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IHO Week 2 - WLB > Anemia II - Krafts > Flashcards

Anemia II - Krafts Flashcards

1
Q

What hemoglobinopathy is the most important?

A

Sickle cell

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2
Q

What happens to sickle cells in the circulation?

A
  • Hemolysis (fragile)
  • Vaso-occlusion (get stuck in tiny blood vessels)
  • Aggregate and polymerize on deoxygenation
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3
Q

What is wrong with the hemoglobin in all Hemoglobinopathies?

A
  • Qualitative hemoglobin abnormality
    • change in quality
  • Structurally abnormal hemoglobin
    • often one amino acid away from normal
    • usually change in beta-chain
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4
Q

What is the best lab test to diagnose Hemoglobinopathies?

A

Hemoglobin Electrophoresis

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5
Q

What are the clinical features of Sickle Cell Anemia?

A
  • Eight percent of blacks in US are heterozygous (heterozygosity is called sickle cell trait)
  • Severity of disease is variable
  • Chronic hemolysis (Hb from 6-10)
  • Vaso-occlusive disease (acute crisis caused by infection, hypoxia, etc.)
  • Increased infections leading to AUTOSPLENECTOMY (recurrent hemorrhage and fibrosis)
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6
Q

What five morphological features are present with a Sickle Cell Anemia patient in the “Post-splenectomy blood picture”?

A
  • Nucleated RBCs
  • Target red cells
  • Howell-Jolly bodies (cluster of DNA inside RBC)
  • Pappenheimer bodies (RBCs with abnormal granules)
  • Slightly increased platelet count (kicked out of spleen)
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7
Q

What is the treament for Sicke Cell Anemia?

A
  • Prevent triggers (infections, fever, dehydration)
    • keep patient well oxygenated
  • Vaccinate against encapsulated bugs (especially after they lose their spleen)
  • Blood transfusions in severe cases
  • Bone marrow transplantation is last resort
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8
Q

What is wrong with the hemoglobin in Thalassemia?

A
  • Quantitative defect in hemoglobin
    • alpha-thal: deletion of alpha chain genes
      • 4 genes = 4 chances to mess it up
      • results in decreased amount of alpha chains
    • beta-thal: defective beta chain genes
      • 2 genes = only 2 chances to ruin it
      • results in decreased amount of beta chains
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9
Q

How do the genes in Beta-thalassemia relate to the severity of the defect?

A
  • Beta gene: normal gene
  • Beta+ gene: produces some Beta chains
  • Beta0 gene: produces no Beta chains
  • Beta-thalassemia minor (asymptomatic)
    • Beta0/Beta OR Beta+/Beta
  • Beta-thalassemia intermedia (less severe)
    • Beta0/Beta OR Beta+/Beta+
  • Beta-thalasemia major (severe)
    • Beta0/Beta0 OR Beta0/Beta+
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10
Q

How do the genes in Alpha-Thalassemia compare to the severity of the disease?

A
  • Problem: alpha-chain genes are absent
  • Gene combinations:
    • -α/αα = silent (still have 3)
    • –/αα OR -α/-α = α-thal trait (Sx variable)
    • –/-α = HbH disease (pretty severe)
    • –/– = Hydrops fetalis (incompatable with life)
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11
Q

What causes the anemia in thalassemia?

A
  • α-thalassemia
    • not enough α-chains
    • see excess unpaired beta, gamma, or delta chains
  • Beta-thalassemia
    • not enough beta-chains
    • excess unpaired α-chains
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12
Q

What are the morphologic features of blood in thalassemia?

A
  • Hypochromic, microcytic anemia
  • Often has minimal decreased anisocytosis (size) and poikilocytosis (shape)
  • Target cells
  • Basophilic stippling (blue dots in red cells)
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13
Q

How can you tell the difference morphologically in Thalassemia and Iron Deficiency Anemia?

A
  • IDA
    • fair amount of anisocytosis (size variety → increased RDW)
    • decreased RBC
  • Thalassemia
    • minimal amount of anisocytosis (normal/decreased RDW)
    • increased RBC
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14
Q

What ethnic groups is alpha thalassemia most prevalent in?

A

Asians, blacks

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15
Q

What ethnic groups is beta thalassemia most prevalent in?

A

Mediterraneans, Blacks, Asians

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16
Q

When does G6PD appear?

A
  • after exposure to certain oxidizing agents, like fava beans, or certain medications
    • Lack of or decreased G6PD → peroxides → cell lysis
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17
Q

Why is G6PD an important enzyme in the body?

A
  • It catalyzes the initial step in the pentose phosphate pathway of glycolysis.
  • Need G6PD to reduce NADP to NADPH, which in turn keeps glutathione in the reduced state
    • reduced glutathione detoxifies hydrogen peroxide and other organic peroxides
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18
Q

Why do G6PD-deficient red cells die?

A
  • They can’t reduce free radicals (“nasties”)
  • Free radicals attack hemoglobin bonds
  • Heme breaks away from globin
  • Globin denatures, then sticks to red cell membrane → form Heinz body
  • Spleen bites out Heinz bodies
19
Q

What areas have the highest incidence of G6PD Deficiency?

A

Areas where malaria is epidemic!

(It may confer a protective advantage against malaria because G6PD-deficient red cells lack the ribose derivatives bugs need to grow. )

20
Q

What is the clinical presentation of G6PD Deficiency?

A
  • X-linked
    • most males have full disease expression
    • heterozygous females are clinically normal
  • 10% of black men in US have gene
  • Episodic hemolysis
    • may present with jaundice from hemolysis
    • Spontaneous resolution (new cells better able to handle oxidants)
21
Q

What does the blood morphology in G6PD Deficiency look like?

A
  • Without exposure to oxidants, no anemia
  • After exposure, get acute hemolysis
    • Bite cells, fragments
    • Heinz bodies
22
Q

What is the mechanism underlying Microangiopathic Hemolytic Anemia?

A
  • red cells are ripped apart by physical trauma
    • either fibrin strands snag them or mechanical devices bash them
23
Q

What is the most important thing to consider in Microangiopathic Hemolytic Anemia?

A
  • Find out why!
    • underlying pathology it may signify:
      • artificial heart valve/vessel abnormalities
      • disseminated intravascular coagulation (widespread clotting and bleeding)
      • thrombotic thrombocytopenia purpura (enzyme deficiency, renal failure, fever, CNS dysfunction)
      • hemolytic-uremic syndrome (complication of E.coli infection)
      • malignant hypertension
      • SLE
24
Q

How do fragmented cells form in Microangiopathic Hemolytic Anemia?

A
  • Get caught on fibrin strand in microcirculation
  • Cell is ripped in two
    • Larger part becomes helmet cell
    • Smaller part becomes a microspherocyte
    • Fragments of rip = Schistocytes
25
Q

How can you tell the difference between Acute vs. Chronic Anemia of Blood Loss?

A
  • Acute:
    • traumatic
    • hemoglobin normal at first (recheck after fluid resuscitation)
    • after 2-3 days see reticulocytes
  • Chronic:
    • causes iron deficiency anemia (hypochromic, microcytic)
26
Q

What three groups of diseases can cause Anemia of Chronic Disease?

A
  • Infections (PID, meningitis, chronic UTI)
  • Inflammation (RA, SLE)
  • Malignancy (leukemia, lymphoma, MM)
27
Q

When does Anemia of Chronic Disease Develop?

A

Anemia develops during the first two months of the chronic disease, and doesn’t progress thereafter.

28
Q

What is disturbed in Anemia of Chronic Disease? Why?

A
  • Iron metabolism is disturbed (iron doesn’t get into normoblasts)
  • Mucosal cells seem to absorb iron okay, but don’t release it well into plasma.
  • Can’t get iron into hemoglobin
  • Hepcidin over-expressed, over-produced
  • Shortened RBC life-span
  • Impaired marrow response to anemia
29
Q

How can you tell the difference between Anemia of Chronic Disease and Iron Deficiency Anemia?

A
  • IDA:
    • low serum iron
    • increased TIBC
    • low ferritin
    • low marrow storage iron
    • hypochromic, microcytic
  • ACD
    • low serum iron
    • low/normal TIBC
    • high ferritin
    • high marrow storage iron
    • normochromic, normocytic anemia with minimal anisocytosis and poikilocytosis
30
Q

Why is anemia present in end-stage renal failure?

A

Lack erythropoietin:

Kidneys make most of erythropoietin

(hormone that stimulates red cell growth)

31
Q

What type of red cells do you see in Anemia of Renal Disease?

A
  • normocytic, normochromic anemia with minimal anisopoikilocytosis
  • The only really unique finding is the occasional presence of echinocytes, or “burr” cells, which are red cells with a bunch of short, spiky surface projections.
32
Q

How do you manage Anemia of renal disease?

A
  • If mild, need not treat
  • If severe, replace erythropoietin
33
Q

Why is anemia frequent in liver disease?

A
  • shortened red blood cell survival
  • impaired bone marrow response typically seen in patients with chronic liver disease
  • alcoholic liver disease- folate deficiency (which leads to megaloblastic anemia)
  • hemorrhage from upper GI varices or hemorrhoids (which leads to iron deficiency anemia)
  • Pure, “uncomplicated” anemia (without the above factors) is actually uncommon.
34
Q

Why do red blood cells not live very long in patients with liver disease?

A
  • congestive splenomegaly that accompanies most cases
  • ethanol inhibits erythropoiesis (and the cause of many cases of chronic liver disease is alcoholism)
  • small but significant amount of erythropoietin secreted by the liver is diminished
35
Q

What morphologic features are seen in blood with “uncomplicated” Anemia of Liver Disease?

A
  • Mild anemia
    • usually normocytic (sometimes macrocytic)
    • Poikilocytosis (weird shape)
      • target cells
      • acanthocytes (spiky surface projections)
36
Q

What are the “complicated” cases of Anemia of Liver Disease?

A
  • Megaloblastosis (from folate deficiency)
  • Microcytosis (from iron deficiency)
  • 3/4 of patient’s with liver disease are anemic
    • most cases are “complicated”
  • alcohol abusers may get hemolytic episodes that resolve with withdrawal of alcohol
37
Q

What is the clinical presentation of Aplastic Anemia?

A
  • Pallor, dizziness, fatigue (anemia)
  • Recurrent infection (leukopenia)
  • Bleeding, bruising (thrombocytopenia
  • Pancytopenia = all cell lines are down
38
Q

What are the causes of Aplastic Anemia?

A
  • Idiopathic (most cases)
  • Pregnancy
  • Drugs (chemo)
  • Viruses
  • Fanconi anemia
    • hereditary disease characterized by skeletal abnormalities, chromosomal instability, pancytopenia and increased risk of leukemia.
39
Q

What are the blood morphologies seen in Aplastic Anemia?

A
  • Blood = empty
    • large spaces between cells on blood smear
  • Bone marrow = empty (mostly fat cells)
    • little/no hematopoietic precursors in bone marrow
40
Q

What are the treatment options for Aplastic Anemia?

A
  • Avoid further exposure (if known causative agent)
  • Give blood products
  • Drugs: G-CSF, Prednisone, ATG
  • Bone marrow transplant as last resort
  • 3-year survival: 70%
41
Q

What is a Heinz body made of?

A

Denatured globin chains

42
Q

Malignancy, obstetric complications, sepsis and trauma can all cause what findings on a blood smear?

A

Schistocytes

43
Q

Why are the red cells in sickle cell disease more susceptible to hemolysis?

A

They possess an abnormal hemoglobin which polymerized upon deoxygenation.

IHO Week 2 - WLB (10 decks)

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