Constipation

Source: Powell PH and Fleming VH. Diarrhea, Constipation, and Irritable Bowel Syndrome. In: DiPiro, JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM. Pharmacotherapy: A Pathophysiologic Approach. 8th ed. http://accesspharmacy.com/content.aspx?aid=7978775. Accessed April 29, 2012.

• Functional constipation is bowel disorder characterized by difficult, infrequent, or seemingly incomplete defecation that does not meet criteria for irritable bowel syndrome (IBS).1

• Constipation may be primary (occurs without underlying identifiable cause) or secondary (result of constipating drugs, lifestyle factors, or medical disorders).

• Constipation is not a disease but symptom of underlying disease or problem.
• Drugs that inhibit neurologic or muscular function of gastrointestinal (GI) tract, particularly colon, may result in constipation (Table 1).
  • All opiate derivatives associated with constipation to varying degrees.
  • Orally administered opiates appear to have greater inhibitory effect than parenterally administered agents.

• Prevalence in North America ranges from 12-19%.
• More common in women and the elderly.

• Increase dietary fiber
• Initiate agents to soften stool when opiates are started.
• Increase activity level.

• Lack of activity
• Lower socioeconomic status
• Depression

Signs and Symptoms

• Infrequent bowel movements
• Stools that are hard, small, or dry
• Difficulty or pain on defecation
• Feeling of abdominal discomfort
• Incomplete evacuation

Means of Confirmation and Diagnosis

• History and physical examination to clarify what patient means by constipation. Ask specifically about alarm signs and symptoms:
  • Hematochezia
  • Melena
  • Family history of colon cancer
  • Family history of inflammatory bowel disease
  • Anemia
  • Weight loss
  • Anorexia
  • Nausea
  • Vomiting
  • Persistent constipation refractory to treatment
  • New onset or worsening constipation in elderly patients without evidence of primary cause
• Rectal examination should be performed for presence of anatomical abnormalities, stricture, rectal mass, or fecal impaction.
• Identify underlying secondary causes or conditions.

Laboratory Tests

• No routine lab tests recommended.
• Thyroid function studies, electrolytes, and blood glucose to determine presence of metabolic or endocrine disorders.
• If alarm signs and symptoms present or when structural disease a possibility, select appropriate diagnostic studies:
  • Proctoscopy
  • Sigmoidoscopy
  • Colonoscopy
  • Barium enema

• Relieve symptoms and restore normal bowel function.
• Prevention of further episodes through alteration of lifestyle, particularly diet

• General measures believed to be beneficial in managing constipation:
  • Dietary modification to increase amount of fiber consumed daily
  • Exercise
  ...