Chronic, relapsing abdominal pain: Often crampy and located in the lower abdomen.
Altered bowel habits: The primary feature used for subtyping.
IBS-C: Predominantly constipation.
IBS-D: Predominantly diarrhea.
IBS-M: Mixed diarrhea and constipation.
Symptom characteristics: Pain is typically related to defecation (may improve or worsen), associated with a change in stool frequency or form.
Other common S/S: Bloating, abdominal distension, sensation of incomplete evacuation, and mucus in stool.
Exacerbating factors: Symptoms are often worsened by stress and certain foods.
Diagnostics
Rome IV criteria for irritable bowel syndrome
Timing: ≥ 6 months since the onset of symptoms
Symptoms
Recurrent abdominal pain (≥ 1 day per week during the previous 3 months)
PLUS ≥ 2 of the following
Abdominal pain related to defecation
Change in stool frequency
Change in appearance of stool
Treatment
Lifestyle & Diet (First-line):
Patient education and reassurance.
Dietary modification: Trial of a low FODMAP diet (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols) is effective for global symptoms.
Fiber: Soluble fiber (e.g., psyllium) can help with global symptoms, particularly in IBS-C. Insoluble fiber (e.g., bran) may worsen bloating.
Pharmacotherapy (Symptom-directed):
IBS-D:Loperamide for episodes of diarrhea. Rifaximin (a non-absorbable antibiotic) and Eluxadoline (a mixed opioid receptor agonist) are second-line options.
IBS-C: Laxatives (e.g., polyethylene glycol). Secretagogues like Lubiprostone (chloride channel activator) and Linaclotide (guanylate cyclase-C agonist) are effective.