What causes PUJ obstruction?
There is usually an abnormality in the structure of the wall of the PUJ. This can exist from birth or develop later in life secondary to other causes such as stones or, very rarely, cancer. In about one in three cases to two in three cases, the PUJ passes over a blood vessel known as a crossing vessel and this may cause the obstruction sometimes also. Even if PUJ obstruction is present in birth, symptoms may not occur until later in life.
