Summary: Overactive bladder is a common urological diagnosis which is often untreated as patients fail to seek help for this embarrassing problem. Elizabeth Waine and Mark Stott summarise the symptoms and investigations for overactive bladder and provide an overview of the treatments available.
Authors: Elizabeth Waine, MRCS, ChB, MB, is urology specialist registrar; Mark Stott, FRCS, MD, is consultant urologist; both at Royal Devon and Exeter NHS Trust.
Overactive bladder (OAB) syndrome is a symptomatic diagnosis characterised by the presence of urgency, which is a sudden and compelling desire to pass urine which cannot be deferred, with or without urge urinary incontinence (UUI). UUI is the involuntary leakage of urine accompanied by or preceded immediately by urgency. The patient may also experience urinary frequency as well as nocturia, which is the desire to void which wakes the patient from sleep.
In order to make the diagnosis of OAB, the presence of urinary tract infection or other pathology must be excluded (Abrams et al, 2002). A large proportion of patients with symptoms will not seek help and therefore the true prevalence of this disorder is difficult to estimate.
A study carried out in six European countries estimated that 16.6% of the population aged 40 or above had symptoms of OAB, frequency being most commonly reported (85%), while urgency (54%), and urge incontinence (36%) were the next most commonly reported symptoms (Milsom et al, 2001). Sixty percent had sought a medical consultation and 27% were receiving treatment.
OAB has a social and economical impact on people. The University of Michigan reported that OAB and more notably UUI occurred in 37% of women between 18 and 60 years of age within their study. Of those with severe symptoms, 88% reported a reduction in concentration, performance of physical activities, self-confidence or the ability to complete tasks without interruption (Fultz et al, 2005). The overall cost of OAB in the US in 2000 was estimated to be between $US9.1bn (Getsios et al, 2005) and $US12.6bn (Huetal,2004).
Cause of OAB
The true cause of OAB has not yet been established but several theories have been suggested, all of which imply an abnormality within the nervous control of bladder muscle (detrusor) contraction. This theory is supported by the action of the medical treatments given for overactive bladder, which work at the neuromuscular junction by blocking the release of the neurotransmitter acetylcholine and this prevents contraction of the detrusor muscle.
Assessment of a patient with symptoms of OAB
It is important to take a thorough history and fully examine the patient. The impact that the patient’s symptoms are having on their daily activities is extremely useful as this can help to monitor the effect of an intervention.
Excluding the presence of blood in the urine (haematuria) or pain on voiding may help eliminate other causes for the symptoms, for example bladder tumours or bladder stones.
A detailed past medical history, including any previous surgery, a comprehensive drug history, and, if the patient is female, a full obstetric and gynaecological history, should be taken.
Thorough questioning may highlight the presence of conditions such as untreated heart failure, which may aggravate symptoms, or irritable bowel syndrome which is associated with the symptoms of OAB (Cukier, 1997).
It is important to ask the patient about smoking and the possible exposure to carcinogens during their working life. For example, painters and hairdressers may have been exposed to carcinogenic dye.
Daily fluid intake should also be assessed. It may be possible to identify lifestyle changes that can be made to alleviate symptoms.
Physical examination includes abdominal examination to assess for the presence of a palpable bladder. Incomplete bladder emptying may mimic the symptoms of OAB but requires different treatment.
A full neurological examination should be carried out.
In men, a digital rectal examination assesses the presence of faecal loading or of an enlarged and/or abnormal prostate. In women, a pelvic examination is carried out, and observation of simple disorders such as vaginal dryness or vaginal or uterine prolapse should be made. Gynaecological prolapse can alter the shape of the bladder and make complete emptying of the bladder difficult. Vaginal dryness can signify atrophic vaginitis which has an association with urethral narrowing.
In addition to the history and examination a number of simple tests can be carried out to help make the correct diagnosis (Box 1).