A patient has a condition where the exit of urine from the kidney is blocked, resulting in backup of urine and distension of the renal pelvis. the medical name for this condition is

The condition is called hydronephrosis.

Hydronephrosis is a medical condition characterized by swelling of the kidneys (or one kidney). This happens when urine can't drain from a kidney and retains there as a consequence. The hydronephrosis occurs due to the blockage of ureters or due to reverse flow of urine already in the bladder (reflux). Symptoms include pain in the back, pain during the urination, frequented urination ...