What is constipation?

What is Constipation?

Constipation is defined as the slow movement of feces through the large intestine, resulting in infrequent bowel movements and the passage of dry, hard stools, which can significantly impact quality of life. 1, 2

Clinical Definition

According to the Rome III criteria, chronic constipation is diagnosed when a patient presents with at least two of the following symptoms for at least 12 weeks in the previous 12 months (not necessarily consecutively):

• Straining during bowel movements 1, 2
• Lumpy or hard stool 1, 2
• Sensation of incomplete evacuation 1, 2
• Sensation of anorectal blockage or obstruction 1, 2
• Manual evacuation procedures to remove stool 1, 2
• Fewer than 3 bowel movements per week 1, 2

Pathophysiology

Constipation represents a disruption of normal colonic function:

• Normal bowel function involves colonic absorption of fluids and transport of waste through peristalsis 1
• The colon normally absorbs fluids and electrolytes while moving waste to the rectum through periodic contractions mediated primarily by serotonin (5-HT) 1
• Average colonic transit time is 20-72 hours 1, 2
• Constipation occurs when this process is disrupted, resulting in excessive dryness of fecal content, diminished perception of rectal distension, or dysfunction of the rectal sphincter 1, 3

Subjective Experience

The experience of constipation is highly subjective and involves two key aspects:

• Measurable objective symptoms (stool characteristics and frequency) 1, 2
• Patient perception (level of discomfort and ease of defecation) 1, 2

Types of Constipation

Constipation can be classified as:

• Primary (intrinsic problems of colonic or anorectal function) 4
• Secondary (related to organic disease, systemic disease, or medications) 4
• Opioid-induced constipation (OIC) - defined as "constipation triggered or worsened by opioid analgesics" according to the Rome IV criteria 1, 2

Clinical Significance and Complications

Constipation can lead to significant morbidity if left untreated:

• Major cause of distress for patients, particularly those with cancer 1
• Can be complicated by hemorrhoids, anal fissures, bowel obstruction, and urinary retention 1, 2
• Prevalence increases with age, with elderly individuals being five times more prone to constipation than younger people 1, 3
• Particularly common in cancer patients (40-90% prevalence) and those receiving opioid therapy 1, 3

Risk Factors

Several factors can increase the risk of constipation:

• Advanced age 3
• Medications (especially opioids, which cause constipation without development of tolerance) 3
• Inadequate fluid intake and low-fiber diet 3
• Lack of privacy when toileting 3
• Medical conditions (hypercalcemia, hypokalemia, uremia) 3

Occasional vs. Chronic Constipation

• Occasional constipation is defined as "intermittent or occasional symptomatic alteration(s) in bowel habit" including "a bothersome reduction in the frequency of bowel movements and/or difficulty with passage of stools" 5
• Episodes may last for a few days or weeks and may require lifestyle modifications or over-the-counter treatments 5
• Chronic constipation is more persistent and meets the Rome criteria described above 1, 2

Understanding constipation as a symptom rather than a disease is crucial for proper diagnosis and management, as it can significantly impact quality of life and lead to complications if left untreated 1, 2.