Constipation is a condition characterized by infrequent bowel movements, hard or dry stools, difficulty passing stool, or a sensation of incomplete evacuation. Fewer than three bowel movements per week is a commonly used indicator, but frequency alone does not capture all forms of constipation. It may occur temporarily, persist as a chronic bowel disorder, or accompany another condition or medication use. (niddk.nih.gov)
Symptoms and bowel patterns
Typical symptoms include straining, painful passage of stool, hard or lumpy stools, and a feeling that stool remains after a bowel movement. Normal bowel frequency varies considerably: healthy people may have bowel movements between three times daily and three times weekly. A daily bowel movement is therefore not a requirement for normal bowel function. Stool consistency, ease of passage, and changes from an individual's usual pattern are also important. (niddk.nih.gov)
Constipation can occur alongside irritable bowel syndrome with constipation, often abbreviated IBS-C. In this disorder, recurrent abdominal pain is a prominent part of the clinical picture, rather than constipation being the only principal complaint. (patient.gastro.org)
Mechanisms and types
Constipation may reflect slow movement of stool through the colon, difficulty emptying the rectum, or both. Clinical classification distinguishes several patterns:
- Normal-transit constipation: constipation symptoms occur despite a measured transit time within the normal range.
- Slow-transit constipation: stool moves unusually slowly through the colon.
- Defecatory disorders: impaired coordination or relaxation of the pelvic floor and anal muscles interferes with evacuation.
A defecatory disorder can coexist with either normal or delayed colonic transit. In pelvic floor dysfunction, the muscles involved in evacuation may fail to relax appropriately, producing straining and a sensation of blockage or incomplete emptying. (gastro.org)
The term chronic idiopathic constipation describes persistent constipation without an identified secondary cause. Secondary constipation results from factors such as medication effects, another illness, or a structural abnormality of the digestive system. (gastro.org)
Causes and contributing factors
Low dietary fiber intake, insufficient fluids, reduced physical activity, and repeatedly suppressing the urge to defecate can contribute to constipation. Changes in routine, travel, aging, and pregnancy may alter bowel habits. Several contributing factors can be present simultaneously; chronic symptoms can also persist despite adequate nutrition. (niddk.nih.gov)
Medication-related causes include opioid pain medicines, iron supplements, antacids containing aluminum or calcium, anticholinergic medicines, some antidepressants, and calcium channel blockers. Associated medical conditions include diabetes mellitus, hypothyroidism, neurological disorders, and injuries affecting the brain or spinal cord. Intestinal obstruction and anatomical abnormalities can also cause constipation. (niddk.nih.gov)
Clinical evaluation
Diagnosis begins with the duration and pattern of symptoms, stool appearance, medication and supplement use, diet, activity, medical history, and physical examination. A rectal examination may contribute information about anorectal function. Laboratory testing is selected according to the clinical context and can help identify conditions such as anemia, hypothyroidism, or celiac disease. (niddk.nih.gov)
Specialized investigations examine different aspects of bowel function:
- Colonic transit studies measure the movement of material through the colon.
- Anorectal manometry assesses anorectal pressures, sensation, and muscle function.
- Balloon expulsion testing assesses the ability to expel a small balloon from the rectum.
- Defecography uses imaging to examine evacuation and relevant anatomical abnormalities. (niddk.nih.gov)
Colonoscopy can identify structural disease, including colorectal cancer, but is generally unnecessary solely for constipation when colorectal screening is current and warning features are absent. Warning features include rectal bleeding, unexplained weight loss, anemia, persistent abdominal pain, vomiting, or inability to pass gas. These findings affect the scope and urgency of clinical investigation. (patient.gastro.org)
Treatment approaches and limitations
Treatment is directed toward the underlying cause and the mechanism of constipation. Nonpharmacological management commonly includes dietary and fluid adjustments, physical activity, and regular opportunities for defecation. Medication-related constipation may be addressed through clinician-supervised changes to the causative treatment. (niddk.nih.gov)
Laxatives include fiber supplements, osmotic agents, and stimulant agents. Osmotic agents increase fluid in bowel contents, while stimulant agents promote intestinal movement. The 2023 joint American Gastroenterological Association–American College of Gastroenterology guideline supports polyethylene glycol for adults with chronic idiopathic constipation and also evaluates fiber, magnesium oxide, lactulose, bisacodyl, sodium picosulfate, and senna. The strength of evidence and recommended circumstances of use differ between agents. (gastro.org)
Prescription treatments include lubiprostone, linaclotide, plecanatide, and prucalopride. Some increase intestinal fluid secretion, while prucalopride promotes colonic movement. These therapies are not interchangeable with treatment for an evacuation disorder. Pelvic floor biofeedback instead retrains the coordination of muscles involved in defecation. (niddk.nih.gov)
Refractory constipation denotes ongoing unsatisfactory bowel function despite adequate trials of appropriate treatments. Evaluation includes reassessing secondary causes and testing anorectal function and colonic transit. Surgery is restricted to selected cases; consideration of colectomy requires documented slow transit and exclusion of an ongoing defecatory disorder. (gastro.org)
Complications
Possible complications include hemorrhoids, anal fissures, bleeding, and fecal impaction, in which retained stool forms a hard mass. Liquid stool may pass around an impaction, producing leakage that can resemble diarrhea. Excessive straining can also contribute to rectal prolapse. These complications are distinct from the underlying cause of constipation and may require separate clinical assessment. (patient.gastro.org)
References
- Constipation — NIDDKniddk.nih.gov
- Symptoms & Causes of Constipation — NIDDKniddk.nih.gov
- Diagnosis of Constipation — NIDDKniddk.nih.gov
- Constipation — AGA GI Patient Centerpatient.gastro.org
- Your Gastro Bites: IBS-C questions answeredgastro.org
- Pharmacological management of chronic idiopathic constipationgastro.org
- Treatment for Constipation — NIDDKniddk.nih.gov
- ACG and AGA guideline on chronic constipation management is first to recommend supplements Magnesium Oxide and Senna as evidence-based treatmentsgastro.org
- Evaluation and management of refractory constipationgastro.org