PEDBASE.org - The Pediatric Database - Detailed information of SIDEROBLASTIC ANEMIA

SIDEROBLASTIC ANEMIA

DEFINITION:

A heterogeneous group of disorders characterized by the ab normal utilization of iron resulting in a microcytic anemia.

EPIDEMIOLOGY:

incidence: ?
age of onset:
- childhood
risk factors:
- see below

PATHOGENESIS:

1. Classification of Sideroblastic Anemias

1. Hereditary

1. X-linked

2. Autosomal Recessive

2. Acquired

1. Idiopathic

2. Secondary

1. Drugs

alcohol, chloramphenicol, cytotoxic drugs (aza-thioprine, nitrogen mustard), isoniazid, lead

2. Diseases

1. Hematologic

hemolytic anemia, leukemia, megalobastic anemia

2. Inflammatory

autoimmune disorders, polyarteritis nodosa, rheumatoid arthritis

3. Neoplastic

Hodgkin's Lymphoma, Non-Hodgkin's Lymphoma

2. Pathogenesis

in Sideroblastic Anemia, there appears to be an inadequate or abnormal utilization of intracellular iron for hemoglobin synthesis despite adequate or increased amounts of iron within the mitochondria of RBC precursors

CLINICAL FEATURES:

1. Anemia

mild to severe
tends to be mild during childhood becoming more severe and refractory to treatment in adulthood
complications
1. Extramedullary Hematopoiesis
- hepatosplenomegaly (hepatomegaly)
2. Hemosiderosis
1. Cardiomyopathy

arrhythmias, congestive heart failure, recurrent pericarditis
2. Gastrointestinal

hepatic fibrosis and cirrhosis
3. Endocrinopathies

diabetes mellitus; secondary hypopituitarism, hypoparathyroidism, hypothyroidism
4. Cutaneous

darkening of the skin due to iron-stimulated melanin production

INVESTIGATIONS:

1. Serum

1. CBC

hypochromic, microcytic anemia

2. Smear

marked anisocytosis and poikilocytosis

3. Iron Studies

elevated serum ferritin
elevated serum iron
decreased (or normal) transferrin (TIBC)

2. Bone Marrow

erythroid hyperplasia
course hemosiderin granules (containing iron), form a peri-nuclear ring within the normoblasts and these cells are called "ringed sideroblasts" - increased in the bone marrow of patients with Sideroblstic Anemia