Female doctor discussing constipation diagnosis with the patient.

Constipation, a common gastrointestinal complaint, requires meticulous evaluation for accurate diagnosis.

This article explores various diagnostic approaches for constipation, emphasizing the importance of thorough medical history, including surgical, dietary, and drug history, alongside the Bristol stool chart assessment.

Other essential methods include the detailed examination of defecation patterns, family medical history, and symptoms, including stool diary analysis.

Furthermore, physical examinations, perianal assessments, and digital rectal examinations provide crucial insights.

To ensure the comprehensive evaluation of constipation, health experts require patients to take blood tests, radiographic tests, and specialized studies for colonic and anorectal function.


The Medical History of The Patient:

  • medical history;
  • surgical history;
  • dietary history;
  • drug history;
  • Bristol stool chart.

The diagnosis of constipation involves knowing the medical history of the patient first.

Healthcare providers typically begin by gathering a comprehensive medical history of the patient, which encompasses various aspects.

This process includes reviewing the patient's medical history, which provides insights into any underlying medical conditions or previous gastrointestinal issues.

Surgical history identifies any prior abdominal surgeries that could contribute to constipation.

Dietary history is crucial. Specific nutritive patterns, like insufficient fiber consumption or inadequate fluid intake, may increase the likelihood of constipation in individuals.

Doctors examine the patient's drug history to identify medications that could potentially cause constipation as a side effect.

The Bristol stool chart aids in diagnosing constipation by classifying stool consistency, which helps assess the severity of constipation and guides treatment decisions.

By thoroughly evaluating these aspects of the patient's history, healthcare providers can accurately diagnose constipation and develop a tailored treatment plan to address the underlying causes and alleviate symptoms effectively.

According to medical review article on diagnosis, and management of constipation disorders:

“Clinical assessment, stool diaries and Rome IV diagnostic criteria can facilitate diagnosis, evaluate severity and distinguish between IBS with constipation, chronic idiopathic constipation and dyssynergic defecation.”


The Defecation History of The Patient:

  • patient bowel habits;
  • onset of constipation;
  • duration of the symptom;
  • severity of the symptom;
  • other related health events;
  • laxative use – type, number, and frequency;
  • medication history.

The diagnosis of constipation also involves a thorough assessment of the patient's defecation history.

This process involves examining the patient's bowel habits, including their frequency, consistency, and any alterations.

Understanding the onset of constipation provides valuable insight into potential triggers or underlying causes.

Evaluating the duration and severity of symptoms helps gauge the chronicity and impact of constipation on the patient's quality of life.

Additionally, inquiring about other related health events, such as recent illnesses or surgeries, can uncover factors contributing to constipation.

Detailed information regarding laxative use, including type, dosage, and frequency, is essential as it may indicate prior attempts to alleviate symptoms and their effectiveness.

A comprehensive medication history aids in identifying drugs that could be exacerbating constipation as a side effect.

By meticulously examining these aspects of the patient's defecation history, healthcare providers can formulate an accurate diagnosis of constipation and devise an individualized treatment plan to address the underlying factors and alleviate symptoms effectively.


The Family Medical History of The Patient:

  • diabetes;
  • colon cancer;
  • bloody stools;
  • inflammatory bowel disease.

The family medical history of the patient is crucial when doctors establish a diagnosis of constipation.

The presence of conditions such as diabetes, colon cancer, bloody stools, or inflammatory bowel disease in family members can provide valuable insights into potential genetic predispositions or shared environmental factors contributing to constipation.

Diabetes, for instance, is associated with neuropathy, which can affect bowel motility and increase the risk of constipation.

Similarly, a family history of colon cancer or inflammatory bowel disease may indicate a higher likelihood of gastrointestinal issues, including constipation.

Health experts from the American Journal of Gastroenterology state that:

“Subjects with more family members having constipation will have a higher risk of constipation.”

Symptoms such as bloody stools in family members could suggest underlying gastrointestinal conditions that may manifest similarly in the patient.

By incorporating the family medical history into the diagnostic process, healthcare providers can better understand the patient's risk factors and tailor their approach to diagnosing and managing constipation effectively.


Symptoms and Stool Diary:

  • food diary;
  • fluid intake;
  • Bristol stool form scale.

Recording symptoms and maintaining a stool diary can provide valuable insights into diagnosing constipation.

Keeping a food diary helps identify dietary factors that may worsen constipation, such as low fiber intake or inadequate fluid consumption.

Monitoring fluid intake is essential as dehydration can worsen the symptoms.

Utilizing the Bristol stool form scale aids in characterizing stool consistency, enabling health experts to assess the severity of constipation and guide treatment decisions accordingly.

According to a medical study called Mechanisms, Evaluation, and Management of Chronic Constipation (published by the U.S. NLM):

“A 2-week bowel diary provides a more refined assessment of day-to-day variations and the relationship between stool form and other symptoms.”

By diligently documenting symptoms and stool characteristics, patients and health experts can collaborate effectively to identify triggers, track progress, and tailor management strategies to alleviate constipation symptoms and improve bowel function.


Physical Examination:

  • abdominal examination;
  • neurological examination;

A thorough physical examination, which includes a detailed neurological assessment, aids in identifying systemic diseases that could lead to constipation.

It's crucial to carefully examine the abdomen for stool presence, mainly focusing on the left quadrant.

Ruling out a gastrointestinal mass is essential, even though patients often exhibit a typical physical examination.

During the diagnosis of constipation, the doctor conducts an abdominal examination to assess for any abnormalities or signs of underlying conditions.

This process may involve palpating the abdomen to check for tenderness, masses, or impacted stool.

Health experts from The American Academy of Family Physicians state that:

“Evaluating abdominal pain requires an approach that relies on the likelihood of disease, patient history, physical examination, laboratory tests, and imaging studies. ”

Assessing abdominal pain involves employing a method that considers the probability of illness, patient medical background, physical assessment, laboratory analyses, and imaging scans.

For example, if a patient presents with severe abdominal distension and tenderness, it could indicate a possible obstruction contributing to constipation.

The examination allows the doctor to gather essential clinical information to guide further evaluation and management of the patient's constipation.

Also, the doctor performs a neurological examination to assess nerve function and identify any issues affecting bowel movements.

This examination may involve testing reflexes, sensation, and muscle strength.

For instance, if a patient exhibits diminished anal sphincter tone or absent rectal sensation, it could suggest nerve damage contributing to constipation.

By conducting a thorough neurological assessment, the doctor can pinpoint potential neurological causes of constipation and tailor treatment accordingly to address underlying issues.


Perianal Examination:

  • The inspection of the anus and surrounding tissues.
  • Testing of perineal sensation and the anocutaneous reflex.
  • Digital palpation and maneuvers to asses anorectal function.

The diagnosis of constipation relies significantly on thorough perianal examination techniques.

This process requires meticulous inspection of the anus and surrounding tissues, enabling the identification of various abnormalities such as thrombosed external hemorrhoids, anal fissures, or rectal prolapse.

Observing the perineum during straining episodes may reveal additional indicators like stool leakage or internal hemorrhoid prolapse.

Digital rectal examination plays a pivotal role in assessing anorectal function.

Experiencing excruciating pain during this examination often points towards the presence of anal fissures.

Evaluation of resting sphincter tone aids in identifying potential causes of evacuation disorders, with high resting tone often linked to internal anal sphincter muscle dysfunction.

Palpation of rectal walls facilitates the detection of polyps, masses, rectoceles, or intussusception.

Physicians recommend an in-depth diagnosis of functional constipation even if the symptoms are typical and the physical examination yields normal findings.

During the physical examination, the emphasis should be on assessing growth. Conducting an abdominal examination, inspecting the perianal region, and examining the lumbosacral region are essential.

These comprehensive examination techniques provide crucial clinical data for effective management.


Digital Rectal Examination:

  • resting tone;
  • digital palpation;
  • squeeze maneuver;
  • pushing and bearing down maneuver.

The diagnosis of constipation often involves a detailed digital rectal examination (DRE), employing various maneuvers to assess anorectal function.

Digital palpation entails the insertion of a lubricated finger into the rectum, enabling the clinician to detect tenderness, masses, strictures, or stool consistency.

Evaluation of resting tone involves assessing the strength of the sphincter tone, categorizing it as normal, weak or increased.

The squeeze maneuver prompts the patient to contract and sustain tension in their sphincter muscles, providing insight into the muscle function. The muscle function can be normal, weak, or heightened.

During the pushing and bearing down maneuver, doctors instruct the patient to simulate defecation while the examiner assesses push effort, anal relaxation, and perineal descent.

This comprehensive assessment detects abnormalities such as weakened muscle tone, impaired relaxation, or excessive perineal descent, all of which contribute to the diagnostic process of understanding the underlying causes of constipation.

Through these meticulous DRE techniques, clinicians can gather vital information for formulating effective management strategies for constipation.

Health experts recommend patients perform a digital rectal examination to evaluate for signs of dyssynergic defecation. If a suspicion arises, conduct an additional investigation through high-resolution anorectal manometry.


Blood tests:

  • glucose level (primary);
  • complete blood count;
  • serum calcium test;
  • serum protein electrophoresis (extra);
  • urine porphyrins (extra);
  • serum parathyroid hormone (extra);
  • serum cortisol (extra).

Diagnosing constipation often involves a comprehensive assessment that may include blood tests to rule out underlying metabolic or pathological conditions.

Primary among these is the measurement of glucose levels, along with a complete blood count and serum calcium test.

These tests, alongside thyroid function tests, serve as initial screenings.

When suspicion persists, clinicians may request additional tests like serum protein electrophoresis, urine porphyrins, serum parathyroid hormone, and serum cortisol levels. However, there is currently no definitive evidence supporting the routine clinical value of these tests.

The American College of Gastroenterology Task Force advises against routinely recommending these tests for patients under fifty years old who lack alarm features or signs of organic disease.

Alarm features include new onset or worsening constipation, onset after age 50, bloody stools, weight loss, fever, anorexia, nausea, vomiting, or a family history of inflammatory bowel disease or colon cancer.

Hence, the diagnostic approach to constipation integrates numerous tests based on clinical suspicion and patient characteristics.


Radiographic tests:

  • defecography;
  • barium enema;
  • anorectal ultrasound;
  • plain abdominal X-Ray;
  • magnetic resonance imaging;
  • flexible sigmoidoscopy and colonoscopy (endoscopy).

Constipation diagnosis incorporates various radiographic tests to delineate underlying anatomical and functional abnormalities.

Plain abdominal X-ray, once a common adjunct in diagnosis, has diminished in utility due to its limited correlation with colonic transit and considerable inter-observer variation.

Barium enema is capable of identifying anatomic anomalies. However, it struggles to detect organic lesions effectively.

Defecography is a valuable tool, offering insights into rectal evacuation dynamics and anorectal function. There are two drawbacks, such as radiation exposure and inconsistent methodology.

Magnetic resonance imaging (MRI), particularly dynamic pelvic MRI, facilitates a comprehensive evaluation of pelvic floor anatomy and motion. MRI helps in the diagnosis of conditions like rectal intussusceptions and dyssynergia.

Endoscopic procedures like flexible sigmoidoscopy and colonoscopy help to rule out mucosal lesions and malignancies, especially in patients with alarming symptoms or those over 50 years old.

However, evidence supporting routine colonoscopy in constipated patients lacking alarm features remains scant.

Thus, while each radiographic test offers unique advantages and insights, a comprehensive diagnostic strategy integrating clinical assessment and selective use of imaging modalities is paramount in managing constipation effectively.


Studies for Colonic Function:

  • wireless motility capsule;
  • colonic transit study with scintigraphy;
  • colonic transit study with radiopaque markers;
  • colonic transit study with ingestion of pressure (ph capsule);

Diagnosing constipation requires a comprehensive evaluation of colonic function, often employing various studies to assess transit time and motility.

The Wireless Motility Capsule (WMC) offers a non-invasive approach, measuring colonic transit, gastric emptying, and small bowel transit time through pH changes as it passes the gut.

Studies demonstrate its efficacy in diagnosing slow transit constipation and guiding treatment plans.

Colonic transit scintigraphy, utilizing isotopes and gamma-camera imaging, quantifies total and regional transit time, aiding in distinguishing between pelvic outlet obstruction and slow transit constipation.

While validated and reliable, cost and availability limits scintigraphy.

Colonic transit studies, using radiopaque markers or pressure-sensitive capsules, provide objective measures of transit time.

The retention of markers on abdominal radiographs indicates slow transit constipation, offering insight into infrequent defecation.

These methods (though varying in invasiveness and cost) contribute to a comprehensive diagnostic approach, facilitating tailored management strategies for constipation.


Test for Anorectal Function:

  • anorectal manometry
  • high-resolution manometry;
  • balloon expulsion test (BET);
  • rectal barostat test;
  • colonic manometry.

The diagnosis of constipation involves assessing anorectal function through various tests to identify structural and functional abnormalities.

Anorectal manometry evaluates pressure activity, rectal sensation, and anal sphincter function, aiding in the detection of defecatory disorders like dyssynergia.

High-resolution manometry offers detailed pressure plots, enhancing the characterization of dyssynergia.

The balloon expulsion test provides a bedside assessment of the ability to expel an artificial stool, often confirming impaired evacuation.

Rectal barostat testing assesses rectal sensation, tone, and compliance. These things aid in detecting conditions like megarectum.

Each test offers valuable insights and a comprehensive diagnostic approach, including history-taking, digital rectal examination, and selective use of tests (like colonic transit studies and defecography).

Anorectal manometry is the preferred method for diagnosing dyssynergia, guiding the selection of patients who would benefit from biofeedback therapy.

These tests collectively contribute to identifying the underlying mechanisms of constipation and guiding tailored management strategies for patients with refractory bowel symptoms.

According to a medical study called “Diagnostic value of balloon expulsion test and anorectal manometry in patients with constipation: a systematic review and meta-analysis”:

“The balloon expulsion test and anorectal manometry demonstrate comparable diagnostic performance, each offering unique advantages. These diagnostic procedures hold significance in the diagnosis of constipation.”

Last medically reviewed on 29.04.2024


1. Rectal hyposensitivity. MA Gladman, PJ Lunniss, SM Scott, M Swash.

2. Advances in diagnostic assessment of fecal incontinence and dyssynergic defecation. Satish S.C. Rao.

3. The Value of a Balloon Expulsion Test in the Workup of Obstructed Defecation. Roy Dekel, Keren Hod, Yishai Ron.

4. Ambulatory 24-Hour Colonic Manometry in Slow-Transit Constipation. Rao, Satish S.C. M.D., Ph.D., F.R.C.P; Sadeghi, Pooyan B.A; Beaty, Jennifer M.D;

5. Comparison of Anorectal Manometry, Rectal Balloon Expulsion Test, and Defecography for Diagnosing Defecatory Disorders. John W. Blackett, Misha Gautam, Rahul Mishra, Kent R. Bailey.



My name is Sebastian D., and I am the senior editor of constipationguide.com. With the help of my mentor, Dr. Horia Marculescu, I decided to create a practical guide to constipation relief.. read more

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