Fig. 20.1
The urinary tract
Ureters
Ureters are narrow muscular tubes that provide a route for urine from the renal pelvis to the bladder. They cross the pelvic brim at L4, anterior to the bifurcation of the common iliac arteries before blending with the muscular trigone of the bladder.
The ureters demonstrate three areas of constriction:
- 1.
Pelvoureteric junction.
- 2.
Crossing the pelvic brim/bifurcation of common iliac arteries.
- 3.
Vesicoureteric junction.
Bladder
In the pelvic cavity, the urinary bladder is a distensible muscular sac (detrusor muscle), the location of which depends upon its volume. It lies posterior to the pubic symphysis and is infraperitoneal. In females it is found anterior to the vagina and in males it rests on the prostate gland. The bladder can be divided anatomically into the fundus (postero-superiorly), body, neck and apex (antero-inferiorly). The trigone constitutes a smooth region of detrusor muscle located on the posterior wall of the bladder. Here, the two ureters converge onto the bladder and at the apex the urethral orifice is formed. The trigone is important in the control of bladder emptying with autonomic and voluntary innervation. Sympathetic fibres from the hypogastric plexus and parasympathetic pelvic splanchnic nerves inhibit and promote detrusor muscle activity respectively. This autonomic innervation prevents and facilitates urination respectively through the internal urinary sphincter. These reflexes can be over-ridden with learned voluntary control of the external urinary sphincter via the deep branch of the perineal nerve.
Urethra
The male urethra is 20 cm long compared to 4 cm in females. The urethra is lined with transitional epithelium as it exits the bladder. The main length is lined with pseudostratified columnar and stratified columnar epithelia and at the external urethral orifice stratified squamous epithelium is found.
The female urethra is a simple, uncomplicated tube running between the bladder and the external urethral orifice. The male urethra however is comprised of four parts (Fig. 20.2):
Fig. 20.2
Portions of the male urethra
- 1.
Pre-prostatic urethra: Intramural section between the bladder and prostate.
- 2.
Prostatic urethra: Found within the prostate gland. It includes openings for the ejaculatory duct to convey sperm and ejaculatory fluid from the vas deferens and seminal vesicles respectively. Prostatic ducts and the utricle are also found here.
- 3.
Membranous urethra: This is the narrowest portion of the urethra. It lies deep to the external urethral sphincter.
- 4.
Spongy urethra: The longest section of urethra, conveying urine and semen through the corpus spongiosum, with openings for the bulbourethral and urethral glands.
Core Conditions
There are some key principles and topics in urology that anyone working with a urology team must know about:
- 1.
Urinary retention and how to catheterise (urethral and suprapubic).
- 2.
How to assess frank haematuria.
- 3.
How to assess renal colic.
- 4.
How to assess acute testicular pain.
- 5.
How to reduce a paraphimosis.
Urinary Retention
Key Points
It can be acute (painful) or chronic (typically painless).
It is typically caused by obstruction (prostatic in men, or pelvic mass in women), or bladder dysfunction (must exclude a neurological cause).
It can lead to disorders of renal function due to back pressure on the kidneys.
Assessment
Confirm retention (dull suprapubic mass/inability to pass urine).
Check for cause – Is there a clear precipitant? (constipation/cold and flu remedies, history of progressive LUTS and known prostatic problems). Remember to check prostate (rectal exam), exclude pelvic mass in women (bimanual vaginal exam), and exclude any obvious neurology in the lower limbs if no obstructive cause or clear precipitant can be found. Clearly record the most likely cause and differentials when clerking the patient in.
Once catheterised, the most important factors to observe are:
The residual urinary volume (volume of urine drained in the first 5 min).
Subsequent renal function.
This will form the basis for ongoing management
Catheterisation of a Male Patient
Don’t delay if in acute painful retention.
Aseptic technique.
Ensure correct catheter for patient (not a female short catheter for a male patient!). Typically a 14 French 2 way catheter for male patients is required.
Clean skin with sterile solution, and insert a whole tube of lignocaine lubricant anaesthetic gel into the urethra. Milk it down the male urethra. Leave to work a few minutes before inserting the catheter. Warn the patient the gel can sting initially.
Use your sterile hand to push the catheter through the urethra until urine flow confirms correct placement in the urinary bladder. Push slightly further to ensure that the balloon will not be inflated in the urethra. Inflate the catheter balloon with 10 ml of saline and give a gentle tug to confirm that it does not slip into the urethra.
Tape or strap the catheter tube and bag to the patient’s leg to prevent the catheter pulling, which can be painful.
Trouble-Shooting
If the catheter won’t go in, never force it. Try inserting it again (gently), using two tubes of lubricating anaesthetic jelly to distend the urethra more. Try to think how far down the urethra the catheter is sticking. If it is at the prostate level, try upsizing to a 16 French catheter – the larger catheter will buckle less going round the prostate.
If this does not work, get help. Alternatively, include a coude (angled) tip catheter, a catheter introducer (only for senior/ expert hands only), or a suprapubic catheter (SPC).
A suprapubic catheter is contra-indicated if there is unexplained haematuria, a history of bladder cancer, the patient is on warfarin or has a clotting abnormality (often a favourite question!). If there is any lower midline abdominal incision, additional care should be taken during insertion due to the increased risk of bowel injury. An ultrasound guided approach using a seldinger technique should be used to make the insertion.
Frank Haematuria
Key Points
Bleeding can occur at any point throughout the urogenital tract. Think of the urological system anatomically, and this will help you think of the locations and then allow you to create a differential diagnosis.
Haematuria can be a sign of urological cancer (there could be more than one), so approach such patients with this in mind.
Ask where the blood comes in the stream:
At the start e.g. urethral pathology.
At the end e.g. prostatic pathology.
All the way throughout the stream e.g. bladder or upper renal tract pathology.
Haematuria is easier for male patients to detect as they stand to pass urine so can see their stream. When women present with frank haematuria, it is because they see blood in the pan after passing urine. It is important to always keep an open mind to consider other sources of bleeding, including vaginal bleeds in such cases.
Key Assessment
Renal causes:
Renal cancer arises from the renal parenchyma. It can be visualised well with a renal USS or CT Urogram (in the pre-excretion arterial phase). The classical triad of a renal cancer (favourite question) is frank haematuria, a loin mass, and loin pain, although all three are only seen in a small proportion of patients.
Transitional cell cancers (TCC) can arise from the urothelial lining of any part of the urinary tract. In the upper renal tract, this can occur in the calyces of the kidney, the renal pelvis or the ureters (see Fig. 20.1). Lesions are not well seen with renal USS, but demonstrated well on CT Urogram (in excretion phase). If a clear view is not seen, the upper tract can be assessed more directly with cystoscopy and ureteroscopy to look up the whole length of ureter and inside the renal pelvis (uretero-renoscope or URS).
Bladder causes: TCC of the bladder urothelium is also known as bladder cancer, and is the most important bladder cause of haematuria to exclude. Risk factors for bladder cancer (favourite question) include a history of smoking (cause of 1 in 3 cases) and exposure to industrial chemicals including those in dye factories, rubber, leather, textiles, printing, gasworks, plastics and paint manufacture. Benign causes of bleeding from the bladder include infection (haemorrhagic cystitis), bladder stones or inflammation of the bladder lining (interstitial cystitis). Stones and large tumours can be picked up with USS, while infection can be diagnosed with urinalysis, microscopy and culture. Urine cytology can be useful to pick up malignant cells, which shed into the urine from higher-grade bladder cancers. Bladder pathologies can be easily assessed and directly visualised using a flexible cystoscope, which is done under a local anaesthetic (if infection excluded). If any biopsy or treatment is needed this will need to be performed with a larger scope under a general anaesthetic.
Prostatic/urethral causes:
Prostatic: A large benign prostate gland can often develop friable blood vessels, which can pop and bleed in much the same way as a nosebleed. These can be easily assessed and diagnosed with a flexible cystoscope. Prostate cancer does not typically present with bleeding, but it is important to always check the prostate via a rectal examination
Urethral: Benign urethral pathologies such as a urethral stricture or inflammation or infection (urethritis) can present with bleeding. Urethral cancer is very rare, but a differential to exclude. Infection is best assessed with urinalysis, microscopy and culture, as well as with a urethral swab. Looking inside the urethra with a flexible cystoscope (in the absence of infection) will detect everything else
Investigations
USS and CT Urogram to assess the upper tract and kidneys.
Flexible cystoscopy to assess the lower tract (bladder, urethra, prostate).
Urinalysis, microscopy and culture to exclude infective cause.
Urine cytology to exclude a bladder cancer.
Don’t forget to perform a rectal exam to asses the prostate and bimanual vaginal exam to exclude other possible causes of bleeding.
Renal Colic
Key Points
Renal Colic is often associated with kidney (or renal) stones.
Passing a kidney stone is very painful – appropriate pain relief is essential.
Patients who have had stones before or have a family history of stones are more at risk of developing stones.
Stones are more likely to develop when dehydrated (low fluid intake, excessive sweating, hot climate).
Stones are more common in patients with GI pathology such as inflammatory bowel disease and chronic diarrhoea.
The ureter has three points of natural constriction where stones get stuck (a favourite question). These constrictions are described in the anatomy section.
Key Assessment
Patients with renal colic present with acute, severe colicky abdominal pain, often with nausea and vomiting. Patients should be considered to have an ‘acute surgical abdomen’ until stones have been confirmed as the cause. The pain is classically loin to groin on the affected side. When the stone moves down to the lower ureter, the pain may refer to the genital region, and be associated with urinary frequency.
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