Gastrointestinal and nutritional Flashcards
(489 cards)
1
Q
what is the benefit of combining magnesium salts and aluminum hydroxide in an antacid preparation
A
to reduce adverse side effects
aluminum hydroxide causes constipation and magnesium salts cause diahrrea
2
Q
indication for magnesium salts and aluminum hydroxide
A
neutralize gastric acid and relieve gastroesophageal reflux symtpoms
3
Q
what is the function of cholangiocytes
A
bile duct epithelial cell that transports solutes and electrolytes into bile
4
Q
what is the function of hepatocytes
A
protein, cholesterol, and bile synthesis
gluconeogenesis
drug and fatty acid metabolism
5
Q
function of Kupffer cells
A
macrophages within hepatic sinusoids
phagocytosis of bacteria and RBCs
6
Q
function of stellate cells
A
quiescent phase: vitamin A storage
activated phase: transform into myofibroblast to secrete collagen (primarily involved in hepatic fibrosis)
7
Q
what cell type contributes to scar formation and cirrhosis in the liver
A
stellate (ito) cells
8
Q
what are the manifestations of cirrhosis (clinical signs)
A
jaundice
scleral icterus
spider angiomas
elevated liver enzymes
9
Q
what is Meckel’s diverticulum
A
partial failure of the ophalomesenteric (vitelline) duct to obliterate
10
Q
how might Meckel’s diverticulum present?
A
(most are asymptomatic)
rectal bleeding or intestinal obstruction
11
Q
what is the rule of 2s with Meckel’s diverticulum
A
2% of the population 2 feet from the ileocecal valve 2 inches in length 2% are symptomatic males are 2 times more likely to be affected
12
Q
what layers are present in a false diverticula vs a true diverticulum
A
false: mucosa and submucosa
true: mucosa, submucosa, muscularis
13
Q
in addition to mucosa, submucosa and muscularis, what other tissue might be present in a Meckel’s Diverticulum
A
ectopic mucosa
(gastric epithelium is most common and pancreatic tissue is the next most common)
(ectopic gastric tissue secretes gastric acid that can cause ulceration and lower GI bleeding)
14
Q
what is the pathogenesis of diabetic gastroparesis
A
autonomic neuropathy
destruction of enteric neurons
failure of relaxation in fundus and uncoordinated peristalsis
15
Q
what is the clinical presentation of a patient with diabetic gastroparesis
A
postprandial bloating and vomiting
early satiety
impaired nutrition and weight loss
16
Q
treatment for diabetic gastroparesis
A
promotility drugs: metoclopramide, erythromycin
17
Q
after food passes down the esophagus, vagally stimulated enteric neurons release ______ to induce relaxation of the fundus of the stomach and accommodate the incoming food bolus
A
nitric oxide
18
Q
specialized gastric pacemaker cells (_______) initiate pacesetter potentials (slow waves), which generate circumferential contractions of the gastric smoth muscle (peristalsis)
A
interstitial cells of Cajal
19
Q
what is the diagnosis of someone with a BMI <18.5 with enlarged parotid glands
A
anorexia nervosa
if they are under 18.5, even if they binge and purge, they are diagnosed with anorexia
20
Q
how does C. Dif. cause diahrrea
A
toxins inactivate Rho-regulatory proteins involved in actin cytoskeletal structure –> loss of cytoskeleton integrity –> cell rounding/retraction –> disruption of intercellular tight junctions –> increased paracelljular fluid secretion
21
Q
how does C. Dif. cause pseudomembrane formation
A
toxins have inflammatory effects (neutrophil recruitment) and can induce apoptosis which results in pain and pseudomembrane formation
22
Q
gastrin: action and secretion site
A
increase gastric H+ secretion G cells (gastric antrum and duodenum)
23
Q
somatostatin: action and secretion site
A
decrease secretion of most GI hormones D cells (pancreatic islets, gut mucosa)
24
Q
cholecytokinin: action and secretion site
A
increase pancreatic enzyme and HCO3 secretion I cells (small intestine)
25
secretin action and secretion site
increases pancreatic HCO3 secretion and decreases gastric H+ secretion
K cells
26
GIP action and secretion site
```
increases insulin release and decreases gastric H+ secretion
K cells (small intestine)
```
27
motilin action and secretion site
```
increases GI motility
M cells (small intestine)
```
28
what is the most potent stimulus for secretin release
release of gastric acid into the duodenum
| begins at pH below 5 and rises dramatically as the pH drops below 3
29
what are gastric varices
dilated submucosal veins that can cause life threatening bleeding in the upper gastrointestinal tract
30
the ____ vein runs along the posterior surface of the pancreas and can develop a blood clot from pancreatic inflammation
splenic
31
the ____ veins drain the fundus of the stomach into the splenic vein
short gastric
32
splenic vein thrombosis can increase pressure in the short gastric veins and cause gastric varices only in the ____. The rest of the stomach and esophagus are not usually affected.
fundus
33
what areas of the intestine are hindgut derivatives
distal 1/3 of transverse colon
descending colon
sigmoid colon
rectum
34
hindgut structures receive blood from ____
inferior mesenteric artery
35
what is the inferior mesenteric artery a branch of?
aorta
36
the hindgut derivatives drain into the ____ which drains into the _____
inferior mesenteric vein
| portal vein
37
pellagra is due to ____ deficiency
niacin
38
what are "the 3 D's" which characterize pellagra
dermatitis
diarrhea
dementia
39
what is the dermatitis presentation in peelagra
bilateral and symmetric on sun exposed areas of the body
| characterized by rough, thick, scaly skin
40
what causes diarrhea in pellagra,
atrophy (and occassional ulceration) of columnar epithelium of the gastrointestinal tract
41
niacin (vitamin B3) is an essential component of what 2 coenzymes that participate in redox metabolism
NAD
| NADP
42
if niacin is not obtained through dietary intake, what can it be endogenously synthesized from
tryptophan
43
what changes occur in the small intestine due to the immune mediated reaction in celiac disease causing impaired nutrient absorption
villous atrophy
crypt hyperplasia
intraepithelial lymphocyte infiltration
44
screening for celiac disease tests for elevated serum levels of ______ and ______
IgA anti-endomysial and anti-tissue transglutaminase antibodies
45
how is diagnosis of celiac disease confirmed
endocscopic biopsy
46
when and how does celiac disease classically present
between 6-24 months
| abdominal pain, diarrhea, vomiting, weight loss
47
what supplies blood to the stomach, part of the duodenum, gallbladder, liver, spleen and pancreas
celiac trunk
48
the superior mesenteric artery and inferior mesenteric artery are connected by a pair of anastomoses: _____ and ____
marginal artery of Drummond (principal anastomosis)
| arc of Riolan (inconsistently present)
49
how might Chron disease cause gallstones
terminal ileum (typical location of Crohn disease) inflammation --> bile acids lost in feces --> increased cholesterol/bile acids ration
50
protein yields ____ calories per gram
4
51
fat yields ___ calories per gram
9
52
carbohydrates yield __ calories per gram
4
53
ethanol yields __ calories per gram
7
54
define cholescystitis
inflammation of the gallbladder
55
acute cholecystitis is cause by what in more than 90% of cases
gallstone obstruction of cystic duct
56
what causes colicky pain in cholecystitis
ingestion of fatty foods --> contraction of gallbladder against impacted stone
57
how is ultrasonography used to diagnose acute cholecystitis
diagnosis can be made by identifying signs of gallbladder inflammation (wall thickening, pericholecystic fluid)
58
when ultrasound is inconclusive of cholecystitis diagnosis what can be used
nuclear medicine hepatobiliary scanning (cholescintigraphy) to asses cystic duct patency and make diagnosis
59
what causes hepatic encephalopathy
neurologic complication of cirrhosis due to liver's inability to convert ammonia to urea (excess ammonia crosses BBB --> altered mental status)
60
how can GI bleeding precipitate hepatic encephalopathy
hemoglobin breakdown leads to increased nitrogen products. nitrogen breakdown by intestinal bacteria = primary source of ammonia
61
how does Rifaximin treat hepatic encephalopathy
it is a nonabsorbable antibiotic that alters GI flora to decrease intestinal production and absorption of ammonia
62
how does lactulose help treat hepatic encephalopathy
it is catabolized by intestinal bacterial flora to short chain fatty acids which lowers the colonic pH and increases conversion of ammonia to ammonium
63
why is vitamin D supplementation indicated in infants
if they are exclussively breastfed
lack of sunlight exposure
dark skin pigmentation
64
breast milk contains all vitamins except__ and ___
vitamin D
| vitamin K
65
how is vitamin K supplmeneted to new borns
intramuscular injection at delivery to prevent hemorrhagic disease in the newborn
66
what causes annular pancreas
abnormal migration of the ventral pancreatic bud
67
the ventral pancreatic bud is a _____ derrivative that appears the 5th week of gestation and rotates ___ the duodenum during the 7th week
foregut
| behind
68
the ventral pancreatic bud gives rise to what portions of the pancreas
uncinate process portion of the head and the main painceatic duct (of Wirsung)
69
what is an annular pancreas
congenital anomaly in which pancreativ tissue completely surrounds the second part of the duodenum
70
while most patients with annular pancreas are asymptomatic, what are 2 ways it can cause symptoms
it can compress the duodenal lumen causing obstruction or result in obstructed pancreatic drainage and cause acute or chronic pancreatitis
71
what are 2 ways that gastric secretions are neutralized in the gut
alkaline mucous secreted by submucosal Brunner glands
| pancreatic alkaline secretions
72
where are submucosal (Brunner) glands found
most numerous at the pylorus but may be found intermittently up to the ampulla Vater
73
how are submucosal (Brunner) glands stimulated
tactile stimulation and increased parasympathetic activity following meals
acid --> secretin release --> stimulation of submucosal glands and pancreas
74
what can cause hyperplasia of the submucosal (Brunner) glands
chronic overproduction of gastric acid
75
what does the presence of a fluid filled cavity in the liver in conjunction with fevers, chills, and right upper abdominal pain suggest
hepatic abscess
76
what is the most common cause of hepatic abscesses in developing countries
parasitic infections (entamoeba histolytica, echinococcal)
77
what are hepatic abscesses in the united states most oftenly caused by
bacterial infection
78
what route of hepatic access would cause a hepatic abscess due to staphylococcus aureus
hepatic artery due to hematogenous seeding
79
how could Entamoeba histolytica cause a hepatic abscess
(most often transmitted though foodborne exposure)
| ascending from the colon through the portal venous system
80
how can enteric bacteria cause hepatic abscesses
ascending the bilary tract (ascending cholangitis)
portal vein pyemia
direct invasion from adjacent area (cholecystitis)
81
Is Hep B or C more likely to be passed sexually
```
Hep B
(Hep C is more commonly spread through intravenous drug use)
```
82
acute hepatitis B presentation
systemic, skin, and joint symptoms; hepatomegaly; elevated transaminase levels
patients may also develop serum sickness-like syndrome and right upper quadrant pain
83
what is the most important early serum marker of acute infection of hepatitis B
hepatitis B surface antigen (HBsAg)
84
the spleen is derived from what embryologic tissue
mesoderm
85
how do diltiazem and verapamil cause constipation
they are non-dihydrophyridine calcium channel blockers
constipation is due to inhibition of the colonic migrating motor complex resulting in slowed contractions of colonic smooth muscle
86
what is ascites
accumulation of fluid within the peritoneal cavity
87
what effect does portal hypertension in cirrhosis have on splanchnic vascular resistance
nitric oxide is released in cirrhosis --> splanchnic vasodilation --> decreased splanchnic vascular resistance
88
what effect does cirrhosis have on effective arterial blood volume
NO release --> splanchnic vasodilation --> blood pools in splanchnic vascular bed --> decreased effective arterial blood volume
89
what effect does cirrhosis have on RAAS
low perfussion pressure --> activation of RAAS --> retention of sodium and water
90
how is vascular permeability altered in chirrosis
it is not changed
91
what change does cirrhosis have on oncotic pressure
decreased plasma oncotic pressure (due to hypoalbuminemia due to impaired hepatic function)
92
what are the 3 main causes of HIV associated esophagitits
Candida
CMV
HSV
93
how can CMV esophagitis be characterized endoscopically?
large, shallow linear ulcerations with intraneuclear and cytoplasmic inclusions microscopically
94
where does most cutaneous lymph from the umbilicus down drain?
superficial inguinal lymph node
| exceptions = glans penis and posterior calf drain to deep inguinal nodes
95
where does lymph from the superior portion of the bladder drain?
external iliac nodes
96
where does lymph drain from inferior portion of the bladder
internal iliac nodes
97
lymph from the prostate drains primarily to what lymph node?
internal iliac nodes
98
lymph from the testes drains where?
abdominal para-aortic lymph nodes
99
lymph from the upper 1/3 of the rectum drains to where?
inferior mesenteric lymph nodes
100
what can cause diabetic diarrhea
diabetic autonomic neuropathy
101
what are the branches of the splenic artery
pancreatic branches
left gastroepiploic artery
short gastric branches
102
why are tissues supplied by the short gastric arteries vulnerable to ischemic injury following splenic artery blockage
they have poor anastomoses
103
the splenic artery originates from the ___ artery
celiac
104
what is pernicious anemia
autoimmune disorder caused by cell mediated destruction of parietal cells --> decreased intrinic factor--> B12 deficiency --> megaloblastic anemia
105
where are parietal cells found? (layer and area of stomach)
upper glandular layer of gastric body and fundus
106
what substrate can bypass phosphofructokinase in glycolysis
fructose
107
why is fructose metabolized by the liver faster than the other monosaccharides
fructose bypasses phosphofructokinase which is one of the key enzymes involved in regulating the rate of glycolysis
108
dietary fructose is phosphorylated in the liver to ____ by _____
fructose-1-phosphate
| fructokinase
109
what does 99mTc-pertechnetate have an affinity for and what does increased uptake of 99mTc-pertechnetate in the periumbilical/right lower quadrant indicate?
parietal cells
| Meckel diverticulum
110
what is the prognosis of colorectal cancer confined to the basement membrane or lamina propria? what is the strongest predictor of metastatic potential in colorectal cancer
good prognosis
| lymph node spread
111
what type of transport is blocked by omeprazole
primary active transport (K+H+ ATPase)
112
A histopathologic analysis of a colon sample shows acute inflammatory changes, epithelial necrosis, and a layer of denuded epithelium, fibrin, and inflammatory cells overlaying the mucosa. What is this describing?
a psuedomembrane (can be caused by C. Diff)
113
Patients with severe C. Dif. may develop nonobstructive colonic dilation, aka ________, which increases their risk of colonic perforation
toxic megacolon
114
what is Wilson disease?
autosomal recessive disorder characterized by excessive copper deposition in the liver, basal ganglia, and cornea due to impaired hepatocellular copper transport (decreased biliary excretion of copper)
115
what is the first line treatment of Wilson disease and how does it work
penicillamine
copper chelating agent
binds free copper and reduces copper bound to other proteins --> increases urinary excretion of copper
116
in a female presenting with a tender bulge below the inguinal ligament, lateral to the pubic tubercle, what has likely occurred?
femoral hernia
117
in a femoral hernia, what are the structures that run directly lateral to teh bulge
femoral vein --> femoral artery --> femoral nerve
118
what muscles must relax in order to defecate?
```
internal sphincter (reflex)
external sphincter and puborectalis muscle (voluntary)
```
119
what is dyssyndergia
stool remains in rectal vault despite attempts to initiate bowel movement
120
what causes secondary lactase deficiency
aquired condition resulting from inflammation/infection (ie bacterial overgrowth, infectious enteritis, Crohn disease) that causes injury to mucosal brush border where lactase is expressed
121
what changes in stool pH are seen in lactase deficiency
decreased stool pH
| fermentation of undigested lactose --> short chain fatty acid production
122
what changes in hydrogen breath content are seen in lactase deficiency
increased breath hydrogen content (due to hydrogen production during lactose fermentation in the gut)
123
what changes are seen in stool osmolarity in lactase deficiency
elevated stool osmolarity due to high amounts of undigested lactose in the stool (causes excess water to enter lumen causing osmotic diarrhea)
124
what vitamins can be produced by enteric bacteria that may overgrown in the gut?
vitamin K
| folate
125
enteric bacteria can digest unabsorbed dietary sugars and convert them to ____
fatty acids
126
small intestinal bacterial overgrowth results in a deficiency of most vitamins and iron, but increased production of ____ and ____
folic acid
| vitamin K
127
vitamin B12 (cobalamin) is acquired from ______
animal products and cannot be obtained from plant products
128
vitamin B12 deficiency develops only after the complete absence of intake for ____ years
4-5
| body is capable of storing about 1,000 times the daily requirement
129
what severe neurologic changes can occur due to vitamin B12 deficiency
subacute combined degeneration of the spinal cord
130
to discourage abuse, diphenoxylate is combined with ____, which induces adverse effects if taken in high doses
atropine
131
A patient with impaired driving in low light conditions (night blindness) and thickened, dry skin (hyperkeratosis) are suggestive of ____ deficiency.
vitamin A
132
what are causes of vitamin A deficiency in patients who have adequate dietary intake of vitamin A
Malabsorption related to biliary obstruction, exocrin pancreatic insufficiency, or bowel resection (ie Crohn disease, bariatric surgery)
133
what age related changes happen in the liver which decrease its ability to metabolize drugs
decreased liver mass
decreased hepatic blood flow
decreased cytochrome P-450
reduced rate of hepatic regeneration
134
do aminotransferase levels change naturally due to age?
no (elevations should raise concern for hepatic disease or hepatotoxin exposure)
135
vitamin B12 deficiency can result in elevated levels of serum ____ and ______
methylmalonic acid
| homocysteine
136
in patients with vitamin B12 deficiency, increased levels of ____ can disrupt myelin synthesis and result in subacute combined degeneration of the doral columns and lateral corticospinal tract
methylmalonic acid
137
what is the mnemonic for retroperitoneal abdominal organs?
```
SAD PUCKER
suprarenal (adrenal) glands
aorta and inferior vena cava
duodenum (except first part)
pancreas (head and body)
ureters
colon (ascending and descending)
kidneys
esophagus
rectum (mid-distal)
```
138
what is gallstone ileus
an uncommon complication of longstanding cholelithiasis that usually occurs in elderly women when a large gallstone causes formation of a cholecystoenteric fistula between the gallbladder and adjoining gut due to pressure necrosis and erosion of these tissues
the gallstone passes into the small bowel and becomes trapped at the ileum (narrowest portion) an causes symtpoms of a small bowel obstruction
139
what is pneumobilia
when gas enters the biliary tree
140
what is biliary atresia
progressive, complete, or partial obstruction of extrahepatic bile ducts
biliary tree is normal at birth but subsequently undergoes destruction
141
what symptoms are caused by biliary atresia
jaundice within first 2 months
dark urine
acholic (pale/clay colored) stools
142
what laboratory finding is indicative of cholestasis
elevated direct bilirubin
| and elevated gamma-glutamyl transferase
143
how is Strongyloides stercoralis transmitted?
filariform (infectious) larvae found in soil contaminated with human feces, on contact the larvae penetrate the skin
144
how does Strongyloides stercoralis spread within the body?
```
penetrates the skin
migrates hematogenously to the lungs
enter alveoli
travel up bronchial tree to pharynx
swallowed
develop into adults in intestines and lay eggs
```
145
what is found in the stool of a person infected with Strongyloides stercoralis
rhabditiform (noninfectious) larvae
146
how is Strongyloidiasis treated
ivermectin
147
what is larva currens (see in stronguloidiasis infection)
pruritic, erythematous linear streaks that may occur on the thighs and buttocks as the larva migrate subcutaneously away from perianal region
148
how does a strongyloides stercoralis become a hyperinfection?
Rhabditiform larvae can mature into filariform larva in the human gastrointestinal tract, precipitating an autoinfection cycle and can massively disseminate leading to multiorgan dysfunction and septic shock
149
a draining fistula near a patients coccyx who is complaining of abdominal cramping pain over several years and fluctuating diarrhea likely has what diagnosis
Crohn Disease
| inflames all layers of the bowel making it likely to form fistulas
150
anal fissures occur most commonly at what location
posterior midline (likely due to decreased blood flow in this area)
151
low fecal elastase can help diagnose what?
pancreatic insufficiency
152
what does Sudan staining on stool samples identify?
fecal fat
153
what are the 3 main airway protective movements that occur during normal swallowing
displacement of the larynx superiorly and anteriorly under the tongue
tilting of the epiglottis
adduction of the vocal folds
154
a chin tuck maneuver (flexion of the head and neck during swallowing) is helpful to some stroke patients to prevent choking by simulating what air way protective movement of normal swallowing
elevation of the larynx
155
what infection can cause achalasia and is endemic to central and south america
```
trypanosoma cruzi
(Chagas)
```
156
what are possible manifestations of Trypanosoma cruzi (Chagas) infection?
achalasia
nonischemic cardiomyopathy
megacolon
157
what is the only part of the duodenum that is not retroperitoneal
first part
158
what portion of the duodenum contains the ampulla of Vater and is in close relation to the head of the pancreas
second part
159
what is the ampulla of vater
the site where pancreatic and common bile duct secretions are released
160
what part of the duodenum courses over the abdominal aorta and inferior vena cava
third part
161
what portion of the duodenum is in close association with the unicate process of the pancreas and the superior mesenteric artery and vein
third part
162
what is the vasa recta
terminal vessels derived from the superior and inferior mesenteric arteries
163
how are diverticula related to the vasa recta
diverticula tend to form at weak points in the colon such as where the vasa recta penetrate through the smooth muscle layer of the colon
164
what is the likely cause of painless hematochezia in a patient with chronic diverticula
as diverticula enlarge, the vasa recta are exposed and become vulnerable to chronic injury which can lead to intraluminal hemorrhage
165
bisacodyl MOA
stimulant laxative
| others include senna and castor oil
166
what is the manifestation of Reye syndrome
acute liver failure
| encephalopathy
167
what affect does administering salicylates to children with viral infection have that precipitates Reye syndrome
salicylates can damage mitochondria within hepatocytes and inhibit enzymes involved in FA beta oxidation --> liver cannot keep up with metabolic demands --> acute liver failure --> build up of ammonia --> enceophalopathy
168
an acid fast stain revealing oocysts in stool and histopathology showing villous blunting with inflammatory infiltrate in the lamina propria in a HIV patient with diahrrea likely has what infection
cryptospordium parvum
169
ulcers located on the ____ wall of the duodenal bulb are more likely to perforation
anterior
170
ulcers located on the ___ wall of the duodenal bulb are more likely to cause hemorrhage
posterior
171
when an ulcer penetrates the posterior duodenal wall, it is likely to erode into the ____ artery
gastroduodenal
172
The distal esophagus is normally attached to the diaphragm by the ________ at the _____ junction
phrenoesophageal membrane
| gastroesophageal
173
sliding hiatal hernias are the most common form of hiatal hernia and occur due to _____
laxity of the phrenoesophageal membrane
174
what causes paraesophageal hernias and what structure herniates into the thoracic cavity?
defects in the membrane
| gastric fundus
175
Wilson disease is characterized by copper accumulation due to defective ____
copper transport protein (ATP7B)
176
in midgut malrotation, the cecum rests in the right upper quadrant and _______ connect the retroperitoneum in the RLQ to the right colon/cecum by passing over the second part of the duodenum causing intestinal obstruction
Ladd's (fibrous) bands
177
what is midgut volvus
intestinal ischemia due to twisting around the blood vessels
178
cystic fibrosis causes steatorrhea and failure to thrive due to malabsorption secondary to _____
pancreatic insufficiency
| pancreatic enzyme supplementation can help correct this
179
explain the inflammation distribution of the liver in acute viral hepatitis
panlobular lymphocytic inflammation
| it may bridge into adjacent hepatic lobules due to collapse of the reticulin framework
180
in acute viral hepatitis what causes hepatocytes to appear as Councilman bodies: round, acidophilic (pink on hematoxylin and eosin staining)
cytotoxic T cell mediated apoptosis
181
describe the inflammation in chronic viral hepatitis
usually significant inflammation surrounding the portal triad
182
intravenous drug use is a major risk factor for hepatitis ___ and ____
B
| C
183
what is intussusception
invagination of a portion of the intestine into the lumen of the adjacent intestinal segment (telescoping)
184
where is the most common region that intussusception occurs
area of ileocecal valve/ileocolic junction
185
what are the symptoms of intussusception
intermittent, sever, colicky abdominal pain
currant jelly stools
palpable mass in the right lower abdominal quadrant (sometimes)
186
Zollinger Ellison syndrome is caused by a ____-secreting neuroendocrine tumor
gastrin
187
symtpoms of Zollinger-Ellison syndrome
abdominal pain and acid reflux
| sometimes diarrhea as gastric acid damages intestinal epithelial cells and inactivates pancreatic enzymes
188
what should be excluded when making a diagnosis of zollinger ellison syndrome
multiple endocrine neoplasia type 1
189
what is Lynch syndrome
hereditary nonpolyposis colon cancer due to defective DNA mismatch repair
190
mutations in what 2 genes account for around 90% of cases of Lynch syndrome
MSH2 and MLH1
| MutS and MutL
191
Cirrhosis can cause hyperestrinism which results in what clinical features
gynecomastia
spider angiomata
testicular atrophy
decreased body hair
192
cholangiocarcinoma is malignancy of the _____
bile duct epithelium
193
what condition is cholangiocarcinoma associated with? (although it can occur sporadically)
sclerosing cholangitis
194
when does cholangiocarcinoma start to produce symptoms
when the tumor obstructs bile drainage
195
what symptoms are caused by cholangiocarcinoma
```
progressive weight loss
RUQ pain
jaundice
hepatomegaly
(cholestatic liver injury)
```
196
how does loperamide slow peristalsis
inhibits acetylcholine release
197
All biochemical functions of folate require the reduced ______ form of the vitamin which is synthesized by dihydrofolate reductase (rate limiting step in folate metabolism)
tetrahydrofolate
198
The enzyme ____ is responsible for converting dUMP to dTMP
thymidylate synthase
199
folate deficiency inhibits the synthesis of nucleic acids but ____ supplementation bypasses this enzyme and can reduce erythroid cell apoptosis
thymidine
200
prognosis of esophageal squamous cell carcinoma
poor
201
the histopathological features of esophageal ______ include solid nests of neoplastic squamous cells with abundant eosinophilic cytoplasm and distinct borders with areas of keratinization (keratin pearls and intracellular bridges.
squamous cell carcinoma
202
what is the initial diagnostic testing done for celiac disease
anti-tissue transglutaminase IgA assay
203
diagnosis of celiac disease is confirmed with duodenal biopsy showing what
earliest histologic finding= intraepithelial lymphocytosis
| later: crypt hyperplasia and villous blunting
204
celiac disease occurs almost exclusively in individuals with what HLA sterotypes
HLA-DQ2 or DQ8
205
what is acute acalculous cholecystitis
acute inflammation of the gallbladder in absence of gallstones that typically occurs in critically ill patients (those with sepsis, severe burns, trauma, immunosupression) due to gallbladder stasis and ischemia
206
how do hydrophilic bile acids treat gall stones
reduce cholesterol secretion and increase biliary bile acid concentration which increases cholesterol solubility and promotes stone dissolution
207
what arteries run along and perfuse the lesser curvature of the stomach and are a common source of hemorrhage from penetrating gastric ulcers
left and right gastric arteries
208
why are infarcts in an otherwise normal liver rare?
it has a dual blood supply (portal vein and hepatic artery)
209
what is a possible diagnosis for postpradial epiastric pain which does not respond to antacids and associated food aversion/weight loss in a patient with generalized atherosclerosis
chronic mesenteric ischemia
210
what is the diagnosis of a newborn with respiratory distress, unilateral decreased breath sounds, scaphoid abdomen and chest xray revealing cystic structures
congenital diaphragmatic hernia
211
congenital diaphragmatic hernia is a congenital malformation caused by failure of the ______ folds to close
pleuroperitoneal
212
what 4 tissues form the diaphragm
septum transversum
esophageal mesentery
musculature from the body wall
pleuroperitoneal folds
213
______ is a nonmalignant lesion, most commonly occuring in young women that appears as small, solitary, pale nodules composed of cords of normal-appearing hepatocytes and central stellate scar with fibrous septae that surround abnormally large artery
focal nodular hyperplasia
214
what is the best, most sensitive strategy for screening for malabsorption
test for fat malabsorption via qualitative assay of stool with Sudan III stain
(stool should usually contain no measurable fat)
215
how does carbon tetrachloride induce hepatic injury
it is oxidized by p450 and forms free radicals resulting in lipid degeneration and hydrogen peroxide formation (lipid peroxidation)
216
the venous components of internal hemorrhoids drain into the ____ vein which communicated with the ____ vein
superior rectal
| inferior mesenteric
217
external hemorrhoids drain via the _____ vein into the _____ vein which communicates with the ____- veins
inferior rectal
internal pudendal
internal iliac
218
parietal cells release HCl in response to what 3 major stimulants
histamine
vagal output/ Acetylcholine
gastrin
219
gastric cancer occurs with highest incidence in patients from eastern asia, eastern europe, and south africa possible due to increased consumption of _____
salt preserved foods
220
what is systemic mastocytosis
clonal mast cell proliferation in bone marrow, skin, and other organs
221
mast cell proliferation often is associated with mutations in the ____ receptor tyrosine kinase
KIT
222
what are some symptoms of systemic mastocytosis
```
(all due to increased histamine release)
hypotension
flushing
pruritus
hypersecretion of gastric acid
```
223
excessive _____ secretion can result in watery diarrhea, hypokalemia, and achlorhydria (WDHA) syndrome
vasoactive intestinal peptide
| pancreatic cholera
224
vasoactive intestinal peptide stimulates pancreatic ___ and ____ secretion
bicarbonate
| chloride
225
how does vasoactive intestinal peptide cause secretory watery diarrhea
binds intestinal epithelial cells --> activated adenylate cyclase --> increased cAMP --> sodium, chloride, and water secretion into bowel
226
what decreases VIP production and can be used to treat some VIPomas
somatostatin (ocretotide)
227
epidural metastasis (most commonly from lung cancer) can cause which syndrome causes bilateral lower extremity weakness, bowel/bladder dysfunction, and impaired perineal sensation
cauda equina syndrome
228
what nerves provide parasympathetic innervation to the hindgut, bladder, and urinary sphincters
pelvic splanchnic nerves
| S2-S4
229
what stimulant of gastric acid secretion also has trophic effect on parietal cells causing parietal cell hyperplasia
gastrin
230
zollinger-ellison syndrome causes peptic ulcers and parietal cell hyperplasia with _____ enlargement due to gastrin hypersecretion
gastric fold
231
what cellular changes characterize hepatocyte necrosis
cellular swelling and cytoplasmic emptying
| ballooning degeneration
232
what cellular changes occur during acute hepatits
hepatocyte ballooning degeneration
apoptosis
mononuclear cell infiltration
233
proton pump inhibitors can cause malabsorption of what 4 things?
calcium
iron
magnesium
vitamin B12
234
why might PPI initiation increase fat absorption in patient on exogenous pancreatic enzyme replacement
lipase is inactivated by acidic environment
| PPI increases lipase activity by protecting it in stomach by decreasing acidity
235
what is primary biliary cholangitis
chronic liver disease characterized by autoimmune destruction of the intrahepatic bile ducts and cholestasis
236
what is usually the first symptom of primary biliary cholangitis
pruritus
| fatigue is also often reported
237
primary biliary cholangitis diagnosis is confirmed by _____ antibodies
anti-mitochondrial
238
What causes hypervariability in hepatitis C virus
no proof reading 3' --> 5' exonuclease activity
239
why can D-xylose be absorbed normally in pancreatic insufficiency
it is a monosaccharide which do not requires pancreatic enzymes, they are directly taken up by epithelial cells of small intestine through sodium dependent cotransport or facilitated diffusion
240
how does NSAID use affect risk of esophageal adenocarcinoma
NSAIDs may be protective
241
what are risk factors for esophageal adenocarcninoma
chronic GERD
obesity
smoking
meds that lower esophageal sphincter pressure (nitroglycerin)
consumption of nitroso containing foods (processed meats)
242
____ is important cofactor for carboxylase enzymes, playing a role in carbohydrate, lipid, and amino acid metabolism. In the liver it is required for conversion of pyruvate to oxaloacetate for gluconeogenesis
biotin (vit B7)
243
what disorder causes abdominal pain, heme positive stool, and noncaseating granulomas on microscopy of colon biopsy
Chron disease
244
what changes are seen in intestinal epithelium for patients with celiac disease
loss of small bowel intestinal villi and mucosal atrophy
245
what causes microcytic anemia in celiac disease
iron deficiency due to less absorption in the duodenum
246
what age related changes occur in the parotid salivary glands causing dysphagia in the elderly
acinar atrophy and fatty infiltration
247
are the following likely to be high or low in a patients gall bladder with gall stones?
cholesterol
phosphatidylcholine
bile acids
cholesterol: high
bile acids: low
phosphatidylcholine
248
what promotes aggregation of cholesterol into stones
mucis hypersecretion
calcium salts
gallbladder hypomotility
249
what does a positive anti-HAV IgM indicate
active disease
250
what is the common route of infection of Hepatitis A in the united states
shellfish
| transmitted fecal orally and contaminates water or food
251
what causes Whipple disease
Tropheryma whipplii
252
whipple disease is a rare systemic illness that involves what 3 parts of the body?
small intestine
joints
central nervous system
253
in Tropheryma whipplii infection, Whipple disease, the actinomycete proliferates only within what cells?
macrophages
254
classic histologic staining of Whipple disease includes foamy macrophages packed with ____ and _____
rod-shaped bacilli
| PAS-positive, diastase-resistant granules
255
clinically, Whipple disease is most commonly seen in middle-aged Caucasian males, presenting with what possible symptoms?
```
malabsorption
diarrhea
weight loss
arthropathy
polyarthritis
psychiatric abnormalities
cardiac abnormalities
```
256
If the appendix cannot be identified by palpation during an appendectomy, it can be located by following the _____ to its origin at the cecal base
teniae coli
257
the teniae coli are 3 separate ______ that travel longitudinally on the outside of the colon and converge at the root of the _____
smooth muscle ribbons
| vermiform appendix
258
describe esophagus contractions in diffuse esophageal spasm
several segments contract inappropriately at the same time which appears as disorganized non-peristaltic contractions
259
how does diffuse esophageal spasm appear on barium esophagogram
corkscrew
260
what is the pathogenesis of diffuse esophageal spasm
impaired inhibitory neurotransmission within the esophageal myenteric plexus
261
what is the presentation of diffuse esophageal spasm
intermittent solid/liquid dysphagia, chest pain, heartburn, and food regurgitation
262
define cholestasis
any condition in which bile flow from the liver stops or slows
263
what is characterized by the deposition of bile pigment within the hepatic parenchyma, often with green-brown plugs in the dilated bile canaliculi
cholestasis
264
in contrast to true cysts with walls lined by epithelial cells, the walls of pseudocysts consist of ____
granulation tissue and fibrosis
265
what are the common symptoms of anal squamous cell carcinoma
rectal bleeding
pain
pruritis
266
what is the histologic description of anal squamous cell carcinoma
large, eosinophilic, hyperchromatic squamous cells with scant cytoplasm arranged in islands
nuclear atypia and prominent keratinization and/or keratin pearls are usually observed
267
what disease is associated with anogenital and oropharyngeal squamous cell carcinoma
HPV (types 16 and 18 are particularly associated with malignancies)
(also HIV due to immunocompromised state)
268
A vitelline duct cyst forms if peripheral portions of the vitelline duct obliterate but central parts remain. The cyst is connect to the ____ and the abdominal wall by fibrous bands
ileum
269
Hepatitis B virus does not have cytotoxic effects itself so what causes liver damage in HBV?
HBsAg and HBcAg on the cell surface stimulate CD8 T lymphocytes to destroy infected hepatocytes
270
what is an autosomal recessive disorder characterized by defective hepatic excretion of bilirubin glucuronides due to mutation in the canalicular membrane transport protein
Dubin-Johnson syndrome
271
In Dubin Johnson syndrome, patients have episodes of what symptom
jaundice
| otherwise it is asymptomatic and benign
272
in Dubin Johnson syndrome, the liver appears black due to impaired excretion of _____ metabolites that accumulate within lysosomes
epinephrine
273
How is hepatitis B transmitted
sexual
percutaneous
vertical
274
what does Anti-HBsAg indicate
successful HBV vaccination
or
HBsAg clearance
(indicator of non-infectivity and immunity)
275
how is hepatitis C transmitted
intravenous drug use
276
how is HDV transmitted
inoculations (vaccination)
blood transfusions
sexual transmission is far less common
277
neural crest cells give rise to ganglion cells of the submucosal and myenteric plexus of the bowel wall, where do they enter and how do they migrate?
enter developing foregut mesenchyme then migrate caudally reaching the rectum lastly at week 12
278
The arrest of migration of neural crest cells causes ____ disease, in which a distal segment of colon lacks ganglion cells
Hirschsprung disease
279
what are clinical features of Hirschsprung disease
delayed passage of meconium in neonates
chronic constipation
abdominal distension
280
If the angle between the superior mesenteric artery and aorta diminishes less than 20 degrees, the _____ can get entrapped between the SMA and aorta
transverse portion of the duodenum
281
What can cause narrowing of the aortomesenteric angle
diminished mesenteric fat (low weight, recent weight loss, severe burns, etc)
pronounced lordosis
following surgical correction of scoliosis (decreased mobility of SMA due to lengthened spine)
282
irritation to what nerve can cause hiccups due to spasmodic diaphragmatic contraction pulling air against a closed larynx
phrenic
283
although a majority is converted to nontoxic metabolites, what metabolite of acetaminophen is hepatoxic
unconjugated NAPQI
| product of CYP450 metabolism
284
when acetaminophen dosage is appropriate, NAPQI is conjugated by ____ into a nontoxic compound and eliminated in urine
glutathione
285
although ethanol is primarily metabolized by alcohol dehydrogenase, it can also be converted to acetaldehyde by _____
cytochrome P450 2E1
286
If a patient has an elevated alkaline phosphatase, what can be checked next in order to determine if it is of hepatic or bony origin
gamma glutamyl transpeptidase (GGTP)
| not present in bone
287
Leptin decreases the production of _____, a potent appetite stimulant, in the arcuate nucleus of the hypothalamus
neuropeptide Y
288
Leptin stimulates the production of _____ in the arcuate nucleus.
proopiomelancortin
| POMC
289
_____ is produced by cleavage of POMC and inhibits food intake
alpha melanocyte stimulating hormone
| alpha-MSH
290
If the leptin receptor is mutated, what will the serum leptin levels and body weight of the specimen be?
elevated
| profoundly obese
291
if leptin production is impaired, what will the specimen's leptin levels and body weight be?
decreased serum leptin
| obese
292
how is methylnatrexone able to treat opiate induced constipation without causing withdrawal symptoms
```
peripherally acting (does not cross blood brain barrier)
so it will not induce withdrawal symptoms or disrupt analgesic effects of opioid treatment
```
293
______ is a potential manifestation of chronic cholecystitis and is often associated with multiple gallstones. It is due to dystrophic intramural deposition of calcium salts in the setting of chronic inflammation.
porcelain gallbladder
294
porcelain gallbladder is associated with an increased risk of ________
adenocarcinoma of the gallbladder
295
what is the diagnosis of an esophageal mass that significantly narrows the lumen and has flattened polyhedral or ovoid epithelial cells with eosinophilic cytoplasm, keratin nests or pearls within or between cells, and intercellular bridgin
esophageal squamous cell carcinoma
296
what are risk factors of esophageal squamous cell carcinoma
cigarette smoking and alcohol intake are most significant in US
N-nitroso containing foods
underlying esophageal disease
ingestion of high temperature liquids
297
children with watery diarrhea should be treated with oral rehydration solutions containing hypotonic, equimolar concentrations of ____ and ____ to help prevent dehydration and electrolyte abnormalities
sodium
| glucose
298
congenital pyloric stenosis is thought to develop secondary to hypertrophy of the _____
pyloric muscularis mucosae
299
alcohol and gallstones are the most common causes of pancreatitis. A less common cause is hyper-______
hypertriglyceridemia
| also hypercalcemia
300
In a patient with alcoholic liver disease, hematemsis, orthostatic symptoms, and normocytic anemia are likely due to acute bleeding where?
from esophageal varices
301
Any condition that causes portal hypertension can lead to splenomegaly with congestive hyperslenism, causing apparent expansion of the ____ of the spleen
red pulp
302
the red pulp of the spleen is composed of blood-filled sinuses and cords lined by _____ cells
reticuloendothelial-type
303
how can somatostatin/octreotide reduce portal venous pressure
inhibit release of glucagon and vasoactive intestinal peptide which induce splanchnic vasodilation
(vasodilation increases the portal blood flow)
304
what is CREST syndrome
systemic sclerosis
| Calcinosis, Raynaud phenomenon, Esophageal dysmotility, Sclerodactyly, Telangiectasia
305
What is the function of alpha-1 antitrypsin
serine protease inhibitor
306
what causes liver disease in patients with alpha-1 antitrypsin deficiency
accumulation of improperly folded alpha-1 antitrypsin
307
what is the pathogenesis of biliary cholangitis
autoimmune liver disease (antimitochondrial antibody positive)
lymphocytic infiltrates cause destruction of small and midsized intrahepatic bile ducts
308
the pathogenisis of acute pancreatitis begins with either a toxic or an ischemic injury to the acinar cells that leads to premature activation of ___ inside the pancreatic acini
trypsin
309
Pancreatic zymogens are normally converted into their active form by __ in the duodenal lumen
trypsin
310
what is characterized histologically by the presence of "spotty necrosis" with ballooning degeneration (hepatocyte swelling with wispy/clear cytoplasm), Councilman bodies and mononuclear cell infiltrates
hepatitis A
311
what are Councilman bodies (histologic finding in hep A)
eosinophilic apoptotic hepatocytes
312
what are the typical presenting symptoms of hepatitis A
```
fever
malaise
anorexia
nausea/vomiting
upper right quadrant pain
```
313
what symptoms of Hepatitis A arise about a week after prodromal symptoms arise
signs of cholestasis: jaundice, pruritis, dark-colored urine, and acholic stool
314
what autoimmune liver disease is histologically represented by interface hepatits: portal and periportal lymphoplasmocytic infiltrate
autoimmune hepatits
315
what autoimmune liver disease is histologically represented by florid duct lesion: granulomatous destruction of small bile ducts
primary biliary cholangitis
316
what autoimmune disorder is histologically represented by fibrous obliteration of bile ducts with concentric periductal deposition of connective tissue (onion skin pattern)
primary sclerosing cholangitis
317
how does CMV esophagitis usually present
odynophagia (pain with swallowing) or dysphagia (difficulty swallowing) that can be accompanied by fever or burning chest pain
318
what does an endoscopy of CMV esophagitis show
linear and shallow ulerations in the lower esophagus that sometimes diffusely involve the esophagus
319
what does tissue biopsy of CMV esophagitis usually show
enlarged cells with basophilic or eosinophilic intranuclear inclusion bodies
320
what receptor should be targeted by an anti-emetic treating nausea in a patient with travelers diarrhea
5HT3
321
what type of hernia originates lateral to the inferior epigastric vessels
indirect inguinal
322
what type of hernia emerges inferior to inguinal ligament
femoral
323
what type of hernia protrudes medial to the inferior epigastric vessels
direct inguinal
324
what is the pathophysiology of indirect inguinal hernias
patent processus vaginalis
325
what type of hernia protrudes through the deep inguinal ring into inguinal canal and may extend into the scrotum
indirect inguinal
326
what is the pathophysiology of a direct inguinal hernia
weakness of transversalis fascia
327
what is the pathophysiology of a femoral hernia
widening of the femoral ring
328
what 2 deficiencies can cause megaloblastic anemia
folic acid
| B12 (cobalamin)
329
if megaloblastic anemia due to cobalamin (B12) deficiency is treated with folate, what symptom will not improve and may get worse
neurologic dysfunction
330
drug induced liver injury caused by inhaled anesthetic hepatotoxicity is most frequently associated with what drug
halothane
331
how can a GI bleed exacerbate hepatic encephalopathy
GI bleeding causes increased hemoglobin to go to the gut which is converted to ammonia and absorbed into the bloodstream
332
in hepatic encephalopathy, accumulation of ammonia and other neurotoxins results in increased _____ neurotransmission and decreased _____ neurotransmission
(excitatory or inhibitory)
increased inhibitory
| decreased excitatory
333
what location of the intestine should be biopsied when making a diagnosis for celiac disease
duodenum or proximal jejunum
334
what antibodies are markers for celiac disease
tissue transglutaminase IgA
| antiendomysial antibodies
335
what are pigment gallstones composed of
calcium salts of unconjugated bilirubin
336
what is typical cause of brown pigment gallstones
secondary to bacterial or helminthic infection of biliary tract
337
what enzyme is released from damaged hepatocytes and bacteria in order to form brown pigment gallstones
beta glucuronidase
338
beta glucuronidase hydrolyzes bilirubin glucuronides --> increased ______
unconjugated bilirubin
339
what is the typical cause of black pigment gallstones
chronic hemolysis or increased enterohepatic cycling of bilirubin
340
both brown and black gallstones are the result of increased levels of ______
unconjugated bilirubin
341
how does pregnancy increase risk of GERD
progesterone decreases LES tone
342
how does pregnancy increase risk of cholelithiasis or cholecystitis
estrogen increases cholesterol secretion into bile
| progesterone reduces gallbladder motility
343
what causes increased constipation, bloating and flatulence in pregnancy
progesterone decreases colonic smooth muscle activity and decreases fasting migrating myoelectric complex
gravid uterus mechanically impedes small intestine transit
344
how does pregnancy cause increased risk of hemorrhoids
gravid uterus increases venous pressure
345
what is pneumobilia?
air in the biliary tract
346
Cesarean delivery typically involves midline vertical separation of the rectus abdominis muscle but when additional space in necessary, it can be transected horizontally which puts what vessel at risk?
inferior epigastric artery
347
why are the inferior epigastric arteries more susceptible to injury below the arcuate line?
lack of a supporting posterior rectus sheath
348
failure of what embryologic event results in a reducible, soft, nontender bulge at umbilicus that protrudes with increased abdominal pressure
incomplete closure of abdominal muscles/umbilical ring
| congenital umbilical hernia
349
SPINK1 function
(serine peptidase inhibitor Kazal-type 1)
| inhibits activity of trypsinogen molecules that become prematurely activated in the pancreas
350
what determines if a carcinoid tumor will cause carcinoid syndrome or not?
secreted vasoactive substances must bypass the liver to avoid being degraded so tumor must be extraintestinal (ie. metastasized to the liver)
351
what are symptoms of carcinoid syndrome
skin flushing, telangiectasia, cyanosis;watery diarrhea; bronchospasms, dyspnea
352
diagnosis of carcinoid syndrome includes elevated urinary excretion of _____
5-HIAA
| 5-hydroxyindoleacetic acid
353
what is the result of perforated viscus in the abdomen and can be visualized on a thoracic xray
pneumoperitoneum (free air under the diaphragm)
354
what antiemetics can be used to treat chemo induced nausea and vomiting
dopamine receptor antagonist
5-HT3 receptor antagonist
NK1 receptor antagonists
355
what are 3 contributing factors of benign neonatal hyperbilirubinemia
high bilirubin production bc fetal RBCs have shorter life span
low bilirubin clearance from lower levels of hepatic uridine diphosphogluconurate (UDP) glucuronsultransferase
low bacteria in gut which usually reduces bilirubin, allowing it to be excreted into the stool
356
Hepatitis B infection causes the hepatocellular cytoplasm to fill with ______
hepatitis B surface antigen
357
Hepatocytes with finely granular, pale eosinophilic, ground glass appearing inclusions are characteristic of what disease
hepatitis B
358
nonocclusive ischemia resulting in ischemic colitis occurs primarily at the watershed areas: _____ and _____
splenic flexure
| rectosigmoid junction
359
In a patient with acute pancreatitis, what causes chalky, white lesions to appear in the mesentery
lipase digests adipose cells --> fatty acids bind calcium ions --> insoluble calcium salts
these can spread to mesentery, omentum, and other parts of abdominal cavity
360
Abdominal distension, bloody stools, and pneumatosis intestinalis is diagnostic for what?
necrotizing enterocolitis
361
why are premature newborns susceptible to necrotizing enterocolitis
immunologic immaturity + bacteria introduction during enteral feeding --> bacteria proliferate excessively --> inflammation and ischemic necrosis
362
what are possible manifestations of schistosoma infections
urinary (hematuria, dysuria, pyelonephritis, squamous cell carcinoma bladder)
intestinal (diarrhea, abd pain, ulceration)
hepatic (hepatomegaly, fibrosis, portal HTN)
363
The spleen is intra or retroperitoneal?
intraperitoneal
364
what is the blood supply to the spleen
splenic artery off the celiac trunk
365
venous return from the spleen courses through the ____ vein to return to portal circulation rather than systemic circulation
splenic
366
the spleen is of what embryonic tissue origin
mesodermal
367
what is the mechanism of action of fibrates (2)
upregulate lipoprotein lipase
| inhibit cholesterol 7 alpha hydroxylase
368
how can fibrates increase risk of gallstones
inhibition of cholesterol 7 alpha hydroxylase --> inhibited synthesis of bile acids
less bile acids --> decreased cholesterol solubility in bile and favors formation of cholesterol stones
369
A patient who develops lower abdominal tenderness and diarrhea while in the hospital after a round of antibiotics should be assessed for what pathogen
C dif
370
what is the most sensitive test of C. dif diagnosis
nucleic acid amplification test (PCR for bacterial gene encoding toxin)
(enzyme immunoassay is more specific but has poor sensitivity
371
what are 6 potential nutritional deficiencies of people on vegan diets
```
vitamin B12
vitamin D
calcium
iodine
iron
zinc
```
372
H pylori preferentially colonizes what portion of the stomach causing duodenal ulcers
antrum
373
how does H. pylori cause duodenal ulcers
decrease somatostatin --> increased gastrin secretion --> increased gastric acid production from parietal cells
374
what portion of the stomach does H. pylori colonize that is associated with gastric ulcers
gastric corpus (body of the stomach)
375
Statins competitively inhibit what enzyme
HMG CoAreductase
376
what effect does cholestyramine have on hepatic cholesterol and bile acid synthesis
increases both
377
cholestyramine MOA
bile acid binding resin
378
gemfibrozil MOA
fibrate: reduce bile acid synthesis by inhibiting cholesterol 7-alpha hydroxylase
379
anti- smooth muscle antibody elevation is highly specific for what liver disease
autoimmune hepatitis
380
what histologic findings demonstrate autoimmune hepatitis
lymphocyte and plasma cell infiltration of portal and periportal regions of the liver
381
secretin stimulates the pancreatic ductal cells to secrete what?
bicarb
382
secretin is produced by duodenal S cells in response to what
increased duodenal H+ concentrations
383
repetitive vomiting leads to what acid-base status
metabolic alkalosis
384
what causes a linear mucosal tear at the gastroesophageal junction
(Mallory-Weiss syndrome)
forceful retching is most common or straining during defecation or weight lifting, seizures, blunt abdominal injury or upper GI endoscopy
385
what are the 4 sites where prolonged portal hypertension can cause varices
esophagus
rectum
umbilicus
retroperitoneal
386
in evaluation of Hirschsprung disease, biopsy should be done of what segment and what layer of the instesine?
rectal (narrowed segment) submucosa to see if submucosal ganglia are absent
387
what is the most common benign liver tumor that morphologically consist of cavernous, blood filled vascular spaces lined by a single epithelial layer
cavernous hemangiomas
388
how do the lesions and location of colitis-associated colorectal cancer differ from sporadic
origins of dysplasia are flat (nonpolypoid) lesions and tumors are multifocal
(sporadic: polypoid lesions and singular tumors)
389
in sporadic and colitis associated colorectal cancer, which which has early/late p53/APC gene mutations
sporadic: early APC, late p53
| colitis associated: early p53, late APC
390
what vessels are used as landmarks in a laparoscopic hernia repair to distinguish between direct and indirect inguinal hernias
inferior epigastric vessels
391
Where do direct and indirect hernias protrude in respect to the inferior epigastric vessels
direct: medial to inferior epigastric vessels
indirect: lateral
392
A poor prognosis in cirrhotic patients is indicated by poor liver functioning. what serum lab values could best indicate this (3)
hypoalbuminemia
elevated bilirubin
prolonged PT
393
what are the symptoms of scurvy and what nutritional deficiency causes it
Ascorbic acid (vitamin C)
microvascular bleeding
gingivitis
impaired wound healing
394
alcohol induced hepatic steatosis appears related to decreased _____ oxidation
free fatty acid
395
what causes decreased free fatty acid oxidation in alcohol induced hepatic steatosis
excess NADH from alcohol metabolism
396
what is a good stain for identifying tropheryma whippelii
PAS
397
PAS staining stains what dark pink?
polysaccharides
398
perinicious anemia occurs as a result of CD4 cells mediated immune response against what?
parietal cells
399
how is vitamin B12, gastric acid secretion, and gastrin secretion affected by perinicious anemia
decreased vit B12 (loss of intrinsic factor)
decreased gastric acid secretion
increased gastrin secretion
400
what is primary biliary cholangitis
Tcell destruction of small intralobular bile ducts
401
how does primary biliary cholangitis appear histologically
dense lymphocytic inflammation of portal tracts with granulomatous destruction of interlobular bile ducts
402
what antibodies are highly characteristic of primary biliary cholangitis
antimitochondrial antibodies
403
what is the cause of intestinal atresia of the jejunum/ileum
vascular injury in utero
404
what is the cause of duodenal atresia
failure of recanalization at 8-10 wks gestation
405
what changes occur in the gallbladder due to cystic duct obstruction that causes acute calculous cholecystitis
mucosal disruption by lysolecithins
bile salt irritation of luminal epithelium
proataglandin release with transmural inflammation
gallbladder hypomotility
increased intraluminal pressure causing ischemia
bacterial invasion
406
how is peristalsis and sphincter tone effected in achalasia
decreased amplitude of peristalsis in mid esophagus
| incomplete relaxation at LES
407
what is the cause of achalasia
reduced number of inhibitory ganglion cells in the esophageal wall
408
are the following increased or decreased in ascites: serum antidiuretic hormone, urine sodium, total body volume
serum antidiuretic hormone: increased
urine sodium: decreased
total body volume: increased
409
what are the 3 causes of benign neonatal hyperbilirubinemia
increased bilirubin production from increased hemolysis
decreased bilirubin conjugation from lower UDP glucuronosyltransferase
increased enterohepatic circulation of bilirubin due to gut sterility
410
external hemorrhoids have cutaneous innervation from what nerve?
rectal nerve, a branch of the pudendal nerve
411
Abetalipoproteinemia is an inherited inability to synthesize ______
apolipoprotein B
412
what is the cause of Gilbert syndrome
decreased hepatic UDP glucuronosyltransferase activity --> decreased conjugation of bilirubin
413
When excess ammonia is present in the blood, it crosses the blood brain barrier and is taken up by astrocytes, increasing ______ production
glutamine
414
Lymphatic drainage of the rectum proximal to the anal dentate line occurs in what nodes? distal to the dentate line?
proximal to dentate line: inferior mesenteric and internal iliac nodes
distal: inguinal nodes
415
what supplementations are recommended in vegan diet due to common deficiences
vitamin B12 (cobalamin)
calcium
vitamin D
(other less common deficiencies: iodine, iron, zinc)
416
what causes the rebound gastric acid hypersecretion when PPIs are stopped?
increased gastrin release in response to increased pH while on PPI
417
what is seen on histologic examination of patients with primary lactase deficiency
normal
418
Are duodenal ulcers associated with increased risk of carcinoma in the same location? what about gastric? esophageal? colon?
duodenal: no
| gastric, esophageal, colon: may be malignant and biopsy is required
419
appendicitis causes dull visceral pain at ____ due to afferent pain fibers entering at T10. Progressive inflammation irritates the parietal peritoneum shifting the pain to ______
umbilicus
| McBurney's point
420
what 2 medications are often used to increase natriuresis and prevent electrolyte disturbances in ascites
spironolactone
| furosemide
421
Shigella sonnei infection is specific to infecting what cells?
Microfold (M) cells
(within Peyer patches)
(via endocytosis)
422
What is the most common pathologic lead point for intussusception
(intussusception = intestine telescopes into itself)
| Meckel diverticulum
423
what is pancreas divisum
when the ventral and dorsal pancreatic buds fail to fuse and the pancreatic secretions are instead drained via two separate duct systems
424
The ventral pancreatic bud is a precursor to what 3 portions of the pancreas?
uncinate process
inferior/posterior portion of the head
major pancreatic duct
425
What causes obstruction to portal venous flow upstream to the liver, causing portal hypertension while not affecting liver parenchyma
portal vein thrombosis
426
in Budd-chiari syndrome, there is an occlusion of the ____ vein. What will the liver biopsy show
hepatic
| centrilobular congestion and fibrosis
427
what causes bowel obstruction in Chron disease
strictures due to bowel wall edema, fibrosis, and hypertrophy of the muscularis mucosae which narrows the intestinal lumen
428
What is the diagnosis of someone having white-yellow plaques composed of fibrin, inflammatory cells, and cellular debris on the colonic mucosa
Clostridium difficile
429
What is the diagnosis of someone with fibrosis and nodular parenchymal regenerations in the liver
cirrhosis
430
what is the most important risk factor for cancer in polyps
increasing polyp size
431
what histology on adenomatous polyps increase risk of cancer
villous histology and high grade dysplasia
432
Esophageal varices is due to what portal vein anastomosing with what systemic vein?
left gastric
| esophageal
433
anorectal varices is due to what portal vein anastomosing with what systemic vein
superior rectal
| middle and inferior rectal
434
caput medusae is due to what portal vein anastomosing with what systemic vein
paraumbilical
| superficial and inferior epigastric
435
what is hemochromatosis
increased intestinal iron absorption with deposition of excess iron in parenchymal tissues
436
why do men present earlier than women with hemochromatosis
premenopausal women have ongoing blood and iron losses due to menstruation
437
what branch of the aorta supplies the liver and spleen
celiac trunk
438
what mutation causes hereditary hemochromatosis
missense mutation in HFE gene
439
what causes iron accumulation in hemochromatosis
increased intestinal iron absorption
| decreased hepcidin synthesis in hepatocytes --> increased ferroportin expression
440
what occurs in hepatocytes to cause Reye syndrome
mitochondrial toxicity --> impaired fatty acid metabolism --> microvesicular fat deposits in the liver --> hepatic dysfunction
441
carcinoid tumors are malignant transformations of what cell type
neuroendocrine
442
what are causes of secondary lactose intolerance
inflammation (celiac) or infection (giardiasis) --> damaged cells sloughed off and replaced with immature cells with little lactase expression
443
Why are newborns who do not receive prophylactic supplementation at risk for bleeding complications? Why is the risk increased in cystic fibrosis
vitamin K does not cross the placenta well and it is not in breast milk
cystic fibrosis --> poor absorption of fat soluble vitamins
444
_____ is produced primarily in the stomach in response to fasting, levels surge leading up to meals and fall after eating
Grehlin
445
what could cause intermittent dysphagia and esophageal food impaction in a child who has ezcema
eosinophilic esophagitis: chronic Th2 cell mediated disorder triggered by food antigens --> eosinophilic infiltration of the esophageal muscosa
446
what causes GERD in pregnant women
pregnancy --> elevated estrogen and progesterone --> relax smooth muscle of LES
also, later in pregnancy, the gravid uterus presses on the stomach and causes increased intrabdominal pressure
447
what lifelong supplementation is required in patients who have undergone total gastrectomy? Why is HCl or pepsin not required?
vitamin B12 due to inability to produce intrinsic factor
| pancreatic enzymes can break down protein without pepsin or HCl
448
what diets increase risk of diverticulosis
high amounts of red meat and fat
| low levels of fiber
449
ulcers found beyond the duodenal bulb and elevated gastrin levels that rise in response to secretin are suggestive of what diagnosis
Zollinger-Ellison syndrome (gastrin secreting tumor, gastrinoma)
450
why would a patient on total parenteral nutrition be at increased risk of gallstones
decreased cholecystokinin release due to decreased enteral stimulation
451
recurrent sinopulmonary infections and congenital absence of vas deferens are consistent with what diagnosis
cystic fibrosis
452
what cell types promote granuloma formation in Crohn disease
Th1
| macrophages
453
what are symptoms of vitamin E deficiency
increased susceptibility of neuronal and erythrocyte membranes to oxidative stress --> ataxia, impaired proprioception and vibratory sensation, hemolytic anemia
454
what is the determinant of colorectal adenocarcinoma prognosis
stage of the tumor (extent of expansion) NOT the grade
455
iron absorption occurs predominantly where?
duodenum and proximal jejunum
| if resected, supplementation is required
456
malabsorption of what 6 things is common after gastric bypass procedures
```
thiamine
folate
vit B12
fat soluble vitamins
calcium
iron
```
457
what are common presenting symptoms of right sided colon cancers vs left sided colon cancers
right: occult bleeding and symptoms of iron deficiency anemia
left: constipation and symptoms of intestinal obstruction
458
motor dysfunction of what muscle is thought to be the underlying mechanism of Zenker diverticulum
cricopharyngeal
| deminished relaxtion --> increased intraluminal pressure
459
MOA sofosbuvir (hepatitis C treatment)
nucleotide/non-nucleoside RNA polymerase inhibitor
| HCV requires RNA-dependent RNA polymerase to replicate
460
Ledipasvir MOA (hepatitis C treatment)
```
NS5A inhibitor
(NS5A is crusial for viral replication and assembly by unclear mechanisms)
```
461
Why might NSAIDs be protective against some types of colon adenocarcinoma
increased activity of COX2 has been linked with some forms of colon adenocarcinoma
462
Patients with Celiac disease are at an increased risk of what cancer
Tcell lymphoma
| Tcell expansion can occur in the small bowl mucosa
463
what connects the liver to the lesser curvature of the stomach and the beginning of the duodenum
lesser omentum
464
what is a treatment option for C. Dif that is a macrocyclic antibiotic that inhibits sigma subunit of RNA polymerase, leading to protein synthdsis impairment and cell death
Fidaxomicin
465
what serum tumor marker is elevated in patients with hepatocellular carcinoma
alpha fetoprotein
466
what tumor marker is elevated in patients with pancreatic cancer
CA 19-9
467
what tumor marker is commonly elevated in ocarian cancer
CA 125
468
what is the diagnosis of a patient presenting with proximal weakness and inflammatory features affecting the skin such as heliotrope rash
dermatomyositis
469
What cause of diarrhea in an HIV patient will show spindle shaped tumor cells with small vessel proliferation on biopsy of colon lesions
Kaposi's sarcoma
470
why is hepatitis B virus required for a hepatitis D infection
hepatitis B surface antigen must coat the hepatitis D antigen before it can infect hepatocytes and multiply
471
what is the cause of carcinoid syndrome
carcinoid tumor secreting serotonin and other biologically active substances
472
what medication can be used to treat symptoms of carcinoid syndrome before surgery?
octreotide
473
what is the first event in pathogenesis of acute appendicitis
obstruction of the lumen of the appendix
474
what are histological findings of squamous cell carcinoma of the esophagus
sheets of eosinophilic squamous cells with keratin pearls, and intercellular bridges
475
what cause of atrophic gastritis results in pernicious anemia
autoimmune gastritis
476
what are the complications of chronic H. pylori infection
adenocarcinoma
| MALT lymphoma
477
What rare vascular tumor is associated with arsenic and polyvinyl chloride exposure and expresses CD31
hepatic angiosarcoma
478
what structures run through the hepatoduodenal ligament
the portal triad:
hepatic artery
portal vein
common bile duct
479
what could be the sources of right upper quadrant bleeding that persists after occlusion of the portal triad?
inferior vena cava
| hepatic veins
480
what complication of Crohn disease can cause vitamin B12 deficiency and postprandial voluminous diarrhea
short bowel syndrome due to loss of intestinal absorptive surface area
481
Congestive hepatopathy is a complication of what heart problem
right sided heart failure
482
what are the 3 leading causes of infections esophagitis in immune compromised patients
candida albicans
HSV
CMV
483
what cause of infectious esophagitis shows eosinophilic intranuclear inclusions in multinuclear squamous cells at ulcer margins
HSV
484
what type of infectious esophagitis has punched out ulcers? large linear ulcerations?
HSV
| CMV
485
treatment for HSV esophagitis
acyclovir
486
treatment for CMV esophagitis
ganciclovir
487
how is megacolon diagnosed
xray
488
what kind of kidney stones are associated with Chron disease and why?
oxalate
impaired bile acid resorption --> intestinal lipids bind calcium ions --> free oxalate is absorbed unbound to calcium and forms urinary calculi
489
how does hepatitis A cause liver damage
triggers robust CD8 T cell and NK cell response to clear infected hepatocytes
