Some possible causes of a swollen kidney are kidney stones, blood clot, urinary tract infection, tumor and an enlarged prostate, according to the National Kidney Foundation. The medical term for this condition is hydronephrosis, and the swelling results from urine blockage in the kidney. Symptoms of a swollen kidney are pain, nausea and fever depending on the severity of the urine blockage.
Urinary tract obstruction is another condition that can cause swelling of the kidneys. This condition involves a blockage in the urinary tract that prevents the regular flow of urine from the kidney to the bladder. This condition can result from birth defects, scar tissue formation and fecal impaction, states the Merck Manual. Certain drugs and surgery can cause a buildup of fibrous tissue around the kidney that leads to swelling of the organ.
Other possible causes of swollen kidneys are acute unilateral obstructive uropathy and the narrowing of the ureter as the result of a birth defect or injury, notes Healthline.com. Acute unilateral obstructive uropathy involves the sudden development of an blockage in the ureter, most often due to a kidney stone.
Diagnostic tools for swollen kidneys include x-rays, MRIs, and blood and urine tests that check for urine flow irregularities.