47 terms

RBC's Part 2 - Hematology

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Sideroblastic anemia
-E?
-Chronic alcoholism (damages mitochondria)
-Pyridoxine deficiency (vitamin B6) (often d/t Isoniazid treatment, INH competes with pyridoxine)
-Lead poisoning (Pb denature enzymes)
-Hereditary
Sideroblastic anemia
-P?
defect in heme synthesis within the mitochondria -> ringed sideroblasts = in BM, immature RBC's with dark blue iron granules surrounding the nucleus
Macrocytic anemias
-two types?
Megaloblastic = d/t folate or B12 deficiency
Non-megaloblastic = d/t alcohol intoxication
B12 deficiency
-absorption?
-In stomach, partieal cells produce HCL and IF
-gastric acid converts pepsinogen to pepsin
-pepsin frees B12 from ingested proteins, intrinsic factor (synthesized by parietal cells) binds to B12
-IF-B12 complex is reabsorbed in the terminal ileum
Vitamine B12 deficiency causes?
Pernicious anemia
Folate absorption?
-folate is converted into monoglutamates by intestinal conjugate (which can be inhibited by phenytoin)
-monoglutamates are reabsorbed in the jejunum (reabsorption can be inhibited by alcohol and oral contraceptives)
B12 deficiency
-L?
-decreased serum b12
-increased serum homocysteine and methylmalonic acid
-oval macrocytes
-hypersegmented neutrophils
B12 deficiency
-C?
-achlorhydria (lack of gastric acid) = maldigestion
-smooth, sore tongue
-neurologic disease: decreased vibratory sensation & proprioception, ataxia, dementia, d/t demyelination
Folate deficiency
-C?
same as b12 but WITHOUT neuro symptoms
B12/Folate deficiency Rx?
B12 injections, oral folic acid
Aplastic anemia
-L?
-pancytopenia = decreased RBC's, WBC's, AND platelets
Aplastic anemia
-C?
-fever (d/t infection from neutropenia)
-bleeding (d/t thrombocytopenia (low platelets))
-hypocellular bone marrow
Aplastic anemia
-P?
Antigenic alteration of myeloid stem cells -> T cell activation & release of cytokins that SUPPRESSES myeloid stem cells

Bone marrow is damaged = makes NO cells
Chronic renal failure
-blood effects?
-causes decreased EPO production --> normocytic anemia
-burr cells
-platelet dysfunction = prolonged bleeding time
Aplastic anemia
-E?
-can be d/t drugs, chemical agents, infection, radiation, malignancy
Intrinsic vs. Extrinsic hemolytic anemia:
-defect in RBC causes anemia lead to hemolysis
-factors outside RBC lead to hemolysis
Extravascular hemolysis=
RBC's hemolyzed in the spleen & liver --> increase in unconjugated bilirubin (an end product of MACROphage degradation of Hb) --> jaundice
Intravascular hemolysis=
hemolysis WITHIN blood vessels
-causes decreased serum haptoglobin , and hemoglobinuria
haptoglobin=
an acute phase reactant that combines with Hb to form a complex that is degraded by macrophages

-lots of hemolysis = more haptoglobin bound to it, then phagocytosed = decreased haptoglobin level in blood during intravascular hemolysis

-jaundice not produced because NOT much unconjugated bili is produced
Hereditary spherocytosis
-E?
autosomal dominant
-intrinsic defect with extravascular hemolysis
-mutation in ankyrin cell membrane = dysfunctional Na+/K+atpase pump = cells more permeable to Na = sphereocytes
Hereditary spherocytosis
-Rx?
splenectomy!
Hereditary elliptocytosis
-P?
autosomal dominant
-defective spectrin and band 4.1
Hereditary elliptocytosis
-T?
splenectomy!
Paroxysymal ncoturnal hemoglobinuria
-P?
Acquired defect in myeloid stem cells
-mutation casues loss of anchor for decay accelerating factor = unstable C3 and C5 convertase, that adhere;s to RBC's platelets and neutrophils
-At NIGHT, respiratory acidosis --> complement mediated lysis of RBC's neutrophils, and platelets
-intrinsic defects, intravascular hemolysis
Paroxysymal ncoturnal hemoglobinuria
-C?
episodic hemoglobinuria
Sickle Cell anemia
-E?
autosomal recessive
-d/t missense point mutation, valine substituted for glutamic acid at sixth position of the Beta globin chain
Why no sickling for the first 6 months of life?
HbF prevents sickling
Sickle Cell anemia
-hand and foot syndrome=
painful swelling of feet and hands d/t bone infarcts, usually occurs in infants
Sickle Cell anemia
-acute chest=
Chest pain, wheezing, and dyspnea
-d/t pneumonia, infarction, or fat embolism
Howell Jolly bodies=
nuclear remnants in RBC's
-occurs in sickled cell d/t loss of function of macrophages in spleen (autosplenectomy)
Sickle Cell anemia
-Rx?
-treat infections
-pain relief
-transfusion (for acute chest, aplastic anemia)
G6DP deficiency =
-E?
glucose 6 dehydrogenase deficiency
-an X-linked recessive disorder
G6DP deficiency
-P?
-protective against plasmodium falciparum malaria
-decreased synthesis of NADPH and GSH --> oxidation of Hb --> Heinz bodies

Heniz bodies get removed -> bite cells
G6DP deficiency
-C/L?
-Episodic hemolytic anemia, often after exposure to oxidant stress (Fava beans, drugs (primaquine, dapsone, sulfonamides, nitrofuranotoin)
-presents as sudden onset back pain with hemoglobinuria 2-3 days after oxidant stress
Pyruvate kinase deficiency
-E?
autosomal recessive
Pyruvate kinase deficiency
-P?
causes intrinsic defect with extravascular hemolysis
Pyruvate kinase deficiency
-C/L?
Jaundice beginning at birth
-increased in 2,3 BPG causing Right shift
-RBC's with thorny projections (echinocytes)
Autoimmune hemolytic anemia
-d/t?
IgG- coats RBC's --> destruction by splenic macrphages = extravascular hemolysis
Complement --> intravascular hemolysis
Autoimmune hemolytic anemia
-dx?
Coombs test
Direct coombs=
add rabbit Anti-IgG antibody (coombs reagent) to RBC's
-agglutination = RBC's already have IgG antibodies on them
Indirect Coombs =
-take pt's serum (containing IgG?) add test O RBC's, then add Coomb's reagent (rabbit anti-IgG antibody)
-agglutination = Pt's serum has IgG antibodies in it
Micro/macro angiopathic hemolytic anemias=
-L?
-RBC's are injured in circulation (d/t valve defects, HUS, HELLP, DIC....)
-will see schistocytes in blood (fragmented RBC's)
Malaria
-E?
d/t plasmodium infection in RBC's from anopheles mosquito
-causes extrinsic defect with intravascular hemolysis
Malaria
-types & clinical findings?
Plasmodium vivax- tertain fever pattern = q48hrs
Plasmodium falciparum- quotidian fever patern = daily spikes, NO pattern
Plasmodium malariae- quartan fever pattern = q72 hr
-assoc with nephrotic syndrome
Malaria Meds
-prophylaxis?
Chloroquine
-safe during pregnancy :)
or atovaquone-proguanil for resistant strains
Malaria Meds
-treatment of Plasmodium vivax/ovale
Chloroquine + primaquine
Malaria Meds
-treatment of Plasmodium falciparum
-chloroquine sensitive- chloroquine w/o primaquine
-NOT chloroquine sensitive - quinine sulfate + doxycycline