Basics
Description
- Irritable bowel syndrome (IBS) is a common functional GI tract disorder where defecation is disordered and associated with abdominal discomfort.
- Characterized by abdominal pain, bloating, diarrhea or constipation
- Symptoms of IBS do not result from inflammatory, infectious, metabolic, or anatomic causes. However, there can be overlap with other conditions.
- Symptoms typically exacerbated by stress or particular foods (i.e., spices, fatty foods, caffeine)
Epidemiology
- 10 " 15% of the general population is affected by IBS.
- More common in females
- Prevalence estimates vary based on whether the study is community-based or practice-based, as many people do not seek medical care.
- Prevalence is also based on whether Manning, Rome II, or Rome III criteria are used.
- IBS occurs in children and was found to affect 6% of middle school students and 14% of high school students in one community-based study.
Risk Factors
- Prior history of bacterial enteritis
- History of abuse or trauma
Pathophysiology
- IBS considered a disorder of GI function relating to motility, sensation, and/or perception.
- Best model is a biopsychosocial construct with dysregulation of the gut-brain homeostasis affected bidirectionally by both peripheral and central factors.
- The pathogenesis of IBS is believed to be multifactorial and include the following:
- Abnormal gut motility
- Genetics
- Bacterial overgrowth
- Visceral hypersensitivity
- Behavioral response
- Microscopic inflammation
- Dysregulation of brain-gut axis
- Malabsorption
Diagnosis
History
- IBS is not a diagnosis of exclusion.
- Diagnosis is based on careful history with particular attention to characteristics of pain, precipitating factors, and defecation pattern.
- Symptoms that support constipation-predominant IBS (IBS-C) include the following:
- <3 stools per week
- Hard or lumpy stools
- Straining with defecation
- Symptoms that support diarrhea-predominant IBS (IBS-D) include the following:
- >3 stools per day
- Loose or mushy stools
- Urgency
- All IBS types may have the following:
- Sense of incomplete evacuation
- Mucus in stools
- Abdominal bloating
- Symptoms may not only intensify with known stressors (such as school exams), but also with positive experiences (such as parties, amusement park trips, dates, or prom).
Diagnostic Tests & Interpretation
Lab
- There is no laboratory testing that confirms IBS. Tests are done solely to rule out other conditions.
- Selective testing:
- CBC, ESR, or CRP,
- Stool for occult blood
- Stool for parasites (Giardia)
- Total IgA, tissue transglutaminase (IgA)
- Stool lactoferrin or calprotectin
- Consider albumin.
- Consider lactose testing.
- More testing needed if "red flags " present the following:
- Weight loss (over 5 " 10 lb)
- Bloody stool
- Fever
- Anemia
- Family history of inflammatory bowel disease or GI cancer
Imaging
There is no imaging that can be used to diagnose IBS. Imaging studies should be performed if indicated to evaluate for other conditions.
Diagnostic Procedures/Other
- In severe IBS, with weight loss and diarrhea resulting in incontinence or nocturnal stooling, colonoscopy may be required to rule out colitis.
- If history and empiric restriction do not lead to clear answer, as to whether lactose intolerance is a contributing factor, can perform lactose breath testing to objectively quantify lactase activity
Differential Diagnosis
- Giardia infection
- Lactose intolerance
- Fructose intolerance
- Celiac disease
- Inflammatory bowel disease
- Constipation with overflow
- Endometriosis
- Medication effects
- Psychiatric disorder (especially anxiety, depression, posttraumatic stress disorder, or school avoidance)
Treatment
- The aims of IBS treatment are to:
- Improve a global sense of well-being
- Reduce specific symptoms
- It is important to remind patients that treatment will not cure their IBS.
- Comprehensive treatment consists of the following:
- Education about IBS
- Dietary changes
- Fiber
- Probiotics/antibiotics
- Pharmacology
- Herbal and natural products
- Complementary techniques
- Psychological techniques
- Continued provider relationship
Medications
- Antibiotics can be used intermittently for gassiness and bloating symptoms:
- Neomycin, rifaximin (nonabsorbed)
- Metronidazole, norfloxacin (systemic)
- Bile acid malabsorption has been postulated as a trigger in IBS-D (even in absence of liver or ileal disease). Potential medications include cholestyramine (Questran), colesevelam
- Symptomatic relief for diarrhea:
- Consider loperamide (mu opioid receptor agonist).
- Side effects include constipation.
- Symptomatic relief for constipation:
- Consider magnesium, polyethylene glycol, senna, or bisacodyl; however, these therapies are not well-studied for this indication.
- Lubiprostone
- Can be used at 8 mcg b.i.d. for general IBS discomfort or 24 mcg b.i.d. for constipation
- Nausea is a frequent side effect.
- Linaclotide
- Guanylate cyclase receptor agonist
- Recently approved for patients older than 18 years of age with IBS-C
- Minimal side effects as not absorbed systemically
- Antispasmodics (dicyclomine, hyoscyamine)
- Can be used on a regular basis or as needed
- It can be very reassuring to the patient to have a medication available when needed.
- Belladonna/phenobarbital is also described as useful, but is not available in United States.
- Low-dose antidepressants (amitriptyline, citalopram)
- Can be very useful for the treatment of abdominal pain.
- It is important to explain the rationale for using these medications to avoid the misperception by the patient that the diagnosis is a psychiatric disease.
- Placebo rates in IBS are often more than 40% in studies. Effectiveness of known placebos for patients with migraine may also be helpful in patients with IBS.
Additional Treatment
General Measures
- For patients with mild symptoms of IBS, reassurance, education, and lifestyle changes such as avoiding identified triggers may be adequate for management.
- In patients with more severe or complex symptoms, a multidisciplinary approach including pharmacotherapy and psychosocial intervention may be needed.
Complementary & Alternative Therapies
- Probiotics
- Current literature suggests mixed results from clinical trials
- Different individual and combinations of probiotics strains of Bifidobacterium, Lactobacillus, and Saccharomyces have been used.
- 3 " 4 weeks of treatment are considered adequate trial.
- Herbal products
- Chamomile, in the form of warm tea, can be helpful for spasms.
- Peppermint, either tea or capsules of peppermint oil, will relax the smooth muscle via the calcium channel. Can cause heartburn
- Less commonly cited remedies have been reported such as artichoke leaf extract, turmeric, and natural clay powder.
Issues for Referral
- Psychological therapies such a cognitive behavioral therapy (CBT) and psychodynamic therapy are helpful.
- Acquiring CBT skills can help lower stress, address comorbid anxiety or depression, and often have lasting effect.
- Hypnotherapy requires trained provider, but has proven benefits lasting 6 " 12 months.
Diet
- Have patients systematically look at typical dietary triggers:
- Spicy foods
- Fatty or fried foods
- high-sugar foods
- Beans/legumes
- Sugar-free gum, candy, or drinks
- Lactose
- Try gluten withdrawal (after testing to rule out celiac), as some patients can have non-celiac gluten sensitivity.
- In conjunction with a nutritionist, consider trying elimination of FODMAP foods (fermentable oligosaccharides, disaccharides, monosaccharides and polyols)
- Fiber
- Gradually increase to goal of 10 g (adults) or age +5 g (child)
- Fiber can help with global symptoms and constipation, less helpful for pain.
- Soluble fibers (psyllium, ispaghula, calcium polycarbophil) improve symptoms, whereas insoluble (bran, corn) worsen symptoms.
- Adequate trial of any particular fiber is at least 3 " 4 weeks, may need to try multiple types.
Ongoing Care
Follow-up Recommendations
Patient Monitoring
- The provider " patient relationship is an important component of therapy, and ongoing visits can help monitor symptoms.
- Planned medical follow-up also provides a sense of well-being, helps patients to anticipate flares, and prevent repeated evaluations.
Patient Education
- Establish a positive diagnosis:
- It is important that patients perceive that their MD "knows they have IBS " rather than the MD has "ruled everything else out so the diagnosis must be IBS. "
- Reassurance about overall health
- Explain there are many interventions (diet, medication, techniques) that will improve, although not cure, symptoms.
- Reassure patients that you will not abandon them but continue to help.
Complications
- Patients with moderate to severe IBS can have significantly lower quality of life, absenteeism from school/work.
- IBS can also lead to frequent physician visits, unnecessary medical testing, and high health care costs.
Additional Reading
- Bijkerk CJ, de Wit NJ, Muris JW, et al. Soluble or insoluble fibre in irritable bowel syndrome in primary care? Randomised placebo controlled trial. BMJ. 2009;339:b3154. [View Abstract]
- Bijkerk CJ, Muris JW, Knottnerus JA, et al. Systematic review: the role of different types of fibre in the treatment of irritable bowel syndrome. Aliment Pharmacol Ther. 2004;19(3):245 " 251. [View Abstract]
- Chogle A, Mintiens S, Saps M. Pediatric IBS: an overview on pathophysiology, diagnosis and treatment. Pediatr Ann. 2014;43(4):e76 " e82. [View Abstract]
- Cristofoi F, Fontana C, Magista A, et al. Increased prevalence of celiac disease among pediatric patients with irritable bowel syndrome: a 6-year prospective cohort study. JAMA Pediatr. 2014;168(8):555 " 560. [View Abstract]
- Dom SD, Morris CB, Hu U, et al. Irritable bowel syndrome subtypes defined by Rome II and Rome III criteria are similar. J Clin Gastroenterol. 2009;43(3):214 " 220. [View Abstract]
- Halmos EP, Power VA, Shepherd SJ, et al. A diet low in FODMAPs reduces symptoms of irritable bowel syndrome. Gastroenterology. 2014;146(1):67 " 75. [View Abstract]
- Spiegel BM, Farid M, Esrailian E, et al. Is irritable bowel syndrome a diagnosis of exclusion? A survey of primary care providers, gastroenterologists, and IBS experts. Am J Gastroenterol. 2010;105(4):848 " 858. [View Abstract]
Codes
ICD09
- 564.1 Irritable bowel syndrome
ICD10
- K58.9 Irritable bowel syndrome without diarrhea
- K58.0 Irritable bowel syndrome with diarrhea
SNOMED
- 10743008 Irritable bowel syndrome (disorder)
- 197125005 Irritable bowel syndrome with diarrhea (disorder)
- 235839006 Irritable bowel syndrome variant of childhood with diarrhea (disorder)
FAQ
- What is the FODMAP diet?
- The FODMAP diet involves the exclusion of foods that are "fermentable, " as well as those with "oligosaccharides, disaccharides, monosaccharides, and polyols. " Following the FODMAP diet been shown to provide relief for patients with IBS.