Module 2 - Microcytic-Hypochromic Anemias - Sideroblastic Anemia Flashcards
What heterogenous group makes up SA?
heterogeneous group of inherited and acquired disorders.
What characterizes SA?
anemia of varying severity and the presence of ringed sideroblasts in the bone marrow
What are ringed sideroblasts
-erythroblasts that have iron-laden mitochondria arranged in a circle around one-third or more of the nucleus
-these are red blood cells that have iron granules that have not been synthesized into hemoglobin.
Individuals with SA have increased levels of this.
Individuals with SA also have increased tissue levels of iron.
SA have various causes but they have this similarity.
ll have altered heme synthesis in the erythroid cells in bone marrow.
What are the different types of SA?
- Acquired sideroblastic anemias (ASAs)
- reversible sideroblastic anemias (reversible SAs),
- Hereditary (congenital) sideroblastic anemias
This is the most common SA, occur as a primary disorder with no known cause?
Acquired sideroblastic anemias (ASAs)
What are ASA’s associated with?
myeloproliferative or myeloplastic disorders such as myeloma, polycythemia vera, and leukemias.
This type of SA is secondary to conditions such as alcoholism, medication reactions, copper deficiency, and hypothermia.
reversible sideroblastic anemias (reversible SAs)
Reversible SA associated with alcoholism results from what?
nutritional deficiencies of folate.
What the hypothermia cause?
decreased heme synthesis and incorporation into hemoglobin.
This type of SA are rare and occur almost exclusively in males, supporting a recessive X-linked transmission.
Hereditary (congenital) sideroblastic anemias
Which type of SA occur almost exclusively in males?
Hereditary (congenital) sideroblastic anemias
What is the leading cause of primary ASA?
myelodysplastic syndrome (MDS), is a group of disorders of hematopoietic stem cells demonstrating abnormal growth or cell characteristics.7
What are the clinical manifestations of SA anemias?
- moderate to sever
- Hgb 40-100g/L
- cardio and resp symptoms
- signs of overload - hemochromatosis
- mild to moderate enlargement of liver (hepatomegaly) and spleen (splenomegaly)
- Liver function normal or mildly affected
- skin may be bronzed tinted
-**infants and children - growth and development impairment if severely affected
How is SA diagnosed?
bone marrow biopsy
What are treatments?
- identification of cause
- supportive treatment(transfusion)
- alchohol abuse and pyroxidine antagonist causes - shows complete response to pyroxidine. Other etiologies does not show same improvement.
What is the initial treatment for hereditary SA and how effective is it?
pyroxidine therapy, effective 1/3 of individuals but structural abnormalities does not disappear.
What happens to hgb with treatment of pyroxidine?
level can increase but stabilize at less than normal levels
What if no response to pyroxidine?
Need blood tranfusion
What is treatment for iron overload?
iron depletion therapy to minimize organ damage
What is used on individuals with mild to moderate anemia without other complications?
Phlebotomy
What is used for severe iron overload?
the use of deferoxamine, an iron-chelating agent, reduces excess iron levels.
What type of SA will less likely to respond to pyridoxine
Individuals with acquired SA
What are some of the recent treatments for SA’s
- prolonged administration of erythropoietin and stem cell transplant.
