Hemolytic Anemias

Question 1

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

Answer 1

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

Question 2

What test differentiates hereditary spherocytosis from autoimmune hemolytic anemia?

Answer 2

DAT will be negative in hereditary spherocytosis

Question 3

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

Answer 3

Parvovirus B19

Question 4

How is G6PDH deficiency passed on?

Answer 4

X-linked

Question 5

What happens in G6PDH deficiency?

Answer 5

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)

Question 6

What is cell is characteristic of G6PDH deficiency?

Answer 6

Bit cells

Question 7

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

Answer 7

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

Question 8

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

Answer 8

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

Question 9

What are some clinical features of PNH?

Answer 9

Hypercoagulability (thrombi at unusual sites)

Accentuation of lysis at night

Question 10

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

Answer 10

Warm autoimmune hemolytic anemia

Question 11

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

Answer 11

Direct antiglobulin test (DAT)

Question 12

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

Answer 12

B-cell lymphoproliferative disorders

Question 13

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

Answer 13

Cold autoimmune hemolytic anemia

Question 14

How does acute cold AIHA differ from chronic cold AIHA?

Answer 14

Acute is usually 2-3 weeks post-infection

Chronic is usually accompanied by a lymphoproliferative disorder

Question 15

What are some unique clinical features of cold AIHA?

Answer 15

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

Question 16

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

Answer 16

Microangiopathic hemolytic anemia

Question 17

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

Answer 17

Malfunctioning heart valve

Vascular obstructions by microthrombi

Question 18

What is seen on smear review in microangiopathic hemolytic anemia?

Answer 18

Schistocytes

Question 19

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

Answer 19

DIC
TTP
Metastatic cancer
Malignant hypertension

Question 20

How does malaria/babesia lead to a hemolytic anemia?

Answer 20

Intracellular parasites that infect RBCs and cause lysis as they propagate

Question 21

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

Answer 21

> 11 g/dL

Restlessness

Question 22

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

Answer 22

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

Question 23

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

Answer 23

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

Question 24

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

Answer 24

<8
Confusion
Shock

Question 25

What are some rare complications of hemolytic anemia?

Answer 25

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)

Question 26

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

Answer 26

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