Irritable Bowel Syndrome SIGS

Pathophys + Dx

100

This diagnostic criterion requires recurrent abdominal pain related to defecation and stool changes for at least three months.

Bonus (100): This osmotic laxative increases stool water retention to ease constipation.

What is the Rome IV criteria?

Bonus: What is PEG 3350?

200

IBS is classified based on stool consistency. What are at least two of the four subtypes, and how is each generally defined?

• IBS with Constipation (IBS-C):

  • More than 25% of stools are hard or lumpy and less than 25% are loose/mushy or watery.
  • Accounts for ~28% of cases.

• IBS with Diarrhea (IBS-D):

  • More than 25% of stools are loose/mushy or watery and less than 25% are hard or lumpy.
  • Accounts for ~26% of cases.

• IBS with Mixed Bowel Habits (IBS-M):

  • More than 25% of stools are hard/lumpy and more than 25% are loose/mushy or watery.
  • Accounts for ~44% of cases.

• IBS-Unspecified (IBS-U):

  • Stool consistency is insufficiently abnormal to fit the other subtypes.
  • Some patients may switch subtypes over time.

300

Dr. Stevens discusses the "gut-brain connection" with Ms. Lettie and suggests stress-reducing techniques in addition to OMT. What is the role of the vagus nerve in this connection?

Vagus nerve (CN X) regulates parasympathetic input to the gut.

• In IBS, stress can suppress vagal activity, leading to delayed gastric emptying and altered motility.
• Increased vagal tone can improve digestion and reduce hypersensitivity.

OMT to Support the Gut-Brain Connection:

• Suboccipital release may help enhance vagal tone, improving autonomic balance.
• Diaphragm release promotes vagal activation and supports gut motility.

400

A patient with IBS reports worsening symptoms at night, unintended weight loss, and frequent bloody stools. How does this presentation challenge the IBS diagnosis, and what other conditions should be considered?

Bonus (200): What are the two major inflammatory markers that are normal in IBS but elevated in IBD?

What are red flag symptoms that are not characteristic of IBS and suggest an organic rather than functional disorder?

Consider:

• Inflammatory Bowel Disease (IBD) (Crohn’s disease, ulcerative colitis)
• Colorectal cancer
• Celiac disease
• Infectious colitis

Bonus: What are C-reactive protein (CRP) and fecal calprotectin?

500

Ms. Lettie’s IBS symptoms worsen during stressful periods but improve with fiber and probiotics. Based on her case, what is one mechanism that can explain her symptom pattern?

Stress worsens gut function through the gut-brain axis, while fiber and probiotics improve stool consistency and gut microbiome balance.

Gut-Brain Axis Dysfunction

• Increased stress activates the hypothalamic-pituitary-adrenal (HPA) axis, leading to autonomic dysregulation and altered gut motility.
• This can cause worsening constipation and cramping during high-stress periods.

Gut Microbiome Dysbiosis

• Probiotics improve symptoms by restoring healthy gut bacteria balance, reducing fermentation and bloating.
• Fiber supports regular stool formation and gut microbiota health, which helps manage constipation.

Osteo Models & OMT

100

Which osteopathic model focuses on the relationship between structure and function, explaining how lumbar hypertonicity can affect gut motility in IBS?

What is the Biomechanical Model?

200

This osteopathic model focuses on lymphatic drainage and fluid movement.

Bonus (100): This chloride channel activator is FDA-approved for IBS-C and enhances intestinal fluid secretion.

What is the Respiratory-Circulatory Model?

Bonus: What is lubiprostone?

300

Ms. Lettie’s osteopathic structural exam reveals mesenteric drag to the left lower quadrant. What does this finding indicate, and how might it contribute to her IBS symptoms?

Bonus (100): This antispasmodic drug blocks muscarinic receptors in the gut, reducing cramping in IBS.

Mesenteric drag suggests fascial restriction in the intestines, which can impair normal gut motility and circulation.

It may contribute to:

• Reduced lymphatic drainage, leading to bloating and discomfort.
• Restricted peristalsis, worsening constipation.
• Increased visceral hypersensitivity, exacerbating cramping.

Bonus: What is dicyclomine?

400

This Chapman’s point is located along the anterior iliotibial band.

Bonus (100): This stimulant laxative caused cramping and diarrhea when used by the patient.

What is the large intestine (colon) Chapman’s point?

Bonus: What is bisacodyl?

500

Ms. Lettie’s osteopathic structural exam shows increased lumbar lordosis, paraspinal hypertonicity, and mesenteric drag to the left lower quadrant. How do these findings relate to her IBS symptoms?

• Increased lumbar lordosis & paraspinal hypertonicity:

  • Suggests somatic dysfunction at T10-L2, affecting sympathetic tone to the gut.
  • Increased sympathetic tone slows motility, contributing to constipation.

• Mesenteric drag to the left lower quadrant:

  • Indicates fascial restriction and reduced lymphatic drainage, which can lead to bloating and discomfort.

• Clinical Takeaway: OMT can improve gut motility by reducing lumbar tension, restoring autonomic balance, and releasing fascial restrictions.

Psychosocial + Lifestyle Mod

100

This mental health condition is strongly associated with worsening IBS symptoms and can influence gut-brain axis dysfunction.

What is depression?

Depression is linked to increased gut hypersensitivity, altered motility, and microbiome changes through its effects on the gut-brain axis. Many IBS patients experience depression, anxiety, or both, which can exacerbate symptoms.

200

Ms. Lettie has had IBS since college, but her symptoms worsened after starting a new job that requires frequent travel. Based on her history, what likely contributed to this worsening?

Bonus Question (200): Name at least two lifestyle changes recommended for IBS patients to improve symptoms.

• Disrupted routine: Less access to fresh fruits, vegetables, and fiber, impacting gut motility.
• Dehydration: Reduced water intake while traveling can worsen constipation.
• Increased stress: Work-related travel increases HPA axis activation, leading to autonomic imbalances that affect gut function.

Bonus: What are increased water intake and regular exercise?

300

This osteopathic model focuses on stress reduction, counseling, and emotional well-being.

Bonus (100): This guanylate cyclase-C agonist increases fluid secretion and reduces pain sensitivity in IBS.

What is the Behavioral Model?

Bonus: What is linaclotide?

400

Explain how the gut-brain axis contributes to IBS symptom exacerbation in patients with high anxiety or trauma history.

• The gut-brain axis is a bi-directional communication system between the CNS and the enteric nervous system.
• Anxiety and trauma increase sympathetic activation, leading to:
  • Increased gut permeability ("leaky gut")
  • Dysregulated serotonin signaling (affecting motility and pain sensitivity)
  • Altered gut microbiota composition, worsening inflammation and bloating
• Stress exacerbates visceral hypersensitivity, making normal gut distension feel painful.

500

Why do IBS patients with a history of early-life trauma tend to have more severe and treatment-resistant symptoms?

• Early-life trauma (e.g., abuse, neglect) can lead to:
  • Chronic dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, increasing cortisol levels and altering gut function.
  • Increased activation of the amygdala, which processes fear and pain, leading to heightened visceral hypersensitivity.
  • Dysbiosis from chronic stress, which worsens gut inflammation and fermentation processes.
• These neurological and immunological changes persist into adulthood, making symptoms more resistant to conventional IBS treatments.

Diet

100

This type of fiber is preferred for IBS patients with constipation.

Bonus (200):

Probiotics containing this bacterial genus have been shown to help IBS symptoms.

What is soluble fiber?

Bonus: What is Lactobacillus?

200

This diet plan reduces fermentation by gut bacteria and helps IBS patients avoid bloating.

Bonus Question (300 points):

List at least three foods that are taken out in this diet.

What is the low-FODMAP diet?

High-FODMAP foods contain short-chain carbohydrates that are poorly absorbed in the small intestine. When these carbohydrates reach the colon, they:

1. Draw water into the intestines through osmotic effects, leading to bloating and diarrhea.
2. Undergo rapid fermentation by gut bacteria, producing gas (hydrogen, methane, and carbon dioxide), which causes abdominal distension and discomfort.
3. Trigger visceral hypersensitivity, worsening pain perception in IBS patients.

High-FODMAP Foods:

• Oligosaccharides (Fructans & Galacto-oligosaccharides):

  • Wheat, rye, barley (in large amounts)
  • Garlic, onions, leeks, asparagus, artichokes

• Disaccharides (Lactose):

  • Milk, soft cheese, yogurt, ice cream

• Monosaccharides (Excess Fructose):

  • Apples, pears, watermelon, honey, high-fructose corn syrup

• Polyols (Sugar Alcohols):

  • Sugar-free gum and candy (sorbitol, mannitol, xylitol)
  • Stone fruits (cherries, peaches, plums)

1) Elimination Phase (4-6 weeks) – Remove all high-FODMAP foods (e.g., garlic, onions, wheat, dairy, legumes, certain fruits) to reduce symptoms.

2) Reintroduction Phase (6-8 weeks) – Systematically reintroduce individual FODMAP groups one at a time to identify personal triggers.

3) Personalization Phase (Long-Term) – Develop a sustainable diet by avoiding specific trigger foods while maintaining gut microbiome diversity.

300

How can a low-FODMAP diet influence gut microbiota, and what are the long-term concerns with strict adherence?

• Short-term benefits:

  • Reduces fermentation of poorly absorbed carbohydrates
  • Decreases gas production and bloating
  • Relieves diarrhea and abdominal discomfort

• Long-term concerns:

  • Can lead to dysbiosis by reducing beneficial bacteria (e.g., Bifidobacteria)
  • May limit prebiotic intake, which supports gut microbiome diversity
  • Should be followed by a gradual reintroduction phase to avoid malnutrition and microbiome imbalance

400

Why is soluble fiber preferred over insoluble fiber for IBS patients, and what are some good sources?

Bonus (200): Why do some IBS patients who switch to a high-fiber diet initially report worsening symptoms, and how should fiber intake be adjusted?

Soluble fiber dissolves in water to form a gel-like substance, which slows digestion and softens stool, making it beneficial for IBS patients with both constipation and diarrhea. 

In contrast, insoluble fiber can be harsh on the gut, increasing bloating and irritation.

Good sources of soluble fiber:

• Oats
• Psyllium husk
• Bananas
• Carrots
• Sweet potatoes
• Lentils

• Sudden increase in fiber can lead to:

  • Increased fermentation by gut bacteria, causing excess gas production and bloating.
  • More water retention in stool, potentially worsening diarrhea.
  • Poor gut adaptation, leading to cramping and discomfort.

• How to adjust:

  • Start with soluble fiber (psyllium, oats) instead of insoluble fiber (wheat bran).
  • Increase fiber intake gradually over weeks to allow microbiota adjustment.
  • Ensure adequate water intake to support fiber’s effects.

500

Name three active herbs in the poly-botanical supplement STW 5 that provide symptom relief in IBS and generally explain why.

Bonus (100): What's the age and gender prevalence in individuals with IBS?

• Peppermint – Acts as a smooth muscle relaxant, reducing intestinal spasms and cramping.
• Chamomile – Has anti-inflammatory and carminative properties, helping soothe gut irritation and reduce gas.
• Licorice – Supports mucosal protection and has anti-inflammatory effects, which may help with IBS-related discomfort.

Bonus: 

AMBOSS and Clinical Key says 20-39, and that women are 1.5-2 times more likely.

Pharm

100

This chloride channel activator is FDA-approved for IBS-C and enhances intestinal fluid secretion.

What is lubiprostone?

200

Which medication on the patient’s drug list is used to treat hypothyroidism and could contribute to constipation if not properly dosed?

What is levothyroxine?

300

Why did Ms. Lettie experience diarrhea and cramping after taking bisacodyl, while PEG 3350 provided symptom relief?

• Bisacodyl (stimulant laxative): Directly stimulates the enteric nerves, leading to forceful contractions and possibly diarrhea with cramping.
• PEG 3350 (osmotic laxative): Draws water into the colon, softening stools and promoting a gentler increase in motility without overstimulating the gut.
• Clinical Implication: Stimulant laxatives can be too harsh for IBS patients, while osmotic laxatives like PEG 3350 provide more controlled symptom relief.

400

A patient taking PEG 3350 for IBS-C reports that it is effective but causes occasional bloating. How could this be managed, and what alternative treatment could be considered?

• Management Strategies:

  • Reduce dosage frequency to minimize bloating.
  • Encourage increased water intake to enhance its effect.
  • Combine with light exercise to improve gut motility.

• Alternative treatment:

  • Consider lubiprostone if bloating persists, as it increases chloride secretion without fermentation effects.

500

Why might an IBS patient taking dicyclomine for abdominal cramping experience worsening constipation, and what alternative treatments could be used?

Dicyclomine is an anticholinergic, which reduces gut motility, potentially worsening constipation in IBS-C.

• Alternative Treatments:
  • Lubiprostone or linaclotide to increase intestinal fluid secretion and promote stool movement.
  • Lifestyle modifications like fiber, hydration, and squatting.
  • Peppermint oil (natural smooth muscle relaxant) as a non-pharmacologic option.