-Patient meets the definition of IBS.
-H&P performed, see above.
-TSH, BMP, CBC, Stool Studies, FOBT. Abdominal imaging if needed.
Treatments that work for IBS
Nonpharmacologic treatment.
-No alarm symptoms.
-Patient education and reassurance provided.
Exercise and dietary modification
-Exercise
-Exclude gas-producing foods like beans, onions, celery, carrots, raisins, bananas, apricots, prunes, Brussels sprouts, wheat germ, pretzels, and bagels. Also, exclude alcohol and caffeine.
-A trial of lactose-restricted diet.
-Will refer to nutrition for low FODMAP diet.
-Keep a food diary to see if symptoms are related to food intake.
Pharmacotherapy.
-Antidepressants (SSRIs and tricyclics) have shown benefit.
-Psychotherapy: CBT, hypnotherapy, and stress management all work.
-Antibiotics: Rifaximin works but is very expensive.
-Probiotics: Bifidobacterium seems to work.
-Antispasmodics for pain e.g. Dicyclomine 20 mg PO four times daily as needed.
-Peppermint oil (Peppermint oil is an antispasmodic that has moderate evidence of benefit in the relief of abdominal cramping in patients with irritable bowel syndrome (IBS))
-Laxatives, if constipated
-Antidiarrheals, if having diarrhea.
-Lubiprostone is effective for the treatment of constipation-predominant IBS.
-Alosetron is a 5-hydroxytryptamine 3 antagonist and is FDA approved to treat severe diarrhea-predominant IBS only in women who have not improved with conventional therapy.
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Pharmacotherapy should be tailored to the patient’s symptoms and severity.
Pain / bloating: TCAs, SSRIs, Antispasmodics (e.g. Dicyclomine, hyoscyamine). NB: TCAs may cause constipation and worsen IBS-C
Diarrhea: Antidiarrheals (e.g. Loperamide) and Rifampicin (2-week course).
Constipation: Laxatives, lubiprostone. Linaclotide short-term only if laxatives and lubiprostone don’t work.
With IBS, if there is constipation, treat it like you would any other constipated patient e.g. with osmotic laxatives.
“Routine testing for celiac disease should be considered in patients with diarrhea-predominant or mixed-presentation IBS (SOR C). A systematic review that included more than 4000 patients found that 4% of those with diarrhea-predominant or mixed-presentation IBS had biopsy-proven celiac disease.” Am Fam Physician 2012;86(5):419-426.
Alarm symptoms: Age ≥ 50, unintentional weight loss, progressive symptoms, anemia, bloody stools, family history of colorectal cancer, celiac disease, IBD, nocturnal diarrhea.
References
https://www.uptodate.com/contents/treatment-of-irritable-bowel-syndrome-in-adults
http://www.aafp.org/afp/2012/0901/p419.html
http://www.aafp.org/afp/viewRelatedDocumentsByKeyword.htm?keywordId=2374