CHAPTER 1 Clinical evaluation of the lower urinary tract

INTRODUCTION

The bladder and the urethra comprise the lower urinary tract and act as a single (vesico-urethral) unit during normal lower urinary tract function. The role of this unit is to:

• adequately store urine (storage)

• efficiently empty urine (voiding).

If the function of this vesico-urethral unit is disturbed then urinary dysfunction along with associated lower urinary tract symptoms (LUTS) may occur. Management of lower urinary tract dysfunction is based on the findings of:

• a focused history and physical examination

• appropriate laboratory studies

• endoscopy and radiography – to provide structural information when clinically indicated

• urodynamic studies – to provide functional information when clinically indicated.

FOCUSED HISTORY AND PHYSICAL EXAMINATION

First and foremost, a focused history establishes a working diagnosis, helps formulate clinical questions and directs subsequent investigations and management. Previously a plethora of overlapping and confusing terms relating to lower urinary tract dysfunction were in usage; however the International Continence Society (ICS) have published terminology reports to standardize the terms used when describing LUTS. Thus, enabling consistent and accurate reporting of symptoms and enabling further investigations and management to be appropriately directed. It is recommended that only standardized terminology is used when describing LUTS.

The ICS have broadly categorized LUTS into three groups (Table 1.1) related to their timing within the bladder (voiding) cycle. The three stages of the bladder cycle are:

1. Storage – during which passive filling of the bladder occurs, either naturally from urine produced by the kidneys or artificially during a urodynamic study.

2. Voiding – during which the vesico-urethral unit actively expels the bladder contents.

3. Post-micturition – immediately after voiding when the bladder returns to storage function.

Table 1.1 Lower urinary tract symptoms.

Lower urinary tract symptoms
Storage	Voiding	Post-micturition
Urgency Increased daytime frequency Nocturia Urinary incontinence Altered bladder sensation	Hesitancy Intermittency Slow stream Splitting or spraying Straining Terminal dribble	Feeling of incomplete emptying Post-micturition dribble

Specific definitions for lower urinary tract symptoms are listed in the box at the end of this chapter.

The bladder is frequently said to be an ‘unreliable witness’. There are a number of reasons why this statement accurately reflects the situation. First, lower urinary tract symptoms are not disease specific and diverse patho-physiologies can produce similar lower urinary tract symptoms. Second, patients express symptoms in different ways and this is influenced both by what they are experiencing and how they interpret the symptoms they are experiencing. Lastly, as clinicians we all take histories differently and interpret the clinical picture based on our own experience and prejudices.

Clearly however, a careful history with emphasis on allocating symptoms to the appropriate stage of the bladder cycle is an important starting point. Failure to store can be due to overactivity of the bladder, underactivity of the bladder with overflow, or weakness of the bladder outlet. Likewise, while voiding symptoms tend to be associated in many people’s minds with bladder outlet obstruction, they can of course also occur in the context of poor bladder function.

Having taken a careful history and carried out an appropriate clinical examination; laboratory, endoscopic or radiographic tests should be performed prior to urodynamic assessment as clinically indicated.

URODYNAMIC EVALUATION

Appropriate urodynamic tests can only be interpreted after taking an adequate history, with the formulation of specific clinical questions; since the principal aims of the urodynamic assessment are to answer the clinical questions by evaluating the function of the vesico-urethral unit. Urodynamics is particularly of benefit in objectively identifying functional abnormalities of the lower urinary tract such as urinary incontinence and bladder outflow obstruction (BOO). However (particularly with video cystometry) it may also assist in identifying structural abnormalities such as a prolapse associated with stress urinary incontinence (SUI), vesico-vaginal fistulae, urethral diverticula, upper tract vesico-ureteric reflux; or in the context of the male patient, it can be useful in demonstrating attenuation of the prostatic urethra in association with prostatic outlet obstruction or confirming the diagnosis of bladder neck obstruction.

The term ‘urodynamics’ encompasses any investigation of lower urinary tract dysfunction from the simple to the sophisticated, these include:

• Frequency/volume chart (FVC).

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Paediatric urodynamics Urodynamic procedures Basic structure, function and control of the lower urinary tract Pressure/flow cystometry Voiding disorders and bladder outlet obstruction Storage disorders and incontinence

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