Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
29 Cards in this Set
- Front
- Back
|
What is the definition of aplastic anemia?
|
Pancytopenia resulting from defectiive hematopoiesis. It is anemia with either transcytopenia or neutropenia.
|
|
|
What is the pathogenesis of this disease?
|
Stem cell failure due to intrinsic damage to stem cell or an immune reaction against stem cells.
|
|
|
What is the incidence? What is the peak incidence? Which continent is it more common in?
|
1000 new cases every year, peak incidence is ~ 30 years, and it is more common in Asia.
|
|
|
What is the etiology of the disease?
|
1) Idiopathic
2) Acquired 3) Congenital |
|
|
How can one acquire aplastic anemia?
|
It could be due to drugs, radiation (people who live close to nuclear reactors), chemicals, or viral infections.
|
|
|
What is the mechanism of drug acquired aplastic anemia?
|
1) Dose related mechanism- Chemotheraopy (kills bone marrrow so it wont be aplastic anemia unless the BM is recovering), sulfa, chloramphenicol.
2) Idiosyncratic mechanism chloramphenicol,indometacin,gold |
|
|
What chemicals can lead to aplastic anemia?
|
Benzenes, insecticides, hair dyes.
|
|
|
What viral infection can lead to aplastic anemia?
|
Hep A virus.
|
|
|
What does idiosyncratic mechanism mean?
|
It means it has to do with the way the drug works.
|
|
|
What are the clinical presentations of aplastic anemia?
|
Insidious/acute presentations. Symptoms include those related to anemia...weakness, pallor, neutropenia, and thrombocytopenia.
|
|
|
What does the neutropenia lead to?
|
Increased incidence of infections.
|
|
|
What does the thrombocytopenia lead to?
|
It leads to purpura, epistaxis (bleeding from the nose), givgival bleeding, GIT bleeding.
|
|
|
How do you diagnose AA? What do you find in the CBC and BM?
|
Anemic...normocytic/normochromic,
Reticulocyte count <1% Thrombocytopenia, leukopenia. The bone marrow is hypocellular. |
|
|
Why is the reticulocyte count so low?
|
The bone marrow can't over come the anemia because they don't have the stem cells needed.
|
|
|
What do you see in terms of fat cells and normal cells normally? What is the trend?
|
In normal patients there is an inverse ratio between fat cells and age. There is less fat in the young and as they grow older the more fat and less cells.
|
|
|
What do you observe at the age of 50?
|
You see an approximate fat:cell ratio of 50:50
|
|
|
What do you see in patients with aplastic anemia that is suggestive of the diagnosis?
|
You see many area of hypocellular marrow and this is suggestive of aplastic anemia. Again it is hypocellular because you don't have the stem cells to manufacture the cells.
|
|
|
What are the categories of aplastic anemia?
|
Severe AA : defined by presence of 2 of the following:
Neutriphils <500 Platelets <20,000 Reticulocytes <20,000 / <1% Super severe AA: Neutrophils <200 |
|
|
What are your chances of recovery, spontaneous or with treatment?
|
Low.
|
|
|
What are the chances of recovery if you have severe AA?
|
Higher.
|
|
|
What is the differential diagnosis in AA?
|
Acute Myeloid Leukemia or Myelodysplastic syndrome
|
|
|
What is myelodysplastic syndrome? What are the findings in BM and the peripheral blood?
|
Myelodysplastic syndrome is a stem cell disorder associated with distorted RBC, platelets, neutrophil precursor, caused by ineffective neutropeoisis...so the bone marrow is usually hypercellular but there is pancytopenia in the peripheral blood.
|
|
|
How do you treat this disorder?
|
You can treat AA supporotively by RBC transfusion, Platelet transfusion, and Aggressive antibiotics.
|
|
|
What is the definitive treatment of AA?
|
1) Immuno suppressive treatment
I. Anti thrombocytic globulin II. Cyclosporine 2) Allogeneic stem cell transplantation. |
|
|
What is anti thrombocytic globulin treatment?
|
It is a product that you get either from a horse or rabbit – take normal lymphoid cells from normal person, inject into horse/rabbit;
|
|
|
How does it work?
|
Rabbit/horse produces antibodies against the abnormal lymphocytes; collect the serum and give to person, and it should attack these abnormal (mostly t cells, not b cells) lymphocytes, hopefully killing them and letting stem cells recover from attack of t cells;
|
|
|
What is the problem with this treatment? What is it given in conjunction with?
|
There are a lot of allergic reactions that can occur with this treatment. The treatment is often given in conjunction with prednisone or cyclosporin (anti T cell agents).
|
|
|
What is the success rate of this treatment?
|
2/3 of patients show good response but 2/3 of these patients relapse and they need to be treated again.
|
|
|
What is the patient has severe AA?
|
You give them bone marrow transplants...If they are older and there is no matching transplant then you should give immunosuppressive therapy and if it doesn't work do allotransplant with all of its complications
|
