Intestinal Disorders B&B

Question 1

what is the typical cause of appendicitis in adults vs children?

Answer 1

adults - fecaliths (hard fecal masses) obstructing opening to cecum

children - lymphoid hyperplasia obstructs opening to cecum

Question 2

what is the classic clinical presentation of appendicitis?

Answer 2

abdominal pain begins mid-epigastric due to visceral peritoneum inflammation - not well localized

as inflammation progresses, pain moves to RLQ due to parietal peritoneum inflammation - can be localized

classic location = McBurney’s Point: 1/3 distance from the iliac crest to the umbilicus (RLQ)

also presents with fever and nausea

Question 3

what is the significance of McBurney’s Point

Answer 3

classic location of appendicitis pain - 1/3 distance from the iliac crest to the umbilicus (RLQ)

Question 4

Pt is 48yo M presenting w/ fever, nausea, and abdominal pain that began around the stomach and has now moved to the RLQ - what are you concerned about?

Answer 4

appendicitis: abdominal pain begins mid-epigastric due to visceral peritoneum inflammation (not well localized), then moves to RLQ due to parietal peritoneum inflammation (better localized)

classically ends up in McBurney’s Point - 1/3 distance from the iliac crest to the umbilicus (RLQ)

Question 5

what is meant by “rebound tenderness,” and which 3 causes of this require urgent surgical intervention?

Answer 5

“rebound tenderness” = pain on release after pressing abdomen, reflects peritoneal inflammation

require urgent surgical intervention (”acute abdomen”):
1. appendicitis
2. diverticulitis
3. ectopic pregnancy

acute abdomen can progress to perforation of abdominal viscus!

Question 6

what causes the weakness in the muscularis mucosa that allows diverticulum to form?

Answer 6

diverticulum = blind pouch/sac extending out from GI tract, containing mucosa + submucosa, due to breakdown of muscualris mucosa

occur where the vasa recta penetrate the muscularis mucosa, because these are areas of weakness

[technically these are “false diverticulums” because they lack muscular layer]

Question 7

what is the typical cause of diverticulosis, and where does this typically occur anatomically?

Answer 7

caused by straining to pass stool, which creates wall stress - risk factors include low fiber diet (—> hard stools)

diverticulosis = many diverticula in GI tract, usually in sigmoid colon

[recall diverticulum = blind pouch/sac extending out from GI tract, containing mucosa + submucosa, due to breakdown of muscualris mucosa]

Question 8

hematochezia =

Answer 8

lower GI bleeding

Question 9

what are the presenting symptoms of diverticulitis?

Answer 9

diverticulum = blind pouch/sac extending out from GI tract, containing mucosa + submucosa, due to breakdown of muscualris mucosa

diverticulosis (multiple diverticula in GI tract) is usually asymptomatic, but may cause symptoms if extensive inflammation occurs —> diverticulitis

presents w/ fever + elevated WBC + LLQ pain (“left-sided appendicitis”) because diverticula occur in sigmoid colon + “occult blood” in stool (can’t see but can measure in labs)

Question 10

Pt is a 45yo F presenting w/ fever and LLQ pain. Labs show elevated WBC and occult blood. What are you concerned about?

Answer 10

diverticulum = blind pouch/sac extending out from GI tract, containing mucosa + submucosa, due to breakdown of muscualris mucosa

diverticulosis (multiple diverticula in GI tract) is usually asymptomatic, but may cause symptoms if extensive inflammation occurs —> diverticulitis

presents w/ fever + elevated WBC + LLQ pain (“left-sided appendicitis”) because diverticula occur in sigmoid colon + “occult blood” in stool (can’t see but can measure in labs)

Question 11

of what is colovesical fistula a complication?

Answer 11

colovesical fistula = fistula of GI diverticulus to bladder —> pneumaturia (air in bladder), fecaluria (fecal in urine), dysuria

diverticulum = blind pouch/sac extending out from GI tract, containing mucosa + submucosa, due to breakdown of muscualris mucosa

Question 12

most common cause of small bowel obstruction

Answer 12

adhesions - bands of scar tissue in peritoneal cavity formed after surgery

Question 13

what is intussusception, and how does it present? include where it occurs

Answer 13

intussusception: “telescoping” of intestine as it folds into its own lumen —> causes backup of intestinal content

blocks bloods supply, causing necrosis —> ”currant jelly” GI bleeding

rare in adults, common in children (<1 yo), often near ileocecal junction

medical emergency !

Question 14

what are the causes of lead points for intussusception in children (2) vs adults (1)?

Answer 14

intussusception: “telescoping” of intestine as it folds into its own lumen (at “lead point”) —> causes backup of intestinal content + “currant jelly” GI bleeding (necrosis)

children (<1): Meckel’s diverticulum or lymphoid hyperplasia of Peyer’s patches, strongly associated with adenovirus gastroenteritis

adults (rare): tumors

Question 15

which virus has a strong association with intussusception in children?

Answer 15

intussusception: “telescoping” of intestine as it folds into its own lumen (at “lead point”) —> causes backup of intestinal content + “currant jelly” GI bleeding (necrosis)

strongly associated w/ adenovirus gastroenteritis in children (<1) causing lymphoid hyperplasia of Payer’s patches

Question 16

where does volvulus typically occur (2)?

Answer 16

volvulus = twisting of bowel around mesentery —> obstruction/ infarction

classically occurs at sigmoid colon or cecum

occurs mostly in elderly (~70yo) or secondary to Meckel’s diverticulum in children

Question 17

what are the 2 classic imaging findings of volvulus when it occurs at the sigmoid colon?

Answer 17

volvulus = twisting of bowel around mesentery —> obstruction/ infarction

classic sigmoid findings = dilated sigmoid colon + airless rectum

occurs mostly in elderly (~70yo) or secondary to Meckel’s diverticulum in children

Question 18

what are the common causes of small bowel obstruction (SBO) (3) vs large bowel obstruction (LBO) (3)?

Answer 18

SBO: Adhesion, Bulge (hernia), Cancer [ABC]

LBO: Tumor, Adhesions, Volvulus [TAV]

[volvulus = twisting of bowel around mesentery

Question 19

what is the cause of Hirschsprung’s Disease?

Answer 19

failure of neural crest cell migration —> absent ganglion cells in Meissner’s plexus (submucosa) and Auerbach’s plexus (muscularis)

result is failure of peristalsis and subsequent obstruction

associated with Down Syndrome

Question 20

with what genetic disorder is Hirschsprung’s Disease associated?

Answer 20

failure of neural crest cell migration —> absent ganglion cells in Meissner’s plexus (submucosa) and Auerbach’s plexus (muscularis)

result is failure of peristalsis and subsequent obstruction

associated with Down Syndrome

Question 21

what is the initial presentation of Hirschsprung’s Disease?

Answer 21

failure of neural crest cell migration —> absent GI ganglion cells (Meissner’s, Auerbach’s plexus)

failure of peristalsis —> dilated bowel behind obstruction and failure to pass meconium (first stool) + abdominal distention, bilious vomiting + no stool in rectal vault

associated with Down Syndrome

Question 22

how is Hirschsprung’s Disease diagnosed on imaging and biopsy?

Answer 22

failure of neural crest cell migration —> absent GI ganglion cells —> failure of peristalsis and subsequent obstruction

barium imaging shows cone-shaped ”transition zone” where bowel becomes small

rectal “suction” biopsy shows absence of ganglion cells - this works because the rectum is ALWAYS involved

Question 23

what are common causes of ileus (2)?

Answer 23

ileus = loss of bowel peristalsis, can cause N/V, constipation, obstipation (cannot pass stool)

common causes include narcotics and post-operative (due to anesthesia)

Question 24

ogilvie syndrome

Answer 24

“pseudo-obstruction” of intestines - dilated colon in absence of lesion

usually in hospitalized or nursing home setting in patients w/ severe illness or recent surgery, often associated with narcotics

just think of it as body is so sedentary, the bowel became sedentary, too

Question 25

what is the major risk factor for necrotizing enterocolitis?

Answer 25

intestinal necrosis and obstruction occurring in neonates (1st month)

major risk factor is prematurity and low birth weight (bacteria believed to overgrow immaterial mucosal defenses)

occurs in terminal ileum or colon, can lead to perforation

Question 26

where does angiodysplasia occur, and what is it caused by?

Answer 26

angiodysplasia = aberrant blood vessels in GI tract, commonly in cecum and R-sided colon

caused by high wall stress, and leads to lower GI bleeding (hematochezia)

Question 27

what is the hereditary pattern and presentation of hereditary hemorrhagic telangiectasia?

Answer 27

hereditary hemorrhagic telangiectasia (aka Osler-Weber-Rendu syndrome): autosomal dominant vascular disease

causes telangiectasias throughout GI tract (nasopharynx to rectum) —> nose bleeds, GI bleeding, iron deficiency (blood loss)

rarely also causes AVMs (pulmonary, CNS)