Renal abscess

Renal abscess, also known as pyonephrosis, refers to an extensive suppurative lesion caused by renal parenchymal infection or a cystic cavity accumulating pus due to hydronephrosis and infection of the renal pelvis and calyces following urinary tract obstruction. Causative organisms include Gram-positive cocci, Gram-negative bacilli, or Mycobacterium tuberculosis. It often develops on the basis of diseases such as renal calculi, renal tuberculosis, pyelonephritis, and hydronephrosis, complicated by suppurative infection. Renal abscess refers to the destruction of renal parenchyma due to inflammatory suppuration, forming a purulent cyst, with complete loss of renal function, commonly seen in patients with upper urinary tract obstruction. It usually results from the progression of acute pyelonephritis with necrosis formation.