Constipation can best be defined as unsatisfactory defecation characterized by infrequent stool, difficult stool passage or both (1). Difficult stool passage may include straining, hard stools, a feeling of incomplete evacuation or the need to use manual maneuvers to assist with defecation.
Constipation is one of the most common gastrointestinal complaints. The prevalence of chronic constipation averages between 12-15% of the population in the United States depending on how constipation is defined (2). However, there are reasons to believe the actual rate may be higher. First, this estimate is based upon the number of patients satisfying strict criteria for chronic constipation; it does not reflect those who report regularly feeling constipated but who do not satisfy all criteria. If a patient believes their defecation is unsatisfactory and as a result seeks treatment, then they are constipated whether or not they fulfill strict diagnostic criteria. Furthermore, chronic constipation sufferers under-report their symptoms to their doctors for a variety of reasons, including the relative low cost of over-the-counter therapies, a misunderstanding of their symptoms as "normal" and not indicative of an underlying problem, or simple embarrassment. For example, it has been estimated that only 26% of chronically constipated patients meeting the criteria for the disease actually seek professional medical treatment (3).
The prevalence of constipation increases with age and the rise in prevalence is particularly dramatic after the age of 65. Moreover, 30% of community residing individuals over the age of 65 report that they suffer from constipation symptoms at least monthly. Constipation is nearly three times more common among females than males and is more prevalent among nonwhites than whites. Constipation also seems to be associated with lower socioeconomic status and living in rural areas (4).
Although constipation is more common among those over age 65, it is probably not a consequence of normal aging. Rather there are a number of comorbidities among patients in this age group which likely contribute to their increased risk of developing chronic constipation. These potential risk factors include: immobility, concomitant chronic illness, polypharmacy, and underlying neurologic disease, the most important being dementia although cerebrovascular disease, Parkinson's disease and Multiple Sclerosis also represent significant risk factors.
The onset of constipation is generally insidious, unrelated to any known initiating event. Early in the course of constipation, infrequent or difficult evacuation may represent the only symptom. As constipation progresses in severity, patients typically develop bloating and mild cramping type abdominal pain that is frequently worse after meals. Patients who have suffered from constipation for many years may additionally note fatigue, malaise and anorexia.
Constipation appears to be a slowly progressive disorder that rarely resolves. Despite its slowly progressive course, however, constipation seldom leads to severe morbidity or mortality. Hospitalization solely for constipation is uncommon. Nevertheless, long-standing constipation has been associated with several potentially serious complications. The most common of these is fecal impaction, which is a particular risk among the elderly and even more so among the institutionalized elderly. Indeed, it is of such concern that a fecal impaction is now a reportable quality event in nursing homes. If severe and prolonged, fecal impaction can lead to colonic perforation. Chronic constipation sufferers also are at risk of developing a sigmoid volvulus, or "twist" of the colon. A volvulus typically results from elongation and redundancy of the sigmoid colon. Once the sigmoid has sufficiently elongated, it twists around itself leading to obstruction and subsequent ischemia of the colon at the level of the volvulus. If not resolved, the ischemia also may lead to colonic perforation. A third potential complication of chronic constipation is the formation of a stercoral ulcer. A stercoral ulcer is a pressure ulcer of the sigmoid or rectum which results from stool remaining in the colon for long periods of time, applying pressure to the colon wall. If this condition is prolonged, again, colonic perforation may occur.
Given the potential for serious complications among elderly patients with constipation, particularly those who are institutionalized, it is important to provide effective therapy with consistent follow-up to ensure that these patients first and foremost are comfortable, but also to optimize their quality of life and to ensure that these potentially serious complications of constipation are avoided.
John F. Johanson MD, MSc, FACP, FACG
Beloit Health System
Clinical Associate Professor of Medicine
University of Illinois College of Medicine
(1) American College of Gastroenterology Chronic Constipation Task Force. Am Journal Gastro. 2008;100(suppl 1):S1-S4.
(2) Higgins, P.D.R., Johanson, J.F. Epidemiology of constipation in North America: a systematic review. Am Journal Gastro. 2004;99:750-759.
(3) Schey, R., Rao, S.S.C. Lubiprostone for the treatment of adults with constipation and irritable bowel syndrome. Dig Dis Sci. 2011;56:1619-1625.
(4) Johanson J.F. Geographic distribution of constipation in the United States. Am J Gastro. 1998:93:188-191.