Acute caused by an infection, chronic persistent, or recurrent infection of kidney leading to scarring of the kidney usually associated with renal stones, drugs, ischemia.
Acute localized abscesses may form in medulla and extend to cortex, chronic there is fibrosis, scarring, renal pelvis dilation, blunting
Acute onset, systemic symptoms, constrovertebral tenderness, chronic metabolic acidosis, hyperkalemia, dehydration
Acute rarely causes renal failure, chronic may lead to renal failure
Acute organism is moving up urinary tract, chronic urinary obstruction prevents elimination of bacteria by voiding