Random Mix #2

Question 1

What drug inhibits dihydrofolate reductase?

Answer 1

METHOTREXATE
(tx for cancer, ai, ectopic preg, and abortions)
* can ==> macrocytic anemia from folate defcy

Question 2

Where is Vitamin B12 absorbed?

Answer 2

Ileum

in the form of VitB12-IF complex

Question 3

Which RBC cytoskeleton-membrane tethering proteins are most commonly defective with Hereditary Spherocytosis?

Answer 3

Ankyrin
Spectrin
Band 3

Question 4

What is the mechanism of aplastic crisis with Parvovirus B19?

Answer 4

Parvovirus B19 infects the erythroid precursors stopping production. Without erythroid reserve, patients will suffer an aplastic crisis

• Hereditary Spherocytosis
• beta-Thalassemia Major
• Sickle-Cell Disease

Question 5

What is the single amino acid mutation seen with sickle-cell anemia?

Answer 5

glutamic acid is replaced with valine

Question 6

Why is treatment of sickle-cell disease with Hydroxyurea effective?

Answer 6

Hydroxyurea increases levels of HbF; HbF is protective against sickling.

Question 7

What is the most common cause of death in sickle-cell disease children?

Answer 7

PNA from Strep. pneumo. and H. influenzae

*results from autosplenectomy, which increases risk of infection from encapsulated organisms

Question 8

What is the most common cause of death in sickle-cell disease adults?

Answer 8

Acute chest syndrome

* vaso-oculsion of pulmonary micro-circulation, often precipitated by PNA

Question 9

How does DAF/CD55 (decay accelerating factor) protect blood cells from complement-mediated damage?

Answer 9

DAF inhibits C3 convertase

Question 10

What is the pathophysiology of intravascular hemolysis seen with G6PD Deficiency?

Answer 10

reduced half-life of G6PD
=> less NADPH
=> less glutathione
=> more oxidative injury by H2O2
=> intravascular hemolysis

Question 11

Heinz Bodies are a result of what disease process?

Answer 11

Glucose-6-Phosphate Deficiency (XLR)

-oxidative stress causes Hb to precipitate

Question 12

What is the connection between Fava Beans and bite cells seen on blood smear?

Answer 12

Fava beans cause oxidate stress that can cause Hb to precipitate into Heinz bodies for patients with G6PD Defcy. The Heinz bodies are removed from RBCs by splenic macrophages => bite cells. BOOM.

Question 13

What diseases are associated with IgG-mediated Immune Hemolytic Anemia?

Answer 13

SLE

CLL

Question 14

What infections are associated with IgM-mediated Immune Hemolytic Anemia?

Answer 14

Mycoplasma pneumoniae

Infections mononucleosis

Question 15

How does the presentation of Plasmodium falciparum infection differ from Plasmodium vivax or ovale infections?

Answer 15

P. falciparum = daily fever

P. vivax or P. ovale = fever every other day

Question 16

A decrease in this cell marker indicates increased release of immature cells from bone marrow. (i.e. during bacterial infection or tissue necrosis)

Answer 16

CD16

Fc Receptor

Question 17

CML is classically associated with which form of leukocytosis?

Answer 17

Basophilia

Question 18

Which infection uniquely results in a lymphocytic leukocytosis?

Answer 18

Bordetella pertussis infection

* secretes lymphocytosis-promoting-factor that blocks lymphocytes from leaving the blood to enter the lymph node

Question 19

Where is the area of expansion with CD8+ generalized lymphadenopathy?

Answer 19

Paracortex

• T-cell hyperplasia
  i. e. infectious mononucleosis

Question 20

T-cell hyperplasia causing splenomegaly occurs in what region of the spleen?

Answer 20

Periarterial Lymphatic Sheath

i.e. infectious mononucleosis

Question 21

A negative monospot test suggests…

Answer 21

CMV as a possible cause of Infectious Mononucleosis

or not mono

Question 22

Which parts of the kidney are particularly susceptible to ischemic injury?

Answer 22

Proximal tubule

Medullary segment of the thick ascending limb

Question 23

What is the characteristic urine finding with ethylene glycol ingestion?

Answer 23

Oxalate crystals

Question 24

Where is EPO produced?

Answer 24

Renal peritubular interstitial cells