Prostatic obstruction

If urine can no longer pass through a patient's prostate, as the result of benign enlargement, carcinoma, fibrosis (bladder- neck stenosis), or bladder-neck dysfunction, you will have to relieve his obstruction. He can present with:

(1) Prostatic symptoms before his urinary flow is completely obstructed. He may have: (a) Frequency of micturition which interferes seriously with his sleep, (b) difficult voiding, or (c) a poor stream. Unfortunately, this is an unusual method of presentation in the developing world.

(2) Acute retention of urine (23.5), perhaps precipitated by a recent drinking bout. If you catheterize him, he will usually start to pass urine again, but his retention will probably recur, so he should have his prostate removed after his first attack.

(3) Chronic retention. His bladder remains distended when micturition is over, and he may dribble urine continuously and painlessly (retention with overflow).

(4) ''Acute on chronic' retention. He has had a poor flow for some time, and his bladder is large and has recently become painful. He may progress to retention with overflow.

If he presents with retention, he may be not be well enough for you to remove his prostate immediately, because: (1) His acute retention may be the final episode in a long period of obstructive uropathy; his blood urea may be high and his urine infected. (2) He may have been precipitated into retention by a serious illness, such as pneumonia, or fracture of the neck of his femur. If you try to remove his prostate while he is like this, he will probably not survive the operation. He is more likely to live if you wait, drain his bladder for a week or two, and investigate him meanwhile.

If he presents with retention, and you expect to remove his prostate within 2 weeks, pass a urethral catheter and drain his urine into a closed sterile system. If you have to delay beyond 2 weeks, do a suprapubic cystostomy (23.6). Some surgeons try to avoid doing a suprapubic cystostomy, if they possibly can, and are prepared to leave a plastic urethral catheter, or a polythene tube, in place for several weeks if necessary, changing it every week, or even every 2 or 3 weeks.

If you are in an area where Schistosoma haematobium is endemic, and commonly causes carcinoma of the bladder, try to avoid doing a suprapubic cystostomy. In some areas this is responsible for up to 10% of cases of urinary obstruction. If a patient does have carcinoma of his bladder, and you do a suprapubic cystostomy, it will never close.

If possible, examine him under anaesthesia (do an EUA) and cystoscope him some days before you remove his prostate. This will confirm the diagnosis, distinguish carcinoma of his prostate from carcinoma of the base of his bladder infiltrating his prostate, and enable you to diagnose associated bladder diverticula and stones. An EUA and cystoscopy will also make it easier to plan your theatre lists, because they are are quickly done, whereas a prostatectomy takes time.

URINARY OBSTRUCTION PLAN OF INVESTIGATION. Here is an ideal scheme: do as much of it as you can. Assess the patient's general condition, feel for palpable kidneys, feel the size of his bladder, feel his urethra for strictures and do a rectal examination, having first measured his acid phosphatase, as evidence of carcinoma of his prostate with local or bony secondaries (32.22). If he is in retention, catheterize him. A day or two later, or when his blood urea is down if it was previously raised, examine him under anaesthesia and cystoscope him. Operate at your convenience.

CAUTION ! Measure his acid phosphatase before you do a rectal examination, or more than 48 hours afterwards (32.32).

RENAL FUNCTION. Measure his blood urea. Chronic retention with a blood urea of up to 12 mmol/l is common in the elderly, but provided underlying causes, such as heart failure, are corrected, it is no great risk in itself.

If he has retention of urine with a blood urea of over 15 mmol/l, pass a plastic urethral catheter, or a piece of polythene tubing. Only pass a suprapubic catheter if you fail to pass a urethral one. Drain his bladder for a week to improve his renal function. If his blood urea remains high, say at 15 mmol/l, you can operate, but at only at greater risk. There is no need to try to decompress an obstructed bladder slowly, this is almost impossible, and it does not reduce the incidence of bleeding.

X-RAYS. A straight X-ray of his pelvis is important. Look for: (1) Stones (they are almost always radio-opaque). If you find one, remove it at the same time as his prostate. (2) Secondary deposits from carcinoma of his prostate, which may be osteolytic or osteosclerotic.

An intravenous urogram is unnecessary in acute retention: it gives only incidental information and is expensive. Most of what you need to know can be found from other tests. If you do one, look for: (1) Dilated kidneys or ureters. (2) Signs that he has enough renal function to excrete the contrast medium. (3) Stones or diverticula.

ANAEMIA. Measure his haemoglobin; it should be above 10 g/dl. Don't operate unless you can transfuse him.

ANTIBIOTICS. If his urine is infected, give him an antibiotic. If necessary, catheterize him to make sure it drains adequately.

CYSTOSCOPY. Do this, as in Section 23.3, while he is anaesthetized and in the lithotomy position. If you have difficulty getting the beak of the cystoscope past his prostatic urethra, be gentle. Any force will make it bleed. If it sticks at a urethral stricture, dilate this, or do a suprapubic cystostomy and send him back to the ward.

Allow his urine to flow out. Note the volume of his bladder, and if it looks infected or not. Start by inspecting his internal urinary meatus, with the fenestra of the cystoscope placed so that the edge of the meatus bisects the field of view. Normally, the posterior part of the urinary meatus is flat, and the rest is part of a circle. Look for: (1) carcinoma of his bladder, (2) bladder stones, (3) benign enlargement, (4) fibrosis of the bladder neck (uncommon), (5) diverticula.

Enlargement of the prostate: (1) Enlargement of its lateral lobes will make his prostatic urethra appear as a cleft before you enter his bladder. (2) His median lobe will project from the posterior aspect of his bladder like ''a termite hill', and may make it difficult to see the ureteric orifices (B, 23- 23). (3) His bladder may be trabeculated, showing that its outflow is obstructed.

Diverticula. You will see thick muscle bundles intersecting one another, perhaps with small saccules between them. Diverticula are merely extra large saccules, and are usually above and lateral to the ureteric orifices, with radiating folds around their openings. You may be able to get the beak of your cystoscope inside one. Diverticula rarely matter, once outflow obstruction has been relieved, and diverticulectomy is seldom necessary.

Bladder-neck dysfunction causes retention of urine but cannot be diagnosed cystoscopically.

Bladder-neck fibrosis can be diagnosed cystoscopically, but needs experience. Suspect it if: (1) His bladder is obviously obstructed, as shown by muscle hypertrophy, residual urine, and perhaps diverticula. And, (2) his prostate is small, he has no urethral stricture and no CNS disease. And, (3) the neck of his bladder is tight as you pass the cystoscope.

CAUTION ! There is very little relationship between the appearance of the prostate and the presence or degree of outflow obstruction.

EXAMINATION UNDER ANAESTHESIA. Let the urine out of his bladder, remove the cystoscope, and examine his prostate bimanually with one finger in his rectum. Note its size, and any suspicion of malignancy as shown by its hardness, nodularity, and spread outside the prostatic bed. If it feels malignant, biopsy it with a Vim Silvermannn needle (32.26, 32.22) through his rectum. Or, you may find that he has not got an enlarged prostate, but that it merely felt enlarged, because it was pressed on by a full bladder.

IS PROSTATECTOMY INDICATED? The indications and contraindications are the same for Freyer's transvesical (23.19), and for Ghadvi's perineal method (23.21).

INDICATIONS. (1) Significant symptoms due to outflow obstruction. (2) The harmful effects of outflow obstruction, which are: (a) Difficult voiding and deterioration of his urinary stream. (b) Frequency of micturition (due to outflow obstruction) which interferes seriously with his sleep. (c) Acute retention of urine. (d) Chronic retention with overflow.

Conditions which do not by themselves indicate prostatectomy include: (1) Frequency and nocturia. (2) Haematuria (which is quite common in prostatic hypertrophy). (3) An increased residual urine (difficult to assess).

CONTRAINDICATIONS. (1) A patient whose general condition is very poor. (2) Very poor renal function, which does not improve after catheterization. (3) Severe sepsis. (4) Limited mobility and senility (rather than age alone). A very senile old man is likely to be permanently incontinent anyway, and will be better with permanent urethral drainage through a small Foley catheter, or, if you cannot pass one, with a permanent suprapubic cystostomy. (5) A malignant prostate is a contraindication to Freyer's and especially to Ghadvi's prostatectomy, but is very suitable for transurethral resection, which you will not be able to do. Manage a malignant prostate with oestrogens and catheter drainage, as in Section 32.32.

If he is too sick for prostatectomy, he may be suitable for treatment by the injection method (23.22).

Fig. 23-23 PROSTATECTOMY. A, the normal cystoscopic appearances of the base of the bladder, with the ureteric openings (1), the interureteric bar (2), and the middle lobe as a hardly visible swelling (3). B, in benign prostatic hypertrophy the middle lobe (4) projects into the bladder to obscure the interureteric bar and the ureteric openings. C, enlargement of the middle lobe. D, the position of the wedge to cut out of the neck of the bladder (5). E, the prostate has been removed and a Foley catheter left in the bladder, and secured with a stitch round a roll of gauze on the abdominal wall.