Proximal renal tubular acidosis (pRTA) is a medical condition characterized by the inability of the kidneys to properly reabsorb bicarbonate, resulting in a buildup of acid in the blood. The term "proximal" refers to the fact that the tubules affected are those located in the proximal (closest to the glomerulus) portion of the kidney.
In a healthy individual, the proximal renal tubules play a crucial role in the reabsorption of filtered bicarbonate ions, which helps maintain the acid-base balance in the body. However, in individuals with pRTA, there is a defect in these tubules that impairs their ability to reabsorb bicarbonate. As a result, excess bicarbonate is lost in the urine, leading to a condition called metabolic acidosis.
The main symptoms of pRTA include increased urine pH (alkaline urine), excessive thirst, frequent urination, difficulty in growth (in children), weakness, fatigue, and bone problems. Some individuals may also experience kidney stone formation or electrolyte imbalances, such as low blood potassium levels.
The causes of pRTA can be acquired or inherited. Acquired causes include conditions like autoimmune diseases, certain medications, and toxic substances exposure. Inherited causes are often associated with genetic defects that affect the transporters responsible for bicarbonate reabsorption in the tubules.
Treatment for pRTA primarily focuses on correcting the acid-base imbalance, maintaining adequate hydration, and addressing any electrolyte abnormalities. Medications such as alkali supplements or bicarbonate may be prescribed to help restore and maintain proper bicarbonate levels. Regular monitoring of kidney function, acid-base status, and electrolyte levels is crucial in managing this condition.
