85 y/o male with back pain, left-sided abdominal pain, and no bowel movements for 7 days
Patient will present as → a 65-year-old male with chronic low back pain complaining of bloating, abdominal pain, straining, and pain with bowel movements. He reports less than 3 bowel movements per week that are very hard and difficult to pass. The patient is on 50 mcg of transdermal Fentanyl and takes four 10 mg Norco per day for breakthrough pain.
Functional constipation is infrequent, difficult, or incomplete defecation — defined by the Rome IV criteria as ≥ 2 of the following for the last 3 months (symptom onset ≥ 6 months ago), each in ≥ 25% of defecations:
- Straining · lumpy/hard stools · incomplete evacuation · anorectal obstruction/blockage · manual maneuvers · < 3 spontaneous BMs/week
- Plus: loose stools rare without laxatives, and criteria for IBS not met (IBS-C = pain relieved/related to defecation)
- New-onset constipation after age 50 or alarm features → evaluate for colon cancer
- Opioids are the classic drug cause — prophylax chronic opioid users with a scheduled stimulant laxative (senna) ± PEG — a stool softener alone is NOT enough
- Secondary causes — medications, DM, hypothyroidism, hypercalcemia, Parkinson's/MS, dehydration
Encopresis — recurrent stool soiling into clothing in a child > 4 years old, almost always overflow leakage around impacted stool from chronic withholding constipation
- Exam — distended abdomen, palpable LLQ mass, rectal vault full of stool; anal fissures or perianal irritation from soiling
- TX — disimpaction (oral PEG) → maintenance PEG for months + scheduled toilet sitting and behavioral training — do not punish soiling; it is involuntary
Clinical + rectal exam — hard stool, masses, fissures, hemorrhoids, sphincter tone and push effort, prostate in men, posterior vaginal masses in women
- Labs only if indicated — CBC, CMP (glucose, calcium), TSH for secondary causes; imaging rarely helpful in older adults
- ⚠️ New-onset constipation after age 50 or any alarm feature (blood in stool, weight loss, iron-deficiency anemia, FH of colon cancer) → colonoscopy
- Refractory → anorectal manometry + balloon expulsion (dyssynergic defecation → biofeedback) or colonic transit study
Increase fiber (20–25 g/day), fluids, and exercise — fiber's effect may take several weeks
- Bulk-forming laxatives first-line — psyllium (Metamucil), methylcellulose (Citrucel), calcium polycarbophil, wheat dextrin
- Osmotic laxatives if bulking agents fail — start low-dose PEG 3350 (MiraLAX), effective and well tolerated in older adults
"FYI: Magnesium-based osmotic laxatives, such as magnesium citrate or magnesium hydroxide (Milk of Magnesia), may increase the risk of hypermagnesemia, especially in patients with CKD who are less able to excrete excess magnesium!"
- Stimulant laxatives (senna, bisacodyl) — enhance colonic motility; next step if osmotics fail, and first-line scheduled therapy for opioid-induced constipation (refractory OIC → PAMORA: methylnaltrexone, naloxegol)
- Docusate, suppositories (glycerin/bisacodyl), and enemas — limited efficacy; specific scenarios only
- Refractory constipation → investigate for the underlying cause (see Diagnosis) — linaclotide or lubiprostone for refractory chronic idiopathic constipation
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 Osmosis |
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Question 1 |
A 70-year-old woman presents with a 14-month history of constipation. The workup, including colonoscopy, was negative. What management option would you recommend for her?
Daily laxative Hint: This could be a suitable option for some patients, but long-term use of laxatives can lead to dependency and disrupt normal bowel function. | |
Regular enema Hint: Regular enemas are not typically recommended for managing chronic constipation due to the risk of bowel injury and electrolyte imbalances. | |
Increased fluid intake and high-fiber diet | |
Daily glycerin suppository Hint: Glycerin suppositories are generally safe for occasional use but are not typically recommended for long-term management of chronic constipation. | |
Surgical intervention Hint: Surgery is usually considered as a last resort when all other treatment options have failed and if there is a specific anatomical issue causing the constipation. In this case, the patient’s workup was negative, so surgery would not be the best next step. |
Question 1 Explanation:
Constipation with no underlying etiology should be treated conservatively - Increased fluid intake and high-fiber diet. All other options may not be necessary.
Question 2 |
Functional constipation is difficulty passing stools for reasons other than organic causes. Which of the following is not a component of Rome III diagnostic criteria for functional constipation?
Straining | |
Sensation of incomplete evacuation | |
Lumpy or hard stools | |
> 3 bowel movements per week |
Question 2 Explanation:
According to Rome III criteria for functional constipation, a patient must have experienced at least 2 of the following symptoms over the preceding 3 months:
- Straining
- Sensation of incomplete evacuation
- Lumpy or hard stools
- <3 bowel movements per week
- Sensation of anorectal obstruction
- Manual maneuvering required to defecate.
Question 3 |
Which of the following medications does not cause constipation
Opioids Hint: See answer C for explanation | |
Calcium channel blockers Hint: See answer C for explanation | |
Beta-blockers | |
NSAIDs Hint: See answer C for explanation |
Question 3 Explanation:
Beta-blockers do not cause constipation. All of the other medications do.
Question 4 |
Which of the following is not a pharmacological agent used in treating constipation
Loperamide | |
Docusate sodium Hint: Is a stool softener. It allows incorporation of water and fat into stools, causing stools to soften. It’s indicated for patients who should avoid straining during defecation. | |
Lactulose Hint: Is an osmotic laxative. It produces an osmotic effect in the colon resulting in bowel distention and stimulation of peristalsis. | |
Senna Hint: Is a stimulant laxative. It induces defecation by acting directly on the intestinal mucosa or nerve plexus, which stimulates peristaltic activity. |
Question 4 Explanation:
Loperamide is an antidiarrheal agent.
Question 5 |
Which of the following is the most common organic cause of constipation in children?
Parkinson’s disease Hint: See answer C for explanation | |
Colon cancer Hint: See answer C for explanation | |
Hirschsprung disease | |
Diverticular disease Hint: See answer C for explanation |
Question 5 Explanation:
Hirschsprung disease is the most common organic cause of constipation in children. It is a congenital anomaly of innervation of the lower intestine, usually limited to the colon, resulting in partial or total functional obstruction. Symptoms are obstipation and distention. Diagnosis is by barium enema and rectal biopsy. All others occur in adulthood.
Question 6 |
A 72-year-old man presents with complaints of constipation, abdominal bloating, and occasional rectal bleeding. He has a history of hypertension and type 2 diabetes mellitus. His last colonoscopy was 10 years ago and was normal. Which of the following is the most appropriate next step in the management of this patient?
Initiate a trial of over-the-counter laxatives Hint: While these can be used to manage constipation, the patient's age and rectal bleeding warrant further investigation before initiating treatment. | |
Repeat colonoscopy | |
Abdominal X-ray Hint: This can identify fecal impaction but is less useful in excluding serious underlying pathology. | |
Prescribe a high-fiber diet and increased fluid intake Hint: Although beneficial in managing constipation, it's important to first rule out serious pathology in this patient. | |
Stool softeners and osmotic laxatives Hint: These are treatment options, but the patient first needs a thorough evaluation due to his age and symptoms. |
Question 6 Explanation:
Given the patient's age, history of rectal bleeding, and the fact that his last colonoscopy was 10 years ago, a repeat colonoscopy is warranted. This is important to rule out colorectal cancer or other significant pathologies, which are more common in older adults and can present with constipation and rectal bleeding.
There are 6 questions to complete.
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References: Merck Manual · UpToDate