Pathology of the GI Tract- SI and Colon (4)

Question 1

besides diarrhea and malabsorption, what other GI anomaly can occur in the small intestine and colon?

Answer 1

the small intestine and the colon are frequently affected by infectious and inflammatory disorders

Question 2

where is the most common site of GI neoplasia in western populations?

Answer 2

the colon

Question 3

when do the small and large intestines undergo rapid growth?

Answer 3

during weeks 4 and 5 of development

Question 4

what are 2 common GI anomalies that occur during development?

Answer 4

gastroschesis and omphalocele

Question 5

what are the two main symptoms related to pathology of the GI tract?

Answer 5

abdominal pain and GI hemorrhage

Question 6

where do endoscopes of the upper GI usually stop?

Answer 6

they don’t go past the second portion of the duodenum

Question 7

where do colonoscopes reach?

Answer 7

they don’t go further than the cecum

Question 8

what is capsule endoscopy?

Answer 8

a capsule fitted with a disposable mini video camera can examine parts of the SI that standard scopes cannot reach

Question 9

what 4 things could cause a mechanical obstruction?

Answer 9

hernias, adhesions, volvulus, or intussusception

Question 10

where can abdominal obstruction occur?

Answer 10

may occur at any level, but the SI is most often involved because of its relatively narrow lumen

Question 11

besides hernias, adhesions, volvulus, and intussusception, what else could cause mechanical obstructions?

Answer 11

tumors, infarction, and other causes of strictures (Crohn disease)

Question 12

what are the 4 clinical manifestations of obstruction?

Answer 12

abdominal pain, distention, vomiting, and diarrhea

Question 13

on a KUB, what is the sign of an obstruction?

Answer 13

air fluid levels

Question 14

what is a functional bowel obstruction?

Answer 14

paralytic ileus- a temporary disturbance of peristalsis in the absence of mechanical obstruction

Question 15

what is the most common etiology of functional bowel obstruction?

Answer 15

postoperative ileus

Question 16

besides postoperative ileus, what else could cause paralytic ileus?

Answer 16

metabolic disturbances (hypokalemia), endocrinopathies (hypothyroidism), and certain drugs (anticholinergics)

Question 17

how do you differentiate between a mechanical obstruction and a functional bowel obstruction?

Answer 17

the appearance is the same- it’s the clinical history that helps

Question 18

what is the most frequent cause of intestinal obstruction worldwide?

Answer 18

hernias

Question 19

what is the third most common cause of obstruction in the US?

Answer 19

hernias

Question 20

what happens if there is increased pressure at the neck of the pouch of a hernia?

Answer 20

it may impair venous drainage of the entrapped viscus; the resultant stasis and edema increase the bulk of the herniated loop, leading to permanent entrapment and overtime arterial and venous compromise (strangulation) and infarction

Question 21

what is the most common cause of intestinal obstruction in the US?

Answer 21

adhesions/fibrous bridges

Question 22

how does one get adhesions/fibrous bridges?

Answer 22

they are most often acquired–> surgery, trauma, intra-abdominal infection, endometriosis

Question 23

how does a volvulus present?

Answer 23

with features of both obstruction and infarction

Question 24

where does a volvulus most often occur?

Answer 24

in large redundant loops of sigmoid colon, followed in frequency by the cecum, small bowel, stomach, or rarely, transverse colon

Question 25

who tends to develop sigmoid volvulus in the industrialized world?

Answer 25

older patients, and a third of patients either have mental illness or are institutionalized

Question 26

what is initial treatment of a sigmoid volvulus?

Answer 26

correction of fluid and electrolyte imbalance followed by endoscopic decompression

Question 27

if a patient has a sigmoid volvulus, what are the indications for emergency laparotomy?

Answer 27

clinical signs and symptoms of colonic ischemia, failed decompression, and clinical features suggestive of colonic ischemia at colonoscopy

Question 28

what is the most common cause of intestinal obstruction in children younger than 2 years of age?

Answer 28

intussusception

Question 29

what is the pathophysiology of intussusception?

Answer 29

it occurs when a segment of the intestine, constricted by a wave of peristalsis, telescopes into the immediately distal segment

Question 30

what happens if intussusception goes untreated?

Answer 30

it may progress to intestinal obstruction, compression of mesenteric vessels, and infarction

Question 31

what are four causes of intussusception?

Answer 31

idiopathic, viral infection and rotavirus vaccination, intraluminal mass or tumor/polyps, 1% of CF patients

Question 32

what is the treatment/management like of intussusception?

Answer 32

it varies by age and etiology

Question 33

what are the vascular pathologies that can occur in the GI tract?

Answer 33

ischemic bowel disease and angiodysplasia

Question 34

what are the major variables that determine the severity of ischemic bowel disease?

Answer 34

the severity of vascular compromise, the time frame during which it develops, and the vessels affected

Question 35

what is a common area to see ischemic bowel disease?

Answer 35

the marginal artery–> around the splenic flexure

Question 36

what is acute vascular compromise usually due to?

Answer 36

it is vascular obstruction–> thrombosis or embolism

Question 37

what is chronic vascular compromise usually due to?

Answer 37

it is non obstructive–> cardiac failure, shock, dehydration, or vasoconstrictors

Question 38

intestinal responses to ischemia occur in two phases, what are they?

Answer 38

hypoxic injury and reperfusion injury–> the one-two punch

Question 39

what is the classic clinical presentation of acute ischemia?

Answer 39

most commonly in patients >70 and in females

Question 40

how does acute ischemia present?

Answer 40

sudden onset of cramping left lower abdominal pain, desire to defecate, passage of blood or bloody diarrhea (hematochezia or BRB per rectum)

Question 41

when evaluating a patient with acute abdominal ischemia, what is the evidence of infarction?

Answer 41

decreased bowel sounds, guarding or rebound tenderness

Question 42

what is the classical clinical presentation of chronic ischemia?

Answer 42

abdominal pain that starts about 30 minutes after eating; pain worsens over an hour; pain goes away within one to three hours

Question 43

what can untreated chronic mesenteric ischemia become?

Answer 43

it can become acute or lead to severe weight loss and malnutrition

Question 44

what other things could resemble chronic mesenteric ischemia?

Answer 44

CMV, radiation enteritis, other abdominal emergencies such as acute appendicitis, perforated peptic ulcer, acute cholecystitis

Question 45

what are 2 different outcomes of acute mesenteric compromise?

Answer 45

mucosal/ non-transmural infarcts and transmural infarcts

Question 46

which type of acute mesenteric compromise is worse?

Answer 46

transmural; and worst outcome with superior mesenteric artery occlusion

Question 47

what is angiodysplasia characterized by?

Answer 47

malformed submucosal and mucosal blood vessels that are dilated and thin walled

Question 48

where is angiodysplasia most commonly found?

Answer 48

in the cecum or right colon, and usually, come to clinical attention after the 6th decade of life

Question 49

while the prevalence of angiodysplasia is less than 1% in adults, why is it significant?

Answer 49

angiodysplasia accounts for 20% of major episodes of lower intestinal bleeding in older populations

Question 50

what is the presentation like of angiodysplasia?

Answer 50

it can range from chronic and intermittent to acute and massive hemorrhage