Urology

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CHAPTER 16 Urology

Congenital disorders of the urinary tract

Kidney and ureter

Congenital absence of one kidney

Incidence is 1:2500.

Pelvic kidney

Incidence is 1:800. Often associated with reflux or PUJO. Large pelvic kidney may interfere with childbirth.

Horseshoe kidney

Incidence is 1:1000 to 1:1800. The combined kidney lies lower than normal. Renal pelvis rotated anteriorly and the lower pole medially. Often associated with reflux, undescended testes.

Congenital hydronephrosis (PUJO)

Aetiology unknown. Lower pole vessel may aggravate but rarely responsible for condition. Failure to thrive, recurrent UTI, mass, hypertension. Often discovered on prenatal USS.

Infantile polycystic disease

Incidence is 1:10 000. Rare, autosomal recessive.

Adult polycystic disease

Incidence is 1:1500. Autosomal dominant, involving both kidneys. Patients usually present aged 30–40 with hypertension, mass, haematuria, renal failure. May be associated with cysts in the liver. Family screening and genetic counselling.

Medullary sponge kidney

Incidence is 1:20 000. Characterized by congenital dilatation or cysts of the distal collecting ducts. May be associated with hypercalciuria, impaired urinary concentration.

Ureteric duplication

Often bilateral. The upper pole ureter lies medial and inferior to the lower pole ureter at the bladder.

Ureterocele

Dilatation of the submucosal portion of the ureter. Filling defect on IVU.

Megaureter

Secondary to either dysplastic (non-obstructed) or obstructed ureter. May be associated with stones, UTI, reflux.

Vesicoureteric reflux

Reflux is the abnormal passage of urine from bladder to the ureter. Primary reflux is due to a defect of the vesicoureteric junction. Usually resolving spontaneously in 70% of cases. Secondary reflux is usually due to outflow obstruction – 20% of children presenting with recurrent UTI have reflux.

Diagnosis

Voiding, micturating cystourethrogram.

Treatment

Consists of antibiotics, regular voiding, ureteric reimplantation.

Bladder

Ectopia vesica (exstrophy of the bladder)

This occurs in 1:20–40 000. It is more common in the male. The anterior wall of the bladder fails to close. The posterior bladder wall, the trigone and posterior urethra are exposed and urine leaks onto the skin. Associated anomalies include wide separation of the pubic symphysis with waddling gait, epispadias, umbilical and inguinal hernias, imperfectly descended testes, and rectal prolapse.

Complications

Ureteric dilatation and pyelonephritis.

Treatment

Involves reimplantation of the ureters into an ileal loop conduit with excision of the bladder and repair of the abdominal wall defect. In some cases, bladder reconstruction may be possible.

Urachal abnormalities

Defects may result from the primitive urachal connections between bladder and umbilicus. If the tract persists, urine may discharge from the umbilicus. An urachal cyst may occur if part of the urachus persists but is closed off above and below. Infection may occur in an urachal cyst. Treatment is by excision.

Urethra

The urethra may terminate on the ventral aspect of the penis (hypospadias) or on its dorsal aspect (epispadias). Hypospadias may result in difficulty with intercourse. Plastic reconstruction of the urethra may be required. Epispadias is rare and more disabling and difficult to correct than hypospadias. It may be associated with incontinence. Plastic reconstruction or urinary diversions are possible treatments. In the female, the urethra may open on to the anterior vaginal wall.

Urethral valves may occur in the posterior urethra. The condition is rare, occurring with an incidence of 1:5000, 50% of cases occurring under 1 year of age. They cause dilatation of the prostatic urethra, bladder, ureters and pelvis. It is often diagnosed on prenatal USS. Rarely, there may be uraemia with palpable bladder and kidneys at birth. Milder cases present later in childhood with difficulty in voiding, recurrent UTIs and uraemia. Treatment is by transurethral resection of the valves. With early presentation the prognosis is good. With extensive renal damage, dialysis and transplantation may be required.

Haematuria

Haematuria is the passage of red blood cells in the urine. This may vary from a few red cells detected on ‘stix’ testing to the passage of frank blood. Haematuria may be noted at the beginning of micturition, throughout micturition or at the end of micturition. Care must be taken to avoid menstrual bleeding being mistaken for haematuria. Other causes of red urine include excessive beetroot ingestion, rifampicin, porphyria, haemoglobinuria and myoglobinuria. (For causes of haematuria → Table 16.1.)

TABLE 16.1 Causes of haematuria

Kidney	Glomerular disease
	Polycystic kidneys
	Carcinoma
	Stone
	Trauma (including renal biopsy)
	Tuberculosis
	Embolism
	Renal vein thrombosis
	Vascular malformation
Ureter	Stone
Ureter	Neoplasm
Bladder	Carcinoma
	Stone
	Trauma
	Inflammatory – cystitis, tuberculosis, bilharzia
Prostate	Benign prostatic hypertrophy
Prostate	Neoplasm
Urethra	Trauma
	Stone
	Urethritis
	Neoplasm
General	Anticoagulants
	Thrombocytopenia
	Haemophilia
	Sickle cell disease
	Malaria

Symptoms and signs

Family history, e.g. polycystic kidney. Painless haematuria is suggestive of neoplasia. Loin pain or ureteric colic suggests stone or clot colic associated with tumour. Suprapubic discomfort suggests bladder stone. Terminal bleeding with pain suggests bladder calculus. Urethral bleeding independent of micturition suggests a urethral lesion. Check the drug history. Spontaneous bruising. Palpable kidney. Palpable bladder. Enlarged prostate on examination PR.

Treatment

Appropriate to the underlying condition.

Obstructive uropathy

Hydronephrosis is the distension of the calyces and pelvis of the kidney owing to obstruction to the outflow of urine. It may be bilateral or unilateral. (For causes of hydronephrosis → Table 16.2.)

TABLE 16.2 Causes of hydronephrosis

Unilateral

Pelviureteric junction obstruction

• congenital pelviureteric junction obstruction

• aberrant renal vessels

• tumours of the renal pelvis

Ureteric obstruction

• ureteric invasion, e.g. cervical, rectal or colonic tumours

• iatrogenic – damage at surgery

Bilateral Urethral valves Urethral or meatal stenosis Prostatic enlargement Extensive bladder tumours Retroperitoneal fibrosis

Symptoms and signs

Loin pain. Upper abdominal pain. Fever. Rigors – if infection. Ureteric colic. Hesitancy, poor stream, frequency, distended bladder with suprapubic discomfort. Uraemia may be presenting complaint. Palpable kidney. Palpable prostate.

Investigations

• KUB: enlarged renal outline, opaque calculi

• USS: confirms diagnosis and may demonstrate lesion

• IVU (→ Fig. 16.1): early stages show pelvic dilatation with clubbing of the calyces, site of obstruction, function of kidney, trabeculation of bladder, residual urine (if bilateral hydronephrosis and uraemia, no further information would be obtained from an IVU)

• Cystoscopy: cause of bladder outlet obstruction or bladder tumour

• Retrograde pyelogram defines exact site of obstruction.

Figure 16.1 Intravenous urogram. There is a right-sided hydronephrosis and hydroureter. Note the dilatation of the pelvis with clubbing of the calyces and also dilatation of the ureter down to its entry into the bladder.

Treatment

Directed at the underlying cause. With a small ureteric stone the obstruction may be relieved with the passage of the stone. The presence of acute infection or marked renal impairment requires urgent decompression of the urinary tract under antibiotic cover. This may be done by percutaneous nephrostomy, suprapubic cystostomy, ureteric catheter drainage or urethral catheter drainage. A non-functioning kidney, especially if infected, should be removed.

Complications

Infection: pyonephrosis. Stone formation in stagnant urine. Hypertension due to renal ischaemia. Traumatic rupture of a hydronephrotic kidney. Uraemia.

Calculous disease

Urinary calculi are often idiopathic. They also arise secondary to stasis and infection and also in association with metabolic disorders, e.g. cystinuria. Stones may form in the kidney or bladder. Ureteric calculi are in transit from the kidney to bladder. Stones occur in about 1% of the population. The majority is composed of calcium, magnesium ammonium phosphate, or urate.

Types of calculi

Calcium oxalate (75%)

‘Mulberry’ stones covered with sharp projections. They cause bleeding and are often black owing to altered blood on their surface. Because of their sharp surface they give symptoms when comparatively small. Occur in alkaline urine.

Phosphate (15%)

Usually compound of calcium, magnesium and ammonium phosphate. Smooth and dirty white. They may enlarge rapidly and fill the calyces taking on their shape, i.e. staghorn calculus. Occur in strongly alkaline urine.

Urate (5%)

Arise in acid urine. Hard, smooth, faceted and light brown in colour.

Cystine (2%)

Usually multiple. Arise in acid urine and are of metabolic origin owing to decreased reabsorption of cystine from the renal tubules. White and translucent.

Xanthine and pyruvate stones

Rare. Due to inborn error of metabolism.

About 90% of calculi are radio-opaque. Usually only urates are radiolucent, cystine stones being radio-opaque because of their sulphur content. Precipitating factors include: diet, dehydration, stasis, infection, hyperparathyroidism, idiopathic hypercalciuria, milk-alkali syndrome, hypervitaminosis D, cystinuria, inborn errors of purine metabolism, gout, and chemotherapy (excess uric acid following treatment of leukaemia or polycythaemia).

Symptoms and signs

Renal calculi

May be asymptomatic even with large stone. Loin pain. Haematuria. Dysuria. Signs of uraemia. Colic if stone impacts in pelviureteric junction.

Ureteric calculi

Severe colicky pain radiating from loin to groin. Sweating. Nausea. Vomiting.

Bladder calculi

Dull suprapubic discomfort, terminal haematuria, dysuria, strangury. Patient may have loin tenderness, pyrexia if infection, kidney may be palpable with gross hydronephrosis or pyonephrosis.

Treatment

Acute symptoms – ureteric colic:

• Relieve pain – diclofenac sodium i.m. or p.r.; or pethidine.

• Admit to hospital

• Intravenous fluids or increased oral fluids

• Collect and sieve all urine to retrieve calculus for analysis

• Check radiographs to assess progress of stone

• Stones <4 mm will usually pass spontaneously; 50% of stones between 4 mm and 6 mm will pass spontaneously. Stones >6 mm usually require removal

• Obstruction and infection require removal of stone

• Stone removal may be carried out by: ureteroscopy and fragmentation of the stone; pushing the stone back into the renal pelvis followed by fragmentation with extracorporeal shock wave lithotriptor.

Routine treatment of established urinary calculus

Removal of renal or bladder calculus by open surgical technique is now rare. Minimal invasive surgery using endoscopic techniques or extracorporeal shockwave lithotripsy is now the treatment of choice.

Percutaneous nephrolithotomy

A nephroscope is inserted into the kidney under radiographic control via a previously dilated track. The stone is then removed by grasping forceps (if small), ultrasonically disintegrated and removed by suction or disrupted into small fragments by electrohydraulic or laser lithotriptors.

Extracorporeal shockwave lithotripsy

This consists of an external energy source focused to provide a high-pressure zone that is directed to fragment the calculus. The calculus is fragmented into small particles, which pass in the urine.

Open surgery

This is used less often. A stone may be removed through the kidney substance (nephrolithotomy), or through the renal pelvis (pyelolithotomy). Surgery may be needed to correct hydronephrosis associated with a stone. If the kidney is irreparably damaged, nephrectomy is required.

Bladder calculi

Small stones may be removed cystoscopically after crushing with a lithotrite or disintegration using an electrohydraulic lithotriptor. Large stones >5 cm are removed by suprapubic cystostomy.

The stone must be analysed. The underlying cause must be treated if possible, e.g. parathyroidectomy or correction of an obstructive lesion. Attempts should be made to prevent recurrence.

Prevention of recurrence

Up to 50% of patients may have recurrence within 5 years. Prevention involves: (1) high fluid intake, especially in hot weather; (2) reduce milk intake; (3) prompt treatment of urinary tract infections; (4) calcium stones: low-calcium diet, thiazide diuretics, acidify urine; (5) oxalate stones: reduce oxalate intake – exclude rhubarb, spinach, tomatoes, strawberries, tea and chocolate; (6) urate stones: allopurinol, urinary alkalinization.

Tumours of the renal tract

Kidney

Benign tumours are rare. Adenocarcinoma accounts for 80% of renal tumours. Transitional cell tumours occur in the renal pelvis. Squamous cell carcinomas may occur in the renal pelvis and are associated with squamous metaplasia due to chronic irritation caused by stone or infection.

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