It is a common question among people with IBS: “Can I really be having constipation and diarrhea at the same time?”
There are several reasons why you might be experiencing both of these symptoms together. As always, changes in your typical IBS symptoms should be discussed with your doctor. IBS is often unpredictable, and by definition it is associated with altered bowel habits. Nevertheless, if new symptoms or patterns emerge, they could be a sign of another condition and they should be investigated.
IBS With alternating constipation and diarrhea
Mixed IBS (IBS-M) might be the most common IBS subtype.1 It is defined as >25% of stools being loose and watery and >25% of stools being lumpy and hard when you are not taking laxatives or antidiarrheals.1
IBS is different for each person, and the mixed subtype of IBS is an especially diverse category.1 People with IBS-M report symptoms that are common in people who have IBS with constipation (IBS-C), such as straining, the feeling of having an incomplete bowel movement, and manual evacuation of the bowels. They also report urgency, which is more typical of IBS with diarrhea (IBS-D).
More studies of people with IBS-M are needed to describe this condition more accurately. Currently, there are few treatments specifically for this subtype.1
Terminology: Are you and your doctor using the same language?
Diarrhea is defined as “frequent, loose stools preceded by lower abdominal cramping.”2 On the Bristol Stool Form Scale, types 6 and 7 indicate diarrhea.
To doctors, constipation is “hard, pellet-shaped stools” or types 1 and 2 on the Bristol Stool Form scale.2 However, many people think constipation is also:3
Infrequent bowel movements
Straining or pushing during a bowel movement
Feeling that you cannot completely empty your bowels
Feeling like you need to have a bowel movement but can’t
Loose stool followed by a feeling of having had an incomplete bowel movement might seem like constipated diarrhea.4 In order to get the right treatment, it is important to be as clear as possible when describing your symptoms.
A sign of a different condition
A small number of people who have had constipation for a very long time have what is called “fecal impaction with overflow diarrhea.”5 This could happen when a large lump of hard stool is stuck in the rectum.6 The rectum stretches out, and liquid stool flows around the fecal mass. Symptoms of overflow diarrhea are small, pellet-like stools alternating with watery diarrhea.5,6 Other symptoms include abdominal cramps, bloating, and straining. Long-term use of laxatives, certain pain medications, and anticholinergic medications can be a cause of fecal impaction.6 Overflow diarrhea is often misdiagnosed and treated with an anti-diarrheal medication, which actually makes the condition worse.5
Su AM, Shih W, Presson AP, Chang L. Characterization of symptoms in irritable bowel syndrome with mixed bowel habit pattern. Neurogastroenterol Motil. 2014;26:36-45.
Wilkins T, Pepitone C, Alex B, Schade RR. Diagnosis and management of IBS in adults. Am Fam Physician. 2012;86:419-426.
International Foundation for Functional Gastrointestinal Disorders. IBS with Constipation. Accessed July 13, 2016 at: http://www.aboutibs.org/ibs-with-constipation.html.
Drossman DA. Constipated Diarrhea. International Foundation for Functional Gastrointestinal Disorders website. Accessed July 13, 2016 at: http://www.aboutibs.org/constipated-diarrhea.html.
Kolar GJ, Tabibian JH, Mangan TF. 20-year history of diarrhea with intermittent constipation. Am Fam Physician. 2014;89:739-740.
MedlinePlus. Fecal Impaction. Accessed July 13, 2016 at: https://medlineplus.gov/ency/article/000230.htm.