GI - Pathology (Hirschsprung disease & other intestinal disorders)

Question 1

What defines/characterizes Hirschsprung disease? What causes it?

Answer 1

Congenital megacolon characterized by lack of ganglion cells/enteric nervous plexuses (Auerback and Meissner plexuses) in segment on intestinal biopsy. Due to failure of neural crest cell migration.; Think: “of Hirschsprung as a giant spring that has sprung in the colon”

Question 2

With what mutations is Hirschsprung disease associated?

Answer 2

Associated with mutations in the RET gene

Question 3

What are 3 signs/symptoms with which Hirschsprung disease presents?

Answer 3

Presents with bilious emesis, abdominal distention, and failure to pass meconium in the first 48 hours of life, ultimately manifesting as chronic constipation

Question 4

What is the “transition zone” of Hirschspring disease?

Answer 4

Dilated portion of the colon proximal to the aganglionic segment, resulting in a “transition zone”

Question 5

Is the rectum involved in Hirschsprung disease?

Answer 5

Involves rectum

Question 6

With what condition is the risk of Hirschsprung disease increased?

Answer 6

Risk increased with Down syndrome

Question 7

How is Hirschsprung disease diagnosed? How is it treated?

Answer 7

Diagnosed by rectal suction biopsy; Treatment: resection

Question 8

What defines intestinal adhesion? When does it commonly form?

Answer 8

Fibrous band of scar tissue; commonly forms after surgery

Question 9

What is the most common cause of small bowel obstruction?

Answer 9

Adhesion

Question 10

What can be significant in the histology of intestinal adhesion?

Answer 10

Can have well-demarcated necrotic zones

Question 11

What is angiodysplasia, and what effect can it have?

Answer 11

Tortuous dilation of vessels => hematochezia

Question 12

At what 3 locations in the GI tract is angiodysplasia most often found? In what patient population is it more common?

Answer 12

Most often found in cecum, terminal ileum, and ascending colon. More common in older patients.

Question 13

How is the diagnosis of angiodysplasia confirmed?

Answer 13

Confirmed by angiography

Question 14

What signs/symptoms does duodenal atresia cause, and why?

Answer 14

Causes early bilious vomiting with proximal stomach distention (“double bubble” on X-ray) because of failure of small bowel recanalization

Question 15

With what condition is duodenal atresia associated?

Answer 15

Associated with Down syndrome

Question 16

What is ileus, and what signs/symptoms does it have?

Answer 16

Intestinal hypomotility without obstruction => constipation and decreased flatus; distended/tympanic abdomen with decreased bowel sounds.

Question 17

What are 4 conditions/factors with which ileus is associated?

Answer 17

Associated with abdominal surgeries, opiates, hypokalemia, and sepsis

Question 18

What is the pathophysiology of ischemic colitis? What major sign/symptom can it have, and why?

Answer 18

Reduction in intestinal blood flow causes ischemia. Pain after eating => weight loss

Question 19

What are 2 locations in the colon where ischemic colitis commonly occurs?

Answer 19

Commonly occurs at splenic flexure and distal colon

Question 20

What patient population does ischemic colitis typically affect?

Answer 20

Typically affects elderly

Question 21

In what condition does meconium ileus occur, and what are its pathophysiology and effect?

Answer 21

In cystic fibrosis, meconium plug obstructs intestine, preventing stool passage at birth

Question 22

What defines necrotizing enterocolitis, and what is a possible complication?

Answer 22

Necrosis of intestinal mucosa and possible perforation.

Question 23

What part of the GI tract is usually involved in necrotizing enterocolitis, and what parts can be involved?

Answer 23

Colon is usually involved, but can involve entire GI tract

Question 24

In what patient population is necrotizing enterocolitis more common, and why?

Answer 24

In neonates, more common in preemies (low immunity)