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Hematology > 10.10.18 Hemoglobinopathies > Flashcards

10.10.18 Hemoglobinopathies Flashcards

1
Q

genetically heterogeneous conditions resulting from imbalance between the amounts of alpha and beta globin chains that are synthesized

A

Thalassemia

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2
Q

How are thalassemia’s classified?

A
  1. Severity of clinical manifestations
  2. Major hemoglobin species formed
  3. Genotype
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3
Q

If a mutation causes absent beta globin synthesis

A

B0 thalassemia

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4
Q

If a mutation has decreased (but still present) beta globin synthesis

A

B+ thalassemia

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5
Q

What region is beta thalassemia most common in?

A

Southern Europe (Also SE Asia, Africa, Middle East)

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6
Q

What is the genotype for Cooley’s Anemia

In which population is it typically seen in?

How would you diagnose?

A

B0/B0; B Thalassemia major

Mediterraneans

Hb electrophoresis

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7
Q

What are the symptoms of homozygous beta thalassemias?

A
  1. Ineffective erthropoiesis
  2. Destruction of produced RBC
  3. Splenomegaly
  4. Skeletal deformaties
  5. Iron overload- transfusions; iron hyperabsorption
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8
Q

Hemolysis of red cell precursors inside the marrow

A

Intramedullary hemolysis

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9
Q

Heterozygoies state where one allele is normal and the other allele is Beta +; enough beta to pair with alpha so not so many a4 tetramers

A

Beta thalassemia minor (trait)

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10
Q

What are the lab findings in beta thalassemia?

A
  1. Microcytic
  2. May or may not be anemic (if present it is mild)
  3. RBC count elevated
  4. Normal RDW
  5. Higher HbA2 levels
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11
Q

Characteristics of this alpha thalassemia include:

  • typically silent
  • minimal microcytosis
  • anemia not present
  • electrophoresis normal
A

aa/a-

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12
Q

Characteristics of this alpha thalassemia include:

  • Mildly anemic
  • Microcytosis
  • Hgb electrophoresis normal in adults; abnormal in newborns
A

aa/– and a-/a-

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13
Q

What population has aa/– and which population has a-/a-

A

a-/a- : AA

aa/–: Asians

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14
Q

Characteristics of this alpha thalassemia include:

  • Hemoglobin H = B4 tetramers
  • Heinz bodies –> bite cells –> hemolytic anemia
  • Splenomegaly
  • Low MCV and MCH, high RDW
A

a-/–

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15
Q

Characteristics of this alpha thalassemia include::

  • Hydrops fetalis
  • Hemoglobin barts = Gamma4 tetramers
  • Intrauterine death; treated in utero
A

–/–

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16
Q

Disorder in which sixth aa in beta chain is changed from glutamate to valine; less soluble and polymerizes

A

Hemoglobin S

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17
Q

Disorder in which sixth aa in beta chain is changed from glutamate to lysine; leads to increased cellular dehydration and founnd in West African descent

A

Hemoglobin C

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18
Q

Under what conditions do HbS polymerize and cause cells to sickle?

A

Hypoxia and acidosis

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19
Q

How do multiple cycles of sickling/unsickling affect the cell?

A

Leads to cellular dehydration which reduces threshold for further sickling

20
Q

What cells have abnormal adhesion to endothelial cells?

A

Sickle cells

21
Q

What genotypes are classified as sickle cell disease vs anemia?

A

Anemia= homozygous SS

Disease= SC, S beta thalassemia

22
Q

What are the types of sickle cell crises?

A
  1. Splenic sequestration crisis
  2. Aplastic crisis
  3. Painful (vaso-occulusive) crisis
23
Q

In children, rapid and extensive trapping of RBC in spleen;

profound anemia, massive splenomegaly, hypovolemic shock

A

Splenic sequestration crisis

24
Q

Parovirus B19 leads to marrow suppression with rapid development of anemia (but not so fast as in sequestration crisis)

A

Aplastic crisis

25
Q

Most common type of sickle cell crises

Periodic episodes of acute vascular occlusion

Attacks of pain usually affecting bones and large joints

A

Painful (Vaso-occulusive) crisis

26
Q

What are the hematologic manifestations of sickle cell?

A
  1. Anemia
  2. Leukocytosis
  3. Throbocytosis
  4. Functionally asplenic
  5. Thromboses- risk for venous clots
27
Q

What are triggers of painful crisis?

A
  1. Exercise
  2. Dehydration
  3. Infection
  4. Cold
  5. Stress
  6. Menstruation
  7. Surgery/trauma
  8. Pregnancy
28
Q

How do you manage painful crisis

A
  1. Treat underlying infection
  2. Treat pain
  3. Supplement oxygen
  4. Folate replacement
  5. Replace fluid if dehydrated
29
Q

What are you at risk for infection with in sickle cell?

A

Encapsulated organisms

30
Q

If undergoing iron chelation therapy in sickle cell what are you at risk for?

A

Yersinia or Vibrio organisms

31
Q

What can cause osteomyelitis and septic arthritis?

A

Salmonella osteomyelitis

32
Q

most common cause of death in patients with sickle cell disease

Hypoxemia, New infiltrate on CXR, New fever, chest pain, dyspnea or cough

A

Acute Chest Syndrome

33
Q

What are respiratory complications associated with sickle cell?

A
  1. Acute Chest Syndrome

2. Pulmonary Hypertension

34
Q

What are the causes of acute chest syndrome

A
  1. Infection with atypical organisms- chlamydia and mycoplasma
  2. Fat embolism from necrotic bone marrow
35
Q

How do you treat acute chest syndrome?

A

Antibiotics, oxugen, Transfusion (simple or exchange)

36
Q

Not due to atherosclerosis but because of disordered blood vessels; occurence at 5 yo

A

Stroke

37
Q

How do you treat stroke acutely and chronically?

A

Acute- exchange transfusion

Chronic- chronic regular transfusion

38
Q

This type of transfusion gives red cells

A

Simple

39
Q

This type of transfusion takes old red cells out while putting new red cells in

A

Exchange

40
Q

What are complications of transfusion in SCD?

A
  1. Iron overload

2. Allo-immunization

41
Q

What organs are damaged with iron overload and how do you treat?

A

heart, liver, and endocrine

Treat with chelation

42
Q

How do you prevent allo-immunization?

A

Transfuse with blood negative for C, E, and Kell groups

43
Q

What are complications occur in SCD?

A
  1. Renal
  2. Leg ulcers
  3. Avascular Necrosis (AVN)
  4. Priapism
44
Q

What should you treat SCD with?

A

Hydroxyurea

45
Q

What are the effects of hydroxyurea?

A
  1. Increases baseline Hb
  2. Reduces sickle crises
  3. Reduce acute chest syndrome
  4. Prevents pulmonary hypertension
  5. Reduces mortality
46
Q

What are hallmarks of Hb C Disease?

A
  1. Microcytosis
  2. Target cells
  3. Splenomegaly

Hematology (23 decks)

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