What is the definition of chronic constipation?

Definition of Chronic Constipation

Chronic constipation is defined as the presence of at least two of the following symptoms for at least 12 weeks in the previous 12 months: straining during bowel movements, lumpy or hard stools, sensation of incomplete evacuation, sensation of anorectal blockage or obstruction, manual maneuvers to facilitate defecation, or fewer than 3 bowel movements per week. 1, 2

Key Characteristics of Chronic Constipation

• Chronic constipation is a symptom, not a disease, that involves persistent difficulties with bowel movements 1
• While physicians often focus on infrequent bowel movements (fewer than 3 per week), patients experience a broader range of symptoms including hard stools, incomplete evacuation, abdominal discomfort, bloating, and distention 1
• Not infrequently, patients who have daily bowel movements may still describe constipation due to other symptoms such as straining or incomplete evacuation 1
• Reduced stool frequency is poorly correlated with delayed colonic transit 1
• The experience of constipation is highly subjective and involves both measurable objective symptoms (stool characteristics and frequency) and patient perception (discomfort and ease of defecation) 1

Clinical Subgroups of Chronic Constipation

Chronic constipation can be classified into three main subgroups:

1. Defecatory Disorders

• Characterized by impaired rectal evacuation from inadequate rectal propulsive forces and/or increased resistance to evacuation 1
• May result from high anal resting pressure ("anismus") and/or incomplete relaxation or paradoxical contraction of pelvic floor muscles during defecation ("dyssynergia") 1
• Structural disturbances (rectocele, intussusception) and reduced rectal sensation may coexist 1
• Also known as outlet obstruction, obstructed defecation, dyschezia, anismus, or pelvic floor dyssynergia 1

2. Normal Transit Constipation (NTC)

• Patients have normal anorectal function and normal colonic transit 1
• Symptoms of constipation persist despite normal transit time 1

3. Slow Transit Constipation (STC)

• Patients have normal anorectal function but slow colonic transit 1
• Some patients have colonic motor disturbances (reduced propulsive activity or increased uncoordinated motor activity in the distal colon) 1
• Resected colonic specimens from patients with STC who undergo colectomy reveal marked reduction in colonic intrinsic nerves and interstitial cells of Cajal 1

Secondary Causes of Constipation

• Constipation may be secondary to diseases of the colon (stricture, cancer, anal fissure, proctitis) 1
• Metabolic disturbances (hypercalcemia, hypothyroidism, diabetes mellitus) can cause constipation 1
• Neurologic disorders (parkinsonism, spinal cord lesions) may lead to constipation 1
• Medications, particularly opioids, can cause constipation 1
• Opioid-induced constipation is specifically defined as "constipation triggered or worsened by opioid analgesics" according to Rome IV criteria 1, 2

Clinical Significance

• Chronic constipation affects approximately 16% of adults overall and 33% of adults older than 60 years 1
• It represents a significant source of morbidity and distress that is often under-appreciated 1
• While most cases are not life-threatening, constipation can significantly impact quality of life 1, 3
• Complications can include hemorrhoids, anal fissures, bowel obstruction, and urinary retention if left untreated 2

Pathophysiology

• Normal bowel function involves colonic absorption of fluids and transport of waste through peristalsis 1
• Peristalsis is mediated principally by serotonin (5-HT) 1
• Average colonic transit time is 20-72 hours 1, 2
• Constipation represents a disruption of these normal mechanisms 1

Understanding this comprehensive definition of chronic constipation is essential for proper diagnosis and effective management of this common and distressing condition.