Mucus in stool
Written and medically reviewed by Bahir Hadi, specialist in surgery, PhD
Mucus in stool: When is it normal - and when should it be investigated?
The bowel naturally produces mucus every day to lubricate the stool and protect the mucosa; the exact volume in humans is not established [1]. Small amounts of visible mucus can therefore occur without underlying disease. New, persistent or accompanied mucus, for example mucus with blood or mucus together with a change in bowel habit, is assessed on the overall clinical picture. Age alone does not automatically trigger a particular examination.
What is bowel mucus?
Mucus (mucin) is secreted by goblet cells in the bowel mucosa and forms a protective layer against bacteria, acid and digestive enzymes. The amount naturally increases with:
- Constipation (slower passage = more mucus)
- Diarrhoea (acute secretion to protect the mucosa)
- Dehydration
- Pregnancy
Common (benign) causes
| Cause | Typical signs |
|---|---|
| Irritable bowel syndrome (IBS) | Mucus + bloating, alternating stool, abdominal pain relieved by defecation |
| Hemorrhoids | Mucus + fresh red blood, possibly prolapse, itching |
| Anal fissure | Mucus + pain on defecation, slight bleeding |
| Chronic constipation | Mucus around hard stool |
| Gastrointestinal infection | Acute mucus + diarrhoea, possibly fever - typically Salmonella, Campylobacter, Shigella |
Serious causes requiring prompt work-up
Mucus in the stool can also be an early sign of:
- Inflammatory bowel disease (IBD) - ulcerative colitis and Crohn's disease often present with mucus + blood + diarrhoea.
- Intestinal polyps - particularly large villous adenomas can secrete large amounts of mucus.
- Colorectal cancer - mucus + blood + altered bowel habit for >6 weeks is an alarm symptom.
- Diverticulitis - mucus + left-sided pain + fever.
- Rectal prolapse - continuous mucus/leakage.
When should you see a doctor?
Contact your GP promptly if you have:
- Mucus + visible blood in the stool (contact a doctor straight away, not after a period of observation)
- Mucus with a persistently altered bowel habit (more frequent, looser, thinner). The longer it lasts, the more it argues for assessment, but do not wait for a particular number of weeks to pass
- Mucus + unintentional weight loss
- Mucus + abdominal or night-time pain
- Higher age without previous evaluation, weighed together with the other findings
- Family history of colorectal cancer or IBD
How mucus in the stool is investigated
- History and stool diary - frequency, consistency (Bristol scale), blood, pain.
- Stool samples - F-calprotectin (helps distinguish IBS from IBD; the cut-off depends on assay and laboratory, and a normal value does not rule out disease when alarm symptoms are present), F-Hb (immunochemical blood test), possibly culture and parasites.
- Blood tests - CRP, haemoglobin, ferritin, leukocytes.
- Colonoscopy - chosen after an overall assessment of symptoms, alarm features, age and test results such as calprotectin or F-Hb [2].
- Sigmoidoscopy - may suffice for isolated rectal symptoms.
Treatment
Treatment depends entirely on the cause:
- IBS: dietary modification (FODMAP), fibre regulation, possibly antispasmodics.
- Hemorrhoids: dietary fibre, band ligation, possibly surgery.
- IBD: medical treatment by a gastroenterologist (5-ASA, immunomodulators).
- Polyps: polypectomy during colonoscopy.
- Colorectal cancer: surgery in collaboration with oncology.
Treatment at Kirurgen.dk
We offer work-up with colonoscopy and sigmoidoscopy after referral from a doctor. Questions about referral, cover and price are clarified with the clinic or your GP before treatment; see contact. See also our articles on rectal bleeding and intestinal polyps.
References
- Johansson MEV, Sjövall H, Hansson GC. The gastrointestinal mucus system in health and disease. Nat Rev Gastroenterol Hepatol 2013;10(6):352-61. PMID: 23478383
- Rao SSC, Bharucha AE, Chiarioni G, et al. Anorectal disorders. Gastroenterology 2016;150(6):1430-42.
- Lacy BE, Mearin F, Chang L, et al. Bowel disorders (Rome IV). Gastroenterology 2016;150(6):1393-407.
- Vasen HFA, et al. Revised guidelines for the clinical management of Lynch syndrome. Gut 2013;62(6):812-23.
More on this topic at Kirurgen.dk
Category: Gastrointestinal