GIT

Question 1

Normal rotation of the midgut in embryology

Answer 1

270 degrees counter clockwise

Question 2

Most common type of malrotation

Answer 2

failure of the cecum to move into the right lower quadrant –> cecum is abnormally positioned in the right upper quadrant, and is fixated to the right lateral abdominal wall by bands of peritoneum

Question 3

Why is failure of the caecum to rotate to normal position an issue?

Answer 3

failure to form the normal broad-based adherence to the posterior abdominal wall –> mesentery, including the superior mesenteric artery, is tethered by a narrow stalk, which can twist around itself and produce a midgut volvulus

Question 4

How to Ladd bands cause an issue in the case of a volvulus

Answer 4

Bands of tissue (Ladd bands) can extend from the cecum to the right upper quadrant, crossing, and possibly obstructing, the duodenum
1. Bands predispose to obstruction + constriction of blood flow
a. 360 degree twist –> venous + lymphatic engorgement and bile stained vomiting
b. 720 degree twist –> arterial ischaemia

Question 5

Double bubble sign

Answer 5

Usually duodenal atresia, sometimes volvulus

Question 6

Hirschsprungs gene

Answer 6

RET proto-oncogene

Question 7

Risk of recurrence of Hirshsprungs

Answer 7

i. 3% recurrence risk for short-segment disease
ii. 17% recurrence risk if long-segment disease
iii. Higher risk if multiple family affected