Chronic Constipation

Chronic constipation is a persistent disorder of difficult, infrequent, or incomplete defecation lasting months, encompassing both a symptom and, when no organic or drug cause is found, the functional disorder often termed chronic idiopathic or functional constipation. It is commonly grouped physiologically into normal-transit, slow-transit, and defecatory (evacuation) subtypes.

Definition

Chronic constipation is the persistent presence, for at least several months, of difficult, infrequent (typically fewer than three spontaneous bowel movements per week), or incomplete defecation, often with hard or lumpy stools and straining; when not attributable to a structural, metabolic, or drug cause, it is classified as functional (chronic idiopathic) constipation under the Rome IV criteria.

Scope

The entry covers the definition and symptom criteria of chronic constipation, its main pathophysiological subtypes, epidemiology, and the broad evidence base, as a reference topic. It does not give dosing, drug selection, or individualised management, which are addressed by current clinical guidelines.

Core questions

• How is chronic constipation defined and when is it classified as functional or idiopathic?
• What distinguishes normal-transit, slow-transit, and defecatory-disorder subtypes?
• How do colonic transit testing and anorectal function studies inform classification?
• Why is functional constipation distinguished from secondary causes such as medications, metabolic disease, or structural obstruction?

Key concepts

• Functional (chronic idiopathic) constipation
• Normal-transit constipation
• Slow-transit constipation
• Defecatory (evacuation) disorder and dyssynergic defecation
• Rome IV criteria for functional constipation
• Colonic transit time
• Anorectal manometry and balloon-expulsion testing
• Secondary constipation

Mechanisms

Chronic constipation arises through several non-exclusive mechanisms. In slow-transit constipation, delayed colonic propulsion reflects reduced or disordered colonic motor activity, sometimes associated with abnormalities of the enteric nervous system or interstitial cells of Cajal. In defecatory disorders, the problem lies in the coordination of rectoanal and pelvic-floor muscles during attempted evacuation (dyssynergic defecation) or in impaired rectal sensation. Many patients have normal-transit constipation, in which transit is measured as normal but symptoms persist, overlapping with irritable bowel syndrome. Secondary constipation results from medications, metabolic and neurological disease, or mechanical obstruction, which must be considered before a functional label is applied.

Clinical relevance

Chronic constipation is among the most frequent gastrointestinal complaints in primary and specialty care, and distinguishing its physiological subtypes underpins the rationale for transit and anorectal testing in refractory cases. This entry presents the concept and classification for reference and education; it does not recommend specific therapies, which depend on individualised assessment and current guidelines.

Epidemiology

Chronic constipation is highly prevalent in the general population, increasing with age and more common in women, and is a major contributor to ambulatory visits, laxative use, and reduced quality of life. Prevalence estimates vary with the definition applied.

Evidence & guidelines

Functional constipation is defined by the Rome IV criteria, and joint society guidelines address its pharmacological and non-pharmacological management; specific recommendations are updated periodically and should be taken from the current versions rather than from this overview.

History

Constipation has long been recognised clinically, but the modern physiological classification into normal-transit, slow-transit, and defecatory subtypes emerged from twentieth-century colonic transit and anorectal physiology studies. The Rome consensus criteria standardised the symptom-based definition of functional constipation, and subsequent guideline development organised the evidence for evaluation and management.

Debates

Where is the boundary between functional constipation and constipation-predominant IBS?

The two conditions share features and overlap substantially, differing chiefly in the prominence of abdominal pain; whether they are distinct entities or part of a continuum remains debated and affects classification and study design.

Key figures

• Anthony Lembo
• Michael Camilleri
• Adil E. Bharucha
• Lin Chang

Seminal works

• lembo-2003
• lacy-2016

Frequently asked questions

What is the difference between chronic constipation as a symptom and functional constipation?

Chronic constipation as a symptom can have many causes, including medications, metabolic disease, and obstruction; functional (chronic idiopathic) constipation is the diagnosis applied when those secondary causes are excluded and symptoms meet the Rome IV criteria.

What are the main physiological subtypes of chronic constipation?

They are normal-transit constipation, slow-transit constipation, and defecatory (evacuation) disorders such as dyssynergic defecation; identifying the subtype, usually only in refractory cases, helps frame the rationale for testing and treatment.