The kidneys filter blood of impurities to form urine, which flows out through tubes called ureters, is temporarily stored in the bladder and passes outside the body through a tube called the urethra. When an obstruction occurs in the flow of urine, pressure builds up above the blockage and within the kidney (hydronephrosis). Possible causes of an obstruction include a stone, tumor, clot, scar tissue, pressure created by an enlarged prostate gland or infection in the kidney or anywhere along the urinary tract. Kidney obstruction can produce dull or severe pain in the side of the back, abdomen or groin region, problems with urination, nausea, vomiting, but occasionally you experience no symptoms.
Your doctor will perform a physical examination along with imaging studies to identify the cause of obstruction. Treatment depends on the cause of the blockage. Infection can be managed by antibiotics which treat the obstruction by reducing inflammation. Small kidney stones are managed by increasing your water intake and taking certain medications provided by your doctor. Larger stones may be removed by lithotripsy, a minimally invasive procedure that uses ultrasound to fragment stones so that they can easily pass out with urine. An enlarged prostate may be treated with medication or surgery. Excessive urine collection in the kidneys can be managed by a nephrostomy (tube inserted into your kidney through your skin to drain urine) or a stent that passes through your ureter into the bladder.