Random Mix #2 Flashcards
What drug inhibits dihydrofolate reductase?
METHOTREXATE
(tx for cancer, ai, ectopic preg, and abortions)
* can ==> macrocytic anemia from folate defcy
Where is Vitamin B12 absorbed?
Ileum
in the form of VitB12-IF complex
Which RBC cytoskeleton-membrane tethering proteins are most commonly defective with Hereditary Spherocytosis?
Ankyrin
Spectrin
Band 3
What is the mechanism of aplastic crisis with Parvovirus B19?
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
What is the single amino acid mutation seen with sickle-cell anemia?
glutamic acid is replaced with valine
Why is treatment of sickle-cell disease with Hydroxyurea effective?
Hydroxyurea increases levels of HbF; HbF is protective against sickling.
What is the most common cause of death in sickle-cell disease children?
PNA from Strep. pneumo. and H. influenzae
*results from autosplenectomy, which increases risk of infection from encapsulated organisms
What is the most common cause of death in sickle-cell disease adults?
Acute chest syndrome
* vaso-oculsion of pulmonary micro-circulation, often precipitated by PNA
How does DAF/CD55 (decay accelerating factor) protect blood cells from complement-mediated damage?
DAF inhibits C3 convertase
What is the pathophysiology of intravascular hemolysis seen with G6PD Deficiency?
reduced half-life of G6PD => less NADPH => less glutathione => more oxidative injury by H2O2 => intravascular hemolysis
Heinz Bodies are a result of what disease process?
Glucose-6-Phosphate Deficiency (XLR)
-oxidative stress causes Hb to precipitate
What is the connection between Fava Beans and bite cells seen on blood smear?
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.
What diseases are associated with IgG-mediated Immune Hemolytic Anemia?
SLE
CLL
What infections are associated with IgM-mediated Immune Hemolytic Anemia?
Mycoplasma pneumoniae
Infections mononucleosis
How does the presentation of Plasmodium falciparum infection differ from Plasmodium vivax or ovale infections?
P. falciparum = daily fever
P. vivax or P. ovale = fever every other day
A decrease in this cell marker indicates increased release of immature cells from bone marrow. (i.e. during bacterial infection or tissue necrosis)
CD16
Fc Receptor
CML is classically associated with which form of leukocytosis?
Basophilia
Which infection uniquely results in a lymphocytic leukocytosis?
Bordetella pertussis infection
* secretes lymphocytosis-promoting-factor that blocks lymphocytes from leaving the blood to enter the lymph node
Where is the area of expansion with CD8+ generalized lymphadenopathy?
Paracortex
- T-cell hyperplasia
i. e. infectious mononucleosis
T-cell hyperplasia causing splenomegaly occurs in what region of the spleen?
Periarterial Lymphatic Sheath
i.e. infectious mononucleosis
A negative monospot test suggests…
CMV as a possible cause of Infectious Mononucleosis
or not mono
Which parts of the kidney are particularly susceptible to ischemic injury?
Proximal tubule
Medullary segment of the thick ascending limb
What is the characteristic urine finding with ethylene glycol ingestion?
Oxalate crystals
Where is EPO produced?
Renal peritubular interstitial cells
