Bristol Stool Form Scale
Through the Bristol Stool Form Scale, a diagnostic medical tool, it is possible to classify IBS patients based on a standardized scale for stool consistency. The method makes it easy to assess the stool and describe its shape and type.
The illustration above shows the 7-point scale from Type I indicating the hardest form and Type 7 the loosest. Types 1 and 2 indicate varying degrees of constipation while types 5-7 indicate increasing degrees of diarrhea. An optimally functioning stomach indicates type 3 and 4 because the body has an easy time getting rid of the residual products when the consistency looks like this.
Different types of IBS
Based on the Bristol Stool Form Scale, we can classify IBS into 4 types with common symptoms. The advice for the various groups differs, so it is good to know what kind of IBS you suffer from.
IBS-C is IBS with constipation, where at least one in four stools is hard (Bristol 1-2) and fewer than one in four are loose (Bristol 6-7).
IBS-D is IBS with diarrhea, where at least one in four stools are loose (Bristol 6-7) and fewer than one in four are hard (Bristol 1-2).
IBS-M is variable IBS, with at least one in four hard stools (Bristol 1-2) and at the same time at least one in four loose stools. (Bristol 6-7). Sometimes also called IBS-A (alternating).
The last variant is a so-called undifferentiated unsubtyped-IBS. Here, the stool pattern is too variable to fit into any of the other groups above.
What type of IBS is most common?
Among adults, the distribution between the different types of IBS is relatively even. IBS-C (constipation) and IBS-D (diarrhea) each comprise about a third of IBS sufferers. Studies show that IBS-C is the most common form in children.
C, D, M, U – but what is PI-IBS?
You might come across other designations such as PI-IBS (PI: Post Infectious). PI-IBS does not involve a special stool pattern but it is a type of IBS caused by a previous acute gastrointestinal infection. Such an infection is believed to be able to disturb the intestinal mucosa, for example through inflammation or changes in the bacterial composition.
Johanna Sundin, a researcher at the University of Gothenburg, points out that although it may take many years, a large proportion of PI-IBS patients become free of symptoms.