Immunology and Gut Health
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What is the result of targeted disruption of the genes for the T-cell receptor and the cytokine IL-2 in mice?

  • No significant effects on the immune system
  • GI tract disease resembling ulcerative colitis (correct)
  • GI tract disease resembling Crohn's disease
  • Immune system suppression

    • What is the primary mechanism by which the hygiene hypothesis contributes to the development of IBD?

  • Increased exposure to pathogenic microbes leads to chronic inflammation
  • Changes in food storage conditions lead to mucosal damage
  • Altered gut microbiome composition leads to defective immune regulation (correct)
  • Decreased exposure to beneficial microbes leads to overactive immune responses

    • During which period does the patterning activity of certain aspects of the immune system strongly influence immune responses in the adult?

  • Adult period
  • Elderly period
  • Adolescent period
  • Neonatal period (correct)

    • What is the role of interleukin-10 in mice models of IBD?

    <p>It inhibits the development of TH1 cytokine profiles</p> Signup and view all the answers

    What is thought to be an important component of the pathogenesis of IBD?

    <p>Early exposure to intestinal microbiota</p> Signup and view all the answers

    What is the effect of monoclonal antibodies to tumor necrosis factor alpha (TNFa) on inflammation in mice models of IBD?

    <p>They reduce inflammation</p> Signup and view all the answers

    What is a common presentation of Crohn's disease in approximately 20% of patients?

    <p>Acute onset with RLQ pain, fever, and bloody diarrhea</p> Signup and view all the answers

    What is the role of the gut microbiota in the pathogenesis of IBD?

    <p>It is a contributing factor to the development of IBD</p> Signup and view all the answers

    What is a potential trigger for disease reactivation in Crohn's disease?

    <p>Specific dietary items</p> Signup and view all the answers

    What is a potential complication of colonic disease in Crohn's disease?

    <p>Iron deficiency anemia</p> Signup and view all the answers

    What is the relationship between the development of regulatory processes in the neonatal immune system and the risk of IBD?

    <p>The inadequate development of regulatory processes in the neonatal immune system increases the risk of IBD</p> Signup and view all the answers

    What is the effect of smoking on the risk of developing IBD?

    <p>It increases the risk of developing IBD</p> Signup and view all the answers

    What is the primary mechanism by which mothers influence the development of the immune system in their offspring?

    <p>Through the transmission of intestinal microbiota</p> Signup and view all the answers

    What is the typical pattern of disease activity in Crohn's disease?

    <p>Intermittent attacks with asymptomatic periods</p> Signup and view all the answers

    What is the role of genetic risk in the development of IBD?

    <p>It is a contributing factor to the development of IBD</p> Signup and view all the answers

    What is the category of susceptibility genes that is associated with IBD?

    <p>All of the above</p> Signup and view all the answers

    What is the relationship between smoking and Crohn's disease?

    <p>Smoking is a risk factor for disease development but smoking cessation does not result in disease remission</p> Signup and view all the answers

    What is the effect of infections on the development of IBD?

    <p>They increase the risk of developing IBD</p> Signup and view all the answers

    What is the impact of the neonatal period on the development of the immune system?

    <p>It has a significant impact on the development of the immune system</p> Signup and view all the answers

    What is the relationship between the development of IBD and autoimmune diseases?

    <p>Many of the genes linked to IBD are also associated with other autoimmune diseases</p> Signup and view all the answers

    What is a common complication of extensive small bowel disease?

    <p>All of the above</p> Signup and view all the answers

    Where does the disease typically occur?

    <p>Distal ileum</p> Signup and view all the answers

    What is the characteristic appearance of the involved mucosa?

    <p>Cobblestone</p> Signup and view all the answers

    What is a common extraintestinal manifestation of Crohn's disease?

    <p>All of the above</p> Signup and view all the answers

    What is a common complication of fibrosing strictures?

    <p>Small intestinal obstruction</p> Signup and view all the answers

    What is a common therapy for Crohn's disease?

    <p>All of the above</p> Signup and view all the answers

    What is a common symptom of Crohn's disease?

    <p>All of the above</p> Signup and view all the answers

    What is a common location for fistula formation?

    <p>All of the above</p> Signup and view all the answers

    What is a rare complication of Crohn's disease?

    <p>Amyloidosis</p> Signup and view all the answers

    What is a characteristic feature of Crohn's disease?

    <p>Discontinuous distribution of disease</p> Signup and view all the answers

    What is the current treatment for Celiac Disease?

    <p>Adherence to a strict gluten-free diet (GFD)</p> Signup and view all the answers

    What is a complication of untreated or undiagnosed Celiac Disease?

    <p>Increased risk of bone fractures</p> Signup and view all the answers

    What is the minimum amount of gluten that can induce inflammatory changes in the small intestine?

    <p>50mg</p> Signup and view all the answers

    What is a characteristic of Crohn's disease?

    <p>Typically transmural and granulomatous in character</p> Signup and view all the answers

    What is a complication of refractory Celiac Disease?

    <p>Pharyngeal or esophageal cancer</p> Signup and view all the answers

    What is the name of the two disorders that comprise Inflammatory Bowel Disease (IBD)?

    <p>Ulcerative Colitis and Crohn's Disease</p> Signup and view all the answers

    What is the difference between Ulcerative Colitis and Crohn's Disease?

    <p>Both the distribution of affected sites and the morphologic expression of disease</p> Signup and view all the answers

    What is a urogenital complication of untreated or undiagnosed Celiac Disease?

    <p>Recurrent miscarriage</p> Signup and view all the answers

    What is a musculoskeletal complication of untreated or undiagnosed Celiac Disease?

    <p>Osteoporosis and increased risk of bone fractures</p> Signup and view all the answers

    What is a hematopoietic complication of untreated or undiagnosed Celiac Disease?

    <p>Non-Hodgkin lymphoma</p> Signup and view all the answers

    What is the primary tumor location in Zollinger-Ellison Syndrome?

    <p>All of the above</p> Signup and view all the answers

    What is the effect of hypergastrinemia in Zollinger-Ellison Syndrome?

    <p>Increased mucosal ulceration</p> Signup and view all the answers

    What is the best single screening test for Zollinger-Ellison Syndrome?

    <p>Fasting serum gastrin</p> Signup and view all the answers

    What is a common complication of Zollinger-Ellison Syndrome?

    <p>All of the above</p> Signup and view all the answers

    What is the goal of medical treatment in Zollinger-Ellison Syndrome?

    <p>Medical control of gastric acid hypersecretion</p> Signup and view all the answers

    What is the most common cause of massive lower GI bleeding in the elderly?

    <p>Diverticula</p> Signup and view all the answers

    What is the primary mechanism of achalasia?

    <p>Failure of the lower esophageal sphincter to relax</p> Signup and view all the answers

    What is a characteristic of Esophageal Achalasia?

    <p>Tremendous enlargement of the esophagus</p> Signup and view all the answers

    What is the main treatment approach for Esophageal Achalasia?

    <p>Pneumatic dilation or surgical myotomy</p> Signup and view all the answers

    What is the primary risk factor for Gastroesophageal Reflux Disease (GERD)?

    <p>Incompetence of the lower esophageal sphincter</p> Signup and view all the answers

    What is the percentage of gastric ulcers associated with H. pylori infection?

    <p>75%</p> Signup and view all the answers

    What is the effect of bile on the mucosal barrier in the stomach?

    <p>It diminishes the barrier function</p> Signup and view all the answers

    What is the consequence of delayed emptying of gastric contents into the duodenum?

    <p>Increased gastric secretion and acid production</p> Signup and view all the answers

    What is the effect of prostaglandins (PG) on mucosal blood flow and bicarbonate secretion?

    <p>They increase mucosal blood flow and bicarbonate secretion</p> Signup and view all the answers

    What is a common cause of gastritis?

    <p>All of the above</p> Signup and view all the answers

    Study Notes

    Inflammatory Bowel Disease (IBD)

    • Targeted disruption of genes for T-cell receptor and cytokine IL-2 in mice results in GI tract disease resembling ulcerative colitis.
    • Patterning activity of the immune system during the neonatal period strongly influences immune responses in adults.
    • Early exposure to intestinal microbiota may be an important component of the pathogenesis of IBD.
    • Maternal effects are thought to be a contributing factor to GI disease, as composition of the intestinal microbiota is in large part transmitted by the mother.

    Crohn's Disease

    • Clinical manifestation:
      • Disease begins with intermittent attacks of mild diarrhea, fever, and abdominal pain.
      • Approximately 20% of patients present acutely with RLQ pain, fever, and bloody diarrhea.
      • Periods of active disease are typically interrupted by asymptomatic periods that last for weeks to many months.
      • Disease reactivation can be associated with external triggers, including physical or emotional stress, specific dietary items, and cigarette smoking.
      • Individuals with colonic disease may develop iron deficiency anemia due to blood loss.

    Epidemiology

    • Exact causes of IBD are unknown despite progress in understanding its pathogenesis.
    • The hygiene hypothesis suggests that increasing incidence of IBD is related to improved food storage conditions, decreased food contamination, and changes in gut microbiome composition.
    • Some mucosa-associated microbes trigger persistent and chronic inflammation in response to susceptible hosts.
    • Other potential explanations for increased IBD prevalence include the idea that preservatives and other materials added to processed foods induce low-grade mucosal damage that predisposes to IBD.

    Pathogenesis

    • Results from a combination of genetic risk and environmental factors.
    • Genetic risk includes abnormalities in susceptibility genes related to immune regulation, host-microbiome interactions, and epithelial barrier functions.
    • Environmental factors include pathogenic microorganisms, the repertoire of indigenous intestinal microbes, dietary factors, smoking, and defective immune responses.
    • Psychosocial factors may also contribute to the pathogenesis of IBD.

    Complications

    • Undiagnosed or untreated CD may lead to complications, including:
      • Gastrointestinal complications, such as pharyngeal or esophageal cancer, lymphoma, or cancer of the small intestine.
      • Hematopoietic complications, such as non-Hodgkin lymphoma.
      • Urogenital complications, such as infertility, recurrent miscarriage, premature birth, and premature menopause.
      • Musculoskeletal complications, such as osteoporosis and increased risk of bone fractures.

    Treatment of Celiac Disease

    • The only current available treatment is adherence to a strict gluten-free diet (GFD).
    • Even very small amounts of gluten (50mg or a breadcrumb) can induce inflammatory changes in the small intestine and trigger symptoms in patients with CD.

    Hemostasis and Diverticular Bleeding

    • Hemostasis can be attempted by endoscopic methods (cautery, injection, or clips) or by interventional radiology.
    • Diverticula are a source of bleeding in 3-5% of patients with diverticulosis.
    • Diverticular bleeding is typically painless and not believed to be associated with a focus of inflammation.
    • The differential diagnosis of painless bleeding per rectum also includes internal hemorrhoids and angiodysplasia.

    Esophageal Achalasia

    • Esophageal achalasia is a motor disorder in which the lower esophageal sphincter (LES) fails to relax properly in response to swallowing.
    • Characteristics of achalasia include:
      • LES more tightly contracted and loss of normal peristalsis in the esophageal body.
      • Failure of a hypertensive LES to relax and the absence of esophageal peristalsis.
    • Clinical manifestations of achalasia include:
      • Dysphagia (inability to swallow).
      • Regurgitations.
      • Chest pain.
      • Tremendous enlargement of the esophagus.
      • Esophagus can hold as much as 1 L of putrid, infected material → risk of aspiration pneumonia.
      • Progressive severe weight loss.
      • Mucosal ulceration.
      • Infections.
      • Esophageal rupture.
      • Death.
    • Etiology of achalasia includes:
      • Degeneration of the myenteric plexus.
      • Loss of inhibitory enteric neurons that release VIP, nitric oxide.
    • Diagnosis of achalasia is based on:
      • A failure of the LES to completely relax with swallowing, confirmed via esophageal manometry, a contrast esophagram, or esophagoscopy.
    • Differentiation of achalasia includes:
      • Chagas' disease.
      • Malignancies.
    • Treatment of achalasia includes:
      • Reducing the pressure at the lower esophageal sphincter.
      • Medications: long-acting nitrates or calcium channel blockers.
      • Injection with botulinum toxin (Botox).
      • Widening (dilation) of the esophagus at the location of the narrowing.
      • Surgery (esophagomyotomy).

    Reflux Esophagitis: Gastroesophageal Reflux Disease (GERD)

    • Chronic symptoms or mucosal damage produced by the abnormal reflux in the esophagus.
    • Backflow of gastric or duodenal contents or both into the esophagus.
    • Due to:
      • Incompetence of the LES.
      • Transient LES relaxation.
      • Impaired expulsion of gastric reflux from the esophagus.
      • A hiatus hernia.
    • LES provides an effective barrier to reflux of acid from the stomach back into the esophagus.
    • Effectiveness of the barrier can be altered by:
      • Increased frequency of transient LES relaxations.
      • Loss of secondary peristalsis after transient LES relaxations.
      • Loss of LES tone.
      • Hiatal hernia.
      • Increased stomach volume or pressure.
      • Increased production of acid.
      • Alkaline injury: pancreatic juice reflux.
    • Factors influencing the rate of spontaneous transient LES relaxation:
      • Hormones.
      • Neural agents.
      • Foods.
      • Other factors.
    • Clinical presentation of GERD:
      • Burning chest pain (heartburn).
      • Dysphagia.
      • Hemorrhage.
      • Perforation.
      • Hoarseness.
      • Coughing.
      • Wheezing.
      • Aspiration pneumonia.
      • Barrett's esophagus.
    • Diagnosis of GERD:
      • Barium swallow radiograph.
      • Upper endoscopy.
      • pH monitoring examination.
    • Treatment of GERD:
      • Drugs: antacids, H2 blockers, proton pump inhibitors, prokinetics.
      • Surgery: fundoplication (Nissen).

    Acid-Peptic Disease: (APD)

    • Disorder of the GIT which results from superficial or deep lesion of the GI mucosa as a consequence of imbalance between protective and aggressive factors.
    • Different forms of APD:
      • Duodenal ulcer.
      • Gastric ulcer.
      • Gastritis.
    • Etiology of APD:
      • Bacterium Helicobacter pylori.
    • Zollinger-Ellison Syndrome:
      • Caused by gastrin-secreting tumor (gastrinoma).
      • Stimulates the acid-secreting cells of the stomach to maximal activity.
      • Hyperproliferation of gastric glands and parietal cells.
      • Excess secretion of gastric acid.
      • Consequently: gastrointestinal mucosal ulceration.
      • May occur:
        • Sporadically.
        • As part of an autosomal dominant familial syndrome Multiple Endocrine Neoplasia type I (MEN I).
      • Symptoms of Zollinger-Ellison Syndrome:
        • Secondary to hypergastrinemia.
        • Gastrointestinal mucosal ulceration.
        • Diarrhea.
        • Malabsorption.
        • Abdominal pain.
        • Diarrhea.
        • Heartburn.
        • Other symptoms.
      • Physical examination:
        • May be normal.
        • Paleness in GI bleeding.
        • Jaundice.
        • Epigastric tenderness.
        • Dental erosions.
        • Hepatomegaly.
      • Diagnosis of Zollinger-Ellison Syndrome:
        • Fasting serum gastrin.
        • Gastric acid secretory tests.
      • Complications of Zollinger-Ellison Syndrome:
        • Abdominal perforation.
        • Esophageal stricture.
        • Obstruction.
        • GI bleeding.
        • Gastric carcinoids.
      • Prognosis of Zollinger-Ellison Syndrome: excellent in patients without metastatic disease.
      • Goals of treatment:
        • Medical control of gastric acid hypersecretion.
        • Surgical resection of the tumor.
        • Chemotherapy.
        • Liver transplantation.
        • Surgical resection or thermoablation in single confined liver metastatic lesion.

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    Description

    This quiz covers the relationship between the immune system and gut health, including the role of T-cells, cytokines, and microbiota in the development of inflammatory bowel disease (IBD).

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