Mucous Stools: Causes and Treatment
Mucous in stools signals inflammatory or infectious colonic pathology requiring immediate evaluation for dysentery (bloody stools with fever), infectious diarrhea, or inflammatory bowel disease, with treatment directed at the specific underlying cause identified through stool testing and clinical assessment.
Clinical Evaluation
When mucous stools present, obtain a focused history examining:
- Stool characteristics: Presence of blood, pus, frequency, and whether watery versus formed 1
- Dysenteric symptoms: Fever, tenesmus, blood/pus in stool indicating invasive pathogens 1
- Volume depletion signs: Thirst, tachycardia, orthostasis, decreased urination, lethargy, decreased skin turgor 1
- Duration: Illness lasting >1 day, especially with fever, bloody stools, recent antibiotics, or day-care attendance warrants fecal specimen evaluation 1
- Associated symptoms: Abdominal pain, cramping, nausea, vomiting 1
Differential Diagnosis by Presentation
Infectious Causes
Bacterial dysentery (Shigella, Salmonella, Campylobacter) presents with fever, abdominal pain, bloody mucous stools, and fecal leukocytes 1. Shigellosis specifically causes frequent loose stools mixed with blood and mucous 2.
Clostridium difficile causes pseudomembranous colitis with diarrhea (usually nonbloody initially), severe abdominal pain, fever, and gross or occult blood in stools 3. This is the most common nosocomial gastrointestinal pathogen 3.
Parasitic infections (amebiasis, giardiasis) may present with mucous stools and require specific antiparasitic therapy only when confirmed 4.
Inflammatory Bowel Disease
Crohn's disease with colonic involvement produces mucous stools, particularly with active perianal disease or fistulae 1. The pattern (inflammatory, stricturing, fistulating) and site must be assessed before treatment 1.
Ulcerative colitis causes bloody diarrhea with mucous, especially in left-sided or extensive disease 1.
Other Causes
Ischemic colitis, Behçet's disease, collagenous colitis, and certain drugs/toxins can produce pseudomembranous colitis with mucous stools 5.
Diagnostic Approach
Obtain fecal studies when:
- Profuse, dehydrating, febrile, or bloody diarrhea 1
- Duration >1 day with fever, bloody stools, systemic illness, recent antibiotics, day-care attendance, hospitalization, or dehydration 1
Testing includes:
- Stool culture for bacterial pathogens 1
- C. difficile testing (culture, cytotoxin B assay, or rapid enzyme immunoassay) 3
- Fecal leukocytes, lactoferrin, and/or occult blood for inflammatory diarrhea 1
- Ova and parasite examination when indicated 4
When C. difficile testing is negative and symptoms persist despite empiric treatment, early gastroenterology consultation and lower endoscopy are indicated 5. Colonic biopsies provide histologic clues to underlying diagnosis 5.
Treatment by Etiology
Infectious Diarrhea
Rehydration is paramount for all cases:
- Oral rehydration salt solution (WHO formula) for mild-moderate dehydration 1, 4
- Ringer's lactate IV for severe dehydration 4
- Food-based oral rehydration therapy reduces stool output 1
Antibiotic therapy is beneficial only for specific pathogens:
Shigellosis: Fluoroquinolones (norfloxacin 800 mg single dose, ciprofloxacin 1 g single dose, or standard courses), azithromycin, or ceftriaxone 2. Older agents (tetracycline, ampicillin, co-trimoxazole) are often ineffective due to resistance 2.
C. difficile: Metronidazole 250 mg four times daily for 10 days is first-line therapy 3. Vancomycin (125-500 mg four times daily for 10 days) is reserved for metronidazole intolerance/failure, contraindications, or first trimester pregnancy 3. For recurrences (20% of cases), use pulsed/tapered antibiotic regimens or Saccharomyces boulardii as adjunct 3.
Cholera: Antibiotics beneficial 4
Amebiasis/giardiasis: Antiparasitic agents only when confirmed 4
Antimotility agents are contraindicated in infectious diarrhea 2.
Inflammatory Bowel Disease
Crohn's disease with perianal/fistulating disease:
- First-line: Metronidazole 400 mg three times daily and/or ciprofloxacin 500 mg twice daily 1
- Second-line: Azathioprine 1.5-2.5 mg/kg/day or mercaptopurine 0.75-1.5 mg/kg/day after excluding distal obstruction and abscess 1
- Refractory cases: Infliximab (5 mg/kg at 0,2,6 weeks) combined with immunomodulation and surgery 1
Active colonic Crohn's disease:
- Mild: Mesalazine 4 g daily 1
- Moderate-severe: Prednisolone 40 mg daily, tapered over 8 weeks 1
- Severe: IV hydrocortisone 400 mg/day or methylprednisolone 60 mg/day with IV metronidazole 1
Ulcerative colitis maintenance: Lifelong aminosalicylates, azathioprine, or mercaptopurine to reduce relapse risk 1.
Critical Pitfalls
- Do not use antidiarrheals for acute infectious diarrhea 4, 2
- Do not delay C. difficile testing in hospitalized patients or those with recent antibiotic exposure 3
- Do not assume all mucous stools are infectious—IBD requires different management 1
- Bismuth subsalicylate use requires physician consultation when fever or mucus in stool is present 6
- Hand washing with soap and water prevents person-to-person transmission of Shigella and C. difficile 3, 2