Anemia (Sideroblastic)

Definition

Definition of Anemia (Sideroblastic)
Sideroblastic anemia or sideroachrestic anemia is a disease in which the bone marrow produces ringed sideroblasts rather than healthy red blood cells (erythrocytes). It may be caused either by a genetic disorder or indirectly as part of myelodysplastic syndrome, which can evolve into hematological malignancies (especially acute myelogenous leukemia). In sideroblastic anemia, the body has iron available but cannot incorporate it into hemoglobin, which red blood cells need to transport oxygen efficiently.

Symptoms

Symptoms of Anemia (Sideroblastic)
Symptoms of sideroblastic anemia include skin paleness, fatigue, dizziness and enlarged spleen and liver. Heart disease, liver damage and kidney failure can result from iron buildup in these organs.

Causes

Causes of Anemia (Sideroblastic)
The primary pathophysiology of sideroblastic anemia is failure to completely form heme molecules, whose biosynthesis takes place partly in the mitochondrion. This leads to deposits of iron in the mitochondria that form a ring around the nucleus of the developing red blood cell. Sometimes the disorder represents a stage in evolution of a generalized bone marrow disorder that may ultimately terminate in acute leukemia.

1. Toxins: lead, copper or zinc poisoning
2. Drug-induced: ethanol, isoniazid, chloramphenicol, cycloserine, Oral Contraceptives
3. Nutritional: pyridoxine (Vitamin B6) or copper deficiency
4. Diseases: Rheumatoid arthritis, or multiple myeloma
5. Genetic: ALA synthase deficiency (X-linked, associated with ALAS2)

Diagnosis

Diagnosis of Anemia (Sideroblastic)
Sideroblastic anemia can be diagnosed through laboratory findings which can check the level of ferritin. Ferritin is a protein found in cells that stores and then releases iron, and protects against too much and too little iron in the blood. Hematocrit is also tested. Hematocrit is the amount of red blood cells in the blood, besides white blood cells, hemoglobin and platelets. The ability of blood to bind iron to transferrin, and the level of iron in the blood are also among the values measured to determine if the disease is present. Transferrin, like ferritin, also balances the level of iron in the blood. With sideroblastic anemia, transferrin levels are normal or low, but ferritin levels are high.

A blood film, where blood is smeared on a slide, allowed to dry, stained, then examined under a microscope, is also useful in helping to diagnose sideroblastic anemia. Red blood cells taken from the bone marrow and stained with Prussian Blue can also reveal the disease.

Treatment

Treatment of Anemia (Sideroblastic)
Occasionally, the anemia is so severe that support with transfusion is required. These patients usually do not respond to erythropoietin therapy. Some cases have been reported that the anemia is reversed or heme level is improved through use of moderate to high doses of pyrodoxine (Vitamin B6). In severe cases of SBA, bone marrow transplant is also an option with limited information about the success rate. Some cases are listed on MedLine and various other medical sites. In the case of isoniazid-induced sideroblastic anemia, the addition of B6 is sufficient to correct the anemia. Desferrioxamine is used to treat iron overload from transfusions. Bone Marrow Transplant (BMT) is the last possible treatment.

Prognosis

Prognosis of Anemia (Sideroblastic)
Sideroblastic anemias are often described as responsive or non responsive in terms of increased Hb level to pharmacological doses of vitamin B6.

1. Hereditary-80% are responsive, though the hematology does not revert completely to normal.
2. Primary acquired-40% are responsive, but the response may be slight and is usually suboptimal.
3. Secondary-60% are responsive, the response also depending on the effectiveness of the treatment of associated conditions.

Prevention

Prevention of Anemia (Sideroblastic)
Consult with your doctor.