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USMLE Step 1 Systems > GI > Flashcards

GI Flashcards

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USMLE® Step 1 flashcards
1
Q

How is D-xylose absorbed?

A

Monosaccharide - by brush border enzymes.

Does NOT need pancreatic amylase.

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2
Q

Gastric erosion vs. ulcer?

A

Erosion - does NOT extend past muscularis mucosa

Ulcer - extends PAST muscularis mucosa into submucosal layers

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3
Q

How does Diphtheria present and pathogenesis?

A

Diphtheria - AB exotoxin which ribosylates EF2 - inhibiting protein synthesis and causing cell death.

Presents as someone who moved here (without vaccine), grayish pharyngeal exudate, enlarged LAD, partial soft palate paralysis

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4
Q

Presentation of cancer in the head of the pancreas? Most impt RF?

A

Jaundice
Progressive weight loss, Anorexia
Courvoisier sign (palpable but nontender gallbladder)
Obstructive jaundice (dark urine, pale stools)

RF: Smoking!

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5
Q

What is superior mesenteric artery syndrome?

A

Transverse portion of the duod gets trapped btwn aorta and SMA, causing SBO.

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6
Q

What disease can cholestasis cause?

A

Osteomalacia.

Cholestasis (deposition of bile pigment within the liver) -> reduction in bile flow -> malabsorption of vit ADEK -> osteomalacia

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7
Q

In liver disease (such as alcoholic cirrhosis), which factor will be deficient first and therefore cause an increase in what time (PT or PTT)?

A

Factor VII

PT

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8
Q

What do they secrete and where are they located?
Parietal Cells
Chief Cells

A

Parietal: HCL and intrinsic factor - superficial gastric glands

Chief: Pepsinogen - deeper gastric glands

Q124

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9
Q

Pancreatic pseudocyst lined with?

A

Fibrous granulation tissue.

Not true cyst bc no epithelium on the inside. in acute pancreatitis, pancreatic enzymes leak out and induces inflammation leading to granulation tissue to wall it off. Takes about 4-6 wks after the acute episode.

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10
Q

HNPCC - what gene mutated?

A

DNA mismatch repair. 1 mutated allele inherited; another hit during life.

Lynch I: just colon cx
Lynch II: colon + extraintestinal

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11
Q

Cause of duodenal atresia vs. intestinal (jejunal, ileal, colonic) atresia

A 
Duod = failure of recanalization
Intestinal = vascular accident in utero. diminished perfusion -> ischemia. can result in "apple core" spiral config around a vessel distal portion.
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12
Q

Ulcer in which location has least risk of malignancy?

A

Duodenum

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13
Q

Anal fissure most commonly found?

A

Posterior Midline distal to the dentate line

P's: 
Below the Pectinate line
Pain while Pooping
Blood on toilet Paper
Located Posteriorly cuz this area is Poorly Perfused.
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14
Q

What structures develop from ventral bud vs. dorsal bud of pancreas?

A 
Ventral = head, main pancreatic duct, uncinate process 
Dorsal = body, tail, isthmus, accessory pancreatic duct
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15
Q

How should B12 be administered in those with B12 deficiency anemia?

A

Parenteral.

Most cases of B12 def are due to poor absorption and dietary B12 def is much less common.

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16
Q

How does the liver take up unconjugated bili from the blood vs. secreting conjugated bili into biliary system?

A

Unconjugated bili -> Liver = PASSIVE.
OATP (organic anion transporting polypeptide)

Conjugated bili -> Biliary System = ACTIVE
MRP2 (organic anion transporter that uses ATP)

If this energy-dependent transporter is inhibited, will develop a conjugated hyperbilirubinemia, with increased excretion of conj, bili into the urine.

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17
Q

Colonic diverticula form by what mechanism?

A

Pulsion - increased intraluminal pressure, such as straining when constipated.

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18
Q

Clinical manifestations of diffuse esophageal spasm mimic what condition?

A

Angina (Chest pain) + Intermittent dysphagia .

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19
Q

Elevated transaminases (viral serologies neg) + neurologic sx = What?

A

Wilson’s disease!

Can get slit lamp to get for kaiser fleischer rings. >.>

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20
Q

What are the portocaval anastomoses?

A

Esophagus: L gastric esophageal vein
Umbilical: Paraumblical epigastric
Rectal: Superior rectal Inf and Middle Rectal

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21
Q

When does a carcinoid tumor present as carcinoid syndrome?

A

Mets to the Liver or Extraintestinal, like Lung.

Intestinal Carcinoid products are metabolized by the liver, so they don’t lead to symptoms.

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22
Q

Wilson’s. How is Cu normally secreted from the body?

A

Hepatic secretion into bile -> stool.

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23
Q

What vascular tumor associated with arsenic (pesticide), vinyl chloride (plastics) and is CD31(+)?

A

Hepatic Angiosarcoma.

24
Q

“moldy” grain causing G->T p53 mutation associated with what cancer?

A

HCC - Aspergillous aflatoxin

25
Q

Histology of Acute viral Hepatitis

A

Ballooning Degeneration
Mononuclear cell infiltrate
Councilman Body (eosinophilic apop body)

26
Q

Secretin influences WHAT cell?

A

Increase HCO3 secretion from PANCREATIC apical cells.

Chloride/HCO3 ion exchange proteins in the apical surface of the cells -> as more HCO3 added to the fluid, more Cl will removed.

27
Q

How does cirrhosis result in splenomegaly?

A

Portal venous hypertension -> splenic vein HTN and splenomegaly 2/2 venous accumulation.

28
Q

Why should you treat duodenal ulcers with antibiotics?

A

Reduce recurrence risk.

Note: Although H pylori can be associated with MALToma and gastric adenocarcinoma and eradication can cause resolution of malignancy in some cases, duodenal ulcers are NOT associated with increased risk of malignancy.

29
Q

How does lactulose treat hepatic encephalopathy?

A

Acidifies the intestines (forms lactic acid and acetic acid)
NH3 -> NH4+ = ammonia excreted.

30
Q

Urine alkalinization is used to treat excess of what compounds?

Urine acidification is used to treat excess of what compounds?

A

Urine alkalinization = Used to treat weak acids

Urine acidification = Used to treat weak bases

Neural forms reabsorbed.
Ionized species trapped in urine.

31
Q

Labs associated with Pernicious Anemia.

A

Pernicious Anemia - autoAb against parietal cells

  • lack of intrinsic factor - B12 def - anemia
  • lack of parietal cells - low gastric acid, achlorydia
  • chronic atrophic gastritis results (fundus/body usually)
  • due to achlorydia - may have high gastrin levels!
32
Q

Acanthosis Nigricans is associated with?

A

Insulin Resistance, Obesity

MALIGNANCY - GI or Lungs.

33
Q

What condition presents as diarrhea + weight loss + epigastric calcifications in a chronic alcoholic?

A

Chronic Pancreatitis - Malabsorption.

34
Q

Difference in prodromal presentation of acute hep B vs. hep C.

A

Acute Hep B: “serum sickness like”
fever, malaise, skin rash, pruritis, LAD, joint pain, GI sx

Acute Hep C: typically asymptomatic, though some may complain of malaise, nausea, RUQ pain

35
Q

Wilson’s is associated with what?

A

Copper is Hella BAD.

Ceruloplasmin decreased, Cirrhosis, Corneal deposits
Hemolytic Anemia
Basal Ganglia Degeneration*
Asterixis 
Dysarthria, Dyskinesia, Dementia
36
Q

How do you treat carcinoid syndrome pharmacologically?

A

Octreotide.

37
Q

What are specific indicators of ALCOHOLIC pancreatitis vs. indicators of pancreatitis due to any etiology?

A

Specific:

  • AST/ALT > 2
  • Macrocytosis (MCV > 100) - direct toxicity of alcohol on marrow and possible nutrition deficiencies
  • Inc. GGT

Nonspecific:

  • Increased WBC
  • HypoCa (Ca bind to the FFA and deposit as soap in the area of necrosis)
  • Hypoinsulinemia, Hyperglycemia
  • HyperNa (due to third spacing, and inadequate volume intake)
38
Q

Two types of stomach cx and distinguishing features:

A
  1. Intestinal Adenocarcinoma
    RF: H.pylori, nitrosamines, smoking, chronic gastritis.
    Grow as nodular, polypoid, well-demarcated masses.
    Histo: well-formed glands, columnar or cuboidal cells.
  2. Diffuse signet-ring cell carcinoma:
    Histo: signet-ring (mucin droplets that push nucleus to one side)
    Linitis Plastica - stomach wall grossly thickened and leathery

Acanthosis Nigricans, Virchow’s node, Krukenberg tumor, Sister Mary Joseph nodule.

39
Q

Histo of squamous cell carcinoma of esophagus.

A

Neoplastic squamous cells with abundant eosinophilic cytoplasm and distinct borders. In poorly differentiated carcinoma, there is no keratinization.

Histo slides Q287

40
Q

Abetalipoproteinemia Presentation

A

Mech: Decreased synthesis of apolipoprotein B48/100 -> inability to generate chylomicrons and VLDL -> fat accumulation within enterocytes

FTT
steatorrhea - malabsorption of ADEK
Ataxia, Night blindness
Acanthocytes

41
Q

What artery supplies descending colon?

A

Inferior Mesenteric! Retard -.-

42
Q

Lactase deficiency have what labs findings?

A

Decreased stool pH (fermentation by bacteria produce hydrogen)

Increased breath hydrogen content

Increased stool osmolarity gap

43
Q

Colorectal carcinoma arising from UC - what features are different from sporadic cases?

A

Duration of disease and extent of colitis are the most significant risk factors for development of CRC from UC.

Diff features:

  • multifocal in nature
  • arise from non-polypoid dysplatic lesions
  • develop early p53 mutations and late APC mutations
  • be a higher histologic grade, signet ring morphology
44
Q

Diagnostic test for acute cholescystitis

A

HIDA - no filling up of gallbladder with radioactive

US - just seeing gallstones not enough. should see distension, gallbladder wall thickening, pericholescystic fluid, positive sonographic murphy’s sign.

45
Q

Posterior duodenal bulb ulcer likely to erode what vessel?

A

Gastroduodenal.

46
Q

Most common location for colon cancer?

A
  1. Rectosigmoid (obstructive sx)

2. Ascending colon (Fe deficiency anemia)

47
Q

Increased activity of what enzyme promotes colon adenoma formation?

A

COX2 overexpression

48
Q 
What cells secrete and what do they do generally? 
Gastrin
CCK
Secretin 
GIP
Motilin 
VIP
Somatostatin
A

Stimulate stomach
Gastrin - G cells stomach

Stimulate pancreas, gallbladder
CCK - I cells
Secretin - S cells

Inhibit Stomach, Inc. Insulin
GIP - K cells

Motilin - small intestine produces migrating motor complexes in states of fasting

VIP - parasympathetic ganglia - electrolyte and water secretion, relax intestinal sphincters

Somatostatin - D cells - shut down everything!

49
Q

VIPoma

A

Pancreatic Tumor

WDHA
Watery Diarrhea
HypoK
Achlorhydria

Tx: somatostatin

50
Q

Stimulators and Inhibitors of H+ secretion by parietal cells

A

Stimulators

  1. Vagus - Ach on M3-R (Gq)
  2. Gastrin directly (Gq)
  3. Histamine (<- gastrin) (Gs)

Inhibitors

  1. Somatostatin (Gi)
  2. Prostaglandins (Gi)
  3. GIP
  4. Secretin
  5. H2 blockers
  6. Atropine
  7. Omeprazole!
51
Q

Pancreatic Pseudocyst on CT

A

Round-fluid filled cyst (not epithelium lined) within parenchyma, usually body or tail.

May compress the IVC.

52
Q

Metoclopramide - Mech, Use, Toxicity/Contraindication

A

Reglan

Mech: D2-R Antagonist. Increased contractility, LES tone, motility. Does not influence colon transport time.

Use:
Gastroparesis - Diabetic, post-surgical.
Antiemetic

Tox: Contraindicated in

  1. Parkinson’s
  2. SBO
53
Q

Vascular supply to rectum

A

Above pectinate line = int. hemorrhoids (not painful)
A: superior rectal artery -> IMA
V: superior rectal vein -> IMV -> portal system
N: visceral

Below pectinate line = ext hemorrhoids (painful)
A: inferior rectal artery -> internal pudendal artery
V: inferior rectal vein -> internal pudendal vein -> internal iliac vein -> IVC
N: inferior rectal branch of pudendal nerve.

54
Q

Abetalipoproteinemia

A

Decreased synthesis of apolipoprotein B -> inability to generate chylomicrons -> decreased secretion of cholesterol and VLDL into bloodstream -> fat accumulation in enterocytes

Sx: presents in early childhood with 
FTT 
steatorrhea
acanthocytosis - star shaped RBC
ataxia
night blindness (vit A) 
ADEK malabsorption!!
55
Q

What travels thru the diaphragm and at what levels?

A

T8 IVC
T10 Esophagus, Vagus
T12 Aorta, Thoracic duct, Azygous Vein (red, white, blue)

I ate 10 eggs at twelve.

USMLE Step 1 Systems (11 decks)

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