Introduction

Obstructive urinary symptoms result from mechanical obstruction to the flow of urine at time of micturition. The level of obstruction can be anywhere from the bladder neck to the external urethral meatus. The term bladder outflow obstruction (BOO) is often used to describe the constellation of symptoms that results. Sometimes urologists will elect to use the term ‘lower urinary tract symptoms ’ (LUTS) if the patient's symptoms are both obstructive and storage (irritative) in nature.

Definition and classification

1. ▪ Obstructive symptoms include: hesitancy, straining, decreased force of urination, intermittent stream, prolonged micturition, post-micturition dribbling and a sensation of incomplete bladder emptying.

2. ▪ Objective measurements include use of basic urodynamic flow studies and completion of validated symptom score e.g. I-PSS (international prostate symptom score).

3. ▪ It is important to distinguish these from storage symptoms, which include frequency, nocturia, urgency and dysuria. Although storage symptoms may result from bladder outlet obstruction, their presence should prompt investigation for a more sinister cause, e.g. carcinoma in situ of the bladder.

Incidence

Obstructive urinary symptoms are far more common in men by virtue of benign prostatic hyperplasia (BPH). Incidence and therefore prevalence is difficult to determine, as there is no standardized definition for BPH. Histologically this is not found in males under 30 years old but is found in 88% of 90-year-old men.

Aetiology

The most common causes include:

1. ▪ BPH

2. ▪ Urethral strictures.

Other causes include:

1. ▪ Bladder neck hypertrophy

2. ▪ Marked prostatitis

3. ▪ Urethral calculi

4. ▪ Urethral meatal stenosis

5. ▪ Phimosis

6. ▪ Neurogenic detrusor/sphincter dysfunction.