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Functional Subtypes of Constipation

How do you distinguish between slow-transit, normal-transit and dyssynergic defecation in a clinical setting?

In chronic constipation, the symptoms of these three subtypes will very often overlap. A patient with slow transit constipation will often say that he or she has no urge to defecate, or report they have a bowel movement only once a week to once every several weeks. This length of time between bowel movements is a good indicator of slow-transit constipation. It is sometimes the case in normal-transit constipation that a patient could go for up to a week without a bowel movement, but not generally. It is most likely to be less than a week.

An indicator of dyssynergic defecation is the complaint of inordinate straining, which suggests the inability to coordinate abdominal, rectoanal, and pelvic floor muscles, but that condition can also overlap with both slow-transit and normal-transit constipation. Dyssynergic defecation can be diagnosed by a rectal examination, or, if that proves inconclusive, the patient may need to be referred for anorectal manometry.

If signs point to normal-transit constipation, it is important to make the distinction between that condition and irritable bowel syndrome with constipation (or IBS-C). Patients with normal-transit constipation will most often report a reduced frequency of bowel movements and/or some difficulty having a bowel movement, including some straining and bloating, but they generally will not report being in a lot of pain. Patients with IBS-C will have moderate to severe pain.

Related References

Mertz H, Naliboff B, Mayer E. Physiology of refractory chronic constipation. Am J Gastroenterol. 1999 Mar;94(3):609-15.

Schiller LR. The therapy of constipation. Aliment Pharmacol Ther. 2001 Jun;15(6):749-63.

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The E-IMPACCT (Elderly IMProvements & Advances in Chronic Constipation Treatment) educational initiative is sponsored through a collaboration of ASCP, AKH Inc., and Medical Communications Media, Inc.

Supported by an educational grant from Sucampo Pharmaceuticals, Inc. and Takeda Pharmaceuticals North America, Inc.


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