Most patients with acute pyelonephritis can be cured after treatment. If acute pyelonephritis delayed treatment, accompanied by complex urinary sensory factors, such as diabetes mellitus, urinary tract obstruction, the sequelae of acute pyelonephritis may occur, the main two points are as follows: 1. Renal papillary necrosis, refers to ischemic necrosis of the renal papilla and its adjacent renal medulla, which is mainly manifested as chills, high fever, severe lumbar or abdominal pain, and hematuria, and can be accompanied by Gram-negative bacilli sepsis, and acute renal failure. Renal colic can occur when there is necrotic tissue dislodged and discharged from the urine to obstruct the ureter.2. Perinephric abscess may occur. When severe pyelonephritis, direct extension and the formation of perirenal abscess, in addition to the original symptoms intensified, often appear obvious unilateral low back pain, in the healthy side of the bending pain intensified.