Urology

The urinary tract is a single tube from glomerulus to meatus, and almost every urological presentation can be placed on it.

The organising tool is: locate the level, then ask whether it is obstructed and whether it is infected.

The level generates the symptom. Loin pain means kidney or upper ureter, groin pain means lower ureter, and voiding symptoms mean bladder outlet or urethra.

Obstruction with infection is the combination that creates an emergency, exactly as it does in the biliary tree, and for the same reason: an obstructed infected system is under pressure and seeds the bloodstream, and it cannot be sterilised until it is drained.

1. Reading the Level

Pain follows the innervation of each segment, so it moves as a stone moves.

A stone at the vesicoureteric junction mimics cystitis, because the trigone shares innervation with the bladder, and patients are regularly treated for urinary infection when they have a stone.

Lower urinary tract symptoms are divided into voiding symptoms, which are hesitancy, poor stream, terminal dribbling and incomplete emptying, and storage symptoms, which are frequency, urgency, nocturia and urge incontinence.

The distinction matters because voiding symptoms suggest obstruction while storage symptoms suggest detrusor overactivity, and the two respond to different drugs.

2. Haematuria

Visible haematuria in an adult is a urological malignancy until proved otherwise, and the proportion in whom a cancer is found is high enough that investigation is mandatory in every case.

Painless visible haematuria is the classic presentation of bladder cancer, and the absence of pain makes it more sinister rather than less.

Timing within the stream localises the source. Initial haematuria suggests a urethral source, terminal haematuria a bladder neck or prostatic source, and haematuria throughout the stream a source anywhere from kidney to bladder.

Investigation requires imaging of the upper tract, usually computed tomography urography, and direct inspection of the bladder by cystoscopy, because neither alone examines the whole tract.

Non-visible haematuria found on dipstick must be confirmed by microscopy, because myoglobin, haemoglobin, beetroot, rifampicin and menstrual contamination all mislead the dipstick.

Coexisting proteinuria, red cell casts or dysmorphic red cells indicate a glomerular source and redirect the patient to nephrology rather than urology.

3. Urolithiasis

Most stones are calcium oxalate. Struvite stones form in infection with urea-splitting organisms such as Proteus, and are the stones that form staghorn calculi. Uric acid stones form in acid urine and are radiolucent. Cystine stones occur in cystinuria and are faintly radio-opaque.

The relationship between infection and stone runs in both directions, and it matters clinically. Urea-splitting organisms alkalinise urine and precipitate struvite, and any stone can obstruct and become infected.

Presentation is severe colicky loin to groin pain with a restless patient who cannot lie still, which distinguishes it from peritonitis where the patient lies motionless.

Non-contrast computed tomography of the kidneys, ureters and bladder is the investigation of choice, detecting essentially all stones including radiolucent uric acid stones, which plain radiography misses.

Ultrasound is preferred in pregnancy and in children to avoid radiation, and detects hydronephrosis reliably even when it cannot see the stone.

Management depends on size, site and whether the system is obstructed and infected.

Stones below about 5 millimetres usually pass spontaneously and need analgesia and fluid. Non-steroidal anti-inflammatory drugs are more effective than opioids in renal colic, because much of the pain is prostaglandin-mediated.

Medical expulsive therapy with an alpha blocker is recommended for distal ureteric stones of about 5 to 10 millimetres in patients suitable for conservative management. Below 5 millimetres it adds little, since those stones pass anyway.

Larger or non-passing stones are treated by extracorporeal shockwave lithotripsy, ureteroscopy with laser fragmentation, or percutaneous nephrolithotomy for large renal and staghorn stones.

Prevention is the part candidates neglect and examiners like, because stone disease recurs in a large proportion of patients and the interventions are specific to stone type.

High fluid intake sufficient to produce more than two litres of urine daily is the single measure that benefits every stone type. Thiazides reduce urinary calcium excretion and are used in recurrent calcium stones, and the mechanism is worth knowing: they increase distal calcium reabsorption.

Potassium citrate alkalinises urine and inhibits crystallisation, and it is the mainstay for uric acid and cystine stones. Allopurinol is added where hyperuricosuria is documented.

Dietary calcium restriction is a classical error. Restricting dietary calcium increases stone formation, because unbound oxalate in the gut is then absorbed and excreted in urine, so normal calcium intake with reduced oxalate and salt is advised instead.

4. Obstruction and Retention

Benign prostatic hyperplasia arises in the transition zone, which is why it obstructs, whereas prostate cancer arises in the peripheral zone, which is why it is palpable on rectal examination and does not obstruct until late.

That single anatomical difference explains most of the clinical contrast between the two.

Assessment uses symptom scoring, a flow rate, a post-void residual volume and prostate-specific antigen where cancer is a consideration.

Medical treatment has two classes. Alpha blockers relax smooth muscle in the bladder neck and prostate and work within days. Five alpha reductase inhibitors shrink glandular tissue and take months, but they reduce prostate volume and the risk of retention and surgery.

Five alpha reductase inhibitors halve the prostate-specific antigen, so a measured value must be doubled to interpret it in a treated patient.

Surgery, usually transurethral resection of the prostate, is indicated for refractory symptoms, recurrent retention, recurrent infection, stones, or renal impairment from obstruction.

Acute retention is painful; chronic retention is painless. That distinction determines the management, because a chronically distended bladder that is decompressed rapidly may develop post-obstructive diuresis and decompression haematuria.

High-pressure chronic retention causes bilateral hydronephrosis and renal impairment, and catheterisation improves the creatinine, which is the diagnostic clue.

5. Infection and the Obstructed System

Uncomplicated cystitis in a woman presents with dysuria, frequency and urgency without fever, and Escherichia coli is the commonest organism.

Pyelonephritis adds fever, rigors and loin tenderness, indicating that the infection has ascended.

An infection in an obstructed system is an emergency, presenting as fever and loin pain with a stone or other obstruction on imaging, and the definitive treatment is drainage rather than antibiotics.

Drainage is by percutaneous nephrostomy or retrograde stent, and it is done urgently, because pus under pressure in the collecting system produces rapid septic deterioration.

Emphysematous pyelonephritis is a necrotising infection with gas in the renal parenchyma, occurring almost exclusively in poorly controlled diabetics, and carries high mortality.

Asymptomatic bacteriuria is not treated, with two important exceptions: pregnancy, where it progresses to pyelonephritis and is associated with preterm birth, and before urological procedures that breach the mucosa.

6. Renal and Urothelial Tumours

Renal cell carcinoma arises from proximal tubular epithelium, and the classic triad of haematuria, loin pain and a mass appears in a small minority and usually indicates advanced disease.

Most renal cell carcinomas are now found incidentally on imaging done for other reasons, which has substantially improved outcomes.

It is notorious for paraneoplastic syndromes, including polycythaemia from erythropoietin, hypercalcaemia from parathyroid hormone related peptide, hypertension from renin, and Stauffer syndrome of non-metastatic hepatic dysfunction.

A left-sided varicocele that does not empty on lying down suggests renal cell carcinoma, because the left testicular vein drains into the left renal vein and tumour thrombus obstructs it.

Renal cell carcinoma is characteristically resistant to conventional chemotherapy and radiotherapy, so treatment is surgical, with partial nephrectomy preferred where feasible, and targeted or immunotherapy in advanced disease.

Urothelial carcinoma of the bladder is the commonest bladder tumour and is strongly linked to smoking and to aromatic amine exposure in the dye and rubber industries.

Squamous cell carcinoma of the bladder is associated with chronic irritation, notably schistosomiasis and long-term catheterisation, which matters in tropical practice.

Diagnosis is by cystoscopy and transurethral resection, which is both diagnostic and therapeutic. The critical division is between non-muscle-invasive disease, managed by resection with intravesical therapy, and muscle-invasive disease, which requires radical cystectomy or radiotherapy.

Intravesical bacille Calmette-Guerin is used for high-risk non-muscle-invasive disease and works by provoking a local immune response rather than by direct cytotoxicity.

7. Prostate and Testicular Cancer

Prostate cancer is usually adenocarcinoma of the peripheral zone, and it is graded by the Gleason system, now expressed as grade groups.

Prostate-specific antigen is organ-specific but not cancer-specific, and it rises with benign hyperplasia, infection, retention, instrumentation and recent ejaculation as well as with cancer.

Screening remains contested because it detects many indolent cancers that would never have caused harm, so it is offered after discussion rather than applied universally.

Multiparametric magnetic resonance imaging before biopsy has improved the process by allowing some men to avoid biopsy altogether and targeting the rest.

Prostate cancer metastasises to bone, and its metastases are characteristically osteoblastic, which is unusual and distinguishes them from most other tumours.

Localised low-risk disease may be managed by active surveillance, which is monitoring with the intention of treating if it progresses, and is a distinct concept from watchful waiting, which is symptom control without curative intent.

Testicular tumours occur in young men and present as a painless firm testicular swelling that does not transilluminate.

Seminomas are radiosensitive with an excellent prognosis. Non-seminomatous germ cell tumours are more aggressive and are treated with chemotherapy.

Markers matter: alpha-fetoprotein is raised in non-seminomatous tumours and never in pure seminoma, while beta human chorionic gonadotropin may be raised in either. Lactate dehydrogenase reflects tumour bulk.

Orchidectomy is performed through an inguinal incision, never a scrotal one, because a scrotal approach breaches a different lymphatic drainage field and seeds tumour to inguinal nodes. Testicular lymphatic drainage follows the embryological origin to the para-aortic nodes.

8. The Acute Scrotum

Testicular torsion is the diagnosis that must not be missed, because the testis is salvageable for only a few hours.

It presents with sudden severe scrotal pain, often with nausea, in an adolescent or young man, with a high-riding testis lying transversely and an absent cremasteric reflex.

Exploration is on clinical suspicion and imaging must not delay it. A Doppler ultrasound showing flow does not exclude torsion, particularly with intermittent or partial torsion, and the cost of a negative exploration is trivial compared with losing a testis.

The underlying anomaly is the bell-clapper deformity, in which the tunica vaginalis invests the testis completely and allows it to rotate freely. It is usually bilateral, which is why the other side is fixed at the same operation.

Epididymo-orchitis is the main differential, with a more gradual onset, fever, dysuria and a preserved cremasteric reflex. Relief of pain on elevating the testis is the Prehn sign, which supports epididymitis but is not reliable enough to decide against exploration.

Torsion of a testicular appendage occurs in younger boys and may show the blue dot sign through the scrotal skin.

9. Incontinence and the Penile Emergencies

Incontinence is classified by mechanism, and the mechanism dictates the treatment entirely.

Stress incontinence is leakage on coughing, laughing or lifting, caused by sphincter or pelvic floor weakness, and it is treated with pelvic floor exercises first and surgery second.

Urge incontinence is leakage preceded by a sudden overwhelming need to void, caused by detrusor overactivity, and it is treated with bladder training and antimuscarinic or beta-3 agonist drugs.

Overflow incontinence is continuous dribbling from a chronically full bladder in a patient who is actually obstructed, and giving them an antimuscarinic for their leakage makes it considerably worse.

That last error is a favourite examination construction, because the symptom looks like urgency while the mechanism is the opposite.

Two penile conditions are genuine emergencies. Paraphimosis is a retracted foreskin that cannot be reduced, which constricts the glans and causes progressive oedema and eventually necrosis, and it is reduced manually after compression or, failing that, by dorsal slit.

Priapism lasting more than four hours is a compartment syndrome of the corpora. The low-flow ischaemic form is painful, has dark deoxygenated aspirate, and requires urgent aspiration and intracavernosal phenylephrine to prevent permanent erectile dysfunction. The high-flow form follows trauma, is painless and is not an emergency.

10. Urological Trauma

Renal injury is graded by imaging and the great majority are managed conservatively, with intervention reserved for haemodynamic instability, an expanding haematoma or a devascularised segment.

Bladder rupture is intraperitoneal or extraperitoneal, and the distinction determines management. Intraperitoneal rupture occurs at the dome, the weakest part, typically when a full bladder is struck, and requires operative repair because urine is leaking into the peritoneal cavity.

Extraperitoneal rupture is associated with pelvic fracture and is usually managed with catheter drainage alone.

Urethral injury is anterior or posterior. Posterior injury accompanies pelvic fracture, with blood at the meatus, a high-riding prostate and inability to void. Anterior injury follows a straddle injury and produces a characteristic butterfly perineal haematoma.

Catheterisation is deferred until urethral injury is excluded by retrograde urethrography, because passing a catheter can convert a partial tear into a complete disruption.

11. Worked Examples

Example 1. A 65-year-old smoker has a single episode of painless visible haematuria that has now settled.

Painless visible haematuria in an adult is a urological malignancy until proved otherwise, and the fact that it has settled is irrelevant, since bladder tumours bleed intermittently.

Full investigation is required: computed tomography urography for the upper tract and cystoscopy for the bladder, because neither examines the whole tract. Smoking is the dominant risk factor for urothelial carcinoma.

Example 2. A 16-year-old boy has sudden severe left scrotal pain for two hours, with a high-riding testis and absent cremasteric reflex. Ultrasound is not immediately available.

This is testicular torsion, and the diagnosis is clinical. Exploration must not wait for imaging, because the salvage rate falls steeply with time and Doppler flow can be preserved in partial or intermittent torsion.

At operation the testis is untwisted and assessed, and both testes are fixed, because the underlying bell-clapper deformity is usually bilateral.

Example 3. A patient with a known 7 millimetre distal ureteric stone develops a temperature of 39 degrees Celsius with loin tenderness and a rising white cell count.

This is infection above an obstruction, which is the urological emergency equivalent of cholangitis. Antibiotics alone will not resolve it, because the infected system is under pressure and cannot be sterilised while obstructed.

Urgent drainage by percutaneous nephrostomy or retrograde stent is required alongside antibiotics and resuscitation, and the stone itself is treated only once the sepsis has settled.

Summary

• Locate the level, then ask whether it is obstructed and whether it is infected.
• A stone at the vesicoureteric junction mimics cystitis.
• Voiding symptoms suggest obstruction; storage symptoms suggest detrusor overactivity.
• Painless visible haematuria in an adult is malignancy until proved otherwise.
• Investigation needs both upper tract imaging and cystoscopy.
• Confirm dipstick haematuria with microscopy.
• Red cell casts and proteinuria indicate a glomerular rather than urological source.
• Most stones are calcium oxalate; struvite stones form staghorns in infection.
• Uric acid stones are radiolucent and are missed on plain films.
• Non-contrast computed tomography is the investigation of choice.
• Use ultrasound in pregnancy and children.
• The restless patient has colic; the motionless patient has peritonitis.
• Non-steroidal anti-inflammatory drugs beat opioids in renal colic.
• Alpha blockers are recommended for distal stones of about 5 to 10 millimetres.
• Benign hyperplasia arises in the transition zone; cancer in the peripheral zone.
• Alpha blockers work in days; five alpha reductase inhibitors take months.
• Five alpha reductase inhibitors halve the prostate-specific antigen, so double it.
• Acute retention is painful; chronic retention is painless.
• High-pressure chronic retention improves its creatinine after catheterisation.
• Infection above an obstruction requires drainage, not stronger antibiotics.
• Emphysematous pyelonephritis occurs in poorly controlled diabetics.
• Asymptomatic bacteriuria is treated only in pregnancy and before mucosal procedures.
• Most renal cell carcinomas are now incidental findings.
• Renal cell carcinoma causes polycythaemia, hypercalcaemia and Stauffer syndrome.
• A non-emptying left varicocele suggests renal cell carcinoma.
• Renal cell carcinoma resists conventional chemotherapy and radiotherapy.
• Bladder urothelial carcinoma is linked to smoking and aromatic amines.
• Squamous bladder cancer follows schistosomiasis and chronic catheterisation.
• The critical bladder cancer division is non-muscle-invasive against muscle-invasive.
• Bacille Calmette-Guerin works by immune stimulation, not cytotoxicity.
• Prostate-specific antigen is organ-specific but not cancer-specific.
• Prostatic bone metastases are osteoblastic.
• Active surveillance intends cure if progression occurs; watchful waiting does not.
• Alpha-fetoprotein is never raised in pure seminoma.
• Orchidectomy is inguinal, never scrotal, because of lymphatic drainage.
• Torsion is explored on suspicion; preserved Doppler flow does not exclude it.
• The bell-clapper deformity is bilateral, so both testes are fixed.
• Fluid intake above two litres of urine daily benefits every stone type.
• Thiazides cut urinary calcium; citrate is used for uric acid and cystine stones.
• Restricting dietary calcium increases stone formation through oxalate absorption.
• Stress incontinence is sphincter weakness; urge is detrusor overactivity.
• Overflow incontinence is obstruction, and antimuscarinics make it worse.
• Paraphimosis constricts the glans and must be reduced urgently.
• Ischaemic priapism over four hours needs aspiration and phenylephrine.
• Intraperitoneal bladder rupture is repaired; extraperitoneal is drained.
• Exclude urethral injury with urethrography before catheterising.