Why is thalassemia microcytic

Next Chapter. Damon L. The Thalassemias. Papadakis M. Maxine A. Papadakis, et al. Current Medical Diagnosis and Treatment McGraw Hill; Accessed November 12, The thalassemias. McGraw Hill. Download citation file: RIS Zotero. Reference Manager. Autosuggest Results. Positive family history. Lifelong personal history of microcytic anemia. Normal or elevated red blood cell count. In beta-thalassemia, elevated levels of hemoglobin A 2 or F.

Subscribe: Institutional or Individual. Username Error: Please enter User Name. The diagnosis is usually one of exclusion. Anemia of chronic disease can be caused by chronic infections or inflammatory processes. Increased levels of cytokines cause a decrease in erythropoietin production, a decreased response to erythropoietin, and interference with iron metabolism.

The anemia is usually mild and not progressive. Additionally, although serum iron levels are decreased in anemia of chronic disease similar to iron deficiency anemia , ferritin levels are increased because ferritin is an acute phase reactant.

Already a member or subscriber? Log in. Interested in AAFP membership? Learn more. S, Minneapolis, MN e-mail: michele. Reprints are not available from the author.

Hematologic diseases. In: Wallach J. Interpretation of Diagnostic Tests. Boston, Mass. Richardson M. Microcytic anemia [published corrections appear in Pediatr Rev. Pediatr Rev. Assessing the iron status of populations. Accessed June 7, Beutler E, Waalen J. The definition of anemia: what is the lower limit of normal of the blood hemoglobin concentration?

Classification of anemia for gastroenterologists. World J Gastroenterol. Prevalence of anemia in persons 65 years and older in the United States: evidence for a high rate of unexplained anemia. Thomas C, Thomas L. Anemia of chronic disease: pathophysiology and laboratory diagnosis. Lab Hematol. Jain S, Kamat D. Evaluation of microcytic anemia.

Clin Pediatr Phila. Hershko C, Skikne B. Pathogenesis and management of iron deficiency anemia: emerging role of celiac disease, helicobacter pylori , and autoimmune gastritis. Semin Hematol. Adamsom J, Longo D. Anemia and polycythemia. Harrison's Principles of Internal Medicine. Evaluation of clinical pallor in the identification and treatment of children with moderate and severe anaemia [published correction appears in Trop Med Int Health. Trop Med Int Health.

Validity assessment of nine discriminant functions used for the differentiation between iron deficiency anemia and thalassemia minor. J Trop Pediatr. Discrimination indices as screening tests for beta-thalassemic trait. Ann Hematol. Most reliable indices in differentiation between thalassemia trait and iron deficiency anemia. Pediatr Int. Brugnara C. Iron deficiency and erythropoiesis: new diagnostic approaches.

Clin Chem. Recommendations to prevent and control iron deficiency in the United States. Centers for Disease Control and Prevention. Waterbury L. Principles of Ambulatory Medicine. Baltimore, Md. Laboratory diagnosis of iron-deficiency anemia: an overview [published correction appears in J Gen Intern Med. J Gen Intern Med. Ferritin for the clinician. Blood Rev. Investigating iron status in microcytic anaemia. Iron deficiency anemia [published correction appears in Am Fam Physician.

Am Fam Physician. Can patient characteristics predict the outcome of endoscopic evaluation of iron deficiency anemia: a multiple logistic regression analysis. Gastrointest Endosc. A prospective, multidisciplinary evaluation of premenopausal women with iron-deficiency anemia. Am J Gastroenterol. Benefit of concomitant gastrointestinal and gynaecological evaluation in premenopausal women with iron deficiency anaemia. Aliment Pharmacol Ther. The diagnostic plot: a concept for identifying different states of iron deficiency and monitoring the response to epoetin therapy.

Med Oncol. Wengrovitz AM. In general, it is best delivered by pumps that allow continuous infusion of this medication via a subcutaneous route. Recently deferisirox, an orally bioavailable iron chelator became available. Beyond regular transfusion therapy and iron chelation to deal with the resulting iron overload, few definitive therapies exist. Bone marrow transplantation is potentially curative, although there are a number of limitations to the widespread use of such therapies.

One needs to find an appropriate donor and there are a number of morbidities associated with such therapies. This includes graft-versus-host disease and graft rejection. There are a number of other therapies that are currently under experimental investigation. While early trials of these therapies are showing some promise, there are many limitations to address before such therapies can become more widely used.

These therapies are currently either in the early stages of development or in early clinical trials. Patients who will undergo splenectomy should be vaccinated against polysaccharide encapsulated organisms including Streptococcus pneumoniae, Haemophilus influenzae type b, and Neisseria meningitides.

Splenectomized patients have an increased risk of acquiring these infections and so appropriate antibiotic coverage may be necessary should such patients become ill. Thalassemia patients can also have a number of endocrine complications.

In particular, impaired growth and hormone deficiencies can be a major problem. The use of hormone replacement can have a valuable role in treating these patients, but this needs to be done under the guidance of an endocrinologist with appropriate expertise.

The bone disease seen in thalassemia can also be improved with the use of calcium supplementation, vitamin D, and bisphosphonates, although more data is needed on the use of these agents and they should be tailored for the individual patient, depending upon the extent of bone disease present.

With regular transfusion therapies and appropriate iron chelation, patients with thalassemia can live into adulthood. Women with thalassemia can even successfully carry pregnancies to term. All patients with these diseases need to be followed by multiple specialists including hematologists, cardiologists, endocrinologists, psychologists, and others to properly manage the various problems and issues that arise from living with thalassemia.

Recent studies of patients with thalassemia intermedia, suggest that a large fraction of patients may be able to survive without major morbidity, even if regular transfusions are stopped.

A major issue in children is ensuring that they are able to reach their maximal growth potential and therefore transfusions may have a role to support growth. Subsequently many patients may not require regular transfusions. Trials of halting transfusions in specific patients with thalassemia may be useful, although these need to be done carefully and with the guidance of a hematologist with expertise in this area.

Future clinical studies will likely address in more depth whether there may be benefit to reducing regular transfusions in a subset of patients who currently receive such therapy.

This in turn results in an anemia from hemolysis and destruction of these red blood cells, as well as some ineffective erythropoiesis from precipitation of HbH in precursors. In order to compensate for this increased destruction of red blood cells, there is an expansion of erythroid precursors within the marrow and in other extramedullary organs, including the spleen.

This results in death of these cells from toxicity and the resulting unfolded protein responses, which leads to ineffective erythropoiesis.

As a result of this, there is an accumulation of erythroid precursors in the bone marrow, as well as at other sites in the body including the spleen, liver, and other extramedullary organs.

The expansion of erythroid precursors within the bone marrow is responsible for the consequent bone disease. Many patients with thalassemia will have hepatosplenomegaly as a result of extramedullary hematopoiesis, which should be assessed on clinical exam.

Furthermore, signs of medullary expansion such as frontal bossing can be helpful in assessing the severity of thalassemia. It is also important to carefully examine growth charts of children with thalassemia, which may affect a decision to transfuse the patient more frequently to support growth.

As noted above, genetic testing to delineate specific mutations may be useful for predicting the clinical course in certain patients. However, limitations exist to make genotype and phenotype correlations. Recent studies suggest that other genetic variation may contribute to the variation in clinical phenotype and therefore in the future, such testing may be of benefit to patients with thalassemia. Hematol Oncol Clin North Am.