Deck XVII Flashcards Preview

USMLE World Missed Questions > Deck XVII > Flashcards

Flashcards in Deck XVII Deck (30):
1

What lab findings are associated with DIC?

Prolonged PTT, prolonged PT, thrombocytopenia and microangiopathic hemolytic anemia, low fibrinogen, elevated fibrin split products (D dimer), low factor V and VIII levels.

2

What is the mechanism of action of 6-Mercaptopurine?

Purine analog that inhibits de novo purine synthesis after being converted to active metabolites by hypoxanthine-guanine phosphoribosyl transferase (HGPRT).

3

6-Mercaptopurine is inactivated by which enzyme?

Xanthine oxidase degradation in the liver.

4

What drug may increase concentration of 6-mercaptopurine?

Allopurinol (xanthine oxidase inhibitor)

5

6-mercaptopurine and 6-thioguanine are prodrugs that require activation by what enzyme?

Hypoxanthine-guanine phosphoribosyl transferase.

6

Name three drugs that cause aplastic anemia.

Carbamazepine, chloramphenicol, sulfonamides.

7

What is a major dose related side effect associated with chloramphenicol?

Dose related anemia, leukopenia, and/or thrombocytopenia

8

What is a major dose independent side effect associated with chloramphenicol?

Aplastic anemia- this may be fatal if not treated with bone marrow transplantation.

9

What lab findings are associated with iron deficiency anemia?

Decreased serum ferritin, increased serum transferrin, and increased total iron binding capacity. Also decreased blood hemoglobin and microcytic hypochromic RBCs.

10

What is ferritin?

Cellular iron storage protein. It is also an acute phase reactant and may be elevated in patients with infections or inflammatory disease.

11

What is transferrin?

Transports iron through the plasma. In normal iron states, approximately 1/3 of circulating transferrin is saturated with iron. Synthesis of transferrin is markedly increased in iron deficiency.

12

What cell marker is diagnostic of small cell carcinoma?

Neuroendocrine markers such as neuron specific enolase, chromogranin, synaptophysin, neurofilaments. They also contain neurosecretory granules in the cytoplasm.

13

What cell marker is used to diagnose sarcomas?

Vimentin, an intermediate filament found in cells of mesenchymal origin.

14

What cell marker is used to diagnose non-small cell carcinomas?

Expression of EGF receptors, mucin, and surfactant associated proteins.

15

What causes hemorrhagic cystitis?

Urinary excretion of the toxic metabolite acrolein.

16

What is filgastrim?

A G-CSF (granulocyte colony stimulating factor) used to stimulate the proliferation and differentiation of granulocytes in patients with neutropenia as can occur after chemotherapy.

17

What enzyme metabolizes pro-carcinogens?

Cytochrome P450 monooxygenase of hepatic microsomes and in the endoplasmic reticula of other tissues. This converts pro-carcinogens to carcinogens capable of causing DNA mutation.

18

What is the HER-2/Neu gene also called?

ERB-B2 gene.

19

What cells appear as blue, enlarged red blood cells on Wright-Giemsa stain?

Reticulocytes.

20

What cellular component of reticulocytes appear blue microscopically after application of the Wright-Giemsa stain?

Ribosomal RNA.

21

What deficiencies are sickle cell patients particularly prone to?

Folic acid deficiency due to increased erythrocyte turnover.

22

What presentation is typical of T-ALL over B-ALL?

Large anterior mediastinal mass that may compress the great vessels causing superior vena cava syndrome. It may also compress the esophagus causing dysphagia and compression of the trachea leading to dyspnea and stridor.

23

What cell surface markers characterize pre-B lymphoblasts?

CD10, CD19, CD20.

24

What cell surface markers characterize pre-T lymphoblasts?

CD2, CD3, CD4, CD5, CD7, CD8.

25

What is the most common malignancy of childhood?

Acute Lymphoblastic Leukemia (ALL)

26

Which type of ALL is most common?

B-cell ALL (70-80%); T cell accounts for 15-17%

27

What is Rituximab?

A monoclonal antibody used in lymphoma immunotherapy to specifically target the CD20 surface immunoglobulin.

28

What is the most common indolent non-Hodgkin lymphoma in adults?

Follicular lymphoma.

29

What is follicular lymphoma?

Follicular B cell lymphoma that has an indolent clinical course marked by remissions and recurrences. It most often presents with painless lymph node enlargement of abdominal discomfort from an abdominal mass.

30

What is overexpressed in follicular lymphoma?

Bcl-2 oncogene.