Constipation Summary

Definition

  • Unsatisfactory defecation
  • Infrequent stools or difficult passage
  • Sensation of incomplete emptying
  • Chronic: ≥12 weeks in preceding 6 months

Key Risk Factors

  • Low fiber diet
  • Lack of exercise
  • Female sex & older age
  • Certain medications

Diagnosis

  • Infrequent/difficult stool passage
  • Sensation of incomplete emptying
  • Abdominal examination
  • Internal rectal examination

Management

  • Dietary fiber & fluid increase
  • Exercise promotion
  • Bulk-forming laxatives first
  • Osmotic/stimulant if needed

Constipation: Diagnosis and Management

Medical guidelines for identifying and treating constipation

Introduction

Constipation is unsatisfactory defecation because of infrequent stools, difficult stool passage, or the sensation of incomplete emptying. Stools are often dry and hard or lumpy, and may be abnormally large or small.

Chronic Constipation

Usually describes symptoms which are present for at least 12 weeks in the preceding six months.

Faecal Loading/Impaction

Retention of faeces to the extent that spontaneous evacuation is unlikely.

Overflow Incontinence

Leakage of liquid stool from the proximal colon around impacted faeces.

Causes and Risk Factors

Risk Factors

Multiple factors can contribute to the development of constipation, including social, psychological, and physical elements.

Social Factors

  • Low fiber diet or low calorie intake
  • Lack of exercise or reduced mobility
  • Difficult access or privacy to the toilet

Psychological Factors

  • Eating disorders
  • History of sexual abuse
  • Anxiety or depression

Physical Factors

  • Female sex
  • Older age
  • Pyrexia, dehydration, immobility

Secondary Causes

Drugs

Many medications can cause constipation including opioids, anticholinergics, calcium channel blockers, and iron supplements.

Endocrine/Metabolic

Diabetes mellitus (with autonomic myopathy), hypercalcaemia/hypermagnesaemia, hypokalaemia, hypothyroidism, uraemia.

Neurological

Autonomic neuropathy, cerebrovascular disease, multiple sclerosis, Parkinson's disease, spinal cord injuries.

Structural Abnormalities

Anal fissures, haemorrhoids, colonic strictures, inflammatory bowel disease, diverticular disease, obstructive colonic mass lesions, rectal prolapse or rectocele.

Complications

Potential Complications

Chronic constipation can lead to several complications that may require additional treatment and management.

Haemorrhoids or anal fissure - Resulting from straining during bowel movements.
Progressive faecal retention - Distension of the rectum, and loss of sensory and motor function.
Faecal loading and impaction - Which can lead to overflow incontinence.
Faecal incontinence - Can be embarrassing and distressing for patients.
Chronic dilatation of the colon - May cause megacolon.
Other serious complications - Bowel obstruction, perforation, or ulceration; recurrent urinary tract infections, obstructive uropathy; rectal bleeding; rectal prolapse.

Diagnosis

Suspect a diagnosis of constipation if an adult presents with defecation which is unsatisfactory because of infrequent stools, difficulty passing stools, or a sensation of incomplete emptying.

Clinical Presentation

Common Symptoms

Infrequent stools, difficult stool passage, sensation of incomplete emptying, lower abdominal pain or discomfort, distension, or bloating.

Elderly Presentation

Consider constipation with non-specific symptoms: confusion or delirium, functional decline, nausea or loss of appetite, overflow diarrhoea, urinary retention.

Faecal Loading/Impaction

Suspect if history of hard, lumpy stools; manual methods to extract faeces; overflow faecal incontinence, or loose stool.

Examination

Assess for signs of weight loss and general nutritional status.
Perform abdominal examination to check for abdominal pain, distension, masses, or a palpable colon (suggesting retained faecal masses).
Perform internal rectal examination, checking for:
  • Anal fissures, haemorrhoids, skin tags, rectal prolapse, rectocele
  • Skin erythema or excoriation (may indicate faecal leakage)
  • Resting anal sphincter tone; rectal mass lesions
  • Retained faecal masses (firm pressure leaves indentation)
  • Pelvic floor dysfunction (paradoxical contraction)
  • Leakage of stool; rectal or anal pain

Management

Treatment Approach

Management of constipation involves a stepped approach beginning with lifestyle modifications and progressing to pharmacological interventions as needed.

General Measures

Advice about increasing dietary fiber through fruits, vegetables, and whole grains.
Encourage drinking an adequate fluid intake (at least 1.5–2 liters daily).
Promote regular exercise and physical activity.
Establish regular toilet habits and adequate time for defecation.

Faecal Loading and Impaction Treatment

For hard stools, consider using a high dose of an oral macrogol.
For soft stool (or ongoing hard stools after treatment with macrogol) consider starting or adding an oral stimulant laxative (e.g., bisacodyl, senna or glycerol).
If response to oral laxatives is insufficient or too slow consider using a suppository (e.g., bisacodyl +/- glycerol) or a mini-enema (e.g., docusate, sodium citrate).
If the response to treatment is still inadequate, consider prescribing a sodium phosphate retention enema.

Laxative Therapy Approach

Step Treatment Indication
1 Bulk-forming laxatives (e.g., ispaghula husk) First-line treatment (except in opioid-induced constipation)
2 Add or switch to osmotic laxative (e.g., macrogol or lactulose) If stools remain hard
3 Add stimulant laxative (e.g., bisacodyl or senna) If stools are soft but still difficult to pass or empty inadequately