Large Intestine: Constipation & Obstruction

General

• The Most Common Digestive Complaint

Diagnostic Criteria (Rome IV) for Chronic Constipation

• ≥ 2 Of:
  • Straining During ≥ 25% of Bowel Movements
  • Bristol Stool Scale #1-2 ≥ 25% of Bowel Movements
  • Sensation of Incomplete Evacuation ≥ 25% of Bowel Movements
  • Sensation of Anorectal Obstruction ≥ 25% of Bowel Movements
  • Manual Maneuvers to Facilitate ≥ 25% of Bowel Movements
  • < Three Bowel Movements Per Week
• Loose Stools Rarely Present without Laxative Use
• Insufficient Criteria for Irritable Bowel Syndrome (IBS)

Causes

• Slow Colonic Transit Time
  • Colonic Inertia – Delayed Transit without Defecation Abnormality
    • Normal Resting Motility but Minimal Increase in After Meals
  • Dyssynergic Defecation – Relaxation Failure of Puborectalis or Anal Sphincter Muscles
  • Dx: Colonic Manometry or Sitz Marker Study (Swallow Radio-Opaque Markers and Follow Progression)
• Irritable Bowel Syndrome
• Diabetes
• Hypokalemia
• Hypothyroidism
• Pregnancy
• Neurologic Disorders (Multiple Sclerosis, Parkinson’s Disease or Spinal Cord Injury)
• Drugs (Opiates, Antihistamines, Iron Supplements, Antipsychotics or Antispasmodics)

Treatment

• Initial Tx: Diet & Lifestyle Modifications with Laxative Therapy
• If Medical Treatments Continually Fail: Consider Subtotal Colectomy & Ileorectal Anastomosis
  • May Not Relieve Associated Symptoms Such as Abdominal Pain & Bloating – Due to High Rates of Dysmotility in Other Areas of the GI Tract

Fecal Impaction

• Massive Amount of Stool Stuck/Impacted in the Rectum or Colon
• Often from Chronic Constipation with Inability to Sense Presence of Stool in the Rectum
• Most Common in Elderly & Institutionalized Patients
• Typically in Rectum but May be More Proximal in the Sigmoid Colon
• Dx: Digital Rectal Exam (DRE) with Copious Stool in the Rectum
  • Proximal Impaction May Require Abdominal XR
• Tx: Digital Disimpaction & Enema Colon Evacuation
  • May Require Local Anesthesia to Relax Muscles
  • Surgery if Considered for Impending Perforation or Ischemia
  • Aggressive Bowel Regimen Once Disimpacted

Stercoral Ulcer

• Hard Impacted Fecaloma Causes Local Ischemia
• Caused by Chronic Constipation
• Associated with NSAID Use
• Most Common Site: Rectosigmoid Anti-Mesenteric Border
• Can Cause Pain, Bleeding or Perforation
• Usually Found Post-Perforation
• Tx: Fecal Disimpaction & Aggressive Bowel Regimen if Not Perforated