Constipation is one of those rare symptoms for which diagnosis does not involve major thought process. Itโs 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 weโll 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 doesnโt feel right.
A wide variety of diseases can cause constipation, ranging from Parkinsonโs to long-standing Diabetes to Chronic Kidney Failure, Pregnancy, and many more.ย 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.ย 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 weโd always review a patientโs 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.ย Weโll discuss this later.
Technically, clinicians should perform a rectal exam on everyone with constipation.ย In the age ofย telemedicine, all weโd be able to do in that sense would be to examine a patientโs outside, an awkward suggestion which Iโm sure nobody would dare try to practice.ย Though I havenโt polled or surveyed any colleagues, hereโs a logical approach which can begin remotely:
1.ย Rule Out Emergencies
This is almost never the case with constipation.ย New onset constipation with abdominal pain could be a sign of a bowel obstruction, but pain would be most prominent symptom that weโd 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.ย Red Flags suggesting serious disease, needing in-person visit and rectal exam โ New Constipation:
- With significant weight loss (possible Colon Cancer)
- In the very Elderly or Debilitated (possible Fecal Impaction)
- With unusual back painย (maybe Spinal Cord Disease)
- With large amount of Bloodย (possible Colon Cancer or Ulcerative Colitis)
- In persons having Anal Sex, esp. if many partnersย (maybe rectal STDs: Gonorrhea / Chlamydia)
- Persons >50 with alternating constipation & diarrheaย (possible Colon Cancer)
3.ย If thereโs 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. Donโt 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.ย Theyโd only be relevant if tender to touch; thrombosed ones are usually swollen and purple.ย Internal hemorrhoids may cause bloody stools, but donโt get clotted unless they prolapse.
Anal fissures, tiny cracks in the skin, may be harder to find.ย Theyโre caused by hard stools, or by trauma (e.g. anal sex).ย We may need to hunt meticulously among the anal folds for a bright red spot or streak, which is tender.
4.ย Stop (if possible) any medications that cause constipation (see above).
5.ย Try basic treatment.
If it successfully controls the constipation, as it often does when thereโs no underlying disease, thereโs no need for further work-up.ย 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 (Miralaxยฎ, and others), Sorbitol, Lactulose, etc. daily
Ifย normal stool consistency:
- Natural or synthetic fibers like Psyllium & others (Metamucilยฎ, CitrucelV, FIberconยฎ, SuprafiberV, etc.), daily
- Polyethylene Glycol (Miralaxยฎ, 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
Nowโs 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) โ for low hemoglobin (bleeding from Colon Cancer)
- Comprehensive Metabolic Panel โ for high calcium, low potassium, high glucose (Diabetes)
- TSH (thyroid test) โ for Hypothyroidism
- ESR &/or CRPย —ย if very high, might suggest the possibility of Colon Cancer (metastatic) or Ulcerative Colitis
- Rectal STD tests for people whoโve had unprotected rectal sex (for Chlamydia & Gonorrhea)
8.ย Who Needs a Gastroenterology referral (& likely colonoscopy) for Constipation?
- Persons >45-50 y.o. with new constipation who donโt 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.ย Itโs often called โIBS-Cโ meaning IBS with Constipation as a main symptom along with discomfort, to distinguish it from โIBS-Dโ when Diarrhea is the main symptom.ย See also a definition of โSyndrome,โ and the difference between IBS and IBD (โInflammatory Bowel Diseaseโ).
IBS-C can be defined simply as having abdominal pain with constipation at least once a week, for 3 months or more.ย A problem with this is it may include many people who wouldnโt say they feel sick.ย But itโs useful for those who feel troubled by their symptoms.ย Weโd never diagnose it without colonoscopy if it began over age 40-50, what we call โcancer ageโ because cancers become more common in general. IBS is a diagnosis of exclusion, meaning thereโs nothing else causing the problem.ย However, itโs 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.ย Nor is it necessary to refer to a Gastroenterologist, unless symptoms are hard to control.
See alsoย Constipationย for the clinicianโs condensed thought-process when face-to-face with a patient.