Sideroblastic Anemia

Sideroblastic anemia is a term used to describe a group of rare blood disorders characterized by the bone marrow's inability to manufacture normal red blood cells.  Although some sideroblastic anemias are hereditary, most are acquired and are associated with drugs (alcohol, isoniazid, chloramphenicol, cytotoxic agents, and other Vit B6 antagonists), heavy metals (lead), and various hematologic, neoplastic and inflammatory diseases.  Ethanol abuse is the most common cause, but the cause cannot always be identified. Sideroblastic anemia is one of the principal types of iron-utilization anemias.  Abnormal, iron-saturated red cells are present in the blood of people who have this disease.  Although the iron circulates normally from the plasma to the bone marrow, where new red blood cells are created, it is not properly incorporated into new red blood cells.

Hereditary Sideroblastic Anemia. The hereditary form is an X-linked recessive trait with variable expression.  Hereditary sideroblastic anemias are usually small (microcytic) and of poor color (hypochromic) and thus must be distinguished from iron deficiency and thalassemia.

Acquired Sideroblastic Anemia. Acquired sideroblastic anemia may be cured when the condition that causes it is treated or removed.  If the cause of a patient's anemia cannot be determined, blood transfusions may be necessary.  Medications are prescribed to stimulate excretion or excess iron that accumulates as a result of these transfusions.

Causes and Development

Sideroblastic anemia is also associated with:

• Leukemia
• Lymphoma ( cancer of the lymph glands)
• Myeloma (cancer of the bone marrow)
• Rheumatoid arthritis
• Other inflammatory diseases.

Signs and Symptoms

Symptoms of sideroblastic anemia are the same as symptoms of the disease that causes the condition, as well as anemia.

Complications

Possible complications of sideroblastic anemia include:

• Congestive heart failure
• Diabetes mellitus
• Enlargement of the liver and spleen
• Formation of liver nodules and scar tissue
• Irregular heartbeat
• Recurring inflammation of the sac that surrounds the heart
• Secondary hypopituitarism (dwarfism)
• Skin darkening
• Underactivity of the thyroid gland (hypothyroidism).

Sideroblastic anemia of unknown origin may lead to leukemia.  It may take as long as 10 years for this disease progression to take place.