UWorld 2017 Flashcards
Function of enteropeptidase + deficiency
In duodenal brush border
Activates trypsinogen to trypsin (that degrades polypeptides + activates chymotrypsin, carboxypeptidase, elastase)
If deficient, impaired protein + fat absorption (diarrhea, failure to thrive, hypoproteinemia)
Adaptive immunity against Giardia lamblia
Secretory IgA
6 precipitating factors for Hepatic encephalopathy
Drugs (sedatives, narcotics) Hypovolemia Electrolyte changes (hypoK) High nitrogen lead (GI bleeding) Infection Portosystemic shunting
Effect of hyperammonemia in brain
Ammonia crosses B-B barrier
Accumulation of excess glutamine in astrocytes
Low conversion to glutamate in neurons
Disruption of excitatory neurotransmission
Complication of Gastric bypass surgery + its consequences
Small intestinal bacterial overgrowth
In blind-ended gastroduodenal segment
Deficiency in Vit B12, A, D, E, iron
Increased production of folic acid + Vit K
2 types of pain in appendicitis
Dull visceral pain at umbilicus: afferent pain fibers entering at T10
Severe somatic pain at Mc Burney: irritation of parietal peritoneum + abdo wall
4 characteristics in histopathology of esophageal squamous cell carcinoma
Solid nests of neoplastic squamous cells
Abundant eosino cytoplasm
Keratinization
Intercellular bridges
Cause of duodenal ulcers
H. pylori antral gastritis: destruction of somatostatin-secreting cells in antrum + high gastrin
H. Pylori ass w/
Duodenal ulcers
Gastric adenocarcinoma
Gastric lymphoma
Presentation of Hepatitis A infection
Acute prodromal symptoms
Then signs of cholestasis
Self-limited
Primary biliary cirrhosis
Granulomatous inflammation
Destruction of intrahepatic interlobular bile ducts
Pruritus + fatigue then signs of cholestasis + hypercholest (xanthelasma)
3 causes of infectious esophagitis in HIV+
Candida albicans (adherent pseudomembranes)
CMV (linear ulcerations)
HSV-1 (punched-out ulcers)
Iron absorption
Duodenum + proximal jejunum
Gastrojejunostomy/gastric bypass result in iron def + malabs of Vit B12, B9, fat-sol vit, Ca
Changes in esophagus in systemic sclerosis
Atrophy + fibrous replacement of esophageal muscularis
Esophageal dysmotility
Incompetence of the lower esophageal sphincter
GERD + high risk of Barrett’s
Portal vein thrombosis
Causes portal HTN, splenomegaly, varicosities at portocaval anastomoses
Normal histo of hepatic parenchyma
No ascites
Intraabdominal infections + abscesses
Polymicrobial
B. fragilis and E. coli +++
HNPCC
Gene resp for DNA mismatch repair (MSH2, MLH1)
Inherited mutation in one allele
Mutation in second allele during adult life
Diverticula
Pulsion: increased intraluminal P*; false div (muc+submuc+serosa); sigmoid
Traction: infl+scarring of gut wall; true div (w/ muscularis); midesophagus (mediastinal lymphadenitis)
Crohn ds + ileal involvement/resection
Bile acid malabsorption
Impaired absorption of fat-soluble vit (ADEK)
Impaired coag (vit K def)
Histology in cirrhosis
Diffuse hepatic fibrosis
Fibrous-lined parenchymal nodules
Gallstone ileus
Large gallstone through cholecystenteric fistula into small bowel
Obstruction of ileum
X-ray: gas in gallbladder + biliary tree
Histo in Primary biliary cholangitis (chronic autoimmune ds)
Lymphocytic infiltrates + destruction of small/mid-sized intrahepatic bile ducts
Similar histo in hepatic GVHD
Cavernous hemangioma
#1 benign liver tumor Cavernous, blood-filled vasc spaces of variable size Single epith layer No biopsy (fatal hge)
Liver function measured by
Serum albumin, bilirubin, PT
+ greatest prognostic significance in ptts w/ cirrhosis
Hereditary hemochromatosis
Missense mutation in HFE gene Excessive intestinal iron absorption Organ damage (cirrhosis, db, CM, arthropathy) No mechanisms to excrete iron (not intest, not renal)
3 risk factors for esophageal squamous cell carcinoma
US: tobacco, alcohol
Asia: betel nut chewing, food w/ N-nitroso
4 risk factors of esophageal adenocarcinoma
Barrett’s esophagus
GERD
Obesity
Tobacco
Brown pigment gallstones
Calcium salts of unconjugated bilirubin
2* to bact or helminthic inf of biliary tract
Beta-glucuronidase released by injured hepatocytes; bact hydrolyzes bili glucuronides to unconj bili
Clonorchis sinensis (liver fluke): East Asian countries
Brown pigment gallstones vs cholesterol gallstones
Calcium salts of unconjugated bilirubin
2* to bact or helminthic inf of biliary tract (Clonorchis sinensis=liver fluke)
Beta-glucuronidase released by injured hepatocytes; bact hydrolyzes bili glucuronides to unconj bili
cholesterol gallstones (inhibition of 7 alpha-hydroxylase)
Internal vs external hemorrhoids
Internal: columnar epith, autonomic innervation (inf hypogastric plexus), only sensitive to stretch. Not pain, temperature, touch
External: modified squamous epith, cutaneous somatic innervation (inf rectal nerve branch of pudendal N), very sensitive to pain, touch, temperature
Alkaline phosphatase + gamma-glutamyl transpeptidase
ALP: esp in bone + liver
GGT: hepatocytes + biliary epith + many organs but not bone
If ALP 3x elevation, not enough. So evaluate GGT to identify if hepatic cause
Conditions ass w/ hepatic angiosarcoma
Exposure to carcinogens (arsenic, thorotrast, polyvinyl chloride)
Cells express CD31
Kidney stones in Crohn ds
Oxalate stones
Impaired bile acid absorption (terminal ileum), loss in feces, fat malabsorption
Lipids bind Ca then excreted
Oxalate (not bound to Ca) absorbed then urinary calculi
Osmotic diarrhea, osmotic laxative
Lactase deficiency
Polyethylene glycol, magnesium hydroxide
Reye syndrome
Hepatic dysfct: vomiting, hepatomegaly, abnl LFTs, microvesicular steatosis without inflammation
Encephalopathy: by hepatic dysfct, toxic hyperammonemia, cerebral edema
MOA of the complications of Crohn’s ds
Transmural inflammation: strictures + fistula
Diffuse esophageal spasm
Impaired inhibitory innervation in myenteric plexus
Periodic, simultaneous, non-peristaltic contractions
Liquid/solid dysphagia w/ chest pain
Adenomatous polyps
Dysplastic mucosa, premalignant
AdenoK prevention: excision + decrease activity of COX-2 by Aspirin
Ttt to control symptoms of carcinoid sd
Octreotide (synthetic somatostatin analog)
Alpha-fetoprotein
Tumor marker
Moderately elevated in chronic viral hepatitis
Strikingly elevated in hepatocellular carcinoma
H pylori
Chronic non-atrophic gastritis in antrum: duodenal ulcers
Chronic atrophic gastritis in body+fundus: rarely ulcers but high risk of gastric adenocarcinoma and MALT lymphoma; iron def anemia
Gallbladder hypomotility
Slow/incomplete emptying in response to cholecystokinin stimulation
Excessive dehydration of bile (gallbladder: actively absorb water from bile)
Viscous biliary sludge; transient bile duct obstr (colic), cholest gallstone
Generalized malabsorption
Fats most severely affected: testing stool for fat (Sudan III stain)
Defects in pancreatic secretion, mucosal disorders, bacterial overgrowth, parasitic ds
Pathogenesis of Crohn’s ds
Increased activity of TH1: increased IL2, IFNg, TNF
Then intestinal injury
Non-caseating granulomas
Dubin-Johnson sd
Defective hepatic excretion of bilirubin glucuronides
Direct hyperbilirubinemia + jaundice
Impaired excretion of epinephrine metabolites (black liver)
HDV infection
HBV surface Ag must coat HDV Ag
Strongyloides stercoralis infection
After skin penetration by filariform (inf) larva
Dg: rhabditiform (noninf) larvae in stool
Hyperinfection sd: massive dissemination, multiorgan dysfct + septic shock
Histo in acute hepatitis
By hepatotropic viruses
Hepatocyte ballooning degen + apoptosis w/ mononuclear cell infiltration
