Constipation

Background

• Acute constipation is intestinal obstruction until proven otherwise
• Red flags:
  • Weight loss
  • Rectal bleeding/melena
  • Nausea/vomiting
  • Fever
  • Rectal pain
  • Change in stool caliber

Differential Diagnosis

Acute

1. Bowel obstruction
   1. Tumor, stricture, hernia, adhesion, volvulus, fecal impaction
2. New medicine
   1. Opiods, antipsychotic, anticholinergics, antacid, antihistamines
3. Change in exercise
4. Change in diet
5. Pain rectal conditions (e.g. anal fissure, hemorrhoids)

Chronic

1. Acute causes
2. Hypothyroidism
3. Electrolytes
   1. Hypomagnesia
   2. Hypercalcemia
4. Hypokalemia

Work-Up

1. Rectal exam
2. Guaiac
3. Chemistry (hypoK or hyperCa)
4. Acute abdominal series (if suspect obstruction)
5. TSH

Treatment

1. Stress adequate fluid (1.5L per day), fiber (10gm per day), and exercise
2. Meds
   1. Fiber
      1. Bran: 1 cup daily
      2. Psyllium (Metamucil): 1 teaspoon TID
   2. Emollient
      1. Docusate (Colace): 100mg QD-BID (facilitates mixture of stool fat and water)
   3. Stimulants
      1. Bisacodyl (Dulcolax): 10mg PR TID
      2. Senna: Two tab PO QD-BID
   4. Saline laxative
      1. Milk of mangesia: 15-30 mL QD-BID
      2. Magnesium citrate: 100-240 mL QD-BID
   5. Hyperosmolar agents
      1. Lactulose 15-30 mL QD-BID
      2. Polyethylene glycol: 1 gallon/4h
      3. Miralax: 17gm

See Also

• Constipation (Peds)