6/7 UWorld

Question 1

Symptoms of carcinoid syndrome

Answer 1

• Symptoms = BFDR
  
  • Bronchospasm
  • Flushing
  • Diarrhea
  • Right-sided heart disease/murmur

Question 2

What is angiodysplasia?

Answer 2

• Tortuous dilation of vessels within the bowel, leading to hematochezia
• Unexplained GI bleeding and anemia

Question 3

What is proctitis

Answer 3

• Inflammation of perianal region and rectum
• Usually due to fecal matter in the area for an extended period of time
• Also associated with ulcerative colitis

Question 4

Describe the progression from adenoma to carcinoma in colorectal cancer

Answer 4

• Order of events = AK=53
• Normal colon
  
  • = APC (adenomatous polyposis coli) gene mutation (loss of APC)
• Colon at risk for polyps
  
  • = KRAS mutation (oncogene)
• Development of polyps/adenoma
  
  • = p53 mutation (loss of tumor suppressor)
• Progression to carcinoma

Question 5

What is Turcot syndrome

Answer 5

• FAP + malignant CNS tumor (medulloblastoma)
  
  • THINK: TURcot = TURban

Question 6

What is the defect in hereditary nonpolyposis colorectal cancer (HNPCC)

Answer 6

Aka Lynch Syndrome

Defect in DNA mismatch repair (MMR)

Question 7

Most common location of diverticulitis

Answer 7

Sigmoid colon (LLQ pain)

Question 8

Most common location of Crohn’s

Answer 8

Terminal ileum; rectal sparing

Vs. UC which can only affect the colon and rectum is always involved

Question 9

Crohn’s vs. Ulcerative colitis

Histology

Answer 9

Crohn - noncaseating granulomas with lymphoid aggregates

UC - crypt abscesses with neutrophils

Question 10

Crohn’s vs. UC - X-ray imaging

Answer 10

Crohns:

• Cobblestone mucosae
• Creeping fat
• Strictures = “string sign” appearance

UC:

• Loss of haustra = “lead pipe” appearance

Question 11

Describe excretion of bilirubin (urobilinogen, stercobilin, and urobilin)

Answer 11

• Colonic bacteria converts bilirubin to urobilinogen
  
  • Most (80%) Urobilinogen is oxidized to stercobilin and excreted in the stool – makes stool brown
• Small amount (20%) of urobilinogen is reabsorbed by the gut
  
  • 90% Enters mesenteric veins and goes back into the liver and into bile – enterohepatic circulation
  • Tiny amount (10%) of reabsorbed urobilinogen is converted to urobilin and excreted in the urine – makes urine yellow

Question 12

Describe primary sclerosing cholangitis (histology, imaging, complications)

Answer 12

• Unknown cause
• Concentric fibrosis of the intra- and extra-hepatic bile ducts (“onion skin” fibrosis)
• Contrast imaging will show “beaded” appearance due to alternating fibrotic and dilated regions
• Mostly occurs in men around age 40
• Associated with (+) pANCA and Ulcerative colitis
• Can lead to secondary biliary cholangitis
• Increased risk for cholangiocarcinoma

Question 13

Describe the source of bilirubin

Answer 13

• Bilirubin metabolism:
  
  • Hemoglobin broken down into heme and globin
  • Heme then broken down into iron and protoporphyrin
  • Protoporphyrin converted into unconjugataed bilirubin (water insoluble)
  • UCB binds to albumin to be brought to the liver
  • Liver conjugates UCB into CB (water soluble)
    
    • UDP glucuronyl transferase (UGT) is the enzyme in the hepatocytes that conjugates bilirubin
  • CB dumped into bile canaliculi to be sent to the gallbladder

Question 14

What is the cause and histology of Primary biliary cirrhosis (PBC)

Answer 14

• Autoimmune destruction of intra-hepatic bile ducts
  
  • Associated with other autoimmune conditions
• Lymphocytic infiltrate + granulomas

Question 15

What is Charcot’s triad of cholangitis?

Answer 15

• Inflammation/infection of the biliary tree
• Charcot’s triad:
  
  • Jaundice
  • Fever
  • RUQ pain
• Reynold’s pentad:
  
  • Jaundice, fever, RUQ pain, Hypotension, AMS

Question 16

Antibody associated with Primary biliary cirrhosis

Answer 16

• Autoimmune destruction of intra-hepatic bile ducts
  
  • Associated with other autoimmune conditions
• (+) anti-mitochondrial antibody (AMA)

Question 17

Causes of acute pancreatitis

Answer 17

• Autodigestion of pancreas by pancreatic enzymes
• Causes:
  
  • Most common:
    
    • Gallstones
    • Alcohol
  • I GET SMASHED:
    
    • Idiopathic, Gallstones, Ethanol, Trauma, Steroids, Mumps, Autoimmune disease, Scorpion sting, Hypertriglyceridemia/Hypercalcemia, ERCP, Drugs (e.g. Sulfa, NRTIs, protease inhibitors)
      
      • ERCP = endoscopic retrograde cholangio pancreatogram

Question 18

What is Trousseau sign

Answer 18

• Hypercoagulability
• Venous thrombosis
• Migratory thrombophlebitis

Caused by adenocarcinoma of the pancreas or lung

Question 19

How do you differentiate between Type I vs. Type II Crigler-Najjar syndrome

Answer 19

• Type I is more severe
• If you give phenobarbital, it will cause decreased UCB in Type II and no change in Type I

Question 20

Presentation of Dubin Johnson syndrome

Answer 20

• Deficiency of bilirubin canalicular transport protein
  
  • Cannot transport CB from liver to bile ducts
• Black liver (due to build up of bilirubin in hepatocytes)
• Increased CB
• Clinically benign

Question 21

What are Mallory bodies and what disease are they seen in

Answer 21

• Intracytoplasmic eosinophilic inclusions of damaged keratin filaments
• Seen in alcoholic hepatitis

Question 22

Why would you see bleeding and bruising in liver failure

Answer 22

Loss of coagulation factors - Coagulopathy and elevated PT and PTT

Question 23

Why do you see edema and ascites in liver failure?

Answer 23

• Loss of albumin = decreased osmotic pressure causing to fluid to leak out of vessels

Question 24

Describe the TIPS procedure used to treat portal HTN

Answer 24

• Transjugular intrahepatic portosystemic shunt
  
  • Shunt between the portal vein and hepatic vein relieves portal HTN by shunting blood to the systemic circulation, bypassing the liver

Question 25

Tumor markers of pancreatic adenocarcinoma

Answer 25

CA19-9 CEA

Question 26

Causes of nutmeg live

Answer 26

Backup of blood into the liver Caused by Budd-Chiari and R heart failure

Question 27

Presenation and treatment of Wilson disease * Autosomal recessive * Mutation in hepatocyte copper-transporting ATPase (ATP7B gene) * Inadequate copper excretion into bile and blood * Decreased serum ceruloplasmin * Increased urine copper * Copper accumulation in: liver, brain, cornea, kidney, joints * Presentation: * Liver disease, Kayser-Fleischer rings, renal disease (Fanconi syndrome) * Treatment: * Chelation with Penicillamine

Answer 27

* Mutation in hepatocyte copper-transporting ATPase (ATP7B gene) * Presentation: * Liver disease, Kayser-Fleischer rings, renal disease (Fanconi syndrome) * Treatment: * Chelation with Penicillamine

Question 28

Presentation of hemochromatosis

Answer 28

* Classic triad: * Cirrhosis * Diabetes mellitus * Skin pigmentation * "Bronze diabetes"

Question 29

Describe the pathogenesis of A1ATD in liver disease

Answer 29

* Liver: * Misfolded gene produce protein aggregates in hepatocellular endoplasmic reticulum à cirrhosis with PAS (+) globules * Lungs: * Decreased a1-antitrypsin = uninhibited elastase in alveoli = decreased elastic tissue = panacinar emphysema

Question 30

Diseases of what body systems will cause and increase in alkaline phosphatase

Answer 30

Liver, biliary, bone

Question 31

Associated risk factors for: * Hepatic adenoma * Hepatic angiosarcoma * Hepatocellular carcinoma

Answer 31

* Hepatic adenoma: * Rare, benign liver tumor * Associations: oral contraceptive, anabolic steroid use * Hepatic angiosarcoma: * Malignant tumor of endothelial origin * Association: exposure to arsenic or vinyl chloride * Hepatocelllular carcinoma: * Most common primary malignant liver tumor in adults * Association: * Hepatitis B * Hepatitis C * All associations with cirrhosis * Hemochromatosis * A1-antitrypsin deficiency * Aflatoxin from Aspergillus

Question 33

What drugs often provoke Prinzmetal angina

Answer 33

Triptans/dihydroergotamin Cocaine/amphetaimes

Question 34

What is the function of zinc fingers in signal transduction

Answer 34

They directly bind DNA Often incorporated into intracellular receptors (VETT CAP) that act directly as transcription factors

Question 35

How does pyruvate kinase deficiency lead to anemia?

Answer 35

* Glycolytic enzyme deficiency (formation of pyruvate) = inability to generate ATP * Cannot maintain Na+/K+ ATPase = RBC swelling and lysis

Question 36

What structure courses through the angle between the aorta and superior mesenteric artery

Answer 36

Transverse portion of the duodenum * Superior mesenteric artery syndrome: * SMA usually forms a 45 degree angle with the aorta, with the transverse portion of the duodenum coursing horizontally between the two * If the angle diminished to less than 20 degrees, the transverse duodenum can get entrapped, leading to small bowel obstruction

Question 37

Which bacterial pathogens are the most common cause of intraabdominal infections (e.g. within fluid released from appendiceal rupture)

Answer 37

Bacteroides fragilis E. Coli

Question 38

How does systemic blood flow effect cerebral circulation, and therefore intracranial pressure

Answer 38

* BP between 60-140 has little effect on cerebral blood volume * Autoregulation (via cerebral blood vessel dilation and contraction) keeps flow constant * BP \> 150 causes increased cerebral vascular volume and blood flow = increased ICP * BP \< 50 causes cerebral hypoperfusion and potential ischemia

Question 39

How does arterial blood gas (specifically PaCO2) affect cerebral circulation, and therefore ICP

Answer 39

* A drop in PaCO2 due to hyperventilation causes vasoconstriction = decreased cerebral blood flow = decreased ICP * So lowering PaCO2 is a treatment option for reduction ICP in patients with cerebral edema