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Hematology > Haemolytic anaemia > Flashcards

Haemolytic anaemia Flashcards

1
Q

Designate the specific types of hemolytic anemias as due to either intrinsic or extrinsic red blood cell defects

A
  • At each stage, check whether they are intravascular or extravascular
  • Intrinsic: pathology within the red blood cell itself: INTRINSIC
  • Extrinsic: pathology outside of the cell
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2
Q

List the different causes of intrinsic red blood cell defects

A
  • Membrane defects
    Hereditary Spherocytosis
    Hereditary elliptocytosis
    Paroxysmal Nocturnal Hemoglobinuria
  • Abnormal Haemoglobin (we don’t have Thalassemia here = MICROCYTIC ANAEMIA)
    Sickle cell Disease
    HbC disease
  • Deficient Enzymes
    G6DP deficiency
    Pyruvate Kinase deficiency

MAD

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3
Q

List the different causes of extrinsic red blood cell defects

A
  • Blood loss > 1 week (reticulocytosis)
  • Immune-mediated hemolysis
  • Micro/ macroangiopathic hemolytic anemia
  • Malaria
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4
Q

Distinguish between intrinsic and extrinsic RBC defects

A

Intrinsic - defect withing the RBS itself
structural proteins, enzymes, membrane defects

Extrinsic - defects outside of the RBC
mechanical destruction, autoimmune

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5
Q

Distinguish between intravascular and extravascular hemolysis

A

Intravascular - a disease in which hemolysis occurs within the blood vessel (abnormal)
- Hemoglobinuria

Extravascular - disease in which hemolysis occurs outside of the blood vessel (spleen)
- Jaundice

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6
Q

Explain the finding of hemoglobinuria due to intravascular hemolysis

A
  • RBC is being destroyed within the blood vessel (not where it normally gets destroyed)
  • Releasing Hb in the vasculature
  • Hb most likely won’t get further degraded (because it’s not at the level of the spleen)
  • Hb will get filtered through the kidney
    = hemoglobinuria
    red urine after waking up or after exercise
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7
Q

Describe the process of red blood cell destruction by extravascular hemolysis

A
  • reticuloendothelial system
  • spleen
  • RBCs removed from the vasculature, taken to cords of Billroth, splenic macrophage will destroy it
  • heme -> Biliverdin -> Bilirubin (unconjugated/ indirect = lipid soluble = JAUNDICE/ ICTERUS)
  • SPLEEN gets destroyed - susceptible to encapsulated microorgansims
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8
Q

What is the most common cause of Iron Deficiency Anaemia?

A

Loss of Blood through menstruation (in women)

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9
Q

What type of anaemia is Haemolytic anaemia?

A

Normocytic anemia
Increased reticulocytosis - bone marrow trying to compensate for the loss (corrected reticulocyte count > or equal to 3%)

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10
Q

What type of anaemia is Haemolytic anaemia?

A

Normocytic anemia
Increased reticulocytosis - bone marrow trying to compensate for the loss (corrected reticulocyte count > or equal to 3%)

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11
Q

List 3 pathologies that lead to extravascular hemolysis

A
  • Sickle cell
  • Spherocytosis
  • IgG + C3b (autoimmune) - opsonins
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12
Q

Describe the laboratory findings related to extravascular hemolysis

A
  • Jaundice
  • Unconjugated Bilirubin increased
  • Lactate dehydrogenase increased
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13
Q

Explain why haptoglobin levels are decreased in intravascular hemolysis

A
  • Haptoglobin = binds with high affinity to free Hb
  • High levels of Hb use up Haptoglobin
  • Measure free Haptoglobin
  • Complex removed by macrophages
  • UCB is not high enough to produce jaundice
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14
Q

List laboratory findings related to intravascular hemolysis

A
  • decreased Haptoglobin
  • Increased Lactate Dehydrogenase (non- specific)
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15
Q

Explain why jaundice is either mild or not found in intravascular hemolysis

A
  • Hb not broken down
  • Not enough unconjugated bilirubin to cause Jaundice
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16
Q

Clinical Findings of Hemolytic anemias - intravascular features

A
  • Hemoglobinemia + hemoglobinuria
  • decreased serum haptoglobin
  • increased serum LDH
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17
Q

Clinical Findings of Hemolytic anemias - extravascular features

A
  • Jaundice
  • increased serum LDH
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18
Q

Clinical Findings of Hemolytic anemias - both

A
  • increased serum LDH
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19
Q

Explain why hereditary spherocytosis results in extravascular hemolysis

A
  • spherocytes are broken down by the spleen as they are abnormal RBCs
  • Spherocytes - membrane fragments are lost and the rbcs lose their biconcave shape - misshapen RBCs are cleared by the spleen - ANEMIA
  • Jaundice
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20
Q

State the 2 proteins most commonly mutated in hereditary spherocytosis

A
  • Ankyrin
  • Spectrin

In cell membrane

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21
Q

Identify spherocytes on a peripheral blood smear

A
  • Spherical
  • No central parlor
  • Can differentiate between spherocytes and warm autoimmune hemolysis by Coombs test (anti-human globulin test) - negative in hereditary spherocytosis

2 diff:
- HS
- Warm type of autoimmune hemolytic anemia

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22
Q

Explain the osmotic fragility test used to diagnose hereditary spherocytosis

A
  • Spherocytes are more fragile
  • They have a decreased ability to expand
  • osmotic pressure increases in spherocytes
  • when placed in saline - they cells expand
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23
Q

Why do pigment stones form in Hereditary Spherocytosis?

A
  • Due to increased destruction of RBCs
  • Increase in bilirubin - pigment stones
  • Splenomegaly
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24
Q

Describe the consequences of a parvovirus B19 infection in a patient with hereditary spherocytosis

A
  • Bone marrow shut down
  • Aplastic crisis with Parvovirus infection - decreased RBC lifespan
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25
Q

State the test used to diagnose hereditary spherocytosis

A
  • Negative Coombs test to differentiate between autoimmune disease and HS
  • Diagnosis: Osmotic fragility test
  • Spherocytes contain more Hb - when in a hypotonic solution, they expand and burst - increased hemolysis
  • Decreased ability to expand
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26
Q

State the result of a Coombs test in a patient with hereditary spherocytosis

A
  • Negative
  • No antibodies on RBCs
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27
Q

Recognize that glucose-6-phosphate dehydrogenase (G6PD) is the rate-limiting enzyme of the pentose phosphate shunt

A
  • rate-limiting step in the pentose pathway shunt
  • forms NADPH- needed for glutathione (protects RBC from antioxidants)
  • Mutations decrease the half-life of the enzymes
  • normal - 62 days
    mutation - 13 days (not a lot of time for an enzyme)
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28
Q

State the inheritance pattern for G6PD deficiency

A
  • X-linked recessive
  • Males at greater risk
  • Females can have the trait
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29
Q

What type of anemia does G6PD deficiency causes?

A

Normocytic hemolytic anemia

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30
Q

Describe the relationship between the pentose phosphate pathway, NADPH, and glutathione

A
  • G6PD needed in the Pentose pathway
  • forms NADPH
  • needed for the recycling of glutathione (which fights against free radicals)
  • Protects the RBC from free radical damage+ and repairs damage caused by oxidative stress
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31
Q

Explain the findings of Heinz bodies and bite cells in G6PD deficiency

A
  • G6PD deficiency leads to oxidative damage
  • Hb precipitation - causes denatured RBCs = Heinz bodies
  • Cells with membrane damage + are partially consumed by macrophages
  • The damaged cells are cleared in the spleen (bite cells)
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32
Q

What type of beans cause oxidative stress?

A

Fava beans

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33
Q

What type of beans cause oxidative stress?

A

Fava beans
- eaten in the Mediterranean countries, Italy, Lebanon
- free radical

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34
Q

What drugs cause oxidative stress?

A

Antimalarial drugs
Atovaquone/Proguanil (Malarone) Chloroquine. Doxycycline. Mefloquine. Primaquine

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35
Q

Is G6PD deficiency intravascular or extravascular?

A
  • based upon the exposure to the oxidative stress
  • both exist with G6PD DEF
  • If it is completely bitten by the phagocytic cells - INTRAVASCULAR HEMOLYSIS
  • If it is just a bite cell - RBC is taken out of the vasculature and degraded by the spleen - EXTRAVASCULAR
  • Patient can have jaundice or hemoglobinuria/ hemoglobinemia
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36
Q

What other condition can be present alongside G6PD def?

A
  • Catalase-positive susceptibility (staphylococcus)
  • Neutrophils are affected (they need NADPH to make NADPH oxidase - which is used in phagocytosis)
  • Not just seen in chronic granulomatous disease - only one cell affected (neutrophils)
  • In G6PD DEF - two cells are affected - RBC and neutrophils
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37
Q

What does NADPH stand for?

A

nicotinamide adenine dinucleotide phosphate (NADPH)

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38
Q

What is the principal function of glutathione in erythrocytes?

A

Prevent oxidative damage

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39
Q

Which of the following are inclusions within red blood cells composed of denatured hemoglobin?

A

Heinz bodies

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40
Q

Which cells are characteristic of an acute attack in a patient with G6PD deficiency?

A

bite cell

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41
Q

What happens to the RBC when a patient with G6PD def has oxidative stress?

A
  • Hb within RBC gets damaged and precipitates
  • Hb within RBC that becomes unrecognizable - becomes an antigen
  • Phagocytic cells are attracted to it - bite taken out of it
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42
Q

What is a bite cell?

A

Cells with membrane damage + are partially consumed by macrophages

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43
Q

The reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) is required in which conversion?

A

Oxidized glutathione to reduced glutathione

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44
Q

Which of the following primarily protects the erythrocyte against free radical damage?

A

Reduced Glutathione (GSH)

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45
Q

Recognize the ethnicities most commonly affected by G6PD deficiency

A
  • African
  • Mediterranean
  • X-linked
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46
Q

List the clinical findings associated with the episodic hemolysis of G6PD deficiency

A
  • palor, fatigue, jaundice
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47
Q

List the common triggers for an episode of hemolysis in a patient with G6PD deficiency

A
  • caused by: fava beans, oxidizing drugs(sulfonamides, nitrofurans, antimalarials), infection
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48
Q

State the deficiency that leads to paroxysmal nocturnal hemoglobinuria (PNH)

A
  • GPI- linked proteins on RBCs, neutrophils, and platelets
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49
Q

Explain why patients with PNH may present with a thrombus

A
  • excess stimulation of platelet function - thrombi formation
  • all over body
  • portal hypertension - if portal vein thrombosis
50
Q

Explain why patients with PNH present with hemoglobinuria

A
  • intravascular hemolysis
  • episodic, nocturnal
  • haptoglobin decreases as it binds to Hb
  • The complex is excreted by the kidneys in urine
  • Fe is lost alongside Hb
  • results in iron deficiency anemia
51
Q

Which types of cells are affected in paroxysmal nocturnal hemoglobinuria?

A

RBCs, neutrophils, and platelets

52
Q

What are the manifestations of portal vein thrombosis?

A

Hemorrhoids, Caput medusae, Esophageal varices, and ascites

53
Q

Which structures with thrombosis result in Budd-Chiari syndrome?

A

Hepatic vein

54
Q

Which type of anemia can be accompanied by paroxysmal nocturnal hemoglobinuria?

A

iron deficiency anemia

55
Q

What is deficient as a result of paroxysmal nocturnal hemoglobinuria?

A

GPI-linked proteins

56
Q

Describe the normal function of decay-accelerating factor

A
  • a type of GPI -linked protein
  • a factor that controls complement activity
57
Q

Explain the consequence of an absence of decay-accelerating factor

A
  • cannot regulate complement activity
  • affects RBCs and platelet
  • excess platelet activity
  • hemolysis - intravascular
58
Q

Explain why the hemolysis in PNH occurs at night

A
  • acidic environment
  • lower CO2
  • optimal environment for the complements
  • destroys RBCs
59
Q

In the absence of the decay accelerating factor (DAF), RBCs are susceptible to which of the following?

A

Complement-mediated damage

60
Q

Hereditary angioedema results from a deficiency of which of the following?

A

C1 esterase inhibitor

  • vasodilation around the mucous membrane
61
Q

Hemolysis in PNH is mainly nocturnal due to which of the following?

A

Acidic environment
- at night -> breathing rate slows down
- increased CO2 in body
- slightly acidic

62
Q

Hypercoagulable state in PNH is due to which of the following?

A

Increased platelet function

63
Q

List the scenarios that can lead to hemolysis in a patient with paroxysmal hemoglobinuria (PNH)

A
  • Respiratory acidosis at night
  • Lactic acidosis during exercise (cramps) - metabolic acidosis
64
Q

Recognize that PNH can lead to iron deficiency anemia

A
  • losing Hb
  • Losing Iron
  • it is attached to the Heme
65
Q

State the test used to diagnose PNH

A
  • flow cytometry - complement action in the patient’s blood is tested
  • look for GPI-linked proteins
66
Q

State the CD markers that are reduced or absent in paroxysmal nocturnal hemoglobinuria (PNH)

A

CD55 (DAF)
CD59 (MIRL)

67
Q

List the laboratory studies that can be done to diagnose PNH

A
  • flow cytometry
  • Fluorescent Aerolysin (FLAER)
68
Q

State what the leukocyte alkaline phosphatase test is measuring

A
  • low LAP score in PNH
  • LAP is also decreased in CML
  • LAP measures the functionality of neutrophils
69
Q

Which of the following CD markers marks for membrane inhibitor of reactive lysis (MIRL)?

A

CD59

70
Q

For what types of cells does leukocyte alkaline phosphatase measure their functionality?

A

Neutrophils

71
Q

Which condition presents with increased leukocyte alkaline phosphatase?

A

Leukemoid reaction

72
Q

State the point mutation responsible for sickle cell anemia

A
  • substitution mutation
  • Glutamic acid is replaced by valine at position 6 of the beta chain
  • screen - E6V
  • Glutamic acid E6V
  • heterozygous vs homozygous pattern
73
Q

State the inheritance pattern for sickle cell anemia

A
  • autosomal recessive inheritance
74
Q

Describe the difference in inheritance between sickle cell trait and sickle cell disease

A
  • needs to inherit both
  • If only one is inherited - trait
  • if both are inherited - disease
    HbS
75
Q

A patient with sickle cell anemia has which point mutations?

A

Glutamic acid is replaced by valine at position 6 of the beta chain

76
Q

List the conditions of low oxygen tension that can lead to the sickling of red blood cells

A

low oxygen tension
- infection (anemic env - G6PD DEF, in HbS disease genetic mutation, in this case, causes sickling after infection)
- dehydration (stress)
- Hypoxia (stress)

77
Q

Explain how the sickling of red blood cells can lead to autosplenectomy

A
  • extravascular hemolysis
  • spleen destroyed
  • encapsulated organism - vaccinate patient
78
Q

Explain how the sickling of red blood cells leads to vasoocclusive crises

A
  • Sickled - polymerized RBC and looks like a sickle
  • they tend to stick together
  • other blood cells can’t move past the cluster of cells
  • block the vessels
  • other RBCs can’t pass-through
  • tissues don’t get oxygen
  • pain - acute chest syndrome, dactylitis, priapism, stroke-like issues (carotid)
  • head to toe - vasoocclusive crisis
  • decreased oxygen to the tissues
79
Q

Identify sickled red blood cells on a peripheral blood smear

A
  • misshapen, sickle-shaped
  • Howell- Jolly bodies - spleen involved
80
Q

Which actions or conditions predispose HbS to polymerize?

A

Respiratory failure. dehydration, hypoxia, infection

81
Q

The presence of small, round, basophilic inclusions in the erythrocytes of a patient with sickle cell anemia indicates…?

A

a non-functional spleen.

82
Q

what are the signs or symptoms of a vaso-occlusive crisis?

A

Dactylitis. Autosplenectomy, Acute chest syndrome, Priapism

83
Q

List the effects of vasoocclusive crises on different organ systems

A
  • A pain crisis - microvascular ischemia causing severe pain
  • 100% of SS patients have this symptom (homozygous - disease)
  • need long-term narcotic treatment (risk of opioid consumption) - respiratory center in the brain is at risk
  • Acute chest syndrome
  • hypoxemia caused by microvascular disease of the lung
  • stroke
  • carotid affected
  • auto splenectomy
  • spleen dies due to increased extravascular hemolysis
  • Howell-Jolly bodies indicate spleen involvement
  • 100% SS auto splenectomy by adulthood
84
Q

Name the organisms that a patient with autosplenectomy is most susceptible to

A

encapsulated
- strep pneumonia
- Haemophilus influenza
- klebsiella pneumonia

85
Q

What is a vaso-occlusive crisis?

A

A pain crisis - microvascular ischemia causing severe pain
- 100% of HbS patients have this symptom
- need long-term narcotic treatment

86
Q

List the complications of parvovirus and Salmonella species associated with sickle cell anemia

A
  • aplastic crisis - Parvovirus B19 infection
  • bone marrow shut down
  • susceptible
  • Salmonella causes osteomyelitis in patients with SS
  • Osteomyelitis - caused by staph aureus, if stepped on a nail then by pseudomonas
87
Q

Explain the different tests that can be done to diagnose sickle cell anemia

A
  • screening E6V
  • Sickle prep - peripheral blood sickles when exposed to sodium metabisulfite (reduces oxygen tension)
  • Hb electrophoresis (HbA, Hb A/S, Hb SS)
88
Q

Explain the findings on hemoglobin electrophoresis for sickle cell trait and sickle cell disease

A
  • Hb electrophoresis (HbA, Hb A/S, Hb SS)
    NORMAL
  • HbA -97%
  • HbA2 -2%
  • HbF- 1%

here - Hb S

89
Q

What is the most common pathogen responsible for osteomyelitis in patients with sickle cell disease?

A

Salmonella species

90
Q

What is the mechanism of action of hydroxyurea in patients with sickle cell disease?

A

increases production of HbF

91
Q

Treatment for homozygous patients?

A
  • hydration
  • hydroxyurea - create more HbF
92
Q

Describe the percentages of the hemoglobin types found on hemoglobin electrophoresis for sickle cell trait and sickle cell disease

A

TRAIT:
- A2 = 2%
- S = 45%
- F = 1%
- A = 52%

  • Anemia: none

DISEASE:
- A2 = 2%
- S = 90%
- F = 8%
- A = -

  • Anemia: Normocytic
93
Q

List different treatment options for sickle cell anemia

A
  • Hydroxyurea - increases HbF
  • Hydration
  • bone marrow transplantation - reticulocytosis, parvovirus
  • analgesics
94
Q

Which of the following values represents a normal hemoglobin electrophoresis pattern?

A

Hemoglobin A, 97%; hemoglobin A2, 2%; hemoglobin F, 1%

95
Q

Describe the role of pyruvate kinase in the glycolytic pathway

A
  • Last enzyme in the process of converting glucose to pyruvate
  • Phosphoenol pyruvate -> pyruvate
96
Q

State the inheritance pattern of pyruvate kinase deficiency

A
  • Autosomal recessive inheritance
97
Q

Explain how pyruvate kinase deficiency can affect the oxygen dissociation curve

A
  • Glycolytic enzyme is deficient -> results in extravascular hemolysis (misshapen RBC)
  • Intrinsic disease
  • Pyruvate is not created _> can’t enter the Kreb’s cycle
  • Phosphoenol pyruvate increases —- 1.3 Bisphosphoglycerate increases —–> 2,3 BPG increases
  • Pathological increase of the release of oxygen from Haemoglobin
  • Oxygen is released more easily
  • There is a right shift in the oxygen dissociation curve
98
Q

In RBCs, which intermediate substrate of the glycolytic pathway is directly responsible for altering the hemoglobin–oxygen dissociation curve?

A

2,3-Bisphosphoglycerate

99
Q

Describe how a pyruvate kinase deficiency affects ATP and NADH levels

A
  • RBC only uses glycolysis for energy (doesn’t have mitochondria)
  • In PK deficiency -> low amounts of ATP and NADH
  • ATP can’t be produced
  • Pyruvate doesn’t enter the kreb’s cycle so NADH isn’t produced
100
Q

Explain how decreased NADH levels in pyruvate kinase deficiency can cause increased levels of methemoglobin

A
  • NADH is necessary to convert Hb-Fe3+ (methemoglobin) to Fe2+ (ferrous iron)
  • in the diet - Fe3+
  • Cytochrome P reductase and NADH help to convert Ferric to the ferrous form of iron
  • deficiency of NADH in pyruvate kinase deficiency
  • the patient is in a state of methemoglobin (Hb - Fe3+)
101
Q

Describe how a pyruvate kinase deficiency can affect the oxygen saturation curve

A
  • 2,3 BPG increases
  • right shift in the oxygen dissociation curve
102
Q

What type of hemolysis do RBCs in pyruvate kinase deficiency undergo?

A

Extravascular hemolysis

  • ATP deficiency causes problems in the Na/K ATPase, leading to osmotic instability and misshapen RBCs
103
Q

Which of the following statements is FALSE?

NADH is used to convert iron from Fe3+ to Fe2+.

In pyruvate kinase deficiency, 2,3-BPG is increased.

The oxidation state of dietary iron that can be absorbed in the intestine is Fe3+.

Pyruvate kinase deficiency may result in methemoglobinemia.

The oxidation status of iron in hemoglobin is Fe2+.

A

The oxidation state of dietary iron that can be absorbed in the intestine is Fe3+.

We need Ferrous iron

104
Q

Recognize the morphology of red blood cells in a patient with pyruvate kinase deficiency

A
  • spiculated RBC
  • needle-like projections coming out
105
Q

State the expected methemoglobin levels in a patient with pyruvate kinase deficiency

A
  • in a child (born with the deficiency)
  • High methemoglobin levels due to lack of NADH
106
Q

Identify echinocytes on a peripheral blood smear and state the cause of this morphology

A
  • ATP deficiency has an effect on the Na/K ATPase pumps
  • Echinocyes are formed
  • Broken down by the spleen
107
Q

List pathologies that can cause mechanical damage to red blood cells

A
  • mechanical or stenotic heart valve (Waring Blender effect) - turbulent blood flow through the valve causes damage to the RBC
  • Malignant hypertension - prothrombotic environment -> small clots in the small vasculature -> as RBCs try to pass through these small occluded vessels, they become misshaped and their cell walls are deformed and ultimately damaged.
108
Q

List pathologies that can cause microthrombus formation

A
  • diffuse microthrombus formation
  • DIC - bleeding, platelet consumed, coagulation factors consumed, thrombi —> causes normocytic, hemolytic microangiopathic anemia (extravascular hemolysis)
  • HUS
  • TTP
109
Q

What is the term used to describe an RBC that is abnormal in shape due to mechanical shearing and destruction?

A

Schistocyte - helmet cell

110
Q

Which conditions are the most likely causes of microangiopathic hemolytic anemia?

A

Disseminated intravascular coagulation

hemolytic uremic syndrome

thrombotic thrombocytopenic purpura

111
Q

What are the typical lab findings seen in disseminated intravascular coagulation?

A

Low platelets, increased PT, increased PTT, increased bleeding time

112
Q

What are the triggers for DIC?

A
  • Acute Myelogenous Leukemia Type 3
  • Amniotic fluid emboli
  • Sepsis
  • Venom (snake)
113
Q

Recognize that red blood cell damage in microangiopathic hemolytic anemia is due to vascular defects in circulation

A

RBCs “shear” when they encounter vascular defects in circulation
- broken up or fragmented
- Schistocyte
- Helmet cells (nickname)

114
Q

What type of abnormal RBCs are likely to be seen in the peripheral blood smear of a patient suspected to have disseminated intravascular coagulation?

A

Helmet cells

115
Q

Identify schistocytes on a peripheral blood smear

A
  • differentiate between sickle cell, bite cells (G6PD def)
  • look like helmets
  • Aortic valve stenosis
116
Q

Explain the relationship between hemoglobinuria and iron deficiency anemia

A
  • During hemolytic anemia - intravascular
  • Hb + haptoglobin removed in urine
  • Iron is also removed in this process
  • leading to iron deficiency anemia
117
Q

Recognize agglutination of red blood cells on a peripheral blood smear

A
118
Q

List the 2 types of autoimmune hemolytic anemia

A
  • Warm
  • Cold
119
Q

Explain how to differentiate between warm autoimmune hemolytic anemia and hereditary spherocytosis

A
  • Coombs test
120
Q

Which of the following microorganisms is associated with cold autoimmune hemolytic anemia?

A

Mycoplasma pneumoniae

Hematology (2 decks)

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