Constipation

Classification

1. Normal transit constipation i.e Functional constipation
2. Slow transit constipation - see Constipation and Slow transit and functional small bowel disease
3. Outlet delay constipation - see Obstructed defecation
   • This can be divided into anatomical and functional
4. Irritable bowel syndrome
5. Secondary constipation
   • Medications - opiates, anticholinergics, antihypertensives, iron supplements, antacids and non-steroidal anti-inflammatory drugs
   • Neurological disease - Hirschsprung’s disease, multiple sclerosis, Parkinson’s disease and diabetic autonomic neuropathy
   • Electrolytes - hypercalcaemia and hypokalaemia
   • Hormonal - hypothyroidism

Functional constipation

Rome IV defintion: Must include two or more of the following:

1. Straining during more than ¼ (25%) of defecations
   1. Lumpy or hard stools (Bristol Stool Form Scale 1-2) more than ¼ (25%) of defecations
   2. Sensation of incomplete evacuation more than ¼ (25%) of defecations
   3. Sensation of anorectal obstruction/blockage more than ¼ (25%) of defecations
   4. Manual maneuvers to facilitate more than ¼ (25%) of defecations (e.g., digital evacuation, support of the pelvic floor)
   5. Fewer than three SBM per week
2. Loose stools are rarely present without the use of laxatives
3. Insufficient criteria for irritable bowel syndrome

Criteria fulfilled for the last 3 months with symptom onset at least 6 months prior to diagnosis

Slow transit constipation

• Slow whole-gut transit (‘colonic inertia’)
• Dysfunction in the enteric nerve plexus.
  • Decreased volume of interstitial cells of Cajal in the myenteric plexus have been demonstrated in resected colon specimens from some of these patients who have had colon resections

Investigations

• Colonic transit study
• Defecating proctography
• Balloon expulsion test
• Anorectal manometry

Treatment

Conservative treatment

1. Dietary fibre supplementation - increases gut transit and stool bulk
2. Laxatives
3. Behavioural therapy (biofeedback)
4. Prokinetics - Prucalopride – can be effective if refractory to laxatives (5-HT4 agonist , serotonin receptor)
5. Suppositories and enemas
   1. Suppositories – may induce chemically induced reflex rectal contraction
   2. Enemas – may stimulate rectal contraction or soften hard stool.
6. Transanal irrigation - Useful for patients with functional constipation and secondary to neurological disease e.g. MS and spinal cord injury

Surgical treatment

• In those patients with proven slow transit who have failed to respond to dietary modification, biofeedback, long-term trials of laxatives and prokinetics, the traditional algorithm dictates consideration of a surgical approach.
• The strongest argument against colectomy for slow transit constipation is that the disorder is a panenteric one, and so mere removal of the colon is unlikely to yield sustained benefit

Total colectomy and ileorectal anastomosis

• Indications:
  • Proven slow transit
  • Failed to respond to dietary modification, biofeedback, long-term laxatives/prokinetics
  • Excluded pelvic floor dysfunction
  • Need careful consideration to ensure no psychiatric disorders
• Issues:
  • Removal of colon may not provide benefit, given that slow transit constipation that is pan-enteric.
  • Adverse effects: diarrhoea, incontinence, subacute bowel obstruction, persistent constipation

Appendicostomy (Malone procedure)

• Can irrigate with water or stimulant or osmotic laxative
• Stoma complications – stenosis, mucus leak, pain.
• High level of patient satisfaction