eMedicine Specialties > Ophthalmology > Neurologic Disorders

Inflammatory Bowel Disease

Author: Mounir Bashour, MD, CM, FRCS(C), PhD, FACS, Assistant Professor of Ophthalmology, McGill University; Clinical Assistant Professor of Ophthalmology, Sherbrooke University; Medical Director, Cornea Laser and Lasik MD
Contributor Information and Disclosures

Updated: Jun 8, 2009

Introduction

Background

Inflammatory bowel disease (IBD) is used commonly to refer to the following 2 illnesses: ulcerative colitis (UC) and Crohn disease (CD). These chronic inflammatory diseases of the GI tract are of unknown etiology. CD is also referred to as regional enteritis, terminal ileitis, or granulomatous ileocolitis.

Pathophysiology

UC primarily involves the mucosa and the submucosa, with formation of crypt abscesses and mucosal ulceration. The mucosa typically appears granular and friable. In more severe cases, pseudopolyp formation occurs. These consist of areas of hyperplastic growth with swollen mucosa surrounded by inflamed mucosa with shallow ulcers. Although unusual, in severe UC, inflammation and necrosis can extend below the lamina propria to involve the submucosa and the circular and longitudinal muscles.

UC arises first in the rectum, where it remains confined in about 25% of cases. In the remainder, contiguous proximal spread occurs.

Pancolitis occurs in 10% of patients. The small intestine is never involved, except when the distal terminal ileum is inflamed in a superficial manner, referred to as backwash ileitis. Even with less than total colonic involvement, the disease is strikingly and uniformly continuous. As the disease becomes chronic, the colon becomes a rigid, foreshortened tube that lacks its usual haustral markings, leading to the lead pipe appearance seen on barium enema. No skip areas like those seen in CD of the colon are present.

CD consists of segmental involvement by a nonspecific granulomatous inflammatory process. The most important pathologic feature is that all the layers of the bowel are involved, not just the mucosa and the submucosa, as is characteristic of UC. Furthermore, the disease is discontinuous, with normal areas of bowel skip areas interspersed between one or more involved areas. Late in the disease, the mucosa develops a cobblestone appearance. This results from deep longitudinal ulcerations interlacing with intervening normal mucosa. The ileum is involved in most cases. However, in 20% of cases the disease is confined to the colon, often with rectal sparing.

Rectal involvement is unusual, but anorectal complications (eg, fistulas, abscesses) are common. One third of patients have disease limited to the small intestine, most commonly in the distal ileum. An increased incidence of gallstones and kidney stones occurs in CD, owing to malabsorption of fat and bile salts. Gallstones are formed because of increased cholesterol concentration in the bile due to a reduced bile salt pool. Calcium oxalate kidney stones are formed in patients with CD who have ileal disease or resection. With the resulting fat malabsorption, unabsorbed long-chain fatty acids bind calcium in the lumen.

Normally, oxalate in the lumen is bound to calcium. Calcium oxalate is poorly soluble and poorly absorbed. However, if calcium is bound to malabsorbed fatty acids, oxalate combines with sodium to form sodium oxalate, which is soluble and is absorbed in the colon (enteric hyperoxaluria). The development of calcium oxalate stones in CD requires an intact colon to absorb oxalate. Patients with ileostomies do not develop calcium oxalate stones.

Extraintestinal manifestations of both types of inflammatory bowel disease include iritis, episcleritis, arthritis, and skin involvement, as well as pericholangitis and sclerosing cholangitis.

Frequency

United States

Prevalence is 70-150 cases per 100,000 population.

Mortality/Morbidity

The quality of life generally is lower with CD than with UC, owing in part to recurrences after surgery.

• The most common causes of death in inflammatory bowel disease are peritonitis with sepsis, malignancy, thromboembolic disease, and complications of surgery. Toxic megacolon, one of the most dreaded complications of UC, can lead to perforation, sepsis, and death.
• Malnutrition and chronic anemia are seen in long-standing CD.
• Children can develop growth retardation.

Race

Incidence in whites is about 4 times that of other races.

• People in Northern Europe and North America are most commonly affected.
• An increased incidence is reported in Ashkenazi Jews, particularly those who have immigrated from Northern Europe.

Sex

Females are affected slightly more than males.

Age

Peak incidence is in the second and third decades of life. A second, smaller peak occurs in individuals aged 55-65 years.

Clinical

History

• UC presents most commonly with bloody diarrhea.
• Abdominal pain and cramping, fever, and weight loss occur in more severe cases. The greater the extent of colon involved, the more likely the patient is to have diarrhea.
• Rectal urgency or tenesmus reflects reduced compliance of the inflamed rectum.
• It is possible for patients to have formed stools if their disease is confined to the rectum.
• As the degree of inflammation increases, systemic symptoms develop. These symptoms may include low-grade fever, malaise, nausea, vomiting, sweats, and arthralgias.
• With severe UC, fever, dehydration, and abdominal tenderness develop, reflecting progressive inflammation into deeper layers of the colon.
• The presentation of CD is more chronic than that of UC, with ongoing abdominal pain, anorexia, diarrhea, weight loss, and fatigue.
• Whereas grossly bloody stools are typical of UC, they are less common in CD.
• Stools may be formed; however, if extensive involvement of the colon or terminal ileum is present, loose stools predominate.
• One half of patients with CD present with perianal disease (eg, fistulas, abscesses).
• On occasion, acute right lower quadrant pain and fever may be noted, mimicking appendicitis.
• Commonly, the diagnosis is established only after several years of recurrent abdominal pain, fever, and diarrhea. CD with gastroduodenal involvement may mimic peptic ulcer disease and can progress to gastric outlet obstruction.
• Many patients with IBD also have irritable bowel syndrome. The latter can produce occasional cramping, irregular bowel habits, and passage of mucus without blood or pus.
• Weight loss is seen more commonly in patients with CD than in patients with UC because of the malabsorption associated with small bowel disease. Patients may reduce their food intake in an effort to control their symptoms.
• Systemic symptoms are common and include fever, sweats, malaise, and arthralgias.
• Patients with toxic megacolon appear septic with high fever; lethargy; chills; tachycardia; and increasing abdominal pain, tenderness, and distention.
• Children may present with growth retardation and delayed or failed sexual maturation.
• In 10-20% of cases, patients present with extraintestinal manifestations, including arthritis, uveitis, or liver disease.
• Recurrences may occur with emotional stress, infections or other acute illnesses, pregnancy, dietary indiscretions, use of cathartics or antibiotics, or with withdrawal of anti-inflammatory or steroid medications.

Physical

• Fever, tachycardia, dehydration, and toxicity may be seen. The magnitude of these factors is related directly to the severity of the attack.
• Although abdominal tenderness is common, evaluate for signs of localized peritonitis. Patients with CD may develop a mass in the right lower quadrant.
• The rectal examination often reveals bloody stool on gross or Hemoccult examination.
• In as many as 90% of patients with CD, complications, such as perianal fissures or fistulas, abscesses, or rectal prolapse, may be seen.
• The examination should include a search for extraintestinal manifestations, such as iritis, episcleritis, arthritis, and dermatologic involvement.

Causes

The etiology of IBD is unknown. Environmental, infectious, genetic, autoimmune, and host factors have been suspected. More likely, interactions among these factors may be more important.

• Cigarette smoking appears to protect against UC, whereas it is associated with CD. On occasion, the onset of UC appears to occur upon smoking cessation.
• Inflammatory mediators  
  • Interleukin 1 (IL-1)
  • Tumor necrosis factor-alpha (TNF-alpha)
  • Aggravated by bacterial infection and inflammatory cascade

• Search for CME/CE on This Topic »

• Inflammatory Bowel Disease (Gastroenterology)
• Inflammatory Bowel Disease (Emergency Medicine)
• Pericholangitis (Gastroenterology)
• Crohn Disease (Pediatrics: General Medicine)

• Inflammatory Bowel Disease Treatment
• Inflammatory Bowel Disease Causes
• Inflammatory Bowel Disease Symptoms
• Crohn Disease Center
• Inflammatory Bowel Disease Overview
• Crohn Disease Overview
• Crohn Disease FAQs

• Thiopurine Treatment of Inflammatory Bowel Disease Linked to Risk for Lymphoproliferative Disorders
• Many Common Loci Associated With Early- and Adult-Onset Inflammatory Bowel Disease
• Patients With IBD at Risk of Developing Nonmelanoma Skin Cancer

• Prospective Study of the Effects of Concomitant Medications on Thiopurine Metabolism in Inflammatory Bowel Disease
• Neuropeptides and Inflammatory Bowel Disease
• Regulatory T Cells in Inflammatory Bowel Disease

• Inflammatory Bowel Disease (IBD) Resource Center