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Flashcards in Hemolytic Anemias Deck (26):
1

What are some possible defects that may lead to hereditary spherocytosis?

Defects in ankyrin (50%), band 3 (15%), band 4.2 or alpha/beta-spectrin --> weakened or absent spectrin causing a weakened RBC cytoskeleton

2

What test differentiates hereditary spherocytosis from autoimmune hemolytic anemia?

DAT will be negative in hereditary spherocytosis

3

What virus could cause aplastic crisis in individuals with hereditary spherocytosis?

Parvovirus B19

4

How is G6PDH deficiency passed on?

X-linked

5

What happens in G6PDH deficiency?

RBC's cannot reduce oxidant stress and accumulate denatured, precipitated Hb (Heinz bodies) that damage the cell membrane and cause lysis (intravascular) or are removed by the spleen (extravascular hemolysis)

6

What is cell is characteristic of G6PDH deficiency?

Bit cells

7

What are some oxidant stressors that could lead to an acute development of G6PDH symptoms?

Fava beans
Infection
Drugs -- dapsone, sulfonamides, primaquine, nitrofurantoin, quinolones

8

What is the pathophysiology of paroxysmal nocturnal hemoglobinuria (PNH)?

Stem cell with deficiency in GPI-linked proteins -- including the anti-complement proteins CD55 and CD59 on RBCs and WBCs

Makes RBCs (and WBCs to a lesser extent) subject to complement mediated lysis

9

What are some clinical features of PNH?

Hypercoagulability (thrombi at unusual sites)
Accentuation of lysis at night

10

RBC autoantibodies that react at 37 degrees causing intravascular coating of RBCs and extravascular lysis in the spleen

Warm autoimmune hemolytic anemia

11

What test is used to determine if an autoimmune hemolytic anemia is present?

Direct antiglobulin test (DAT)

12

What types of disease can be associated with warm AIHA??

B-cell lymphoproliferative disorders

13

RBC IgM autoantibodies that react at <30 degrees and may lead to extravascular hemolysis in the spleen and liver

Cold autoimmune hemolytic anemia

14

How does acute cold AIHA differ from chronic cold AIHA?

Acute is usually 2-3 weeks post-infection
Chronic is usually accompanied by a lymphoproliferative disorder

15

What are some unique clinical features of cold AIHA?

Raynaud phenomenon (obstructive symptoms)
Associated with mycoplasma infections and EBV infections

16

Traumatic shearing and subsequent lysis of RBCs d/t blood flow abnormality

Microangiopathic hemolytic anemia

17

What are some things that can lead to the shearing seen in microangiopathic hemolytic anemia?

Malfunctioning heart valve
Vascular obstructions by microthrombi

18

What is seen on smear review in microangiopathic hemolytic anemia?

Schistocytes

19

What are some states that microangiopathic hemolytic anemia may be associated with?

DIC
TTP
Metastatic cancer
Malignant hypertension

20

How does malaria/babesia lead to a hemolytic anemia?

Intracellular parasites that infect RBCs and cause lysis as they propagate

21

At <20% hemolysis what is the Hgb expected to be and what are some signs and symptoms?

>11 g/dL
Restlessness

22

At 20-30% hemolysis what is the Hgb expected to be and what are some signs and symptoms?

10-11 g/dL
Anxiety, dyspnea with exertion
Orthostatic hypotension; tachycardia with exertion

23

At 30-40% hemolysis what is the Hgb expected to be and what are some signs and symptoms?

8-9 g/dL
Syncope
Orthostatic hypotension; tachycardia at rest

24

At <40% hemolysis what is the Hgb expected to be and what are some signs and symptoms?

<8
Confusion
Shock

25

What are some rare complications of hemolytic anemia?

Pigment induced kidney injury
Folate deficiency d/t increased utilization
Increased risk of venous and arterial thrombosis, including venous thrombosis of atypical sites (portal vein, cerebral venous sinus)

26

What are some clinical features of hemolytic anemia related to the underlying disease process?

Splenomegaly, hepatomegaly -- from extra-medullary hematopoiesis (thalassemia, PK deficiency, hereditary spherocytosis)
Skeletal changes -- from expansion of marrow, chipmunk facies, convex bones (beta thalassemia major)
Asplenia -- sickle cell
Microangiopathic hemolytic anemia