Can you have Irritable Bowel Syndrome (IBS) with constipation only, without diarrhea?

Irritable Bowel Syndrome Can Present with Constipation Only

Yes, irritable bowel syndrome (IBS) can present with constipation only, without diarrhea, and this is specifically classified as IBS with constipation (IBS-C). 1

IBS Subtypes

IBS is categorized into different subtypes based on predominant stool patterns:

• IBS with constipation (IBS-C): Patients have hard stools more than 25% of the time and loose stools less than 25% of the time 1
• IBS with diarrhea (IBS-D): Patients have loose stools more than 25% of the time and hard stools less than 25% of the time 1
• IBS-mixed (IBS-M): Patients experience both hard and soft stools more than 25% of the time 1
• IBS-unclassified (IBS-U): Patients have neither loose nor hard stools more than 25% of the time (approximately 4% of cases) 1

Diagnostic Criteria

For a diagnosis of IBS-C, patients must meet the following criteria:

• Abdominal pain associated with defecation or a change in bowel habit 1
• Symptoms present for more than 6 months 1
• Hard stools predominating (>25% of bowel movements) 1
• Less than 3 complete spontaneous bowel movements per week 2
• Sense of incomplete evacuation is common 1

Treatment Options for IBS-C

Several evidence-based treatments are available for IBS-C:

First-line treatments:

• Soluble fiber (e.g., ispaghula): Effective for global symptoms and abdominal pain; should be started at low doses (3-4g/day) and gradually increased to avoid bloating 1
• Regular exercise: Should be advised for all IBS patients 1
• Dietary modifications: First-line advice for all IBS patients 1

Second-line treatments:

• Linaclotide: A guanylate cyclase-C agonist that is highly efficacious for IBS-C in secondary care. It is likely the most effective secretagogue available for IBS-C, though diarrhea is a common side effect 1, 2
• Lubiprostone: A chloride channel activator that is effective for IBS-C. Less likely to cause diarrhea than other secretagogues, but nausea is a frequent side effect 1
• Plecanatide: Another guanylate cyclase-C agonist effective for IBS-C, though diarrhea is a common side effect 1
• Tenapanor: A sodium-hydrogen exchange inhibitor effective for IBS-C, though diarrhea is a frequent side effect 1
• Tegaserod: A 5-HT4 receptor agonist effective for IBS-C but unavailable outside the USA 1

Neuromodulators:

• Tricyclic antidepressants: Effective for global symptoms and abdominal pain in IBS. Should be started at low doses (e.g., 10mg amitriptyline once daily) and titrated slowly to 30-50mg once daily 1
• Selective serotonin reuptake inhibitors: May be effective for global symptoms in IBS 1

Psychological Therapies

• Cognitive behavioral therapy: May be effective for global symptoms in IBS 1
• Gut-directed hypnotherapy: May be effective for global symptoms in IBS 1

Clinical Pitfalls and Caveats

• IBS is a diagnosis of exclusion - alarm features (age >50 years, weight loss, nocturnal symptoms, rectal bleeding, family history of colon cancer, anemia) warrant further investigation 1
• Many IBS-C patients may eventually alternate between constipation and diarrhea if followed long enough, potentially changing their subtype classification 1
• Treatments for IBS-C often cause diarrhea as a side effect, requiring careful titration and monitoring 1
• Psychological comorbidities are common in IBS patients and may affect treatment response 1
• Severe or refractory IBS symptoms should prompt a review of the diagnosis with consideration of further targeted investigation 1

IBS-C is a distinct subtype of IBS that can present with constipation only, without diarrhea, and has specific evidence-based treatment options that differ from those used for IBS-D.