[Two Cases of Obstructive Pyelonephritis with Hyperammonemia Causing Impaired Consciousness].

We herein report two cases of obstructive pyelonephritis with hyperammonemia causing impaired consciousness. One patient was a 79-year-old female. She was admitted for impaired consciousness and hematuria. Computed tomography (CT) revealed left hydronephrosis and hydroureter indicating obstructive pyelonephritis and her ammonia in the blood was a high level of 208 μg/dl. Her consciousness did not change immediately but improved 10 days after ureteral catheterization. The other patient was an 88-year-old female. She was also admitted for impaired consciousness and hematuria. CT revealed right hydronephrosis and an ureteral stone causing obstructive pyelonephritis and her ammonia level in the blood was a high level of 133 μg/dl. Her consciousness did not change immediately but improved 7 days after ureteral catheterization. Hyperammonemia in patients with obstructive pyelonephritis is a rare entity that can be occasionally observed. In patients with prolonged impaired consciousness due to urinary tract infections, clinicians should consider the possibility of hyperammonemia.