• neurogenic bladder dysfunction
• detrusor overactivity

Because of the complex nature of the neural control of the lower urinary tract, complaints about bladder function are common in patients with neurological disease. The main neural circuits controlling the two functions of the bladder—that is, storage and voiding—are trans-spinal so that intact cord connections between the pons and the sacral segments are necessary to sustain physiological control. Furthermore, input from higher centres is critical in the assessment of appropriate timing of voiding and many types of cortical disease can affect the centres involved with this. In addition to the spinal pathways and input from higher centres, the peripheral innervation to the bladder is through the pelvic plexus, sacral, and pudendal nerves.

However, despite this complexity of neural control, when considered from the point of view of possible dysfunctions, these are limited to those causing a failure of storage or those causing a failure of emptying. Most commonly patients with neurological disease have problems with the former and have incontinence. Some patients, however, may have urinary retention. In addition, there is a large group of patients, particularly those with disruption cord disease, who have a combination of incomplete emptying and bladder overactivity.

Although the patients’ symptoms are generally a good guide as to the predominant underlying bladder disorder if it is detrusor overactivity, this is not the case in those with additional incomplete emptying; it is in these cases that investigations determining management are most important.