Anemias Flashcards

1
Q

Iron deficiency anemia

A

Microcytic
hypochromic

Poor iron intake
Blood loss: menstruation, colon cancer, peptic ulcer
Increased iron demand in pregnancy

Assoc: plummer vinson sn
-iron deficiency anemia
-esophageal webs
-dysphagia
\+/- atrophic glossitis
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2
Q

Alpha thalassemia

A

Defect in globin synthesis
Alpha on Chr 16, 4 alleles

1 abnl allele – no anemia

2 abnormal alleles

  • a-thalaseemia trait/minor
  • no anemia

3 abnl alleles – 1 normal alpha gene
-> HbH – beta 4

4 abnl allels – incompatible with life
Fetus: hemoglobin Barts (gamma 4)
-> generalized fetal edema – hydrops fetalis
-> death

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3
Q

Beta thalassemia

A

Defect in beta globin gene – 2 alleles
Mediterranean populations

Minor: decreased beta globin

  • minimal anemia
  • increased HbA2 – a2delta2

Major: absent beta globin

  • severe anemia
  • blood transfusion -> hemochromatosis (tx: deferoxamine – iron chelator)
  • Peripheral smear: target cells
  • BM hyperplasia
  • XR: crew cut on skull XR
  • > chipmunk facies
  • increased HbF (alpha 2 gamma 2)
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4
Q

Anemia of chronic disease

A
Defective iron utilization
Assoc w/ chronic inflammation
-RA
-Chronic infections
-Malignancy

iron trapped in M0
normal or elevated ferritin
low serum iron

Normocytic first -> microcytic hypochromic

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5
Q

Iron deficiency anemia iron studies

A

Serum Iron: low

TIBC: high

Ferritin: low

% transferrin saturation: low (below 12%)

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6
Q

Anemia of chronic disease iron studies

A

Serum Iron: low

TIBC: not iron deficient - low

Ferritin: nl or high

% transferrin saturation: nl (above 18%)

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7
Q

Hemochromatosis iron studies

A

Serum Iron: high

TIBC: low

Ferritin: high (normal r/o hemochromatosis)

% transferrin saturation: high

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8
Q

Sideroblastic anemia iron studies

A

Serum Iron: high

TIBC: low

Ferritin: high

% transferrin saturation: nl or high

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9
Q

Megaloblastic anemia

A

B12 deficiency (vegans, malabsorption (pernicious anemia, crohn’s dz), diphyllobothrium latum)

Folate deficiency (malnutrition, malabsorption, MTX, TMP, high folate req (hemolytic anemia, pregnancy))

Impaired DNA synthesis
Hypersegmented neutrophils >6 lobes
Glossitis
Elevated homocysteine

B12: neurologic defects -> high methylmelonic acid (MMA)

Other cause:
Orotic aciduria: deficient UMP synthesis -> pyrimidine synthesis impaired
-orotic acid in urine
no hyperammonemia

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10
Q

Nonmegaloblastic macrocytic anemia

A

Liver dz
Alcoholism
Drugs – 5FU, zidovudine, hydroxyurea

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11
Q

Causes of non-hemolytic normocytic anemia

A

Anemia of chronic disease
Renal failure
Aplastic anemia

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12
Q

non-hemolytic normocytic anemia - Renal failure

A

No EPO production

EPO injections needed

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13
Q

non-hemolytic normocytic anemia – anemia of chronic dz

A

Inflammatory mediates (IL6)

  • > liver production of hepcidin
  • inhibits ferroportin
  • iron trapped in M0

labs:
low serum iorn
lower TIBC
nl or high ferritin

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14
Q

Non-hemolytic normocytic anemia – aplastic anemia

A

Pancytopenia

Histo: hypocellular BM w/ fatty infiltration

Anemia: fatigue, malaise, palor

Thrombocytopenia: purpura, petechiae, bleeding

Leukopenia: infections

d/t radiation, benzene
Chloramphenicol 
Cancer drugs
Parvo B19, EBV, HIV, esp sickle cell
Fanconi anemia
Idiopathic after acute hepatitis
Tx: stop offending agent
Immunosuppresants
Transfusions
G-CSF, GM-CSF
BM transplant
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15
Q

Intravascular hemolysis

A

Low haptoglobin
High LDH – high in RBCs

Autoimmune hemolytic anemia
Paroxysmal nocturnal hemoglobinuria
Mechanical destruction of RBCs
G6PD deficiency

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16
Q

Extravascular hemolysis

A
High LDH
High unconjugated (indirect) bilirubin
Hereditary spherocytosis
G6PD deficiency
Pyruvate kinase deficiency
Sickle cell dz
Hemoglobin C dz
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17
Q

Hereditary spherocytosis

A

Ankryin
Spectrin
Band 3, Protein 4.2 : link ankryin to cytoskeleton to membrane

Lack central pallor, smaller

Increased MCHC – same amount of Hb in smaller cell = more concentrated

High RDW – vary in size

Spleen removes abnl cells -> splenomegaly
Jaundice
Pigmented gallstones

Aplastic crisis d/t Parvovirus B19 infection

Test: omotic fragility test
-lyse more readily in hypotonic solution at any given [NaCl]

eosin 5 maleimide: normally binds band 3, reduced binding = band 3 deficiency

Tx: 
Supportive
Folic acid
RBC transfusion
Splectomy -> Howell –Jolly bodies
18
Q

G6PD deficiency

A

Sensitive to oxidative stress -> hemolysis and back pain

Heinz body -> bite cells

Drugs:
Fava beans
Isoniazid
Nitrofurantoin
Dapsone
Sulfonamides
Primaquine
Aspirin – high dose
Ibuprofen
Napthalene
Chloroquine
19
Q

Pyruvate kinase deficiency

A

Glycolytic enzyme deficiency

Can’t generate ATP, no Na+/K+ ATPase activity -> swelling and hemolysis

20
Q

Paroxysmal nocturnal hemoglobinuria

A

Missing CD55 and CD59 surface markers
-> complement attack and lyses RBCs

Dx:
“Ham’s Test” – lysis at low pH – complement activates
Flow cytometry

Hemosiderinuria + thrombosis

21
Q

HbC disease

A

Point mutation on beta globin gene
Glu -> Lys

-> hexagonal crystals

Heterozygous: asx
Homozygous: milder than sickle cell, hild hemolysis and splenomegalyq

22
Q

SC disease

A

Heterozygous mutations
HbS mutation
HbC mutation

Milder than sickle cell dz

23
Q

Sickle cell disease

A

HbS mutation

  • point mutation on Chr 11 beta globin gene
  • Glu -> Val at position 6 -> longer polymerase

sickling triggers:
hypoxemia
dehydration
acidosis

0.2% homozygous

Heterozygous (HbS trait) – 8% AA
-relative resistance to malaria

Newborns asx – more HgF

Complications:
Splenic sequestration crisis
Salmonella osteomyelitis
Aplastic crises w/ Parvo B 19
Pain crisis – vasooclusion -> ischemia
Dactylitis
Acute Chest Sn
Renal papillary necrosis

Skull XR: hair on end of skull, marrow hyperplasia “buzzcut”

Tx: hydroxyurea -> increased HbF
BM transplant

24
Q

Splenic sequestration crisis

A

Complication of sickle cell disease

Infants and toddlers 2-3 yo
H and H drops
Wedge shaped infarct

-> autosplenectomy by 3-4 yo

increase risk of infection by encapsulated organisms

25
Q

Cold agglutinins

A

Ab against RBCs that interact more strongly at low temp 4C than at body temp

Nearly always IgM Ab

Occur regularly in infections w/ EBV or mycoplasma and with malignancies – CLL

Problems/disease occur when there is circulation to a cold extremity -> IgM binds RBC antigen -> complement fixation -> MAC lysis (and opsonization -> phagocytosis)

26
Q

Warm agglutinins

A

Ab that react against RBC protein antigens at body temp – spontaneous

Nearly always IgG

Seen in 
EBV, HIV
Lupus
Malignancies – CLL, NHL
Congenital immune abnormalities
27
Q

Direct coombs test

A

Directed at the RBCs

Ab to anti-RBC Ab cross links RBCs -> agglutination

Ab added to detect Ig already ON the RBC

Positive in:
Hemolytic dz of the newborn
Drug induced autoimmune hemolytic anemia
Hemolytic transfusion reactions

28
Q

Indirect Coombs Test

A

Via Serum

Serum incubated w/ normal RBCs to detect presence of Ab in serum

Positive when:
Ab to foreign RBCs present – prior blood transfusion, screen for maternal Ab to fetus blood

Type and screen

29
Q

Microangiopathic anemia

A

RBC mechanically damaged as pass through lumen of obstructed or narrowed vessel

DIC, TTP-HUS, lupus, malignant HTN
-> schistocytes

30
Q

Macroangiopathic anemia

A

Damage to RBCs by forces in larger vessels
Prosthetic heart valves
Aortic stenosis

Infections -> hemolysis
Malaria
Babesiosis

31
Q

Autoimmune hemolytic anemia

A

Auto-Ab bind RBCs -> lysis

  • warm agglutinins –IgG
  • Cold agglutinins – IgM
  • only problems at cold temps

+ Coombs test

32
Q

Platelets

A
Derived from megakaryocytes
No nucleus
Live 8-10 days
Several different glycoprotein receptors
Contain granules filled w/ various signaling substances
33
Q

Platelet plug formation

A

Platelet adhesion
Platelet activation
Platelet aggregation

34
Q

Von Willebrand factor (vWF)

A

Subunits liked by disulfide bonds
Synthesized by endothelial cells and megakaryocytes

Complexes w/ and stabilizes factor VIII (deficiency -> elevated PTT)

Platelet adhesion to vessel wall and other platelets (deficiency -> increased bleeding time)

35
Q

Platelet adhesion

A

Endothelial damage, vWF, gpIb

36
Q

Platelet activation

A

Secretion of ADP, PDGF, serotonin, fibrinogen, lysosomal enzymes, thromboxane A2, calcium (needed for coagulation cascade), thrombin

Thromboxane A2 -> vasoconstriction and platelet aggregation

Thrombin: fibrinogen -> fibrin

37
Q

Platelet aggregation

A

Via gpIIb/IIIa

Stimulated by binding of ADP to surface receptors -> expression of GpIIb/IIIa extracellularly
-bind fibrinogen released by platelets

38
Q

Aspirin

A

Inhibits COX1 and COX 2
Acetylates
Permanelty blocks conversion of AA to TxA2
Inhibits platelet aggregation

-> prolonged bleeding time
PT/PTT not affected

Uses:
Lower fever
Pain
Anti-inflammatory
Antiplatelet drug
Kawasaki dz

SE: Bleeding
PUD
Hyperventilations – directly stimulates respiratory centers of brain
-> respiratory alkalosis
tinnitus
Reyes Syndrome in kids
Hepatoencephalopathy – liver problems, encephalopathy, hypoglycemia

39
Q

ADP receptor inhibitors

A

Block ADP receptor -> no GpIIb/IIIa to surface -> block platelet aggregation

Clopidogrel
Ticlopidine
Ticagrelor
Prasugrel

Clopidogrel: tx acute MI, post CABG, recurrent stroke prevention
-aspirin allergy

40
Q

Glycoprotein IIb/IIIa inhibitors

A

Abciximab
Tirofiban
Eptifibatide

Blocks GpIIb/IIIa – can’t cross link aggregating platelets

Acute coronary sn – NSTEMI
Angioplasty