Role of Renal Replacement Therapy in Managing Toluene-Induced Acidosis

BACKGROUND Toluene poisoning can occur as a result of occupational exposure in industries such as painting, as well as through misuse, leading to complications such as neurological symptoms due to the accumulation of the metabolic byproduct of hippuric acid and metabolic acidosis. However, the exact mechanisms remain unclear. Hippuric acid is not removed by dialysis, so urinary excretion plays a central role. Symptomatic treatment, primarily involving fluid replacement, remains the standard approach for managing toluene toxicity. Nonetheless, the effectiveness of hemodialysis as a supplementary treatment for toluene poisoning has not yet been conclusively determined. CASE REPORT We present a case of toluene poisoning with prerenal injury in a 52-year-old man with a long history of painting work, which occurred during the summer months. Due to insufficient response to fluid therapy and the persistence of metabolic acidosis, hemodialysis was initiated. Urinary hippuric acid excretion increased after dialysis, suggesting a renoprotective effect of dialysis despite the high protein binding and low dialysability of hippuric acid. This indicates that hemodialysis is a viable treatment option. Following treatment, a furosemide + fludrocortisone loading test was performed to evaluate the reversibility of tubular damage caused by hippuric acid. The test revealed no impairment in acidification, suggesting that the renal tubular acidosis induced by toluene toxicity is likely reversible. CONCLUSIONS This case highlights the diagnosis of renal tubular acidosis secondary to acute toluene poisoning, which was unresponsive to conservative fluid therapy and necessitated hemodialysis. Furthermore, a furosemide and fludrocortisone loading test confirmed the reversibility of the toluene-induced renal tubular acidosis.