Gastrointestinal dysfunction in Parkinson's disease.

In recent years, an increasingly detailed picture of gastrointestinal dysfunction in the setting of Parkinson's disease has emerged. Abnormalities of function may occur at virtually all levels of the gastrointestinal tract. Weight loss, dental deterioration, salivary excess, dysphagia, gastroparesis, decreased bowel movement frequency, and anorectal dysfunction all may occur. The pathophysiologic basis for this dysfunction entails both central and enteric nervous system involvement.