Constipation — Full Text

Constipation is one of those rare symptoms for which diagnosis does not involve major thought process.  It’s rarely due to an undiagnosed underlying disease, and almost always caused by one of several factors which cause the colon (large intestine) to lose efficiency.  We rarely try to sort those out, because constipation is either dependent on lifestyle habits, due to depression, or related to aging.  Our focus is invariably on treatment, not the topic of this website, but we’ll address it nonetheless.

People define constipation in various ways.  It may mean infrequent bowel movements (perhaps fewer than 3 per week, uncomfortable ones, ones difficult to pass.  It may involve a sense of incomplete emptying, or of needing to strain.  There may be abdominal pain.  The main point is that something doesn’t feel right.

A wide variety of diseases can cause constipation, ranging from Parkinson’s to long-standing Diabetes to Chronic Kidney Failure, Pregnancy, and many more.  However, constipation is rarely if ever the first sign of these conditions, so we only consider them in a person already known to have them.  One exception may be Hypothyroidism, which we can find by a simple TSH blood test (see below).

Various medications can cause constipation.  The most common of these are narcotics (opioids) for pain, and iron.  But we’d always review a patient’s medication list for possible culprits, especially if any med was begun just before constipation began.  Laxative Abuse is notorious for perpetuating Constipation; it can require very gradual discontinuation to restore the bowel to its normal function and rhythm.

Chronic constipation, especially among persons under 40, is most often due to Irritable Bowel Syndrome.  We’ll discuss this later.

Technically, clinicians should perform a rectal exam on everyone with constipation.  In the age of  telemedicine, all we’d be able to do in that sense would be to examine a patient’s outside, an awkward suggestion which I’m sure nobody would dare try to practice.  Though I haven’t polled or surveyed any colleagues, here’s a logical approach which can begin remotely:

1.  Rule Out Emergencies

This is almost never the case with constipation.  New onset constipation with abdominal pain could be a sign of a bowel obstruction, but pain would be most prominent symptom that we’d base our diagnostics on (see Acute Abdominal Pain).

• If fever, or significant pain, should go to an ER for X-rays / CT scan and work-up.

2.  Red Flags suggesting serious disease, needing in-person visit and rectal exam – New Constipation:

• With significant weight loss (possible Colon Cancer)
• In the very Elderly or Debilitated (possible Fecal Impaction)
• With unusual back pain  (maybe Spinal Cord Disease)
• With large amount of Blood  (possible Colon Cancer or Ulcerative Colitis)
• In persons having Anal Sex, esp. if many partners  (maybe rectal STDs: Gonorrhea / Chlamydia)
• Persons >50 with alternating constipation & diarrhea  (possible Colon Cancer)

3.  If there’s Anal Pain, especially with Bowel Movements:

Likely causes include Anal Fissure or Thrombosed (clotted) External Hemorrhoid:

• Start treatment with Sitz Baths: Sit in warm water 5-10 minutes.  Don’t immerse the entire body in a bath, because we want to concentrate the heat in just the anal area.
  • 2-4 times a day; can do it every 1-2 hours if patient feels motivated
• Begin stool softeners, 2-4 times a day
• If no significant improvement within a week, needs an in-person visit with rectal exam.

External Hemorrhoids are easily visible.  They’d only be relevant if tender to touch; thrombosed ones are usually swollen and purple.  Internal hemorrhoids may cause bloody stools, but don’t get clotted unless they prolapse.

Anal fissures, tiny cracks in the skin, may be harder to find.  They’re caused by hard stools, or by trauma (e.g. anal sex).  We may need to hunt meticulously among the anal folds for a bright red spot or streak, which is tender.

4.  Stop (if possible) any medications that cause constipation (see above).

5.  Try basic treatment.

If it successfully controls the constipation, as it often does when there’s no underlying disease, there’s no need for further work-up.  This includes:

Very Basic (and Essential) Lifestyle Interventions:

• Increase fiber in diet
• Increase fluid intake
• Increase exercise (cardio)

Simple Medications:

If hard stools, options include:

• Stool Softeners (taken twice a day, every day)
• Polyethylene Glycol (Miralax®, and others), Sorbitol, Lactulose, etc. daily

If  normal stool consistency:

• Natural or synthetic fibers like Psyllium & others (Metamucil®, CitrucelV, FIbercon®, SuprafiberV, etc.), daily
• Polyethylene Glycol (Miralax®, and others), Sorbitol, Lactulose, etc. daily

For feeling an urge but unable to defecate:

• Senna (only when needed)
• Bisacodyl (only when needed)

6.  Basic Treatment Unsuccessful

Now’s a time for an in-person visit with rectal exam.   A gynecological exam in older women may be able to detect a rectocele, intrusion of the rectal wall into a weak vaginal wall, leading to anatomical difficulty passing stool.

7.  Laboratory Tests  (rarely helpful):  .  We might order some simple ones:

• Complete Blood Count (CBC) – for low hemoglobin (bleeding from Colon Cancer)
• Comprehensive Metabolic Panel – for high calcium, low potassium, high glucose (Diabetes)
• TSH (thyroid test) – for Hypothyroidism
• ESR &/or CRP  —  if very high, might suggest the possibility of Colon Cancer (metastatic) or Ulcerative Colitis
• Rectal STD tests for people who’ve had unprotected rectal sex (for Chlamydia & Gonorrhea)

8.  Who Needs a Gastroenterology referral (& likely colonoscopy) for Constipation?

• Persons >45-50 y.o. with new constipation who don’t get better with Basic Treatment
• Persons in #2 above

Irritable Bowel Syndrome (IBS)

This is the most common cause of constipation in persons <40 y.o.  It’s often called “IBS-C” meaning IBS with Constipation as a main symptom along with discomfort, to distinguish it from “IBS-D” when Diarrhea is the main symptom.  See also a definition of “Syndrome,” and the difference between IBS and IBD (“Inflammatory Bowel Disease”).

IBS-C can be defined simply as having abdominal pain with constipation at least once a week, for 3 months or more.  A problem with this is it may include many people who wouldn’t say they feel sick.  But it’s useful for those who feel troubled by their symptoms.  We’d never diagnose it without colonoscopy if it began over age 40-50, what we call “cancer age” because cancers become more common in general. IBS is a diagnosis of exclusion, meaning there’s nothing else causing the problem.  However, it’s not necessary to do a colonoscopy in a younger person, nor uncommon (& often expensive) tests for rare diseases if there are no Red Flags as described above.  Nor is it necessary to refer to a Gastroenterologist, unless symptoms are hard to control.

See also Constipation for the clinician’s condensed thought-process when face-to-face with a patient.