Assessment of the patient with prostatism

Abdominal examination is usually normal. In patients with chronic retention, a distended bladder will be found on palpation, percussion and sometimes on inspection with loss of the transverse suprapubic skin crease. General physical exam­ination may demonstrate signs of chronic renal impairment with anaemia and dehydration. The external urinary meatus should be examined to exclude stenosis, and the epididymes are palpated for signs of inflammation.

Rectal examination

In benign enlargement, the posterior surface of the prostate is smooth, convex and typically elastic, but the fibrous element may give the prostate a firm consistency. The rectal mucosa can be made to move over the prostate. Residual urine may be felt as a fluctuating swelling above the prostate. It should be noted that if there is a considerable amount of residual urine present, it pushes the prostate downwards, making it appear larger than it is.

The nervous system

The nervous system is examined to eliminate a neurological lesion. Diabetes mellitus, tabes, disseminated sclerosis, cervical spondylosis, Parkinson’s disease and other neurological states may mimic prostatic obstruction. If these are suspected then a pressure—flow urodynamic study should be carried out to diagnose BOO. Examination of perianal sensation and anal tone is useful in detection of an S2 to S4 cauda equina lesion.

Serum prostate-specific antigen

The difficulty here is the uncertain benefit of early detection and radical treatment of prostate cancer — this is dealt with in the section on prostate cancer. Certainly men should be informed about the test, the risks of the prostate biopsy that might be required and the risks of the detection of a cancer that we are not certain how best to treat. After suitable counselling, measurement of serum PSA may be helpful. Men in whom a diagnosis of early prostate cancer might influence treatment option such as those under 60 or those with a

positive family history who might be offered radical treatment — should be offered a PSA measurement. If this is in excess of 4 nmol/litre, then transrectal ultrasound scanning (TRUS) plus multiple transrectal biopsies should be considered.

If rectal examination is quite normal with no suspicion of cancer and if no change in treatment policy would result anyway from the diagnosis of early prostate cancer then there seems little point in the routine measurement of PSA in men with uncomplicated BOO.

Flow rate measurement

For this to be meaningful two or three voids should be recorded and the voided volume should be in excess of 150—200 ml. This usually means the patient attending a special flow rate clinic. A typical history and a flow rate <10 mi/second [for a voided volume of >200 ml (Fig. 66.7)] will be sufficient for most urologists to recommend treatment. Usually a flow rate measurement will be coupled with ultrasound measurement of postvoid residual urine.

There are pitfalls in the measurement of flow rates. The machine must be accurately calibrated. The patient must void volumes in excess of 150 ml and two or three recordings are needed to obtain a representative measurement. Decreased flow rates and symptoms of prostatism may be seen in:

  BOO;

  low voided volumes (characteristically in men with detrusor instability);

  men with weak bladder contractions (low pressure—flow voiding).

Pressure—flow urodynamic studies (Fig. 66.8)

Details of these studies are outlined in Chapter 65. They should be performed on the following patients:

men with suspected neuropathy (Parkinson’s disease, dementia, long-standing diabetes, previous strokes, multiple sclerosis)

men with a dominant history of irritative symptoms and men with life-long urgency and frequency

men with a doubtful history and those with flow rates in the near-normal range (— or >15 mI/second)

men with invalid flow rate measurements (because of low voided volumes)

Blood tests

Serum creatinine, electrolytes and haemoglobin should be measured.

Examination of urine

The urine is examined for glucose and blood, a midstream specimen should be sent for bacteriological examination and cytological examination may be carried out if carcinoma in situ is thought possible.

Upper tract imaging

Most urologists no longer carry out imaging of the upper tract in men with straightforward symptoms. Obviously if infection or haematuria is present then the upper tract should be imaged by means of an IVU or USS.

Cystourethroscopy

Inspection of the urethra, the prostate and the urothelium of the bladder should always be done immediately prior to prostatectomy, whether it is being done transurethrally or by the open route to exclude a urethral stricture, a bladder carcinoma and the occasional non opaque vesical calculus. The decision whether to perform prostatectomy must be made before cystoscopy. This should be based on the patient’s symptoms, signs and investigations. Direct inspection of the prostate is a poor indicator of BOO and need for surgery.

Transrectal ultrasound scanning

This increases the rate of detection of associated early prostate cancer but, as pointed out above, unless this would substantially affect treatment there is no need to carry it out routinely. Accurate estimation of prostatic size is possible by means of transrectal or transabdominal ultrasound scanning.