Most of us experience constipation from time to time. This can result from illness, inactivity, travel, medications, and other circumstances. For most people it is acute, meaning it goes away fairly quickly.
It can also be a symptom of a bowel disease. Abrupt onset of constipation that persists, is extraordinarily painful, or is accompanied by fever, bleeding, or vomiting should be promptly reported to a doctor.
Irritable bowel syndrome (IBS) can also cause constipation, but abdominal pain is always present in IBS and the constipation comes and goes, often alternating with diarrhea.
For many others, constipation is a chronic day-to-day condition that has persisted for many years, perhaps since childhood.
Even though constipation is common, it is one of the most difficult gut symptoms to define. Patients, physicians, and physiologists (who study how the body works) have different views of the condition, due to the variable features of constipation.
The Patient View
Constipation appears differently to different people. Individuals may report constipation if they sense something is amiss, or if they are uncomfortable. Most people report having at least 3 bowel movements per week, so fewer is often thought of as abnormal. However, many manage just fine with fewer, while others are uncomfortable within that range.
Frequency alone cannot be considered an indicator of constipation. The consistency or form of the stool, the effort required to expel it, and the accompanying abdominal discomfort and distension are at least as important to consider as frequency.
The Physician View
Physicians ask about signs and symptoms in order to make a diagnosis. In the case of constipation, symptoms vary and are imprecise. In chronic idiopathic constipation, no objective sign can be observed. For these reasons symptom-based diagnostic criteria (Rome criteria) have been developed by groups of experts. The Rome criteria view functional constipation as: "…a group of functional disorders which present as persistent difficult, infrequent or seemingly incomplete defecation." The word functional here implies that the cause is unknown (idiopathic).
The Physiologist View
Physiologists study the workings of the gut. In order to identify constipation they seek to measure gut function and determine differences between normal and abnormal. The simplest of these is to measure gut transit time. The most common method is to track the progress of a number of tiny, swallowed, but x-ray detectable, markers as they move through the gut. In this way the time it takes for stool to move is measured. Other tests measure the contractions of the colon or pelvic muscles related to bowel movements.
A Practical View
Testing is not practical for routine doctor visits, and there are many debates about the definition of a normal test. The Bristol Stool Form Scale is one method that everyone can use. Hard stools (type 1) represent the slowest transit, while loose watery stools (type 7) are those of rapid transit and diarrhea. Difficult or infrequent passage of type 1 or 2 stools provides a rule of thumb for constipation.
|Type 1||Separate hard lumps like nuts (difficult to pass)|
|Type 2||Sausage shaped but lumpy|
|Type 3||Like a sausage but with cracks on surface|
|Type 4||Like a sausage or snake, smooth and soft|
|Type 5||Soft blobs with clear-cut edges (passed easily)|
|Type 6||Fluffy pieces with ragged edges, a mushy stool|
|Type 7||Watery, no solid pieces (entirely liquid)|
Constipation is a common disorder with many features, such as the frequency, consistency, and effort required to expel stool. In the absence of symptoms such as bleeding, anemia, fever, and weight loss, chronic persistent constipation is likely to be a functional disorder, having no known cause. Occasionally special tests may reveal damage to the muscles or nerves of the gut, or another disorder.
Adapted from IFFGD Publication: What is Constipation Anyway? by W. Grant Thompson, MD, FRCPC, Emeritus Professor of Medicine, University of Ottawa, Ontario, Canada.