Constipation is sometimes described as the passage of stools less than three times per week. However, this should also be accompanied by other symptoms, including hard stools, a feeling of incomplete evacuation, abdominal discomfort, distention, bloating, and symptoms of defecatory disorders.
Chronic constipation may be caused by specific diseases or medications (“secondary constipation”). However, more commonly constipation is not found to have a specific cause. This is referred to as “primary" or "functional" constipation. It is important to differentiate between chronic constipation and irritable bowel syndrome with constipation (where pain is the predominant feature).
The diagnosis of chronic constipation is often made without excluding "secondary" causes. This is because constipation is so common, and secondary causes of constipation are rare. In most cases, secondary causes are looked for only if the constipation is severe and difficult to treat. A set of diagnostic criteria for various functional abdominal disorders has been created, and the most common version of this is called the Rome IV criteria.
Rome IV criteria for functional constipation:
The diagnosis should be based upon the presence of the following for at least three months (with symptom onset at least six months prior to diagnosis):
Must include two or more of the following:
- Straining during more than 25 percent of defecations
- Lumpy or hard stools (Bristol Stool Scale Form 1-2) in more than 25 percent of defecations
- Sensation of incomplete evacuation for more than 25 percent of defecations
- Sensation of anorectal obstruction/blockage for more than 25 percent of defecations
- Manual manoeuvres to facilitate more than 25 percent of defecations (eg, digital evacuation, support of the pelvic floor)
- Fewer than three spontaneous bowel movements per week
- Loose stools are rarely present without the use of laxatives
- There are insufficient criteria for Irritable bowel syndrome
Although patients with functional constipation may have abdominal pain and/or bloating, they are not the predominant symptoms.