Distinguishing characteristics of CD and UC

Case History :
  • A 5 year old boy is brought to your clinic with complaints of several episodes of diarrhoea each day for 2 years duration. There is also complaint of failure to gain weight properly for the same duration. He appears ill. He has pallor and dehydration. On examination, his pulse is 150 bpm and his BP is 95/40mmHg. He is mildly febrile. You also notice some depigmented macules on his forearm and legs. He is at 5th percentile for weight and 60th percentile for height. What is your provisional diagnosis and how will you manage this case?
  • A 30 year old male comes to your clinic with complaints of crampy abdominal pain and bloody diarrhea for past 10 days.  He also complains of mild intermittent fever for the same duration.  In the past medical history, he tells you that he has been having several similar episodes for past 5 years. He occasionally takes over the counter medicines sometimes for his illness otherwise it goes away on its own most of the time. He also gives you a history of occasional knee and ankle joints pain for past 2 years. On examination, the patient is thin built. He appears dehydrated and mildly anemic. There is no abdominal tenderness. Rest of the examination is normal. How will you manage this case?

Inflammatory Bowel Disease (IBD) is a
general term given to two diseases:
- Ulcerative colitis
- Crohn's disease

IBD characterized by a tendency for chronic or relapsing immune activation and inflammation within the GIT.
Crohn’s disease (CD) and ulcerative colitis (UC) are the 2 major forms of idiopathic IBD.


Microscopic colitis (collagenous and lynphocytic)
  • Diversion colitis
  • Radiation colitis
  • Drug induced colitis
  • Infectious colitis
  • Ischemic colitis 

CD is a condition of chronic inflammation potentially involving any location of the GIT from mouth to anus.

UC is an inflammatory disorder that affects the rectum and extends proximally to affect variable extent of the colon.


Studies suggested that 1st degree relatives of an affected patient have a risk of IBD that is 4-20 times higher than that of general population.
The best replicated linkage region, IBD1, on chromosome 16q contains the CD susceptibility gene, NOD2/CARD15.
Having one copy of the risk alleles confers a 2–4-fold risk for developing CD, whereas double-dose carriage increases the risk 20–40-fold.

Epidemiologic Features of Inflammmatory Bowel Disease

Incidence (per100,000) 1-10(CD), 2-18 (UC)
Prevalence (per100,000) 20-100 (CD), 40-100 (UC)
Race White >black> Hispanic
Sex M=F
Age at Onset Peak  15-25, second peak 50- 80(CD)
Smoking Associated with CD,inversely associated with UC
Relapse Nonsteroidal anti-inflammatory drugs , oral contraceptives (CD)

  • Both illnesses do have one strong feature in common. 
  • They are marked by an abnormal response of the body's immune system.
The symptoms of these two disorders can be very similar, but there are also two distinct differences:
  • the part of the intestinal tract affected
  • the extent (severity) of the inflammation

  • Mutations within the NOD2/ CARD15 gene contribute to CD susceptibility.
  • Functional studies suggest that inappropriate responses to bacterial components may alter signaling pathways of the innate immune system, leading to 
  • the development and persistence of intestinal inflammation.
  • Initiating pathogen?
  • Infectious?
  • ? Possibly non-pathogenic commensal enteric flora

  • The inflammation is predominantly confined to the mucosa.
  • Non-specific (can be seen with any acute inflammation)
  • The lamina propria becomes edematous.
  • Inflammatory infiltrate of neutrophils
  • Neutrophils invade crypts, causing cryptitis & ultimately crypt abscesses.
  • Specific (suggest chronicity):
  • Distorted crypt architecture, crypt atrophy and a chronic inflammatory infiltrate.

Distinguishing characteristics of CD and UC
Endoscopic features of CD and UC
Pathologic features of CD and UC

How IBD is Diagnosed

Clinical history
  • Physical examination
  • Laboratory tests
  • Endoscopy (Gastroscopy/Colonoscopy)
  • X-ray (contrast) findings 
  • Tissue biopsy (pathology)
  • Exclude other possibilities (need good history, physical exam, labs, imaging and endoscopy with biopsy)
  • There are many distinguishing features of CD and UC.
  • In about 5% it is classified as indeterminate because of overlapping features.
Inflammatory Bowel Disease:

The most common symptoms of IBD are:
  1. abdominal pain
  2. diarrhea
  3. Rectal bleeding
  4. weight loss and fever may also occur
  5. vomiting, and loss of appetite
  6. skin and eye irritations
  • Inflammation invariably involves the rectum. ( sigmoid and whole)  
  • The lesions in ulcerative colitis tend to occur in continuous regions of the gut
  •  The inflammation affects mainly the inner lining of the bowel (the mucosa)
  • Inflammation is confluent and is more severe distally. In long standing pancolitis  the bowel  becomes shortened and ‘pseudopolyps’ develop
  • Histologically  the inflammaory process is limited to the mucosa and spares the deeper layers of the bowel wall.
  • Both acute and chronic inflammaory cells infiltrate  te lamina propria and the crypts. Crypt abscesses are typical.Goblet cells lose their mucus and in long standing cases glands become distorted.
Symptoms of Ulcerative Colitis
  • Symptoms depend on extent and severity of inflammation
  • Rectal bleeding and urgency to evacuate
  • Diarrhea
  • Abdominal cramping
–Extraintestinal (systemic) symptoms
  • Joint pain/swelling
  • Eye inflammation
  • Skin lesions
Physical Signs
  • No specific clinical signs on general examination
  • Tenderness at left iliac fossa
  • Acute illness may reveal peritoneal irritation findings
  • Rectal examination may reveal blood and mucus on the glove
In adults at presentation about 55% have proctitis, 30% left sided colitis and 15% extensive colitis or pan colitis

  • Rectum is almost always involved
  • The diseased areas are contiguous
  • Histology reveals crypt abscess and inflammatory polyps

  • Leucocytosis
  • Anemia
  • ESR elevation
  • Hypoalbuminemia
  • Electrolyte imbalance

Double contrast barium enema exam of the colon
(lead pipe appearance)

  • Associated Autoimmune Diseases
  • Pernicious anemia
  • Systemic lupus erythematosus
  • Hashimoto’s thyroiditis