Last Updated on
A secondary iron overload is to excessive iron absorption, repeated blood transfusions due oral or excessive supply of iron, typically in patients with disorders of erythropoiesis. The diagnosis is made by determining the iron metabolism parameters (ferritin, transferrin saturation). The treatment is usually in the iron chelation.
A secondary iron overload is to excessive iron absorption, repeated blood transfusions due oral or excessive supply of iron, typically in patients with disorders of erythropoiesis. The diagnosis is made by determining the iron metabolism parameters (ferritin, transferrin saturation). The treatment is usually in the iron chelation. Etiology secondary iron overload typically occurs in patients with hemoglobinopathies Innate hemolytic anemias myelodysplasia iron overload is due to the following mechanisms (e.g., sickle cell anemia, thalassemia, sideroblastäre anemias.): Increased iron absorption Exogenous supply of iron for the treatment of anemia Repeated transfusions (each packed red blood cells provides about 250 mg iron; in transfusion of more than about 40 units, there is a significant deposition in tissues) the increased iron absorption in patients with ineffective erythropoiesis can be partially explained on the secretion of Erythroferron [ERDF] by erythroid precursors, which hepcidin (an inhibitor of iron uptake ) suppressed. Patients with hemoglobinopathies and congenital hemolytic anemias reach today usually adulthood, so that complications due to iron overload occur frequently and are clinically significant. In these patients, iron overload, the heart, liver and endocrine organs attacks, frequent cause of death. The survival can be prolonged by removal of excess iron. Diagnostic measurement of serum ferritin, and iron and transferrin saturation patients with impaired erythropoiesis should be examined for a secondary iron overload that is diagnosed by the determination of the serum ferritin, serum iron and transferrin saturation. Therapy Usually iron chelation with deferasirox or deferoxamine or occasionally with deferiprone Some patients can be treated with blood-letting and a Erythropoetingabe to obtain erythropoiesis. Since a bloodletting worsened anemia, it is not recommended numerous patients (z. B. those with a hemoglobin level <10 g / dL or those who are transfusion-dependent or who develop symptoms of anemia after blood-letting). These patients are treated with iron chelators. By treating a transferrin saturation <50% should be achieved. For iron chelation deferoxamine is used traditionally. It is iv over a slow subcutaneous infusion overnight via a portable pump system in 5 to 7 nights per week or more than one given an infusion over 24 hours. (Editor's note: Alternatively, it may by 2 times daily s.c. bolus doses may be administered.) The dose is 1 to 2 g in adults and 20 to 40 mg / kg in children. However, the application of this therapy is complex and requires an unusually high expenditure of time of the patient, resulting in a lack of compliance result. Major side effects include hypotension, gastrointestinal disorders and anaphylaxis (acute) and visual acuity and hearing loss (chronic use). Exjade, an oral chelating agent is an effective and increasingly more frequently used alternative to deferoxamine. Deferasirox reduced iron levels and prevents or delays the onset of complications of iron overload. The initial dose is 20 mg / kg p.o. once a day. Patients are monitored monthly at a dose of up to 30 mg / kg once daily. Treatment can be interrupted if serum ferritin is <500 ng / ml. Adverse effects (occurring in about 10% of patients) may include nausea, abdominal pain, diarrhea and rash. There may be an impaired liver and kidney function; Liver and kidney function should be determined at regular intervals (eg., Monthly, sometimes more often in patients at high risk). Deferiprone, another oral iron chelator, is indicated for the treatment of patients with transfusional iron overload by a thalassemia syndrome when the chelation therapy with deferasirox or deferoxamine is inadequate. The initial dose is 25 mg / kg p.o. 3 times a day. The maximum dose is 33 mg / kg P.L. 3 times a day. The absolute neutrophil count is charged weekly to locate neutropenia (which precedes a agranulocytosis). The ferritin in the serum is measured every 2 to 3 months; the treatment is temporarily interrupted when the values ??are consistent <500 g / l.