The consistency, shape and texture of stool can sometimes change from what is normal for an individual. These temporary fluctuations can occur for various reasons, like when loose stool or diarrhea occurs with food poisoning, or when low dietary fiber and water intake results in constipation. However, there are instances where the daily stool is considered abnormal in terms of its consistency, shape and texture.
What is the Bristol Stool Chart?
The Bristol Stool Chart is a classification of different types of stool based on the consistency, texture and shape. It was developed at the University Department of Medicine, Bristol Royal Infirmary by two doctors, Dr. Ken Heaton and Dr. Stephen Lewis. The chart is part of a broader Bristol Stool Scale that also takes other signs and symptoms into account when assessing conditions like irritable bowel syndrome. These other signs and symptoms include bloating, bowel habit and pain or discomfort.
The Bristol Stool Chart in particular can be useful for every person, even people who are not in the medical field, to assess their own stools. It may help to indicate when there is an underlying problem, either due to a disease, diet or lifestyle. Sometimes an abnormality in stool consistency, shape and texture are the first features of a problem, even before other symptoms arise. Seeking a professional medical opinion can therefore assist with early diagnosis and prompt treatment which greatly improves the prognosis of most conditions.
Normal Bowel Movement Consistency, Shape and Texture
Normal stools should be soft, smooth and sausage-shaped (three S’s). It should be passed out with ease with some effort but not straining. There should be no pain or discomfort when passing stool or after a bowel movement. Furthermore normal bowel habit should be between three bowel movements a week to three bowel movements a day. Beyond either limit is then considered to be constipation or diarrhea, respectively.
Read more on normal and abnormal stool.
How does bowel movement form?
It is important to understand how stool forms in order to understand why it is normally soft, smooth and sausage-shaped. Chyme from the small intestine is a fluid mixture containing particles and is composed of water, wastes, undigested foods, mucus and other substances. It enters the large intestine where the colon transforms it to a soft solid mass that we know as normal stool.
This is a gradual process that occurs as the colon reabsorbs water back into the body. As the fluid travels up the ascending colon to the transverse colon, it is transofmred from a fluid to a mushy liquid. It is then transformed into a soft solid mass by the time it reaches the descending colon. Contractions compact the solid stool and eventually pushes it into the rectum just before defecation.
It is further shaped as the stool pass through the rectum and down the anal canal to eventually be expelled out of the anus.
Read more on feces.
Pictures of Stool Charts
Types of Stool in the Bowel Movement Chart
There are seven types of stool discussed in the Bristol Stool Chart.
- Types 1 and 2 are indicative of constipation.
- Types 3 and 4 are an indication of normal stool and bowel habit.
- Types 5, 6 and 7 are an indicator of diarrhea.
Types 1 and 2
- Type 1 is where the stool is separate hard lumps like nuts which are difficult to pass out.
- Type 2 is where the stool is sausage-shaped but lumpy.
It is evident in these types of stool that there has been excessive water reabsorption thereby leading to dry and hard stool. It occurs when the stool stays for a prolonged period in the colon due to abnormalities like slow bowel motility. This may also arise with insufficient fluid and fiber intake. Usually it is a reflection of bowel habit where there is less than three movements in a week.
Types 3 and 4
- Type 3 is where the stool is sausage-shaped but with cracks on its surface.
- Type 4 is where the stool is sausage-shaped or snake-like, smooth and soft.
This is considered as normal stool and is a reflection of a normal or healthy bowel habit. The latter means that a person passes stool regularly and at least three times in a week but not more than three times in a day. It is also a reflection of sufficient fluid and fiber intake and movement through the bowel that is neither too fast nor too slow.
Types 5, 6 and 7
- Type 5 is where the stool is soft blobs with clear cut edges and passed easily.
- Type 6 is a mushy stool where there are fluffy pieces with ragged edges.
- Type 7 is where the stool is watery and entirely liquid with no solid pieces.
With these types of stool, water reabsorption is insufficient to form soft but solid stool. As a result the stool is loose and watery. This inadequate reabsorption may be due to faster than normal movement through the bowels with insufficient time for water reabsorption, damage or inflammation of the colon wall or excessive fluid secretion into the bowels.
How To Use The Bowel Movement Chart
Ideally a stool sample should be collected and sent to a laboratory for analysis. The results of this analysis along with other diagnostic investigations, medical history and clinical findings allows a medical professional to diagnose underlying abnormalities. It is important to note that constipation and diarrhea are only symptoms of various conditions.
However, any person can use the stool chart to monitor the presence of certain digestive diseases. A stool diary can provide helpful information to a medical professional and also assists with identifying possible factors that are disturbing stool formation and bowel habit.
- Visually inspect the stool after a bowel movement, taking note of its consistency, shape and texture. Photographing it may also be helpful for a visual diary.
- Note any symptoms that may have occurred just before, during and immediately after a bowel movement. Symptoms such as straining to pass stool, discomfort and pain, urging to pass stool after a bowel movement and abdominal cramps are relevant.
- Try to identify possible foods that may be contributing to abnormal stool and bowel habit. Usually these are foods that were consumed on the same day and up to 72 hours prior to a bowel movement. However, in people with constipation this can involve foods eaten even 4 to 5 days prior.