Urology

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chapter 46 Urology

HISTORY AND EXAMINATION

History and examination of genitourinary presentations will necessarily differ between male and female patients.

ADULT MALE

BEDSIDE UROLOGICAL TESTS

Dipstick and/or microbiological examination of the urine is valuable for the diagnosis of urinary tract infection and microscopic haematuria. The collection of urine samples for microbiology should be done aseptically. The GP should instruct the patient in how to collect the sample. The patient should wash their hands and the urethra should be swabbed (from front to back in females) with saline-soaked gauze. In females, the labia should be parted and the initial part of the void should be then made into the toilet, the midstream should be voided into the specimen container and the remainder in the toilet. The specimen should then be labelled and note made of whether the patient is menstruating. The specimen should be placed in a specimen bag for transportation to the laboratory.

Urine examination is carried out at the bedside, usually using urine dipstick analysis or similar cellulose strips. These contain reagents sensitive to various substances in urine such as blood, leucocytes, protein, glucose, nitrite, bilirubin and urobilinogen. A diagnosis of urinary tract infection (UTI) can be made confidently in the presence of leucocytes, nitrites and protein. It is possible to treat on this basis alone but a midstream sample for culture should also be sent, to ensure that the correct antibiotic is used.

Urinary catheters

Urinary catheterisation is usually straightforward in the anatomically normal lower urinary tract. Adult urinary catheters used in urological surgery are sized from 12 French (Charriere or Ch) to 24 French and above. The gauge equates to the circumference in mm and is approximately three times the diameter in mm. Other catheters such as the Coudé tip catheter and the Tiemann’s are used to negotiate the prostatic urethra but these are uncommonly used and inhabit the realms of the specialist. For patients with acute retention of urine, a 12 Ch catheter is usually sufficient. Although these were traditionally made of rubber, silicone is now widely used. Silicone catheters have the advantage of softness without the risk of perishing and can be left in the bladder for up to 12 weeks.

UROLITHIASIS

AETIOLOGY

Theories of stone formation are by no means complete, partly due to the difficulties of mimicking in vivo disease with an in vitro model. What is clear, however, is that supersaturated urine is a prerequisite to stone formation. The nucleation theory suggests that stones originate from crystals in supersaturated urine, whereas the crystal inhibition theory suggests that it is an absence of urinary inhibitors that differentiates the stone former from the non-stone former. Some work has gone into examination of potential inhibitors, particularly magnesium and citrate. Types of stones are listed in Table 46.1.

TABLE 46.1 Types of stones

Type of stone Incidence (%)
Calcium oxalate/calcium phosphate 80–85
Urate 5–10
Struvite (magnesium, ammonium, phosphate) 5–10
Cystine ≈1–2
Xanthine ≈1–2

THERAPEUTICS

PREVENTION

In order to identify risk of further stone formation, certain investigations are carried out in patients after their first episode of colic. Some authors suggest that metabolic evaluation should be carried out only on those patients with multiple or recurrent stones.

Measurement of serum calcium and urate will identify hypercalcaemic and hyperuricosuric patients. Identification of metabolic abnormalities associated with recurrent stone disease is usually carried out by analysis of 24-hour urine excretion (volume, pH, levels of calcium, phosphate and uric acid, oxalate, citrate, creatinine). Stone analysis may also assist following operative procedure or spontaneous passage.

The most common abnormality found is idiopathic hypercalciuria (with normal serum calcium). This is most easily treated with an increased fluid intake of 1.5–2 L per day.

Chemoprevention is a holy grail for stone disease. Urinary inhibitors such as potassium citrate, alone or in combination with a thiazide diuretic, can be used. Thiazide diuretics decrease hypercalciuria by increasing reabsorption of calcium from the distal tubule. Citric acid (as lemon juice) can be taken but large amounts (100–150 mL of pure lemon juice) are required to produce enough citrate in the urine.

Where possible, avoid medications likely to increase stone risk.

URINARY TRACT INFECTION

PREVENTION

UTI IN CHILDREN

INCONTINENCE

Urinary incontinence is the involuntary loss of urine. It is both a clinical sign and a symptom. The prevalence of incontinence increases with age and it is more common in women than men. Estimates are that 7–19% of adult women suffer from some form of urinary incontinence, with wide differences seen between different cultures and races.

Incontinence is not only a hygienic issue but it can negatively affect a patient’s quality of life, with social, psychological and sexual impairment.

Urinary incontinence may be classified as:

THERAPEUTICS