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1. Sideroblastic Anemias

2. Four major problems can manifest during this
delicate process:
• •Qualitative defects of globin chain synthesis result in
hemoglobinopathies such as sickle cell disease.
• •Quantitative defects of globin chain synthesis result in
hemoglobinopathies such as thalassemia.
• •Defects in synthesis of the heme portion result in porphyrias.
• •Defects involving incorporation of iron into the heme molecule
result in sideroblastic anemias.

3. Sideroblastic anemias, a group of
heterogenous disorders, produce a
common defect—failure to use iron
in hemoglobin (Hb) synthesis,
despite the availability of adequate
iron stores.
Sideroblastic Anemias

4. • Sideroblastic anemia or sideroachrestic anemia is a disease
in which the bone marrow produces ringed sideroblasts
rather than healthy red blood cells (erythrocytes).[1]
It may
be caused either by a genetic disorder or indirectly as part of
myelodysplastic syndrome,[2]
which can evolve into
hematological malignancies (especially
acute myelogenous leukemia).

5. •In sideroblastic anemia, the body has iron available
but cannot incorporate it into hemoglobin, which
red blood cells need to transport oxygen efficiently.
•Sideroblasts are atypical, abnormal nucleated
erythroblasts (precursors to mature red blood cells)
with granules of iron accumulated in perinuclear
mitochondria.[3]
Sideroblasts are seen in aspirates of
bone marrow.

6. This is a refractory anaemia with
hypochromic cells in the peripheral blood
and increased marrow iron;
It is defined by the presence of many
pathological ring sideroblasts in the bone
marrow
Sideroblastic Anemias

7. Sideroblastic Anemias
•Disease that interfere with production of heme
•May be microcytic and hypochromic
•Iron abundant in marrow (in contrast to IDA)
•Prussian stain shows normoblasts with iron deposits
in mitochondria surrounding nucleus
•Ringed sideroblasts are hallmark

8. http://www.som.tulane.edu/classware/pathology/Krause/Anemias/Sid_RS.HTML
Example of ringed sideroblasts

9. Prussian blue iron stain on bone marrow aspirate
Normal

10. Eitology of Sideroblastic anemias
•Hereditary
• X-linked (isolated / genetic syndromes)
• Autosomal
•Acquired
• Drugs (chloramphenicol, isoniazid)
• Heavy metals (e.g. lead)
• Chemotherapeutic agents
• Clonal

11. Signs and symptoms
 nonspecific clinical effects, which may exist for several years before being
identified. Such effects include
 anorexia,
 fatigue,
 weakness,
 dizziness,
 pale skin and
 mucous membranes and, occasionally,
 enlarged lymph nodes.
 Heart and liver failure may develop from excessive iron accumulation in these
organs, causing dyspnea, exertional angina, slight jaundice, and
hepatosplenomegaly.
 Hereditary sideroblastic anemia is associated with increased GI absorption of iron,
causing signs of hemosiderosis. Additional symptoms in secondary sideroblastic
anemia depend on the underlying cause.

12. Diagnosis
 CBC: Microscopic examination of blood shows hypochromic or
normochromic, and slightly macrocytic, erythrocytes.
 Bone Marrow: Ringed sideroblasts on microscopic examination of
bone marrow aspirate, stained with Prussian blue or alizarin red
dye, confirm the diagnosis.
 Red blood cell (RBC) precursors may be megaloblastic, with
anisocytosis (abnormal variation in RBC size) and poikilocytosis
(abnormal variation in RBC shape).
 Unlike iron deficiency anemia, sideroblastic anemia lowers Hb and
raises serum iron and transferrin levels. In turn, faulty Hb
production raises urobilinogen and bilirubin levels. Platelet and
leukocyte levels remain normal, but thrombocytopenia or
leukopenia occasionally occurs.

13. Treatment
 The underlying cause determines the type of treatment.
 Hereditary form
 Hereditary sideroblastic anemia usually responds to several weeks of treatment with
high doses of pyridoxine (vitamin B6).
 Primary acquired form
 Elderly patients with sideroblastic anemia—most commonly the primary acquired form—
are less likely to improve quickly and are more likely to develop serious complications.
Deferoxamine may be used to treat chronic iron overload in selected patients.
 Carefully cross-matched transfusions (providing needed Hb) or high doses of androgens
are effective palliative measures for some patients with the primary acquired form of
sideroblastic anemia. However, this form is essentially refractory to treatment and
usually leads to death from acute leukemia or from respiratory or cardiac complications.
 Secondary acquired form
 The secondary acquired form generally subsides after the causative drug or toxin is
removed or the underlying condition is adequately treated. Folic acid supplements may
also be beneficial when concomitant megaloblastic nuclear changes in RBC precursors
are present.

14. Anemia in context of lead poisoning
 Normocytic and normochromic
 Chronic exposure may lead to microcytic,
hypochromic anemia
◦ Also results in hypoplasia of bone marrow
◦ Basophilic stippling seen
 Reticulocyte count can be elevated
◦ Due to hemolytic component
◦ Can be seen by impairment of pentose-phosphate shunt
by lead, leading to oxidant-sensitive stress

15. Sideroblastic anemia
• Very rare in Pediatrics
• Heterogeneous group of disease
• Hereditary (deficiency of an enzyme or enzyme activity required for Hb
production)
• Acquired: drugs, toxins (lead), malignancy, idiopathic
• In bone marrow: Ringed sideroblasts (iron laden mitochondria)
15

16. Summary of sideroblastic anemias
•SA develops when entry of iron into mitochondria
of developing RBCs is blocked
•Iron incorporation into heme blocked by any
deficiency of enzymes of heme synthetic pathway
•Iron accumulates in mitochondria in deposits
around nucleus, called ringed sideroblasts
•Iron studies – elevated total iron, variable iron
binding capacity, normal to decreased transferrin
saturation, and increased ferritin

17. Lead poisoning