RÉSUMÉ
Spontaneous urinary bladder rupture is uncommon, but is associated with significant morbidity and mortality because of delayed diagnosis. A 65-year-old man was admitted to the emergency room because of low abdominal pain and abdominal distention of sudden onset. The previous night, he had consumed a bottle of alcohol and fallen asleep. Diagnosed as peritonitis of unknown origin, he was prescribed antibiotics empirically. However, the ascites progressed and oliguric acute renal failure developed. On the fifth day, we measured the creatinine level in the ascitic fluid and performed retrograde cystography. He was diagnosed as idiopathic spontaneous bladder rupture and underwent a primary repair successfully. When a patient presents with acute abdominal pain, ascites, and oliguric acute renal failure without definite causes, physicians should consider idiopathic spontaneous bladder rupture, measure the creatinine level in the ascitic fluid immediately, and perform retrograde cystography to obtain an early diagnosis.