Clinical aspects of detrusor instability and the value of urodynamics.

According to the International Continence Society, detrusor instability (DI) is not a disease, it is a condition found only by urodynamic examination. Thus, the word instability is misleading. It implies that the bladder is abnormal. We do not think of unstable situations as being normal. It is inappropriate to use the term because it makes it too easy for clinicians to feel they have made a diagnosis when they have not. It curtails further thinking and does not promote the scientific pursuit of fact. What is the evidence that DI is abnormal? As described by the ICS in 1981, the patient must have no neurological bladder abnormality. Studies show it can be provoked in asymptomatic individuals and can be found 'naturally' with ambulatory urodynamic testing. A person may be clinically asymptomatic and totally unaware that the contraction is occurring. The findings are simply phasic pressure increases reflecting typical rhythmic contractions of visceral structures such as bowel and urinary bladder. This paper proposes the term 'phasic detrusor contractions' (PDCs). It has no connotation, describes the finding, and frees the clinician and scientist to explore the matter without prejudice.