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Reserve Step I Cards > GI > Flashcards

GI Flashcards

1
Q

Linkage disequilibrium

A

When a pair of alleles are inherited together in the same gamete (haplotype) more or less often than would be expected given random chance

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2
Q

Gallstone ileus

  1. What is it?
  2. Presentation
  3. Dx
A
  1. Obstruction in the ileum due to passage of a large gallstone through a cholecystenteric fistula in the small bowel
  2. SBO
  3. Dx: Ab XR may reveal gas within the gallbladder and biliary tree
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3
Q

Positive Predictive Value

A

The proportion of indivudals with positive test results who actually have the dz

PPV = TP/ (TP + FP)

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4
Q

Between positive/ negative predicative values, and sensitivity/ specificty, which are dependent on disease prevalence in the tested population?

A

Positive/ negative predictive values

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5
Q

Enteropeptidase

  1. What secretes it?
  2. What does it do?
  3. What does its deficiency lead to?
A
  1. Comes from the jejunal brush border
  2. Activates trypsin from trypsinogen (needed for peptide breakdown and activation of other pancreatic enzymes)
  3. Deficiency impairs protein and fat absorption
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6
Q

Where are dietary lipids digested? Where are they absorbed?

A
  1. Digestion: in the duodenum via pancreatic enzymes
  2. Absorbed: in the jejunum in the form of water-soluble micelles
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7
Q

What type of MHC do APCs express?

A

MHC Class II so that they can present antigen to CD4 cells

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8
Q

Inherited defects involving what signaling pathway, result in disseminated mycobacterial dz in infancy/ early childhood?

A

Interferon-gamma

(needed to activate macrophages)

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9
Q

Where does the gastroduodenal artery sit? How can it be affected by ulceration?

A

It lies along the posterior wall of the duodenal bulb. It is likely to be eroded by posterior duodenal ulcers, leading to potential life-threatening hemorrhage.

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10
Q

Meckel diverticulum

  1. What is it/ How common is it?
  2. What causes it?
A
  1. The most common congenital anomaly of the small intestine
  2. It forms due to incomplete obliteration of the omphalomesenteric duct that connects the midgut lumen and yolk sac cavity
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11
Q

What types of tissues are comonly found in a Meckel diverticulum? Which is most common?

The presence of these tissues is an example of what?

A

Gastric (most common), pancreatic, colonic, endometrial, small bowell, etc.

This is an example of ectopy

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12
Q

Presentation of Meckel diverticulum

A

Most often presents with painless melena (gastric tissue can cause ulceration leading to lower GI bleed). The diverticulum may also become inflamed and simulate presentation of acute appendicitis.

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13
Q
  1. What is the cause of umbilical hernias?
  2. What conditions are they associated with?
A
  1. Incomplete closure of the umbilical ring
  2. Dat Big Hernia –> assc. w/ Down Syndrome, Beckwith-Wiedmann syndrome, Hypothyroidism
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14
Q

What type of polyps are most likely to undergo malignant transformation?

A

Villous adenomas

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15
Q

Vitamin E deficiency

  1. Who does it occur in?
  2. What is defiency in this vitamin associated with?
  3. Clinical manifestations
A
  1. Can occur in individuals with fat malabsorption
  2. Assc. w/ inc. susceptibility of the neuronal and erythrocyte membranes to oxidative stress
  3. Clinical manifestations: ataxia, impaired proprioception and vibratory sensation, and hemolytic anemia
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16
Q

Normal Vitamin E function

A

Protection of fatty acids against oxidation

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17
Q

What type of drug is useful for nausea assc. with GI insults?

For nausea assc. with migraine?

A

GI: 5-HT3 receptor antagonists

Migraine: Dopamine antagonists

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18
Q

What is the best non-surgical tx for cholesterol gallstones?

A

Hydrophilic bile acids (eg ursodeoxycholic acid). These decrease biliary cholesterol secretion and increase biliary bile acid concentration, improving cholesterol solubulity.

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19
Q

How is Campylobacter infection spread?

A

Via domestic animals or from contaminated food

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20
Q

Inapparopriate activation of what enzyme, leads to pancreatitis?

A

Trypsinogen (to trypsin)

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21
Q
  1. Pernicious anemia (Vit B12 def.) is caused by autoimmune destruction of what cells?
  2. What do these cells secrete and where are they located?
A
  1. Destruction of parietal cells (chronic atrophic gastritis).
  2. They secrete HCL and IF, and are found primarily in the superficial region of the gastric glands
22
Q

What are the (3) tx for C.diff and in what situation would you use each?

A
  1. Metronidazole (Initial mild/moderate C. Diff tx)
  2. Vancomycin (Severe or recurrent C. Diff)
  3. Fidaxomicin (recurrent C. Diff and inc. risk of recurrence)
23
Q

The venous component of internal hemorrhoids drain where?

External hemorrhoids?

A

Internal: drain into the middle and superior rectal veins, which communicate with the internal iliac and inferior mesenteric veins

External: drain via the inferior rectal vein into the internal pudendal vein, which communicates with the internal iliac veins

24
Q

Primary Biliary Cirrhosis/ Cholangitis

  1. What characterizes this dz?
  2. Who is it common in ?
  3. Presentation?
A
  1. Chronic liver dz characterized by autoimmune destruction of the intrahepatic bile ducts and cholestasis (elevated alk phos)
  2. Most common in middle aged women
  3. Sx: Severe pruritis (especially at night)
25
Q

What is the main dz Primary Biliary Cirrhosis (PBC) is associated with?

A

Sjrogren’s syndrome (and other autoimmune disorders)

26
Q

What disease are caused by “exotoxin” release by S. aureus?

A
  1. Toxic shock syndrome
  2. Staphylococcal scalded syndrome
  3. Gastroenteritis
27
Q

Describe the process of staphylococcal food poisoning

A

It often occurs after a food handler inoculates food (usually a mayonnaise containing product), w/ S.aureus that is allowed to incubate at room temp, producing heat-stable exotoxin that causes rapid-onset N/V and abdominal cramping

28
Q

Name the genes involved in each of the (3) steps of the “adenoma-to-carcinoma sequence”

A
  1. Progression from normal mucosa to a small polyp: mutation of the APC tumor suppressor gene
  2. Inc. in the size of the polyps: mutation of the K-ras protoncogene
  3. Malignant transformation: requires mutation of both p53 and DCC (Deleted in Colorectal Carcinoma)
29
Q

Name the main organisms that can cause diarrhea with only a small inoculum (4)

A
  1. Shigella
  2. Entamoeba histolytica
  3. Giardia lamblia
  4. Campylobacter jejuni
30
Q

What tumor type(s) is the following tumor marker assc. with?:

Alpha fetoprotein

A
  • Hepatocellular carcinoma
  • Germ cell tumors
31
Q

What tumor type(s) is the following tumor marker assc. with?:

CA 19-9

A

Pancreatic

32
Q

What tumor type(s) is the following tumor marker assc. with?:

CA 125

A

Ovarian

33
Q

What tumor type(s) is the following tumor marker assc. with?:

Carcinoembryonic antigen

A

GI (colorectal)

34
Q

What tumor type(s) is the following tumor marker assc. with?:

HCG

A
  • Choriocarcinoma
  • Germ cell tumors
35
Q

What tumor type(s) is the following tumor marker assc. with?:

PSA

A

Prostate

36
Q

New-onset odynophagia in the setting of chronic GERD usually indicates what?

Dx?

A

Erosive esophagitis and the formation of an ulcer

Dx via upper endoscopy

37
Q

Kehr sign

A

Referred shoulder pain due to irritation of the phrenic nerve sensory fibers around the diaphragm as the result of some abdominal process (ruptured spleen, peritonitis, hemoperitoneum)

38
Q

Embryologically, the dorsal pancreatic bud forms what?

The ventral pancreatic bud?

A
  1. Dorsal: majority of the pancreatic tissue (body, tail, and most of the head)
  2. Ventral: precursor of the uncinate process, inferior/posterior portion of the head, and the major pancreatic duct
39
Q

What is pancreas divisum?

A

Failure of the dorsal and ventral pancreatic buds to fuse

40
Q

Colonic Diverticula

  1. Involve what part of the colon?
  2. What process leads to their development?
A
  1. Usually involve the sigmoid colon
  2. The result of increased intraluminal pressure (pulsion) created during strained bowel movements
41
Q

What is the most superficial layer in which you can appreciate an absence of ganglion cells in Hirschsprung dz?

A

The submucosa of the narrowed area

42
Q

Bile acid-binding resins

  1. Give one major example
  2. MOA
A
  1. Cholestyramine
  2. Binds bile acids, forcing the liver to inc. uptake of LDL in order to create more bile.
43
Q

Describe the relationship between Bile acid-binding resins and Statins

A

BAB resins (ex. cholestyramine) Inc. stimulation of HMg-CoA Reductase, which will need to be compensated by giving a Statin. Synergistic effects with the statin further reduce plasma LDL level.

44
Q

The (2) most signficant risk factors for development of esophageal SCC in the US

A

Smoking tobacco and drinking alcohol

45
Q

Presentation of Right-Sided Colon CA

A
  1. Occult bleeding
  2. Sx of iron deficient anemia
46
Q

Presentation of Left-sided Colon CA

A
  1. Constipation
  2. Sx of Intestinal Obstruction

(Left sided colon CA tends to infiltrate the intestinal wall and encircle the lumen)

47
Q

Ulcers in which of these locations are NOT associated with an increased risk of carcinoma in that location?

  • Duodenum
  • Esophagus
  • Stomach
  • Colon/Rectum
A

Of these, only Duodenal ulcers are not associated with an inc. risk of CA

48
Q

Which blood vessels does the third part of the duodenum interact with?

A

It crosses horizontally acros the abdominal aorta and the IVC at the level of L3.

The Superior mesenteric vessels lie anterior to the duodenum at this location.

49
Q

Location of femoral hernias

A

Inferior to the inguinal ligament, lateral to the pubic tubercle, and medial to the femoral vein

50
Q

Presentation/ potential complications of femoral hernias

A

They can present with groin discomfort or manifest with a bulge on the upper thigh.

Incarceration and strangulation are common complications of femoral hernias.

51
Q

Abetalipoproteinemia

  1. What is it?
  2. Consequence?
  3. Describe the histo
A
  1. An inherited inability to synthesize apoB, which is critical for chylomicrons and VLDL
  2. As a result, lipids absorbed by the small intestine cannot be transported into the blood and accumulate in the intestinal epithelium.
  3. Enterocytes w/ clear/ foamy cytoplasm
52
Q

Achalasia

  1. Cause
  2. What is seen on esophageal manometry?
A
  1. Caused by reduced numbers of inhibitory ganglion cells in the esophageal wall
  2. Manometry shows dec. amplitude of peristalsis in the mid esophagus, w/ increased tone and incomplete relaxation at the LES

Reserve Step I Cards (10 decks)

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