March 16 - GI

Question 1

Osmotic laxatives

Answer 1

Polyethylene glycol, magnesium citrate

Question 2

Pigment stones: two causes

Answer 2

1. Infection of biliary tract with bacteria or helminths. Causes release of beta glucuronidase which increases unconjungated bilirubin by deconjugating bilirubin

2, Crhonic hemolytic anemia

Question 3

Opioids and gallbladder

Answer 3

Opioids can cause contraction of sphincter of Oddi. This increases bile duct pressures causing biliary colic

Question 4

Graft-vs-host disease: liver

Answer 4

Lymphatic infiltration and destruction of small intrahepatic bile ducts, similar to what is seen in PBC

Question 5

Riboflavin deficiency

Answer 5

Riboflavin used to make FAD which is involved in TCA cycle and electron transport chain. In TCA cycle, needed for succinate dehydrogenase.
Def causes stomatitis, chelitits, glossitis, seborrheic dermatitis, anemia

Question 6

TCA cycle steps

Answer 6

1. pyruvate to oxaloacetate
2. oxaloacetate to citrate
3. citrate to isocitrate
4. isocitrate to alpha ketoglutarate + NAD to NADH
5. alpha ketoglutarate to succinyl coA + NAD to NADH
6. succinyl coA to succinate + GDP to GTP
7. succinate to fumarate + FAD to FADH2
8. fumarate to malate
9. malate to oxaloacetate + NAD to NADH

Question 7

C diff colitis: toxins

Answer 7

enterotoxin A: causes watery diarrhea
cytotoxin B: causes colonic epithelial cell necoris and fibrin deposition

Both disrupt actin cytoskeleton, sirupting itght junctions

Question 8

Lipid digestion: location

Answer 8

Digestion occurs in duodenum

Abosrption occurs in jejunum

Question 9

Pus formation

Answer 9

Macrophages at site release IL-8 which calls in neutrophils

Question 10

C3a vs C5a

Answer 10

C3a: chemotactic for basophils and eosinophils
C5a: chemotactic for neutrophils

Question 11

Pancreatic pseudocysts

Answer 11

Occurs as complication of acute pancreatitis. Pancreatic enzymes leak out leading to inflammatory reaction. Granulation tissue forms and encapsulates fulid. Not a true cyst because it is lined by granulation tissue rather than epithelium. Over 4-6 weeks, granulation tissue develops into fibrosis.

Question 12

Causes of intestinal atresia

Answer 12

Duodenal: failure of recanalization
Jejunal/ileal: vascular injury; decreased perfusion results in ischemia which results in narrowing or obliteration of a segment of bowel
Colonic: cause unknown

Question 13

Arsenic poisioning: presentation, causes, treatment

Answer 13

Causes: insecticide ingestion, contaminated well water

Presentation

• acute: garlic odor, vomiting, profuse watery diarrhea, QT prolongation
• chronic: hypo or hyperpigmentation, hyperkeartosis, stocking glove neuropathy

Treatmnet: dimercaprol (chelator that increases urinary excretion)

Question 14

Deferoxamine

Answer 14

Chelator for iron OD

Question 15

CaNa2 EDTA

Answer 15

chelator for lead toxicity

Question 16

Hydroxycobalaminin

Answer 16

antidote for cyanide poisoning

Question 17

Methylene blue

Answer 17

treatment for methemoglobinemia

Question 18

Hamartonatous polyps

Answer 18

Generally benign polys. Disorganized mucosal glands, smooth muscle, connective tissue. Sporadic or associated with Peutz Jehghers or juvenile polyposis.

Question 19

Budd chiari syndrome: pathology and pathophysiology

Answer 19

Pathology: Dilation of sinusoids, perivenular hemoorhage
Cause: acute venous outflow obstruction in liver

Question 20

Anal fissure: presentation and location

Answer 20

Presentation: sharp pain + bright red bleeding with defecation

Location: Posterior midline anus distal to dentate line

Question 21

Gastric varices

Answer 21

Two causes

1) portal HTN as complication of cirrhosis
2) splenic vein thrombosis as complication of chronic pancreatitis or pancreatic cancer. Short gastrics drain the fundus to thrombosis of the splenic vein increases pressure in the short gastrics and causes gastric varices isolated to the fundus

Question 22

Azygos veins and left gastric vein

Answer 22

Azygos: drains esophageal veins to SVC

L gastric: drains upper stomach and lower esophagus to portal vein

Question 23

Crohns and gallbladder

Answer 23

Terminal ileum inflamed in Crohns. Can’t reabsorb bile acids, resulting in increased cholesterol to bile ratio and gallstone formation

Question 24

PAS stain

Answer 24

Stains glycoproteins bright pink. Good for looking at fungal cell walls, mucus secretions, BMs. In GI good for looking for T whippelii in sm bowel (gram po actinomycete)

Question 25

Portal vein thrombosis

Answer 25

Portal HTN with liver unacffected as it si a perisinusoidal process

Question 26

CA19-9

Answer 26

Pancreatic cancer marker

Question 27

CA 125

Answer 27

Ovarian cancer marker

Question 28

Carcinoembryonic antigen

Answer 28

GI cancer marker

Question 29

Crohns vs UC inflammation

Answer 29

Crohns: Th1 process resulting in granulomas UC: Th2 process resulting in mucosal damage

Question 30

Indirect inguinal hernia: population,anatomy, cause

Answer 30

Population: male infants Anatomy: superior to inguinal ligament. Lateral to inferior epigastrics. Protrudes through deep and superficial rings and is coveretd by all three fascial laters Cause: Patent processus vaginalis

Question 31

Direct inguinal hernia: popualtion, anatomy, cause

Answer 31

Population: old men Anatomy: superior to inguinal ligament. Medial to inferior epigastrics. Protrudes through Hesselbach's triangle. Superficial ring only. Covered by external spermatic fascia only Cause: weak transfersalis fascia

Question 32

Femoral hernia: population, anatomy, cause

Answer 32

Population: women Anatomy: protrudes through femoral ring, inferior to inguinal ligament Cause: weak proximal femoral canal

Question 33

Conjugated vs unconjugated bilirubin

Answer 33

Conjugated is water soluble and excess can be excreted in urine

Question 34

Cavernous hemangioma

Answer 34

Most common benign tumor of liver. Most common in adults 30-50. Often asymtpomatic. No biopsy due to risk of bleeding.

Question 35

Liver tumor associated with oral contraceptives

Answer 35

hepatic adenoma

Question 36

Zenker diverticulum: pathophysiology and presentation

Answer 36

Pathophys: Abnormal action of cricopharyngeal muscles during swallowing (either spasm or failure to relax) results in increased pressure in the pharynx resulting in herniation of pharyngeal mucosa to form a false diverticulum Presentation: dysphasia, coughing/choking sensation, halitosis, recurrent aspiration pneumonia

Question 37

Biliary sludge

Answer 37

Forms due to gallbladder hypomotility. Precursro to gallstones

Question 38

Cystinuria

Answer 38

Autosomal recessive. Increased urine cysteine. Early cysteine kidney stones.

Question 39

Locations of heart chambers

Answer 39

LA: most posterior, can compress underlying esophagus RV: lateral right heart RA: anterior and superior LV: left lateral heart

Question 40

Diverticulitis: pathophys/pathology

Answer 40

Pulsion: increased pressure from straining leads to herniation of the mucosa and submucosa through weak areas of the muscularis Most common in sigmoid colon False diverciulum as does not include muscularis layer

Question 41

Bethanechol

Answer 41

Muscarinic agonist

Question 42

Cimetidine

Answer 42

H2 blocker

Question 43

Reye syndrome

Answer 43

1. Hepatic dysfunction: vomiting, hepatomegaly, and increased LFTs. On path, microvescular steatosis (small fat vacuoles in hepatocyte cytoplasm) 2. Encephalopathy: due to increased ammonia

Question 44

Two types of stomach cancer

Answer 44

1. Diffuse type: signet ring cells (nucleus pushed to side), non-gland forming, diffuse involvement due to loss of e-cadherin 2. Intestinal type: resembles colon cancer with well formed glands, grows as a well formed mass

Question 45

Acute viral hepatitis: pathology

Answer 45

ballooning degeneration councilman bodies: eosinophilic/acidophilic apoptotic hepatocytes mononuclear infiltrate

Question 46

Non-atrophic vs atrophic chronic gastritis

Answer 46

Non-atrophic: In antrum, usually due to H pylori, and leads to duodenal ulcers Atrophic: inflammation in body and fundus leading to loss of acid producing cells, risk for cancer

Question 47

Pathogenesis of cholesterol gallstones

Answer 47

Increased cholesterol Decreased bile acids Decreased phosphatidylcholine

Question 48

Kaposi's sarcoma in GI

Answer 48

Can cause diarrhea. Diagnosed by scope which shows red/violet maculopapular lesions to raised hemorrhagic nodules. Biopsy shows spindle cells and BV proliferation

Question 49

NEcrotizing enterocolitis: presentation, pathogenesis, and diagnossis

Answer 49

Presentation: distension and bloody stools in a preemie. Pathogenesis: feeding introduces bacteria to bowel which proliferate excessively, invade the wall, and cause inflammation and ischemic necrosis Diagnosis: thin curvilinear areas of lucency that parallel gut lumen on x-ray

Question 50

Pathogenesis of hepatic steatosis in alcoholics

Answer 50

Incareds NADH produced by EtOH metab | Results in decreased FFA oxidation and accumulation of TGs