3.20 CHESNEY Thalassemias

Question 1

Why do thalassemias exist?

Answer 1

Give carry advantage to survival in certain regions

Question 2

Why is there anemia?

Answer 2

With lack of beta, there will be excess alpha which will ppt out and deform and destroy the RBC (hemolytic anemia)
-BM message to increase RBC production with quick turnover could lead to iron overload

Question 3

What distorts bones in beta?

Answer 3

Increased production in BM can lead to hyperplasia which can lead to thinning of the bones and deformities of the bones
-Usually seen in major

Question 4

What happens to the liver and spleen with Beta

Answer 4

• both are enlarged
• Spleen is overworked b/c of hemolytic anemia and trying to clear everything
• Liver is trying to help and enlarging, could see Fe overload
• Major

Question 5

What are some consequences of Iron overload

Answer 5

• More likely to get infection
• Healing problems which could also lead to infection
• Ulcers on the ankles
• take out spleen, but very dangerous to do b/f the pt is 6y.o.
• Removal of spleen will make pt susceptible to encapsulated bacteria

Question 6

Why iron overload?

Answer 6

• Transfusion Iron (no excretion mech)
• Increased absorption b/c of anemia and signaling to make more RBC
• Iron overload in liver can lead to hepatocellular carcinoma from the cirrosis damage

Question 7

Hypercoaguable?

Answer 7

Membrane damage by alpha hemichromes and oxidant stress
Phosphatidylserine exposed to outside
–recognition site for cell removal during apoptosis
–increased thrombin production
-Increased plasma free Hgb
-Increased platelet activation (esp w/ stasis)
Thrombotic complication reduced with transfusion therapy

Question 8

Why variable presentation?

Answer 8

• Outcome depends on what the pt can make, any beta at all is better than none
• and ability to upregulate other froms of Hgb

Question 9

Peripheral Smear

Answer 9

Target Cells and basophilic stippling, hypochromatic

• means bm is cranking out new cells rapidly and the spleen is overworked b/c it would have otherwise clear these.
• With major will see nucleated RBC

Question 10

Diagnosis

Answer 10

Present with Tiredness, low MCV, normal RDW

• Normal or high iron
• HPLC and electrophoresis with beta to look for increased A2 and other conc of other Hgb’s