Bladder, Bowel, and Sexual Dysfunction in Parkinson's Disease

Abstract

Bladder dysfunction (urinary urgency/frequency), bowel dysfunction (constipation), and sexual dysfunction (erectile dysfunction) (also called “pelvic organ” dysfunctions) are common nonmotor disorders in Parkinson's disease (PD). In contrast to motor disorders, pelvic organ autonomic dysfunctions are often nonresponsive to levodopa treatment. The brain pathology causing the bladder dysfunction (appearance of overactivity) involves an altered dopamine-basal ganglia circuit, which normally suppresses the micturition reflex. By contrast, peripheral myenteric pathology causing slowed colonic transit (loss of rectal contractions) and central pathology causing weak strain and paradoxical anal sphincter contraction on defecation (PSD, also called as anismus) are responsible for the bowel dysfunction. In addition, hypothalamic dysfunction is mostly responsible for the sexual dysfunction (decrease in libido and erection) in PD, via altered dopamine-oxytocin pathways, which normally promote libido and erection. The pathophysiology of the pelvic organ dysfunction in PD differs from that in multiple system atrophy; therefore, it might aid in differential diagnosis. Anticholinergic agents are used to treat bladder dysfunction in PD, although these drugs should be used with caution particularly in elderly patients who have cognitive decline. Dietary fibers, laxatives, and “prokinetic” drugs such as serotonergic agonists are used to treat bowel dysfunction in PD. Phosphodiesterase inhibitors are used to treat sexual dysfunction in PD. These treatments might be beneficial in maximizing the patients' quality of life.

Plasma levodopa peak delay and impaired gastric emptying in Parkinson's disease

“…Slow gastric transport leads to delayed jejunal absorption, resulting in a delayed plasma levodopa peak. This slow gastric transport can be attributed to myenteric plexus pathology in PD [10], where altered balance of cholinergic/5-HT4 serotonergic excitation and D2 dopaminergic inhibition might occur [11]. Although peripherallyacting dopamine on the bowel motility produced conflicting results [11], centrally-acting levodopa did not worsen colonic transit in PD patients [12].…”

Dopamine is produced in the rat spinal cord and regulates micturition reflex after spinal cord injury

“…This will be explored in future experiments. It is possible that lumbosacral DA neurons modulate other pelvic organ functions, as a dysfunctional DA system results in abnormal sexual and bowel function and visceral pain (Shulman et al, 2001; Sakakibara et al, 2011; Jarcho et al, 2012), and is therefore valuable for researchers to pursue.…”

“…Disrupting DA signaling results not only in motor dysfunction but also in autonomic disorders (Shulman et al, 2001; Sakakibara et al, 2011). For instance, irritable hyperactive bladder symptoms, such as urinary urgency, frequency, and incontinence, often occur when midbrain DA neurons are damaged in Parkinson’s disease (PD) (Winge and Fowler, 2006).…”

Animal Models of Parkinson's Disease: A Gateway to Therapeutics?

“…Urinary tract dysfunction can be tested in animal models by demonstrating evidence of parasympathetic and somatic dysfunction, manifested by reduced bladder capacity, external sphincter relaxation, detrusor weakness, and urethral obstruction [115]. In a study of cats, it is found that stimulation of subthalamic nucleus can manifest inhibitory effects on the micturition reflex [116].…”