Detrusor Overactivity With DSD

Detrusor overactivity associated with DSD (UMN) is a type of dysfunction seen with injuries of the spinal cord that compromise communication between the upper motor neurons in the pontine micturition centre (brain) and the sacral micturition centre (i.e. infrapontine, suprasacral lesions). The detrusor becomes overactive due to loss of descending inhibition and reflexively contracts even with small volumes in the bladder. In these cases, disconnection from the pontine micturition centre also disrupts coordination between the detrusor muscle and the sphincters of the detrusor. During normal voiding, the internal and external sphincters relax while the detrusor simultaneously contracts in a carefully coordinated sequence of events. With DSD, the detrusor and sphincters simultaneously contract. The relative obstruction to urine outflow during voiding leads to elevated bladder pressures. Physiological abnormalities of detrusor overactivty with DSD include incontinence due to detrusor disinhibition, incomplete emptying (due to sphincter co-contraction), and ureteral reflux (due to high bladder pressures); which in turn increase risk of recurrent bladder infections, genitourinary stones, hydronephrosis, pyelonephritis, and renal failure.