Normocytic Anemias with Predominant Extravascular Hemolysis Flashcards Preview

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Flashcards in Normocytic Anemias with Predominant Extravascular Hemolysis Deck (37):
1

An inherited defect in the RBC cytoskeleton membrane tethering proteins…

Hereditary Spherocytosis

2

What are the 3 most common cytoskeleton tethering proteins involved in hereditary spherocytosis?

Ankyrin
Spectrin
Band 3

3

Why does anemia result from hereditary spherocytosis?

Spherocytes are formed due to membrane blebing—this makes the RBCs less able to maneuver through splenic sinusoids, which leads to their destruction by the spleen

4

What is seen on the blood smear of a patient with hereditary spherocytosis?

Spherocytes with loss of central pallor

5

With respect to RDW and mean corpuscular hemoglobin concentration (MCHC), how does hereditary spherocytosis affect these values?

Increases both

MCHC—only disease where you’ll see this elevated EXCEPT for autoimmune anemia

6

What are the two most common clinical findings seen with hereditary spherocytosis?

Splenomegaly
Jaundice with unconjugated bilirubin

7

Patients with hereditary spherocytosis are at an increased risk of developing _______ due to extravascular hemolysis?

Bilirubin gallstones

8

Patients with hereditary spherocytosis are at an increased risk of ________ infection to the erythroid precursors, which causes what to occur?

Parvovirus B19—causing aplastic crisis

9

What test is used to diagnose hereditary spherocytosis?

Osmotic fragility test—reveals increased spherocyte fragility in hypotonic solution

10

What is the treatment for hereditary spherocytosis?

Splenectomy

11

Even after splenectomy to treat hereditary spherocytosis, what still remains and what is seen on blood spear?

Spherocytes still remain because spleen is not there to destroy them

Howell-Jolly bodies seen on blood smear due to left over fragments of DNA in RBCs, usually removed by spleen

12

Autosomal recessive mutation in B chain of hemoglobin—caused by a single amino acid change, glutamic acid→ valine…

Sickle cell anemia

13

Patients who are carries of sickle cell anemia have protection against________.

Falciparum malaria

14

What occurs to the RBCs causing them to sickle, in sickle cell anemia?

HbS polymerizes when deoxygenated—causing aggregation of the polymerized HbS→ sickled cells

15

What 3 things increase the risk of sickling of RBCs in sickle cell anemia?

Hypoxemia
Dehydration
Acidosis

16

What type of hemoglobin is protective against sickling?

HbF

17

What drug is given to increase HbF and allowing protection from sickling of cells seen with sickle cell anemia?

Hydroxyurea

18

Extravascular hemolysis seen with sickle cell anemia involves the reticuloendothelial system removing RBCs with damaged membranes. What are the clinical manifestations seen with this and what are these patients at an increased risk of developing?

Anemia
Jaundice with unconjugated hyperbilirubinemia

Increased risk for bilirubin gallstones

19

Intravascular hemolysis is seen with sickle cell anemia and is caused by dehydration of damaged membranes of the RBCs. What scavenger is decreased during this process and what appears on blood smears of these patients?

Haptoglobin decreases

Target cells are seen on blood smears

20

What are the 3 major effects of erythroid hyperplasia seen with sickle cell disease?

1) Expansion of hematopoiesis into the skull and facial bones
2) Extramedullary hematopoiesis with hepatomegaly
3) Risk of aplastic crisis with parvovirus B19 infection to erythroid precursors

21

Expansion of hematopoiesis into the skull and facial bones are seen with erythroid hyperplasia occurring with sickle cell disease. What are the two clinical findings caused by this expansion?

Skull→ crewcut appearance on XRAY

Facial bone→ chipmunk facies

22

Swollen hands and feet caused by vaso-occlusive infarcts in bones…

Dactylitis

23

Patient with sickle cell disease who have extensive sickling are at risk of developing autosplenectomy. This will leave the patient more susceptible to what type of infections?

Infection with encapsulated organisms such as:
-Streptococcus pneumoniae
-Haemophilus influenzae

Also at increased risk of Salmonella paratyphi osteomyelitis

24

What will be on a blood smear of patients with autosplenectomy caused by sickle cell disease?

Howell-Jolly bodies

25

A patient with a history of sickle cell anemia presents with chest pain, shortness of breath and lung infiltrates. What is the most likely diagnosis?

Acute chest syndrome caused by vaso-occlusion in pulmonary microcirculation due to the sickled RBCs

26

Acute chest syndrome is the most common cause of death in _____ patients with sickle cell disease.

Adult

27

What results from renal papillary necrosis caused by extensive sickling seen with sickle cell disease?

Gross hematuria and proteinuria

28

Sickle cell trait is caused by the presence of what?

One mutated and one normal B chain--

29

Why are patient with sickle cell trait most likely to be asymptomatic with no anemia?

Because RBCs with

30

What are the two distinctive abnormal cells are found on blood smear with sickle cell disease?

Sickle cells and target cells

31

What screening test is performed that causes HbS cell to sickle in both sickle cell disease and sickle cell trait?

Metabisulfite screen

32

What test is used to confirm the presence and amount of HbS in sickle cell disease?

Hb electrophoresis

33

What is the hemoglobin distribution seen with sickle cell disease?

HbS—90%
HbF—8%
HbA2—2%
NO HbA

34

What is the hemoglobin distribution seen with sickle cell trait?

HbA—50%
HbS—43%
HbA2—2%

35

An autosomal recessive mutation in the B chain of hemoglobin caused by glutamic acid being replaced by lysine…

Hemoglobin C

36

How does Hemoglobin C present?

Mild anemia caused by extravascular hemolysis

37

What are the distinctive cells seen on a blood smear of a patient with Hemoglobin C?

Characteristic HbC crystals seen within RBCs