Crohn's Disease

Pathogenesis

  • What is it?
  • Crohn's Disease is a chronic inflammatory intestinal disease
  • People with CD will experience many flares and remissions throughout their lives once diagnosed
  • The role of immunity
  • Innate immunity is involved due to defects in the mucous membrane barrier
  • Adaptive immunity is involved due to its reliance on helper T cell lymphocytic response and T cells that are regulated by cytokines
  • The role of inflammation
  • Increased migration of T cells to the site of inflammation alters the extracellular matrix through metalloproteins and adhesion molecules
  • How does CD happen?

Resources

  • CD is sustained by the inflammatory cells interacting with integrins, adhesion molecules, and chemokines, all causing increased production of inflammatory cytokines and therefore, increased mucosal inflammation
  • It can affect any part of the GI tract, but most commonly is seen in the small intestine
  • CD commonly affects the entire thickness of the mucosal wall in the bowel
  • The immune and inflammatory responses trigger neutrophils to infiltrate the crypts in the small intestine
  • Due to all of the neutrophils, abscesses form in the crypts, causing destruction of the crypts
  • Granulomas then often form
  • The mucosa becomes edematous
  • Ulcers form and get deeper, potentially leading to fistulization
  • The ulcers become chronic and CD continues to progress

Incidence/Prevalence

Risk Factors

Diagnostics

Treatments

Clinical Manifestations

  • The average age of onset is 30 years
  • CD typically peaks twice in individuals who have it: once between ages 20-30 and again around age 50
  • CD is most common in North America and Western Europe
  • CD is more common in females than males
  • CD is also more common in Ashkenazi Jewish people as opposed to non-Jewish people
  • 50% of people with CD have involvement in the ileum and the colon
  • CD affects 3-20 in every 100,000 people
  • More than 500,000 Americans are living with CD right now
  • Individuals who smoke are twice as likely to develop CD than those who do not smoke
  • Environmental risk factors
  • Disturbances in the microbiome of the gut
  • GI infections
  • NSAIDs
  • Antibiotics
  • Hormone replacement therapy
  • Cigarette smoking, current and former
  • Diets high in fat, sugar, oil, and meat
  • Genetic risk factors
  • More commonly seen in Jewish and North Americans and less common in African Americans and Hispanics
  • There is correlation between CD and mutations in the genes on chromosomes 5 and 10
  • The risk of CD is increased with mutations to the ATG16L1, IL23R, IRGM, and NOD2 genes
  • If a family member has any IBD, any other family member has a 15-30% chance of developing CD
  • Sleep deprivation
  • Vitamin D deficiency
  • Abnormal Mycobacteria
  • Contraceptives
  • Past medical history
  • The first step in diagnosing CD is taking a look at the medical history of the patient to see if there are any hallmark signs that it could most likely be CD or even be something else
  • Blood tests
  • Assessing for signs of infection or antibodies through the blood samples
  • If there are increased levels of white blood cells or platelets, it could be indicative of inflammation caused by CD
  • Antibody tests to distinguish between the likelihood of either CD or UC
  • Stool tests
  • Assessing for blood in the stool
  • Having blood in the stool is indicative of a digestive issue
  • Assessing for bacteria or disease-causing organisms in the stool
  • If there are abnormal bacteria or organisms found within the stool, this can rule out CD or lead to further testing for it
  • Imaging tests
  • X-rays, CT scans, and MRI scans
  • Each can help to better visualize the GI tract
  • Can diagnose complications of CD, such as fistulas or abscesses
  • Barium swallow for an upper GI series picture
  • Endoscopy
  • Used to examine the inside walls of the colon
  • Usually looking between the small intestine and colon for the purpose of CD diagnosis
  • If granulomas are present, this is often a sign of CD
  • Persistant diarrhea
  • Rectal bleeding
  • Urgent need to have a bowel movement
  • Abdominal pain and cramping
  • Sensation of incomplete bowel evacuation
  • Constipation
  • Loss of appetite
  • Weight loss
  • Low energy and fatigue
  • Fissures of the anus
  • Fistulas of the anal area
  • Visual changes
  • Painful and swollen joints
  • Fatigue
  • Fever
  • Medications
  • Aminosalicylates to decrease inflammation of the lining of the GI tract
  • Sulfasalazine
  • Mesalamine
  • Olsalazine
  • Balsalazide
  • Corticosteroids to suppress the immune system
  • Prednisone
  • Methylprednisolone
  • Antibiotics to treat any bacterial infection in the GI tract
  • Metronidazole
  • Ampicillin
  • Ciprofloxacin
  • Surgery
  • Strictureplasty
  • Chronic inflammation of the GI tract can cause narrowing or strictures in the intestines due to scar tissue buildup
  • The strictureplasty widens the strictures in the jejunum and ileum without resecting any of the intestine
  • Helps to prevent obstructions and blockages
  • Protocolectomy and Colectomy
  • Colectomy is the removal of the colon
  • Protocolectomy is removal of the colon and the rectum
  • This will alleviate many symptoms of CD
  • Colectomy allows the patient to continue to pass stool through the rectum
  • Protocolectomy results in an external pouch for the passing of stool
  • Diet and Nutrition
  • Avoid foods that can trigger a flare-up
  • Lactose
  • Intense spices
  • Sugar
  • Fat
  • Suggested methods for eating
  • Eat 4-6 small meals per day
  • Stay hydrated by drinking enough water that the urine is pale yellow
  • Try not to fry food; boil, steam, or grill instead
  • Have patient get to know what foods are right for them, and focus on meals with those items