Rx_12.29

Question 1

Hx pf antimalarial drug ==> fatigue, dark urine, jaundice/icterus ==> Dx?

Answer 1

• medication-induced hemolytic anemia due to glucose-6-phosphate dehydrogenase (G6PD) deficiency
  
  • _​_G6PD recycles NADP+ to NADPH and deficiency impairs recycling of glutatione and this the inactivation of free radicals/peroxides in face of oxidative stress
• x-linked recessive condtion

Question 2

Sources of oxidative stress ==> hemolytic anemia in G6PD deficient individuals

Answer 2

• antimalarial drugs
• antibiotics w/sulfonamides
• consumption of fava beans
• infection: e.g. hepatitis A

Question 3

Presentation of G6PD deficiency

Answer 3

• previously healthy adult + oxidative stress ==> hemolytic anemia
• more common in African-Americans
• Sx
  
  • fatigue
  • dark urine jaundice

Question 4

Zidovudine: MOA, use

Answer 4

• MOA: nucleoside analog ==> inhibits HIV reverse transcriptase
  
  • prevents incorporation of viral genome into host DNA
• Use
  
  • general propylaxis
  • reduce risk of transmission to fetus during pregnancy

Question 5

-“navir” drugs MOA

Answer 5

usually viral protease inhibitors

Question 6

Dx?

Answer 6

hepatocellular carcinoma

Question 7

Common form of spread/metastasis of hepatocellular carcinoma

Answer 7

• hematogenous dissemination

Question 8

Cancers that spread via hematogenous dissemination + common sites of metastasis

Answer 8

• hepatocellular carcinoma
• renal cell carcinoma
• follicular thyroid carcinoma
• common sites:
  
  • lung
  • portal vein
  • periportal nodes
  • brain
  • bones

Question 9

Renal presentation in goodpasture sydnrome

Answer 9

• histology = linear PAS staining of glomerular basement membrane
  
  • due to autoantibodies against type IV collagen
    
    • also present @ alveoli ==> lung sx
• rapidly progressive glomerulonephritis
  
  • microscopic hematuria ==>
  • renal failure

Question 10

Most common cause of infectious mononucleosis

Answer 10

• Epstein-Barr Virus
• other causes of acute mono-like sx:
  
  • cytomegalovirus
  • acute HIV

Question 11

Common finding on peripheral smear of individual with EBV

Answer 11

• large lymphocytes w/prominent nucleoli
  
  • abnormal circulating cyctotoxic T lymphocytes

Question 12

Presentation of aortic stenosis

Answer 12

• progressive dyspnea on exertion
• fatigue
• syncope
• angina
• low-volume late pulses
• left ventricular hypertrophy
• murmur = crescendo-decrescendo systolic murmur

Question 13

Most common cause of aortic stenosis

Answer 13

• calcification of valve leaflets
• due to proliferative and inflammatory changes

Question 14

Toxoid definition

Answer 14

• toxoid = modified toxin w/antigenic similarity but no toxicity
  
  • e.g. toxoids used in vaccines
• ==> toxoid immunologicaly cross-reacts w/toxin

Question 15

Presentation of tumor lysis syndrome

Answer 15

• result of tx of lymphomas/”bulky” cancers w/cytotoxic therapy
• ==> spilling of tumor cell contents into bloodstream
  
  • increased uric acid ==> gout
  • increased potassium ==> arrhythmias and weakness ==> sudden death
  • decreased calcium
  • increased phosphate

Question 16

Major risk factors for hepatocellular carcinoma

Answer 16

• cirrhosis due to alcohol abus
• hep C or B
• positive family hx

Question 17

Possible rare cause of hepatocellular carcinoma in patients from outside US

Answer 17

• aflatoxin
  
  • mycotoxin produced by Aspergillus flavus
  • causes liver cancer by intercalating into host DNA
• A. flavus may grow on peanuts/grains after harvesting and processing
  
  • foods w/high levels of alfatoxin banned in the US

Question 18

Major histologic feature in Niemann-Pick disease

Answer 18

• lipid-laden “foamy” macrophages in bone barrow
• N-P: deficiency of sphingomyelinase ==> acuumulation of sphungomyelin and cholesterol
  
  • enzyme converts sphingomyelin to cerebroside

Question 19

Common building block for fatty acids

Answer 19

malonyl-CoA (3 carbon unit)

Question 20

Common cause of osteomylitis in IV drug users

Answer 20

• Pseudomonas aeruginosa

Question 21

Tx of Pseudomonas aeruginosa

Answer 21

• ticarcillin
  
  • category: penicillin
  • MOA: cell wall synthesis inhibition
• piperacillin
  
  • category: penicillin
  • MOA: cell wall synthesis inhibition

Question 22

EBV mechanism + presentation

Answer 22

• EBV ==> infectious mononucleosis
• signs/sx:
  
  • fever
  • pharyngitis
  • posterior cervical lymphadenopathy
  • circulating heterophil antibodies
  • hepatosplenomegaly
• mechanism: infects B lymphocytes
  
  • markers: IgM, B7, CD19, CD20

Question 23

Lead poisoning: affected enzyme and accumulated substrate

Answer 23

• lead poisoning ==> inhibition of enzymes in heme synthesis pathway:
  
  • ferrochelatase
  • ALA dehydratase
• accumulated substrates:
  
  • protoporphyrin
  • delta-ALA (aminolevulinic acid)

Question 24

Mechanism of aortic dissection in Marfan’s syndrome

Answer 24

• HTN + cystic medial necrosis ==> aortic aneurysms
• ==> rupture = aortic dissection

Question 25

Amiodarone: MOA, SE

Answer 25

• Amiodarone = class III antiarrhythmic
• MOA = blocks potassium current ==> prolonged repolarization phase
• SE
  
  • pulmonary fibrosis
  • hepatotoxicity
  • thyroid abnormalities
  • can induce arrhythmias

Question 26

Common cause of cholestatic hepatitis

Answer 26

• adverse effect of macrolides
  
  • e.g. clarithromycin
  • Azithromycin
  • Erythromycin

Question 27

Presentation of cholestatic hepatitis

Answer 27

• elevated LFTs
  
  • slightly elevated AST/ALT
  • significantly elevated alk-phos and gamma-glutamyl transpeptidase
  • eleveted direct bilirubin
• jaundice/icterus
• hx: antibiotic tx (macrolides)

Question 28

Macrolides: MOA

Answer 28

• inhibit bacterial protein synthesis by blocking translocation
• bind to 23S rRNA or 50S ribosomal subunit
• bacteriostatic