Sideroblastic anemia

Defective heme biosynthesis within RBC precursors

Etiologies: hereditary/X-linked (ALAS2mutations), idiopathic (MDS-RARS), reversible (alcohol, lead, isoniazid, chloramphenicol, copper deficiency, hypothermia)

Special clinical manifestations: hepatosplenomegaly, iron overload syndromes

Dx: review social, work, & TB hx; can be microcytic, normocytic, or macrocytic;

variable pop of hypochromic RBCs; ↑ Fe, nl TIBC, ↑ ferritin, basophilic stippling,

RBC Pappenheimer bodies (Fe-containing inclusions), ring sideroblasts (w/ iron-laden mitochondria) in BM

Treatment: treat reversible causes; trial of pyridoxine, supportive transfusions for severe anemia; high-dose pyridoxine for some hereditary cases