Pathology of IBD Flashcards
What is the definition of Crohn’s disease?
- Chronic inflammatory and ulcerating condition
- can affect anywhere from the mouth to the anus
What is the most COMMON site for Crohn’s disease to appear?
- terminal ileum and colon
What age are most patients when they are diagnosed with Crohn’s disease?
- Usually Young patients (90% are 10-40 years old)
- Can occur in children
Is Crohn’s disease is more common in males or females?
Males
Where can Crohn’s disease present along the GI Tract?
- 2/3 of patients have small bowel involvement only
- 1/6 have colonic/ anal disease only
- 1/6 have both
- Variable involvement of stomach, oesophagus and mouth
How do patients present with Crohn’s disease? What symptoms do they have?
- Abdominal pain
- Small bowel obstruction
- Diarrhoea
- Bleeding PR
- Anaemia
- Weight loss
Describe the clinical course/ progression of Crohn’s disease.
- Chronic
- Patients have exacerbations and remissions
- Unpredictable response to therapy
- There is a subgroup of patients who go into lasting remission with 3 years of diagnosis
Describe a typical who would present with Crohn’s Disease?
~ 22 years Male Abdominal pain Bloody diarrhoea for 3 months Tender abdomen
How would you investigate a patient with suspected Crohn’s Disease?
- ENDOSCOPY
- MUCOSAL BIOPSY
Describe the pattern of Crohn’s disease seen on endoscopy (colonoscopy)
- Patchy/segmental disease
- skip areas (lesions) anywhere in GI tract
Describe how Crohn’s disease histology differs from that of the normal colonic mucosa
- Chronic active colitis
=> inflammatory cells in the lamina propria
=> crypt branching (cryptitis and abscesses) - granuloma formation!!
(non-caseating)
What are the potential complications of Crohn’s disease?
- Patient doesnt respond to medical therapy (steroids)
- Bowel obstruction
- Surgery
What may lead to patients having surgery for Crohn’s disease?
- Stricturing of terminal ileum
- Deep fissuring ulceration destroys mucosa => cant absorb/ secrete
Fissuring of the mucosa causes what appearance macroscopically?
“Cobblestoning”
Describe how a fissure looks on histology?
Like a knife cutting through the slice of mucosa
What does transmural inflammation in Crohn’s disease mean?
The inflammation is consistent through all layers of the bowel wall
What complications can result from Crohn’s disease?
- Malabsorption
- Fistulas
- Anal disease (Sinuses, Fissures, Skin tags, abscess)
- Bowel obstruction
- Perforation
- Malignancy
- Amyloidosis
Crohn’s disease is thought to be liked to which histocompatibility complex (HLA) groups?
HLA-DR1
HLA-DQw5
=> may have a genetic component
What environmental triggers can exacerbate Crohn’s disease?
- Smoking increases risk
- Infectious agents (viral, mycobacterial) cause similar pathology
- Vasculitis could explain the segmental distribution
- Sterile enviroment theory
Describe the abnormal immune response seen in Crohn’s disease?
- Persistent activation of T-cells and macrophages (failure to switch off)
=> Excess proinflammatory cytokine production
What is the definition of Ulcerative Colitis?
- Chronic inflammatory disorder
- confined to colon and rectum
- Mucosal and submucosal inflammation ONLY (not transmural)
- Unknown aetiology
Who usually gets ulcerative colitis?
- Young patients
- Peak incidence in the third decade
- Can present in the elderly/ children too
- More common in males
How does Ulcerative Colitis usually present?
Diarrhoea, mucus and blood PR
Describe the clinical course of Ulcerative Colitis
- Chronic course
- Exacerbation and remission
- Continuous low grade activity
- Single attack = Acute fulminant colitis (Toxic megacolon)
