MALIGNANT URETERIC OBSTRUCTION
The ureters enter the bladder just a few centimeters from the bladder neck, and it is not difficult to see how a locally advanced prostate or bladder cancer can obstruct them (Clarke 2003) (Fig. 9.2). Similarly, the cervix in women is very closely related to the lower ureters (which is why the latter may be damaged during hysterectomy) and locally advanced cervical cancer can cause lower ureteric obstruction, as can a locally advanced rectal cancer in both sexes (Soper et al. 1988). Other malignancies (colon, stomach, lymphoma, breast, bronchus) can metastasize to pelvic and retroperitoneal lymph nodes, causing unilateral or bilateral malignant ureteric obstruction. In unilateral obstruction with a normally functioning contralateral kidney, the obstruction proceeds silently. In bilateral obstruction, oliguria, leading later to anuria and finally renal failure, is the mode of presentation.
The emergency presentation is usually one of a patient with acute renal failure, who may or may not be known to have cancer. Patients present with a rising creatinine and symptoms
9. UROLOGICAL NEOPLASTIC CONDITIONS PRESENTING AS EMERGENCIES 161
of renal failure including malaise, nausea, vomiting, and in some cases marked oliguria or anuria as the locally advanced or nodal metastases obstruct their ureters. This presentation is sometimes mistaken for urinary retention, particularly if the patient has some lower abdominal pain. However, when the bladder is catheterised it contains only a small volume of urine and the high creatinine level does not fall. In the case of prostate cancer, digital rectal examination (DRE) reveals a firm (craggy) prostate that has extended laterally. A locally advanced rectal cancer may be felt on DRE, and in women vaginal examination may reveal a hard, craggy mass arising from the cervix.
In terms of clinical examination, it is advisable to perform a DRE in both men and women. Vaginal examination should be done in women as should examination of the breasts. General abdominal examination may reveal other evidence of malignant disease. Look for cervical and axillary lymph nodes. Measure the serum creatinine. A renal ultrasound reveals bilateral hydronephrosis, with an empty bladder. An abdominal computed