Inflammatory Bowel Disease

» Gastroenterology

Overview

Overview Inflammatory bowel disease is a common condition. It is divided into two types: Crohn disease and Ulcerative colitis. Both these condition differ in pathology, progression and complication, but they do share a lot similar characteristics as well.

Definition
Colitis: Inflammation of the colon, which may be due to infectious, autoimmune, ischemic, or idiopathic causes.
Inflammatory Bowel Disease: Autoimmune-mediated intestinal inflammation primarily due to either Crohn disease or ulcerative colitis.

Ulcerative Colitis		Crohn’s Disease
Both	Gender	Male<Female
2-19/100,000	Incidence (per year)	21-20/100,000
15-40yo	Onset	15-40yo
Distal colon	Location	Dital ileum and caecum
Continuous superficial inflammatory lesion	Pathology	Discontinuous, patchy transmural inflammatory skip lesions
Severe bleeding, toxic megacolon, perforation, colon cancer	Complications	Stenosis, abcess formation, fistula, strictures, colon cancer

Histological Difference between Crohn Disease and Ulcerative Colitis

Risk Factors

Risk Factors
Ulcerative Colitis	Crohn's Disease
Family history of inflammatory bowel disease	White ancestry
HLA-B27	Family history
Infection	High sugar diet
NSAIDs	Oral contraceptive pill, NSAIDs
Not smoking or former smoker	Cigarette smoking
	Not breastfed

Signs and Symptoms

ULCERATIVE COLITIS CLINICAL PICTURE
	Proctitis (50%)	Left-sided colitis (30%)	Pancolitis (∼20%)
Area affected	Inflammation of the rectum	Inflammation from rectum up to the splenic flexure	Inflammation of the entire colon
Rectum and deification	Rectum always involved. Symptoms of urgency and frequency due to rectal irritablity.	Rectal irritation
Stool	Blood mucus mixed with loose stools (frank bloody diarrhea rare)	Bblood mucus in stools, often leading to diarrhea	Diarrhea

Side note Ulcerative colitis typically presents in young adults with relapsing bloody diarrhoea, malaise, fever and weight loss. Crohn's can have similar presentation or have a more insidious onset with other complications such as malabsorption and pain.

Extra-intestinal Manifestations

Both UC and CD
- Uveitis (Iritis/conjuctivitis)
- Mouth ulcer
- Large joint arthritis
- Skin Rash (Erythema nodosum and/or Pyoderma gangrenosum)
- Anaemia
Ulcerative Colitis
- Liver disease: Primary sclerosing cholangitis, Cirrhosis, Amyloidosis
Crohn Disease
- Renal disease: stones and amyloidosis
- Gallstones
- Osteomalacia

General clinical features of BD

Differential Diagnosis

The differential diagnosis of inflammatory bowel disease includes other causes of chronic diarrhoea

Remember Infection must be excluded, and it is necessary to check for infections with organisms such as Entamoeba histolytica, Salmonella, Shigella, E coli, and Campylobacter, as well as Clostridium difficile, which can occur in the absence of prior antibiotic exposure.

Causes of Colitis (inflammation of the colon)

Inflammatory Bowel Disease
Infection
Radiation
Ischaemic colitis
Diversion colitis
Toxic exposure (chemicals)
Lymphocytic colitis
Collagenous colitis

Differential Diagnosis of IBD (Image adapted from Netter Images)

Investigations

General

Stool culture - to rule out C. difficle colitis
FBC - increase WCC, decrease Hb
ESR/CRP - increased
Serum folate
Serum vitamin B12
Abdominal X-ray - may show oedematous colonic mucosa (thumbprinting)

Specific for Ulcerative Colitis

Colonoscopy – sigmoidoscopy usually shows erythematous, grandular, or frankly ulcerated rectal mucosa with mucus and blood
Biopsy - check severity and to Exclude Crohn's disease
Serological markers – ANCA (70% of patients with UC have this)
Serological marker – ASCA (70% of patients with Crohn’s have this)

Specific for Crohn's Disease

Double-contrast barium enema (rarely used) - in subacute/chronic presentations to show mucosal irregularity and narrowing.
CT - may show an inflammatory mass, abscess formation, localised or free perforation
MRI - for anal disease
Biopsy - check severity and confirm Crohn's disease

Diagnosis

Presence of chronic diarrhea for more than four weeks and evidence of active inflammation on endoscopy and chronic changes on biopsy.
Eliminate differentials with:
- History - risk factors
- Laboratory studies - stool culture for bacteria (C. difficile, Salmonella, Shigella, Campylobacter, Yersinia)
- Endoscopy - continuos inflammatory lesion beginning mainly from the distal colon

Investigation In subacute or chronic presentations, small muscusal disease may be shown by a small bowel contrast study (shows mucosal irregularity and narrowing) or a white cell scan showing ileal 'hot spots'

Pathology

Ulcerative Colitis	Crohn's Disease
Superficial inflammation. Disease present in the distal colon and rectum and spread proximally with increasing extend of disease.	Transmural inflammation. Disease commonly focused in the terminal ileum and caecum, but may affect the anus, colon, or entire small bowel.
Acute neutrophil infiltration in the mucosa and submucosa	Lymphoid aggregates, particularly in the subserosal tissues (Crohn's rosary).
Mucosal crypt abscess with goblet cell mucin depletion	Mucosal crypt ulceration, and fissuring ulceration.
More severe inflammation, there can be aphthous ulcers, granulation tissue -> pseudopolyps	Mucosal thickening and cobblestone.
Chronic 'burnt out' disease leads to a pale, featureless, ahaustral pattern to the colon. Transmural inflammation may occur in sever cases.	Extensive fibrosis and muscle hyperplasisa may occur, giving rise to stenosis. Perforation, fistulation, and abscess formation are occasional sequelae of transmural inflammation.

Gross Pathological changes in IBD

Management

The management differs for UC and CD. CD is more severe and encounters more complications. The principles of medical treatment is to reduce inflammation and prevent complications.

General

Close monitoring - bloods
Acute derangement in blood results should be corrected (ie. blood transfusion for severe anaemia, potassium supplementation, nutrition support).
Diet modification
Medical treatment
- Steroids (suppository or systemic)
- 5-ASA
- Oral immunosuppresives (methotrexate, azathiopurine)
- Immunomodulators (anti-TNFa)
- Antibiotcs
Surgical treatment
- Ulcerative colitis - indicated for acute colitis that fails to respond to treatment and for chronic colitis
- Crohn's disease - deal with septic complications, relieve significant bowel obstruction, and remove as little bowel as possible.

Ulcerative Colitis Medical and Surgical Treatment
	Proctitis (50%)	Left-sided colitis (30%)	Pancolitis (~20%)
Topical steroids (suppsoitories or foam enema)	+	+	+
5-ASA	+	+	+
Systemic Steroids (prednisalone)	-	-/+	+
Oral immunosuppressives (azathiopurine)	-	-	+
Immunomodulators (anti-TNFa)	-	-	+
Surgery is indicated for acute colitis that fails to respond to treatment and for chronic colitis. Surgical treatment include removing parts of bowel or entire colon.

Crohn's Disease Medical and Surgical Treatment
Medical Treatment	Surgical Treatment
5-ASA	Acute: Free perforation, sever haemorrhage, acute severe colitis, complete intestinal obstruction
Systemic steroids (hydrocortisone, prednisolone)	Subacute: Inflammatory mass, subacute obstruction, abscess formation, symptomatic fistulation
Immunosuppressives (azanthiopurine, methotrexate)	Chronic: Steroid dependency or complications, cancer treatment
Immunomodulators (anti-TNFa)
Dietary modification

Complications and Progns

Local Complications

Ulcerative Colitis
- Toxic Megacolon
- Perforation
- Massive haemorrhage
- Strictures
- Carcinoma of the colon
Crohn Disease
- Anorectal Disease
- Obstruction
- Fistula
- Carcinoma of the colon

Extra-intestinal Manifestations

Both UC and CD
- Uveitis (Iritis/conjuctivitis)
- Mouth ulcer
- Large joint arthritis
- Skin Rash (Erythema nodosum and/or Pyoderma gangrenosum)
- Anaemia
Ulcerative Colitis
- Liver disease: Primary sclerosing cholangitis, Cirrhosis, Amyloidosis
Crohn Disease
- Renal disease: stones and amyloidosis
- Gallstones
- Osteomalacia