCO-3 excretion in the urine. ③ Urinary pH can be reduced to a minimum when severe metabolic acidosis occurs; 5.5, and titratable acids and ammonium can be excreted.