INFLAMMATORY BOWEL DISEASES

Inflammatory bowel disease (IBD) is a term used to denote two diseases of unknown etiology with similar general characteristics: ulcerative colitis and Crohn's disease.

Crohn's Disease

• Crohn's disease is a chronic, transmural inflammatory disease of the gastrointestinal tract of unknown cause. 
• Crohn's disease can involve any part of the alimentary tract from the mouth to the anus but most commonly affects the small intestine and colon.
• Crohn's disease can be complicated by intestinal obstruction or localized perforation with fistula formation.
• bimodal distribution 
• The risk for developing Crohn's disease is about two times higher in smokers than in nonsmokers.
• strong familial association
•  genetic role for Crohn's disease show a concordance rate of 67% in monozygotic twins.

Pathology

• The most common sites of occurrence of Crohn's disease are the small intestine and colon.
• The disease process is discontinuous and segmental.
• In patients with colonic disease, rectal sparing is characteristic of Crohn's disease and helps to distinguish it from ulcerative colitis
• Crohn's disease can also involve the mouth, esophagus, stomach, duodenum, and appendix.

Gross Pathologic Features

• Grossly, thickened grayish-pink or dull purple-red loops of bowel are noted, with areas of thick gray-white exudate or fibrosis of the serosa.
• Areas of diseased bowel are separated by areas of grossly appearing normal bowel called skip areas.
• In Crohn's disease there is extensive fat wrapping caused by the circumferential growth of the mesenteric fat around the bowel wall.
• On opening the bowel, the earliest gross pathologic lesion is a superficial aphthous ulcer noted in the mucosa. As the disease progresses, the ulceration becomes pronounced, and complete transmural inflammation results. The ulcers are characteristically linear and may coalesce to produce transverse sinuses with islands of normal mucosa in between, thus giving the characteristic cobblestone appearance.

Microscopic Features

• A chronic inflammatory infiltrate appears in the mucosa and submucosa and extends transmurally.
• Characteristic histologic lesions of Crohn's disease are noncaseating granulomas with Langerhans' giant cells.

Clinical Manifestations

• Crohn's disease can occur at any age, but the typical patient is a young adult in the second or third decade of life. 
• two genders are affected equally
• The onset of disease is often insidious, with a slow and protracted course.
• The most common clinical manifestations are abdominal pain, diarrhea, and weight loss. 
• There is intermittent and colicky abdominal pain, most commonly noted in the lower abdomen. The pain, however, may be more severe and localized and may mimic the signs and symptoms of acute appendicitis.
• Diarrhea is the next most frequent symptom and is present patients with Crohn's disease typically have fewer bowel movements, and the stools rarely contain mucus, pus, or blood
•  Characteristically, there are symptomatic periods of abdominal pain and diarrhea interspersed with asymptomatic periods of varying lengths. 
• Systemic nonspecific symptoms include a low-grade fever (present in about one third of the patients), weight loss, loss of strength, and malaise.

Diagnosis

Barium contrast studies and endoscopy:

Barium contrast studies

• Barium radiographic studies of the small bowel reveal a number of characteristic findings, including a cobblestone appearance of the mucosa composed of linear ulcers, transverse sinuses, and clefts
• Segmental and irregular patterns of bowel involvement may be noted.
• Fistulas between adjacent bowel loops and organs may be apparent .

Endoscopy

• When the colon is involved, sigmoidoscopy or colonoscopy may reveal characteristic aphthous ulcers with granularity and a normal-appearing surrounding mucosa.
• CT may be useful in demonstrating the marked transmural thickening, fistulae, intra abdominal abscess, etc.

Treatment

Medical therapy:

Steroids

Prednisolone 40mgXdaily

Supplement with 5-ASA compounds incase of colonic involvement.

Antibiotics- for pt. having s/s of mass or an abscess.

Infliximab

Nutritional support-iv or NG feedings

Anemia, hyponatremia, electrolyte, vitamins and metabolic problems should all be corrected.

Surgical therapy

Surgery in mainly for the complications. They are:

• Recurrent intestinal obstruction
• Bleeding
• Perforation
• Failure of medical therapy
• Intestinal fistula
• Fulminant colitis
• Malignant change
• Perianal disease

Ileocaecal resection- For ileocaecal disease,

Anastomosis between the ileum and the transverse colon.

Segmental resection- T/T of short segments of small and large bowel.

Colectomy and ileorectal anastomosis- For widespread colonic disease with rectal sparing with normal anus.

Temporary loop ileostomy- Used in pt. with distal Crohn’s disease or in pt. with severe perianal or rectal disease.

Proctocolectomy- Colonic and anal disease not responding to the medical t/t.

Strictureplasty- For t/t of stricture area of Crohn’s disease.

Simple drianage of abscess- For anal diseases.

Ulcerative Colitis

Cause- unknown

All ages are susceptible, but it more commonly affects patients younger than 30 years.

Both sexes are equally affected

More prevalent in 1st degree relative of the pt.

Smoking have protective effect.

Pathologic Features

Gross Appearance

• Ulcerative colitis is a disease in which the major pathologic process involves the mucosa and submucosa of the colon, with sparing of the muscularis.
• The rectum is invariably involved with the inflammatory process.
• The mucosal inflammation starts in the rectum and extends in a continuous fashion for a variable distance into the more proximal colon.
• A diagnostic characteristic of ulcerative colitis is continuous, uninterrupted inflammation of the colonic mucosa beginning in the distal rectum and extending proximally to a variable distance.

Histologic Appearance

• The typical microscopic finding in ulcerative colitis is inflammation of the mucosa and submucosa
• The most characteristic lesion is the crypt abscess, in which collections of neutrophils fill and expand the lumina of individual crypts of Lieberkühn.
• The number of goblet cells in the crypts is diminished, as is mucus production.
• Ulcerative colitis spares the muscular coats of the colon, but in rare cases of severe inflammation characteristic of toxic megacolon in patients with ulcerative colitis, all layers of the colon may be involved, and perforation may occur if treatment is delayed (may be related to factors such as prolonged colonic distention with vascular compromise).

Histo: UC

Clinical Presentation

• The first symptom is watery and bloody diarrhoea.
• Ulcerative colitis and colonic Crohn's disease often have similar clinical presentations. Both may present with diarrhea and the passage of mucus. Patients with ulcerative colitis tend to have more urgency than those with Crohn's disease, likely because ulcerative colitis is invariable associated with distal proctitis. Rectal bleeding is also common in ulcerative colitis; although it may be present in patients with Crohn's disease, it is typically not as severe
• Rectal involvement is present in virtually 100% of patients with ulcerative colitis.

• Extraintestinal Manifestations

Arthritis

Ankylosing spondylitis

Skin lesions: erythema nodosum, pyoderma gangrenosum, aphthous ulceration.

Eye: iritis and 

Liver disease: Primary sclerosing cholangitis

• It is HLA-B27 positive .

Diagnosis

• Barium enema

Signs seen are:
Loss of haustration (esp. in distal colon)
Mucosal changes
Pseudopolyps
Narrow contracted colon ( in chronic cases)

• Sigmoidoscopy

Used for Dx of early and mild disease not seen in barium enema.

• Initial findings are those of proctitis, like:

Hyperaemic mucosa
Bleeds on touch
There maybe pus like exudate seen

• Later- tiny ulcers may be and appear to coalesce
• Colonoscopy and biopsy

To know the extent of inflammation
Helps distinguishing UC from CD
Monitor response to t/t
To access malignant changes

Edoscopy: UC

Treatment

Medical Therapy

• Acute attack

Corticosteroids: inflammation of the rectum (locally) or extensive disease (systemically)

Sulfasalazine and 5-ASA (maintain remission): can be given topically and systemically

• Mild attacks

Mild attack and limited disease- Steroids (rectal)

More extensive disease- Oral prednisolone 20-40 mg/day X 3-4 wks plus sulfasalazine 1g X tid or 5-ASA compounds.

• Moderate attacks

Oral prednisolone 40mg/day, Steroid enema X BD and 5-ASA 

• Severe attacks

NPO

Fluid and electrolyte balance

Correction of anemia

Adequate nutrition

I.V hydrocortisone 100-200mg X qid

• If no imrovement within 5-7 days, surgery is done.

Surgery

Indications for the surgical management:

-Severe or fulminant disease not responding to medical therapy.

-Chronic disease with anemia, frequent stools, urgency and tenesmus.

-Steroid dependent disease.

-Risk of malignant transformation.

-Extraintestinal manifestations.

-Severe hemorrhage/stenosis causing obstruction.

Total abdominal colectomy and ileostomy:

In the emergency situations

Proctocolectomy and ileostomy:

In this there will be a permanent ileostomy.

Restorative Proctocolectomy with an ileo-anal anastomosis with pouch as reservoir (‘J’, ‘S’, or ‘W’ pouches)

Colectomy and ileorectal anastomosis:

This can occasionally be used in case of minimal rectal inflammation.

Ileostomy with a continent intra-abdominal pouch:

Rarely used.