While constipation is one of the most common symptoms managed by practicing gastroenterologists, it can also be among the most challenging. As a presenting complaint, constipation manifests with widely varying degrees of severity and may be seen in all age groups, ethnicities, and socioeconomic backgrounds. Its implications can include chronic and serious functional impairment as well as protracted and often excessive health care utilization. A growing number of pharmacologic and nonpharmacologic interventions have become available and proven to be effective when appropriately deployed. As such, health care providers and particularly gastroenterologists should strive to develop logical and efficient strategies for addressing this common disorder.
While there are a variety of etiologies for constipation (Table 1), a large proportion of chronic cases fall within the framework of functional gastrointestinal disorders, a category with a substantial burden of disease across the population. Prevalence estimates vary, but constipation likely affects between 12% and 20% of the North American population.1 Research has demonstrated significant health care expenditures associated with chronic constipation management; U.S. estimates suggest direct costs on the order of hundreds of millions of dollars per year, roughly half of which are attributable to inpatient care.2 The financial burden of constipation also includes indirect costs associated with absenteeism as well as the risks of hospitalization and invasive procedures.3
Physical and emotional complications can be likewise significant and affect all age groups, from newborns to patients in the last days of life. Hirschsprung’s disease, for example, can lead to life-threatening sequelae in infancy, such as spontaneous perforation or enterocolitis, or more prolonged functional impairments when it remains undiagnosed. Severe constipation in childhood can lead to encopresis, translating in turn into ostracism and impaired social functioning. Fecal incontinence associated with overflow diarrhea is common and debilitating, particularly in the elderly population.
The potential mechanical complications of constipation lead to its overlap with a variety of other gastrointestinal complaints. For example, the difficulties of passing inspissated stool can provoke lower gastrointestinal bleeding from irritated hemorrhoids, anal fissures, stercoral ulcers, or prolapsed rectal tissue. Retained stool can also lead to upper gastrointestinal symptoms such as postprandial bloating or early satiety.4 Delayed fecal discharge can promote an increase in fermentative microbiota, associated in turn with the production of short-chain fatty acids, methane, and other gaseous byproducts.
The initial assessment
Taking an appropriate history is an essential step toward achieving a successful outcome. Presenting concerns related to constipation can range from hard, infrequent, or small-volume stools; abdominal or rectal pain associated with the process of elimination; and bloating, nausea, or early satiety. A sound diagnosis requires a keen understanding of what patients mean when they indicate that they are constipated, an accurate assessment of its impact on quality of life, and a careful inventory of potentially associated complications.
It is critical to define the duration of the problem. Not infrequently, patients will focus on recent events while failing to reveal that altered bowel habits or other functional symptoms have been problematic for years. Reminding the patients to “begin at the beginning” can aid enormously in contextualizing their complaints. Individuals with longstanding symptoms and previously negative evaluations are much less likely to present with a new organic disease than are those in whom symptoms have truly arisen de novo.
Defining constipation by frequency of bowel eliminations alone has proved inaccurate at predicting actual severity. This is in part because the bowel movement frequency varies widely in healthy individuals (anywhere from thrice daily to once every 3 days) and in part because the primary indicator of effective evacuation is not frequency but volume – a much more difficult quantity for patients to gauge.5 The Bristol Stool Scale is a simple, standardized tool that more accurately evaluates the presence or absence of colonic dysfunction. For example, patients passing Type 1-2 (hard or lumpy) stools often have an element of constipation that needs to be addressed.6 However, the interpretation of stool consistency assessments is still aided by awareness of both frequency and volume. A patient passing multiple small-volume Type 6-7 (loose or watery) stools may be the most constipated, presenting with overflow or paradoxical diarrhea attributable to fecal impaction.