Sigmoid volvulus has been associated with each of the following except:

B. Chronic rectal proplapse.

DISCUSSION: The development of sigmoid volvulus depends on the presence of a dilated, redundant sigmoid colon. This acquired redundancy may be secondary to long-term ingestion of a high-residue diet, particularly in parts of the world where the disease is common. In the United States, the most prominent association is chronic constipation and excessive reliance on laxatives or enemas. Other contributing factors include neurologic or psychiatric conditions such as Parkinson's disease, Alzheimer's disease, multiple sclerosis, traumatic paralysis, chronic schizophrenia, pseudobulbar palsy, and senility. Patients are frequently bedridden and are being managed with various neuropsychotropic drugs, both of which may alter bowel motility