RESUMO
PURPOSE: Renal tubular aicdosis (RTA) is a disorder of renal acidification out of porportion to the reduction in glomerular filtration rate. Type IV RTA refers to hyperkalemic metabolic acidosis resulting from aldosterone deficiency or resistance. The incidence of each type RTA has not been reported exactly, however reports on type IV RTA have been recently increasing. METHODS: A retrospective clinical analysis was performed in 50 patients with hyperkalemic distal renal tubular acidosis diagnosed between Jan. 1984 and Feb. 2003 at Department of Internal Medicine, Keimyung University, Dongsan Medical Center. RESULTS: From 1984 to 2003, 50 cases of hyperkalemic distal renal tubular acidosis were diagnosed. The mean age was 50.8+/-19.5 years. The two most common conditions were posttransplantation (28%), and diabetes mellitus (22%), which were followed by hypertension (12%), systemic lupus erythematosus (12%), chronic renal failure (12%), and others (26%). Asymptomatic hyperkalemia (34%), and muscle weakness (28%) were the two most common clinical presentations. All patients demonstrated normal anion gap acidosis with positive urine anion gap. The mean creatinine clearance was 25.6+/-16.4 mL/min. The mean baseline PRA and aldosterone levels were 3.82+/-7.16 ng/mL/hr and 110.02+/-108.2 ng/mL, respectively. Hyperkalemia was well responded to 9-alpha-fludrocortisone, furosemide, K-exchane resin, and combinations of these regimens. CONCIUSION: Type IV RTA is the most common type of RTA in children and adults, and can be an important cause of asymptomatic hyperkalemia. Therefore, type IV RTA should be included in the diffrential diagnosis of unexplained hyperkalemia in various clinical settings.