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Heme and Lymph Exam 2 > Evaluation of Anemia - SRS > Flashcards

Evaluation of Anemia - SRS Flashcards

1
Q

What is shown in the attached image?

What is the stain?

A

Supravital stain

Shows reticulocytes - the dark spots are RNA

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2
Q

What are the two primary types of hemolysis?

Which is most common?

A

Intravascular

Extravascular - more common

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3
Q

Characterize intravascular hemolysis as far as timeline, and impact.

A

Acute, devastating; lysis and destruction of red cells in the intravascular space

(e.g.: transfuse wrong blood type)

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4
Q

Describe extravascular hemolysis as far as timeline and impact.

A

Chronic, enhancement or amplification of normal physiologic removal of red cells.

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5
Q

What type of hemolysis does this scan indicate?

A

Extravascular - note the splenic expansion

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6
Q

Extravascular hemolysis is not really hemolysis but rather an accelerated rate of removal of defective RBCs. It is slow, and not acutely catastrophic.

The degree of anemia is determined by the balance between rate of production and lifespan/rate of removal of defective RBCs.

What are 5 findings you are likely to encounter in this setting?

A
  1. Anemia
  2. splenomegaly
  3. jaundice
  4. elevated EPO levels in blood
  5. Bone marrow hyperplasia
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7
Q

Intravascular hemolysis is sudden, catastrophic, and if sufficient volume is lysed, can cause death. What are the hallmarks of intravascular hemolysis?

(6 with two emphasized)

A
  1. Hemoglobinemia
  2. hemoglobinuria
  3. hemosiderinuria
  4. jaundice
  5. decreased or absent serum haptoglobin
  6. large amounts can cause renal failure and DIC
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8
Q

What will happen to haptoglobin in intravascular hemolysis?

A

Decreases

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9
Q

You pull these stones out of a patient’s gallbladder. What are they and what do they indicate?

A

Pigment/bilirubin stones = hemolytic anemia

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10
Q

What is hereditary spherocytosis?

A

Inherited disorder caused by intrinsit defects in the red cell membrane skeleton that renders the cells spheroid, less deformable and vulnerable to splenic sequestration and destruction.

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11
Q

Hereditary spherocytosis (HS) has highest prevalence in northern Europe, with rates of 1/5000 reported.

What is the inheritance pattern seen in this condition?

A

Autosomal dominant in ~75% of cases

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12
Q

What do the other ~25% of HS patients get instead of the autosomal dominant pattern?

A

A more severe form that is usually caused by the inheritance of two different defects. A state known as compound heterozygosity.

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13
Q

What do the pathogenic mutations most commonyl affect in HS? 4

A
  1. Ankyrin
  2. Band 3
  3. Spectrin
  4. Band 4.2
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14
Q

What do ankyrin, band 3, spectrin and band 4.2 have in common?

A

All involved in one of the two tethering interactions, this complex is important in stabilizing the lipid bilayer.

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15
Q

What are RBCs shaped like early on in their lifespan during HS?

Later?

A

Early - normal in shape

Late - loss of membrane relative to cytoplasm forces cells to assume smallest diameter possible for a given volume… a sphere.

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16
Q

What is the half life of a spherocyte RBC?

A

10-20 days

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17
Q

What is the arrow pointing to?

What does the star indicate?

A

Arrow: spherocyte

Star: Howell-Jolly bodies - small dark nuclear remnants

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18
Q

In two thirds of HS patients the red cells are abnormally sensitive to?

A

Osmotic lysis

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19
Q

Describe the hemoglobin content of HS red cells relative to normal RBCs.

Explain why.

A

Increased mean cell hemoglobin concentration, d/t dehydration caused by the loss of K+ and H20.

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20
Q

What are the three characteristic features of HS?

A

Anemia

Splenomegaly

Jaundice

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21
Q

What are three complications of hereditary spherocytosis? Give an example of each.

A

Aplastic crises - e.g. parvovirus

hemolytic crises - e.g. infectious mono

Gallstones (pigment stones)

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22
Q

What is shown here?

Describe the symptomaticity of this patient.

A

Hereditary elliptocytosis

no symptoms

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23
Q

You have an 8 yo male with otitis media and you decide to tx him with bacterim. He suddenly turns yellow and blood tests show markedly decreased Hgb. What is likely causing the problem?

A

Sulfa/trimethoprim (Bacterim), aggravating G6PD deficiency

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24
Q

What does G6PD do?

A

Maintains glutathione to moderate oxidative stress on RBCs

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25
Q

Other than impaired glutathione metabolism, what abnormality reduces the ability of red cells to protect themselves against oxidative injuries and leads to hemolysis?

A

Hexose monophosphate shunt abnormalities

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26
Q

What is the inheritance pattern associated with G6PD deficiency?

A

Recessive X-linked trait, thus males are at much higher risk of symptomatic disease.

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27
Q

What two variants of G6PD deficiency cause the majority of clinically significant hemolytic anemias?

A

G6PD-

G6PD mediterranean

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28
Q

What are the G6PD levels in G6PD-?

A

Reduced levels

29
Q

What are the G6PD levels like in G^PD mediterranean?

A

Completely absent

30
Q

Why, in spite of the limited inheritance mechanism does G6PD deficiency persist?

A

Confers a malarial protective effect

31
Q

What are the most common triggers of G6PD defieciency?

A
  1. Infection
  2. Drugs
  3. Foods (fava beans)
32
Q

Infection can cause episodic hemolysis in G6PD deficient patients. What is the mechanism that this occurs by?

A

activated leukocytes produce oxygen-derived free radicals, increasing oxidative stress and leading to RBC hemolysis

33
Q

Older RBCs are more prone to hemolysis in G6PD deficiency than young ones. Why?

A

Mature red cells don’t synthesize new proteins, so levels rapidly fall to a point that protection against oxidative damage is inadequate.

34
Q

What type of hemolysis do oxidants cause in G6PD deficient individuals?

A

Both intravascular and extravascular hemolysis

35
Q

What is indicated by the red arrow?

What are they indicative of?

A

Heinz bodies - indicate G6PD deficiency

36
Q

Acute intravascular hemolysis, marked by anemia, hemoglobinemia and hemoglobinuria, usually begins how many days after exposure to oxidants?

A

2-3 days

37
Q

G6PD deficiency episodes are self limiting, since hemolysis ceases when only younger RBC’s remain. What is the recovery phase heralded by?

A

Reticulocytosis

38
Q

After a possible G6PD deficiency episode, when should you test for confirmation?

A

Must wait ten to twenty days for RBC’s to mature

39
Q

The attached sample was taken from a newborn with anemia and jaundice. What does the patient likely have?

A

Pyruvate kinase deficiency

40
Q

How can we rapidly identify sicke cell anemia?

A

Sickledex test - takes about five minutes

41
Q

What do each set of results indicate?

A

Top = normal

AS = sickle cell trait

SS = Sickle cell disease

AC = hemoglobin C disease

42
Q

Sickle cell disease is a common hereditary hemoglobinopathy caused by a point mutation in what?

A

B-globulin that promotes polymerization of deoxygenated hemoglobin.

43
Q

What are three conditions that are suggested to be protective against malaria?

A
  1. Sickle cell
  2. G6PD
  3. Thalassemias
44
Q

What are the three major pathologic manifestations associated with sickle cell disease?

A
  1. Chronic hemolysis
  2. microvascular damage
  3. tissue damage
45
Q

What does the pathology in sickle cell disease stem from?

A

Tendancy of HbS molecules to stack into polymers when deoxygenated.

46
Q

What does the polymerization of HbS in the red cell lead to morphologically/structurally?

A

Converts RBC cytoplasm from free flowing liquid to a viscous gel. With continued deoxygenation HbS molecules assemble into long needle-like fibers, producing the sickle or holly-leaf shape.

47
Q

If you have sickle cell trait, what percent of the hemoglobin is S type? When do these patients sickle?

A

40%

Only under profoundly hypoxic conditions

48
Q

When do infants become symptomatic with sickle cell disease?

Why?

A

At 5 or 6 months.

This is when the HbF levels normally fall.

49
Q

In HbSC, what is the percentage of HbS?

What does this lead to as far as clinical presentation?

A

50%

Symptomatic sickling disorder, but milder than sickle cell disease.

50
Q

Higher HbS concentrations increase the probability that aggregation and polymerization will occur during any period of deoxygenation. Intracellular dehydration, facilitates sickling.

What measure while normally pretty useless is useful as a result of this?

A

MCHC

51
Q

What impact does a decrease in pH have on sickle cell disease?

A

Reduces the oxygen affinity of Hgb, increasing deoxygenated hemoglobin and leading to increased sickling.

52
Q

What microvascular beds do we see sickling confined to typically?

A

Those with slow transit times, such as the spleen and bone marrow. (also inflamed vascular beds)

53
Q

Which causes microvascular occlusion, irreversibly sickled cells or reversibly sickled cells?

A

Reversibly sickled, the irreversibly sickled is hemolysed

54
Q

What is shown in this peripheral smear?

A

Sickle cell disease

55
Q

Describe the findings attached from the spleen of a sickle cell patient.

A

Marked congestion in the red pulp cords and sinusoids. Pale areas of fibrosis resulting from ischemic damage are evident.

56
Q

Sickle cell disease causes a moderately severe hemolytic anemia that is associated with what microscopic findings?

A

Presence of sickled cells

reticulocytosis

Spherocytes (non-specific for HS, also see here)

57
Q

What are the five sickle cell crises?

A
  1. Vaso-occlusive crises (aka pain crises)
  2. hand-foot syndrome (dactylitis of bones of hands and feet or both)
  3. Acute chest syndrome
  4. Sequestration crises
  5. aplastic crises
58
Q

What causes pain crises?

A

Vaso-occlusive crises caused by episodes of hypoxic injury and infarction that cause severe pain in the affected region.

59
Q

What patients tend to get painful bone crises?

A

Children - frequently manifests as hand-foot syndrome

60
Q

Acute chest syndrome is a partucularly dangerous type of vaso-occlusive crisis involving the lungs which typically presents with what 4 findings?

A

Fever

Cough

Chest pain

Pulmonary infiltrates

61
Q

In child sicklers with intact spleens what do we need to be worried about with entrapment of sickled red cells in the spleen?

A

Sequestration crises - massive entrapment leads to rapid splenic enlargement, hypovolemia, and sometimes shock. This is acute, and can kill the patient.

62
Q

Both sequestration crises and acute chest syndrome can be fatal. What should be done to treat these patients?

A

Prompt exchange transfusion

63
Q

Aplastic crises stem from what?

A

Infection of the red cell progenitors by parvovirus B19, causing transient cessation of erythropoiesis and sudden worsening of anemia.

64
Q

Chronic hypoxia is responsible for a generalized impairment of growth and development in sickle cell patients. What can sickling in the renal medulla d/t hypertonicity lead to?

A

hyposthenuria (inability to concentrate urine)

65
Q

Apart from the crises, what is another threat to the sickle cell disease patient

A

Increased susceptibility to infection with encapsulated organisms

Would this only be in splenectomized pts? Food for thought.

Answer seems to be No

66
Q

Defects of uncertain etiology in the alternative complement pathway in sicklers also impair opsonization of bacteria. What are some organisms that sickle cell patients are particularly prone to infection by?

A

Pneumococcus pneumoniae

H. Influenza

67
Q

What is the prognosis for the sickle cell patient?

A

90% survive to age 20

50% survive past age 50

68
Q

What is a mainstay treatment option for sicklers? What benefits does it confer?

A

hydroxyurea

  1. increase in red cell HbF levels (unknown mechanism)
  2. antiinflamatory effect d/t inhibition of leukocyte production

Heme and Lymph Exam 2 (9 decks)

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