Diseases of the Colon

Question 1

What is the clinical presentation of ischemic colitis?

Answer 1

90% of patients are >60yo
Abrupt onset of crampy abdominal pain, typically in LLQ
Urgent need to defecate
Anorexia and N/V indicate the ileum is also involved (paralytic bowel)
Classic presentation is an older individual with cardiac or vascular disease (imagine a bowel stroke)

Question 2

What is the clinical presentation of infectious colitis?

Answer 2

Related to ingestion of contaminated food, water, or foreign travel.
Patients often have history of recent travel
Present weeks after onset of symptoms
Acute and self-limited, except Pseudomembranous Colitis
Labs: Stool enterotoxin assay for C. difficile, Stool culture for other organisms

Question 3

What is the clinical presentations of ulcerative colitis?

Answer 3

Bloody diarrhea with stringy, mucoid material, lower abdominal pain, and cramps
Only involves the colon, always involves rectum
Endoscopic appearance: Diffuse distribution (NO skip lesions), thin wall appearance
Plus extra-intestinal symptoms

Question 4

What are the clinical presentations of Crohn’s disease?

Answer 4

Relapsing-remitting disease
Intermittent attacks of mild diarrhea, may or may not be bloody, fever, abdominal pain.
Involves the colon and ileum with skip lesions, strictures/fistulae, granulomas, and thick walled appearance due to fibrosis.
Plus Extra-intestinal symptoms

Question 5

What are the extra-intestinal manifestations of ulcerative colitis?

Answer 5

Primary sclerosing cholangitis

Pericholangitis

Question 6

What are the extra-intestinal manifestations of Crohn’s disease?

Answer 6

Sacroiliitis
Ankylosing Spondylitis
Erythema Nodosum
Migratory Polyarthritis
Uveitis

Question 7

What are the uniquely differentiating features of ischemic colitis?

Answer 7

Old age with co-existing cardiovascular disease, acute disease course (1-2 weeks) that resolves spontaneously

Question 8

What are the uniquely differentiating features of infectious colitis?

Answer 8

Foreign travel or ingestion of infectious agent. Often acute and self limiting; stool culture is needed.
C. diff infection is not self limiting, requires hospitalization, and typically has history of antibiotic use

Question 9

What are the uniquely differentiating features of ulcerative colitis?

Answer 9

Associated with PSC, chronic condition, always involves rectum, and is restricted to the colon

Question 10

What are the uniquely differentiating features of Crohn’s disease?

Answer 10

Chronic relapsing and remitting occurrence, skip lesions, strictures, fistulae, granulomas, and extra intestinal manifestations

Question 11

What are diverticula, where do they occur, and how to they grow?

Answer 11

Diverticula are outpouchings of the colon wall that contain the mucosa and submucosal layers. They herniate outward through the muscular propria but are contained by serosa, only occurring in the colon. They penetrate the muscular propria via the gaps created by the vasa recta.

Question 12

What is the epidemiology and likely causes of diverticula?

Answer 12

Very common in western countries but essentially non-existent in rural Africa and Asia. Strongly associated with a low fiber diet that results in slowed colonic motility, increased peristaltic squeeze pressure and intracolonic pressure. Age is also highly associated with diverticulosis, >50% of people 80 years and older. 80% of those with diverticulosis remain asymptomatic throughout their lifetime.

Question 13

What are the complications of diverticulosis?

Answer 13

Diverticulum may become impacted with stool and allow bacteria to multiply, eventually leading to rupture - termed “acute diverticulitis”. Acute diverticulitis may be uncomplicated or complicated.

Question 14

What is the presentation and most common location of acute diverticulitis?

Answer 14

Quick onset (

Question 15

What is uncomplicated acute diverticulitis and how is it treated?

Answer 15

If the perforation of the diverticulum is contained with minimal abscess formation around the colon wall, it is an uncomplicated diverticulitis. Treatment is oral or IV antibiotics alone.

Question 16

What is a complicated acute diverticulitis and how is it treated?

Answer 16

If there is a free perforation of the diverticulum that results in a large abscess or the bowel becomes obstructed it is a complicated diverticulitis. Complicated diverticulitis is treated by draining the abscess through placement of a tube via the skin or rectal wall. If this is unsuccessful surgery is required.

Question 17

What is the differential diagnosis for lower GI bleeding?

Answer 17

Diverticulosis
Arteriovenous Malformations (AVM)
Neoplasia
Colitis (IBD, Ischemic Colitis, Infectious Colitis, Radiation)
Iatrogenic (commonly post-polypectomy)
Anorectal Disease (hemorrhoid, fissure)
Miscellaneous etiologies

Question 18

What signs associated with LGIB indicate diverticulosis as the cause?

Answer 18

Sudden onset, painless, large volume hematochezia (passage of red or maroon blood) which stops 2-3 days later.

Question 19

What signs associated with LGIB indicate a neoplastic cause?

Answer 19

Often a history of weight loss, changes in stool caliber or frequency, a personal of family history of polyps or cancer, or microcytic anemia with iron deficiency.

Question 20

What signs associated with LGIB indicate an infectious cause?

Answer 20

Bloody diarrhea (dysentery), history of travel, ill contacts who shared a recent meal, known outbreak, or antibiotic use (C. diff!!)

Question 21

What signs associated with LGIB indicate drug-related cause?

Answer 21

NSAID use, drug induced colitis

Question 22

What is the initial treatment of LGIB?

Answer 22

Stabilization through IV fluids or transfusions if necessary, correcting anemia or clotting disorders (if relevant), avoid PO intake. Hospitalization is usually indicated. Subsequent treatment depends on the specific cause.

Question 23

What are the causes of colonic obstruction?

Answer 23

Most common:
Adenocarcinoma of colon or rectum
Volvulus
Benign strictures from acute diverticulitis
Less common:
Surgical adhesions
Foreign bodies (inserted or ingested, homosexual patients, prisoners, rape victims, drug smugglers)

Question 24

How does colonic obstruction typically present?

Answer 24

Diffuse or upper abdominal discomfort, distention, N/V
Emesis may by feculent
Absence of stool passage (obstipation), or low grade diarrhea/incontinence due to loose stool passing the obstruction.

Question 25

How is colonic obstruction diagnosed?

Answer 25

Clinical presentation and abdominal X-ray. X-rays show dilated loops of colon/small intestine proximal to obstruction, with decompression distally. CT is not required

Question 26

What is a volvulus?

Answer 26

A volvulus typically involves the cecum or sigmoid colon, where a colonic loop twists around on its mesentery, resulting in strangulation and luminal obstruction.

Question 27

What is the treatment for colonic obstruction?

Answer 27

Hospital admission, NPO status, nasogastric tube for decompression of gastric distention. Colonoscopy may be used for tumor diagnosis and location, or for sigmoid volvulus relief (with endoscopic rotation, >50% chance of recurrence).