Understanding renal tubular acidosis

Renal tubular acidosis is a group of disorders characterised by metabolic acidosis, hyperchloraemia, normal anion gap, and potassium imbalance. Genetic mutations, drugs or acquired disorders disrupt the function of various transport proteins and enzymes in the renal tubules, causing diminished bicarbonate reabsorption or inability to excrete hydrogen ions, leading to proximal (type 2) and distal (type 1) renal tubular acidosis, respectively. These conditions are typically associated with hypokalaemia, which, if severe, can cause muscle paralysis and dangerous cardiac arrhythmias. A rare mixed variant (type 3), including features of both type 1 and type 2 renal tubular acidosis, has also been described. On the other hand, aldosterone deficiency or resistance leads to the hyperkalaemic form of renal tubular acidosis (type 4). If untreated, renal tubular acidosis can lead to long-term severe complications such as growth retardation, osteoporosis, rickets, osteomalacia, and renal calculi. Moreover, renal tubular acidosis might be the initial presentation of a more severe underlying pathology, such as autoimmune disease or plasma cell dyscrasias. A better understanding of the condition can help physicians diagnose and treat it early and prevent adverse outcomes.