Hemolytic Anemias Flashcards

1
Q

hemolytic anemia definition

A

conditions in which there is an increased destruction of RBCs causing the BM to respond by accelerating production
RBCs destroyed faster than BM can produce them

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2
Q

Wintrobe classification of hemolytic anemias

A

normocytic, normochromic

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3
Q

general lab findings of hemolytic anemias

A
normo, normo anemia
reticulocytosis, increased IRF
marked polychromasia & NRBCs
elevated indirect/unconjugated bilirubin
normal direct/conjugated bilirubin
decreased haptoglobin (intravascular)
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4
Q

general signs & symptoms of hemolytic anemias

A

jaundice: from increased bilirubin production
gallstones made of bilirubin
dark or red urine due to excretion of plasma hemoglobin (or increased urobilin)
splenomegaly (extra)
general anemia symptoms

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5
Q

Extravascular hemolysis general

A

RBC destroyed outside blood vessels (spleen (!), liver, BM)
phagocytized by macrophages in the spleen & liver
SPHEROCYTES

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6
Q

Intravascular hemolysis general

A
destruction of defective RBCs as they circulate
release hemoglobin into the plasma
decreased haptoglobin 
hemoglobinuria, hemoglobinemia etc
SCHISTOCYTES
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7
Q

normal way RBCs are broken down

A
  1. globin is returned to amino acid pool
  2. iron is separated & stored
  3. protoporphyrin (heme ring) is broken down into bilirubin (indirect/unconjugated)
  4. travels to liver via albumin & is converted to conjugated/direct
  5. secreted as bile & dumped into GI tract where is converted to urobilinogen
  6. majority excreted in stool some reabsorbed and excreted in the urine
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8
Q

intrinsic defects (categories)

A

membrane
enzymes
hemoglobin
most are hereditary & usually extravascular hemolysis

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9
Q

extrinsic defects general

A

antagonist in plasma or soluble factors in environment - toxic to cell & cause hemolysis
physical/mechanical trauma
immune mediated
usually acquired

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10
Q

Hereditary Spherocytosis (HS) general

A

hereditary hemolytic anemia due to RBC membrane defect
most common inherited anemia among whites
RBCs deficient in spectrin (secondary deficiency in ankyrin)- loss of membrane, decreasing surface to volume ratio = SPHEROCYTES

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11
Q

Lab diagnosis of HS

A
normo, normo
mild anemia
spherocytes (!)
elevated MCHC (due to spherocytes)
reticulocytosis
increased osmotic fragility!! (confirmatory test)
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12
Q

Osmotic fragility test

A

RBCs are incubated in varying concentrations of hypotonic NaCl solutions
spherocytes are unable to expand as much & are lysed at a higher concentration of NaCl than normal
confirmatory test for hereditary spherocytosis

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13
Q

Treatment for HS

A

mild forms - no therapy

splenectomy

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14
Q

Hereditary Elliptocytosis (HE) general

A

hereditary hemolytic anemia due to RBC membrane defect
deficiency of alpha-spectrin or beta spectrin are common
90% of patients show no signs of hemolysis

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15
Q

populations with HE

A

Blacks, equatorial african populations

rare in western populations

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16
Q

laboratory diagnosis of HE

A

normo, normo
no anemia, no hemolysis (!!)
elliptocytes (usually more than 25%)

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17
Q

Hereditary pyropoikilocytosis (HPP) general

A

severe subtype of HE
primarily seen in blacks & arabs
severe hemolytic anemia & extreme poikilocytosis
decreased thermal stability of RBCs
2 defects: deficiency of alpha-spectrin & another mutant spectrin = cell destabilization

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18
Q

clinical findings of HPP

A
present at birth
hemolytic anemia
hyperbilirubinemia
splenectomy
striking poikilocytes
decreased MCV (25-55)
increased thermal sensitivity test
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19
Q

Hereditary Stomatocytosis general

A

rare! abnormalities in cation permeability in RBC membrane
[intracelluar cations] increases & water enters the cell & overhydratess = stomatocytes
increased bilirubin, moderate reticulocytosis

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20
Q

Energy for mature RBCs

A

dependent on anaerobic glucose metabolism (no organelles)

21
Q

Glucose-6-phosphate dehydrogenase deficiency ( G6PD) general

A

worldwide (mediterranean, africa, china)
x-linked inheritance (fully expressed in males, females with homozygous)
most common inherited enzyme deficiency
asymptomatic except when combined with: oxidizing chemical/drug (fava bean), severe infection, neonatal jaundice

22
Q

G6PD defect

A

enzyme defect of the hexose monophosphate pathway
RBCs do not make enough or it cannot function properly
necessary to reduce cellular oxidants = hemoglobin could be oxidized to methemoglobin which precipitates to form Heinz bodies (which are removed and cause bite cells & blister cells)

23
Q

Lab diagnosis of G6PD

A
normo, normo anemia
Bite cells, heinz body test (supravital stain)
reticulocytosis
increased unconjugated bili
hemoglobinuria/emia
screening tests for G6PD
24
Q

Pyruvate Kinase (PK) deficiency general

A

most common in norther european ancestry
hereditary hemolytic anemia due to enzyme defect
most common deficiency of the glycolytic pathway
inability of RBC to maintain normal ATP levels = alterations to RBC membrane
loss of K+, gain Na+ & Ca++
deformed or rigid cells that are removed by the spleen

25
Q

lab diagnosis of PK

A
normo, normo anemia
reticulocytosis
echinocytes
elevated indirect bili
reduced PK
26
Q

MAHAs

A

group of clinical disorders characterized by RBC fragmentation in the circulation - intravascular hemolysis
fragmentation occurs as RBCs pass through fibrin deposits inside small blood vessels
characterized by schistocytes, microspherocytes & increased retics

27
Q

disorders associated with MAHA

A

Disseminated intravascular coagulation (DIC)
thrombotic thrombocytopenic purpura (TTP)
hemolytic uremic syndrome (HUS)

28
Q

Hemolytic uremic syndrome (HUS)

A

multi-system disorder
characterized by triad of clinical findings:
1. hemolytic anemia with RBC fragmentation
2. thrombocytopenia
3. acute nephropathy, including renal failure (clots in kidneys)

29
Q

Lab diagnosis of HUS

A
normo, normo mod-severe anemia
schistocytes, helmet cells, spherocytes
polychromasia, occiasonal NRBC
leukocytosis w/ left shift
low to markedly low plts
hemoglobinemia/uria
increased bili, LD
decreased haptoglobin
30
Q

Thrombotic thrombocytopenic purpura (TTP)

A
syndrome of diverse issues
characterized by: 
hemolytic anemia w/ RBC fragmentation
fever
thrombocytopenia (
31
Q

lab diagnosis of TTP

A
low hemoglobin
normo, normo anemia
polychromasia, NRBC
SCHISTOCYTES
Severe thrombocytopenia
hemoglobinemia, hemoglobinuria, increased bili & LD, decreased haptoglobin
32
Q

TTP treatment

A

plasma exchange with FFP

Cyrosupernantant

33
Q

DIC

A

characterized by:
widespread activation of hemostatic system
secondary to: bacterial sepsis, pregnancy complications, neoplasms, trauma etc
easiest way to detect is through coagulation studies

34
Q

thermal injury

A

3rd degree burn patients may have severe acute hemolytic anemia
direct effect of heat on spectrin-loss of elasticity & deformability
schistocytes, spherocytes & acanthocytes

35
Q

exercised induced hemoglobinuria

A
march hemoglobinuria: 
associated with strenuous exercise 
transient hemolysis
usually no anemia
hemoglobinuria/emia
36
Q

Infectious agents of hemolytic anemia

A

malaria- most common cause of hemolytic anemia world wide
bartonellosis
babesiosis
clostridium perfringens

37
Q

general lab findings of immune mediated hemolytic anemias

A

normo, normo anemia
spherocytes, schistocytes & polychromasia
reticulocytosis
POSITIVE DAT!!!!!

38
Q

classification of Immune hemolytic anemias

A

autoimmune
drug-induced
alloimmune

39
Q

3 subcategories of autoimmune hemolytic anemias

A

warm antibody AIHA
cold antibody AIHA
paroxysmal cold hemoglobinuria

40
Q

Warm autoimmune hemolytic anemia general

A

most common (70% of AIHA)
2:1 female prevalence
older adults & children

41
Q

lab diagnosis of WAIHA

A
normo, normo anemia
spherocytes
retic, poly, NRBCs
increased unconjugated bili
POSITIVE DAT
42
Q

cold autoimmune hemolytic anemia

A
cold agglutin disease
16-30% of AIHA
chronic hemolytic anemia
usually >50 yrs older
peak at 70
predominance in females
43
Q

lab diagnosis of CAIHA

A
normo. normo
poly, retic, NRBC
spherocytes
autoagglutination of RBCs
positive DAT
increased unconjugated bili
44
Q

Paroxysmal cold hemoglobinuria

A

rare acute form of cold generated hemolysis
common in children after viral infection
antibody react & induce hemolysis at lower temps
massive acute hemolysis & hemoglobinuria
DONATH-LANDSTEINER ANTIBODY

45
Q

Donath-Landsteiner antibody

A

anti-P antibody
binds in cold temps & causes complement activation upon warming
intracellular hemolysis

46
Q

lab diagnosis of PCH

A
DAT weak positive
retic
spherocytes & schistocytes
hemoglobinuria/emia
serum bili elevated
47
Q

Drug induced hemolytic anemia

A

uncommon acquired cause
drug itself doesn’t cause RBC injury
immune response to drug-induced alteration of RBC

48
Q

Alloimmune hemolytic anemias

A

reacts to transfused cells & HDFN

Transfused: acute & delayed