anemia I&II Flashcards
What maintains the unique shape of RBCs?
biconcave shape is maintained by:
-membrane skeleton = ankryin + spectrin
Describe the maturation and normal life span of an RBC
- pleuripotent stem cell > reticulocyte > RBC
- 120 days life span
- removed from circulation by spleen and components are separated and recycled:
- heme: iron
- poryphorin: bilirubin
- globin: amino acids
Name the three main categories of anemia?
- blood loss: loss of RBCs
- hemolytic: increased destruction
- decreased production
What is the MCV and what does it tell us about types of anemia?
MCV: mean cell volume
80-100: normal range
100: macrocytic
Name the two main categories of hemolytic anemia
intrinsic: within the RBC; genetic OR acquired
extrinsic: outside of RBC; usually in the spleen
What are the main causes of intrinsic hemolytic anemia?
genetic:
- membrane defects: spherocytosis
- enzyme defects: GP6 deficiency
- low [hemoglobin]: thalassemia
acquired: Paroxysmal Nocturnal Hemoglobinuria
What are the main causes of extrinsic hemolytic anemia?
- antibody mediated
- chemical trauma
- infections
- chemical injury
- splenomegaly
What is haptoglobin?
-haptoglobin is what binds to free hemoglobin released from hemolyzed RBCs
so if there is a lot of hemolysis, then [haptoglobin] will be low.
Describe spherocytosis: DDEPCT
D: abnormally shaped RBCs—discoid > spherically shaped
D: MCH + MCHC: elevated; osm fragility test (spherocytes take decreased amount of time to lyse when placed in hypotonic solution)
E: hereditary—auto dom. or auto rec
P: defect in ankyrin protein leads to decreased amounts of spectrin [membrane skeleton proteins]
= less interaction of RBC bilayer and cytoskeleton
= decreased membrane stability
C:
- splenomegaly
- anemia
- jaundice
- aplastic anemia: overworking of the bone marrow + infection = sudden drop of hemoglobin
T: splenectomy: decreases destruction of RBCs
Describe G-6-PD deficiency: DEPCT
D: deficiency in enzyme required to regenerate NADP in order to neutralize oxidative substances via reduced glutathione
E: x-linked, polymorphic, triggered by infections/toxins
P: w/o G-6-PD — heinz bodies
production due to oxidative substances denaturing hemoglobin
>cause intravascular hemolysis and damage to endothelium
>extravascular hemolysis: heinz bodies go to spleen, macrophages in the spleen bite the heinz bodies and spherocytes; spherocytes get stuck in spleen too
C: histo—–heinz bodies [crystal violet stain]
T: treat underlying infection, no specific treatment
Describe sickle cell disease: DEPCT
histo — automatic or induced sickling of RBCs on smear, gel electrophoresis: HgbS and HgbA migrate differently on gel
D: sickle shaped RBCs due to defective hemoglobin (HgbS)
E: African americans
P: mutation in beta globin gene causes hgb to aggregate and polymerize > distortion of RBCs to sickle shape
>hemolytic anemia
>occlusion of small vessels
C: splenomegaly (then fibrosis & auto-splenectomy), ischemic disease and infarct, increased risk of infection, aplastic anemia
T: pain control, blood transfusion, BM transplant
Describe alpha thalassemia: DEPCT
D: decreased alpha strand of hgb synthesis
E: genetic; alpha strand is encoded by two genes = so four total possible mutation leads to variation in the disease severity
P: decreased amount of alpha strands
>leads to less hgb
>imbalance of alpha and beta strands may lead to toxicity
C: anemia
T: no treatment, nutrient supplement, transfusion (severe)
Describe beta thalassemia: DEPCT
histo—target cells
D: absence of beta hgb strand synthesis
E: only 1 gene involved
P: decreased beta = aggregation of excess alpha
>RBC damage and decreased plasticity
»excess phago + hemolysis
C:
>minor: anemia —- trait: only one defective allele
»major: expansion of bone marrow (crew cut appearance)
»>splenomegaly + hematopoeisis in liver and spleen
T: tranfusions
Describe paroxysmal nocturnal hemoglobinuria: DPC
D: abnormal membrane protein
P: mutation in GP1 anchor protein in RBC membrane leads to activation of complement pathway
C:
>intravascular hemolysis
>thrombosis
>aplastic anemia
Which diseases include BOTH Intravascular and extravascular hemolysis?
- sickle cell
- g6pd deficiency
- spherocytosis
Which two types of anemia may be mistaken for each other?
Thalssemia minor and Fe deficiency. IMP to rule out the other via:
> iron study: is iron low?
>Beta strand gel electrophoresis: normal or abnormal beta?
»levels of alpha strands a2 = increased, normal alpha is decreased
Describe anemia caused by mechanical trauma: DEPCT
caused by:
-prosthetic cardiac valves: RBCs destroyed when they run into heart valves
- microangiopathic hemolytic anemia: TTP, HUS, DIC
- *schistocytes caused by abnormal fibrin deposits (via coag cascade) that destroy RBCs
Describe iron deficiency anemia: DEPCT
histo—widened central palor + outer thin ring of hgb
D: microlytic anemia
P: chronic blood loss leads to: >depletion of ferritin >circulating Fe depletion >increased iron binding capacity (last resort) >dec hgb + hemolytic anemia
C: >fatigue >spoon nose >smooth tongue >interstitial malabsorption
T: iron supplements
figure out cause of blood loss
Describe megaloblastic anemia: DEPCT
D: anemia found in large RBCs E: caused by Vit b12 OR folate low in diet and impaired absorption >ileal resection >IF deficiency >tapeworm
P: defective DNA synthesis and maturation leads to large
oval nucleated [immature] RBCs
C: affects parts of the body that are actively dividing
>GI: gastritis
>blood and BM: decreased blood cell components
>CNS effects: seizures, encephalopathy, etc. [decrease methylmalonate] *only in Vit b deficiency
T: vitamin B12 supplements
Describe anemia of chronic disease: DEPCT
How to differentiate with Fe deficiency anemia: increase Fe stores in BM and no increase in binding capacity (Fe deficiency: increased IBC)
D: anemia caused by increased hepcidin levels
E: common in hospitalized pts: chronic infection, malignancy, chronic immune disorders
P: hepcidin blocks transfer of Fe from macrophages to erythroid precursors
>decreased hgb
>microcytic anemia
C: anemia
T: treat underlying disease
Describe aplastic anemia: DPCT
histo: more fat cells than stem cells in the the bone marrow
D: suppression of stem cells in the bone marrow
P: radiation, exposure to toxic chemicals, viral infections
C: anemia+ granulocytopenia + thrombocytopenia = pancytopenia
T: T cell suppression, stem cell transplant
