PANCE Blueprint GI and Nutrition (8%)

Patient with ulcerative colitis will present as → a 32-year-old woman comes to your office with a 6-month history of loose bowel movements, approximately eight per day. Blood has been present in many of them. She has lost 30 pounds. For the past 6 weeks, she has had intermittent fever. She has had no previous gastrointestinal (GI) problems, and there is no family history of GI problems. On examination, the patient looks ill. Her blood pressure is 130/ 70 mm Hg. Her pulse is 108 beats/ minute and regular. There is generalized abdominal tenderness with no rebound. A sigmoidoscopy reveals a friable rectal mucosa with multiple bleeding points.

Patient with Crohn's disease will present as → a 25-year-old man with an 18-month history of chronic abdominal pain. The patient has seen several physicians and has been diagnosed as having a “nervous stomach,” irritable bowel syndrome, and “depression.” Associated with this abdominal pain for the past 3 months have been nonbloody diarrhea, anorexia, and a weight loss of 20 pounds. He has developed a painful area around the anus. On examination, the patient has diffuse abdominal tenderness. He looks thin and unwell. He has a tender, erythematous area in the right perirectal area.

	Crohn's disease	Ulcerative colitis
Site of involvement	Any area of the GI tract - the rectum is usually spared	Only involves the colon - the rectum is usually involved
Pattern of involvement	Skip lesions	Continuous
Diarrhea	Usually non-bloody	Bloody
Severe abdominal pain	Frequent	Rare
Perianal disease	30% of patients	No
Fistula	Yes	No
Endoscopic findings	Aphthoid and deep ulcers; cobblestoning	Erythematous and friable superficial ulceration
Radiographic findings	String sign of terminal ileum, RLQ mass, fistula, abscesses	Tubular (lead pipe) appearance resulting from loss of haustral folds
Histologic features	Transmural, non-caseating granulomas	Mucosa-only, crypt abscesses
Smoking	Worsens course	Protective
Serology	ASCA	p-ANCA

Ulcerative Colitis (“colitis” = confined to the colon)

• Presents with bloody puss-filled diarrhea, rectal/lower quadrant pain, fever, and urgency
• Inflammation isolated to the colon and confined to mucosa and submucosa (unlike Crohn's, not transmural)
• The most common site is the rectum!
• Ulcerative colitis affects the colon in an ascending fashion starting from the rectum up to the ascending colon - remember, ulcerative moves UP from the rectum to the ascending colon!
• Bimodal distribution of peak onset: age 15-25 and age 55-65
• Labs: ↑ WBC, ESR, and anemia
• Diagnosis by barium enema lead pipe appearance and colonoscopy with biopsy both show continuous ulceration starting from the rectum and extending proximally with loss of haustral markings and lumen narrowing
• Complications: Toxic megacolon, colorectal cancer
• Antibody test: Antineutrophil cytoplasmic antibodies (p-ANCA)

Lead pipe appearance on Double-contrast barium enema. Image by Division of Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, MN, USA. License: CC BY 3.0

Endoscopic view of the colon showing continuous superficial ulceration due to severe ulcerative colitis. Image by G.V. (Sonny) Montgomery VA Medical Center and Division of Digestive Diseases, Department of Medicine, University of Mississippi Medical Center, Jackson, MS, USA. License: CC BY 3.0

Crohn's Disease

1. Presents with abdominal pain, weight loss, diarrhea (non-bloody), and oral mucosal aphthous ulcers. Longer-standing disease may have severe anemia, polyarthralgia, and fatigue.
2. The most common site is the terminal ileum
3. Distribution from mouth to anus and will commonly present with thickened bowel wall, cobblestoning, and “skip” lesions
4. Linear fissures and cobblestone appearance. Tends to be transmural vs. UC is limited to the mucosa and submucosa
5. Complications include strictures identified by a string sign on barium study
6. Presents with abdominal pain, weight loss, diarrhea, and oral mucosal aphthous ulcers
7. Obstruction, abscess, fistula, and sinus tracts are common
8. 1-3% cancer risk (low)
9. Antibody test: +Anti-Saccharomyces cerevisiae antibodies (ASCA)

Stenosis of the colon with cobblestoning particular to Crohn's disease

Crohn's disease

The diagnosis of Crohn's disease can sometimes be challenging, and several tests are often required to assist in making the diagnosis. Even with a full battery of tests, it may not be possible to diagnose Crohn's with complete certainty

• Rectal exam, stool exam, and culture, CBC, electrolytes, TSH, CT-abdomen
• Upper GI series with small bowel follow-through
  • ⇒ ↑ ESR, anemia, nutritional and electrolyte imbalance during exacerbation
• Colonoscopy is the most valuable tool for establishing the diagnosis, determining the extent, and guiding treatment
  • ⇒ colonoscopy is approximately 70% effective in diagnosing the disease, with further tests being less effective
  • A biopsy will show involvement of the entire bowel wall; granulomas are frequent
• + Anti-saccharomyces cerevisiae antibodies (ASCA) and perinuclear antineutrophil cytoplasmic antibodies may distinguish Crohn's and UC

Ulcerative Colitis:

Diagnosis of ulcerative colitis typically requires colonoscopy to see the ulcers and take a biopsy

• Show continuous inflammation starting from the rectum and extending proximally with loss of haustral markings and lumen narrowing
• May elect to limit the extent of the exam (flex sigmoidoscopy) if severe colitis is encountered to minimize the risk of perforation of the colon

In addition, radiological imaging may be done with the help of a CT scan, MRI, a barium enema

• Barium enema: Lead pipe appearance (loss of haustral markings) ⇒ may cause toxic megacolon
• A radiograph may show colonic dilation
• Laboratory tests should be done to screen for anemia, decreased albumin, and electrolyte abnormalities
  • Antibody test: Antineutrophil cytoplasmic antibodies (p-ANCA)
  • Labs: ↑ WBC, ↑ ESR, ↑ CRP, and anemia
  • Liver function tests ⇒ elevated alkaline phosphatase and γ–glutamyl transpeptidase levels in patients with major colonic involvement suggest possible primary sclerosing cholangitis
  • To detect nutritional deficiencies, levels of vitamin D and B₁₂ should be checked every 1 to 2 yr

Treatment for UC and Crohn's disease are the same

• Sulfasalazine
  • This is useful if the colon is involved. 5-ASA (mesalamine) is the active compound and is released in the colon—it is more useful in UC than in Crohn's disease.
  • 5-ASA compounds block prostaglandin release and serve to reduce inflammation.
  • There are preparations of 5-ASA that are more useful in distal small bowel disease.
• Metronidazole—if no response to 5-ASA
• Systemic corticosteroids (prednisone/budesonide)—for acute exacerbations and if no response to metronidazole
• Immunosuppressants (azathioprine, 6-mercaptopurine)—in conjunction with steroids if the patient does not respond to the above agents
• Bile acid sequestrants (cholestyramine or colestipol)—for patients with terminal ileal disease who cannot absorb bile acids
• Antidiarrheal agents are generally not a good choice (may cause ileus)
• Nutritional supplementation and support—parenteral nutrition is sometimes necessary
• Surgical UC — is often curative (unlike Crohn's disease) and involves total colectomy.
• Surgical Crohn's (eventually required in most patients) - Involves segmental resection of involved bowel. Disease recurrence after surgery is high—up to 50% of patients experience disease recurrence at 10 years postoperatively