<unk>  is caused by obstruction of urine before the renal pelvis. The obstruction causes dilation of the nephron tubules and flattening of the lining of the tubules within the kidneys which in turn causes swelling of the renal calyces.<unk>  can either be acute or chronic. In acute<unk>  full recovery of kidney function is seen. However, with chronic<unk> , permanent loss of kidney function is seen even once obstruction is removed. Obstruction that occurs anywhere along the upper urinary tract will lead to increased pressure within the structures of the kidney due to the inability to pass urine from the kidney to the bladder. Common causes of upper tract obstruction include obstructing stones and ureteropelvic junction (UPJ) obstruction caused by intrinsic narrowing of the ureters or an overlying vessel. Obstruction occurring in the lower urinary tract can also cause this increased pressure through the reflux of urine into the kidney. Common causes include bladder dysfunction (such as neurogenic bladder) and urethral obstruction (such as posterior urethral valves in male infants) or compression (such as from prostatic hypertrophy in older male adults). In pregnancy, dextrorotation (rotation to the right) of the uterus can cause compression on the right ureter, thus making<unk>  more common in right kidney than left kidney. Besides, hormones such as oestrogen, progestrerone, and prostaglandin can cause ureter dilatation, thus causing<unk>  despite the absence of visible obstruction along the urinary tract.
Hydronephrosis
Pyonephrosis
Glomerulonephrosis
Pyelonephritis
Ureteric stricture
Ureteral cancer
Salpingitis
Obstructive uropathy