Iron avidity is a complication of phlebotomy. Defined as an ardent desire or craving for iron, this condition represents overcorrection of iron overload. Clinically, patients will have low or normal levels of serum ferritin the storage form of iron , yet have elevated transferrin saturation the mobilized form of iron.
Because elevated transferrin saturation is an initial indicator of hereditary hemochromatosis, these laboratory findings may be difficult to reconcile, leading to an underappreciation of iron avidity. If iron avidity occurs, it may have an associated anemia requiring evaluation for a gastrointestinal source of bleeding. Paradoxically, the treatment of iron avidity in patients with hereditary hemochromatosis may include iron supplementation until transferrin saturation and serum ferritin levels return to normal; alternatively, patients can be observed for spontaneous correction.
Waivers for blood centers may be granted to allow hereditary hemochromatosis blood to be used for transfusions; therapeutic phlebotomy may be performed free of charge with a physician's order. Food and Drug Administration, but accepts blood donations from persons with hereditary hemochromatosis only at certain locations. Iron balance normally is maintained tightly; the daily dietary amount absorbed matches the amount lost each day within sloughed cells, or approximately 1 mg.
The American Association for the Study of Liver Diseases AASLD recommends no meal selection adjustments, because 4 mg per day of dietary iron intake is small compared with the amount of iron that is removed with phlebotomy mg per week. Elevated iron stores can impair effective hepcidin bactericidal activity. Preventive Services Task Force recommend against universal genetic screening for hereditary hemochromatosis.
All first-degree relatives of persons with hereditary hemochromatosis should be screened. Children who have one parent with hereditary hemochromatosis should not undergo genetic testing until after the other parent is tested. If the other parent is normal i. Hepatocellular carcinoma accounts for approximately 30 percent of deaths in patients with hereditary hemochromatosis. Hepatocellular carcinoma very rarely occurs in patients without cirrhosis, highlighting the importance of early detection and treatment of iron overload Figure 2 Patients with hereditary hemochromatosis and cirrhosis should have screening ultrasonography every six to 12 months.
If a lesion smaller than 1 cm is found on the liver, the screening interval changes to every three to six months. If the lesion is 1 cm or greater, referral to a gastroenterologist is recommended for four-phase multidetector computed tomography and biopsy. Data Sources: A PubMed search was completed using the key term hemochromatosis. The search included meta-analyses, randomized controlled trials, clinical trials, practice guidelines, genetics, symptoms, therapy, and reviews.
Preventive Services Task Force. Search date: May Already a member or subscriber? Log in. Interested in AAFP membership? Learn more. Address correspondence to Brian K. Reprints are not available from the authors. The opinions and assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the U. Air Force Medical Department or the U.
Air Force at large. Department of Veterans Affairs, for their assistance with this manuscript. Andrews NC. Disorders of iron metabolism [published correction appears in N Engl J Med. Balancing acts: molecular control of mammalian iron metabolism. Relation of hemochromatosis with hepatocellular carcinoma: epidemiology, natural history, pathophysiology, screening, treatment, and prevention.
Med Clin North Am. Effect of dietary iron deficiency or excess on the induction of mammary carcinogenesis by 1-methylnitrosourea. Promotion of dimethylbenz[a] anthracene-initiated mammary carcinogenesis by iron in female Sprague-Dawley rats.
Dietary iron and heme iron intake and risk of breast cancer: a prospective cohort study [published correction appears in Cancer Epidemiol Biomarkers Prev. Cancer Epidemiol Biomarkers Prev. Analysis of aluminium content and iron homeostasis in nipple aspirate fluids from healthy women and breast cancer-affected patients. J Appl Toxicol. Significance of left atrial contractile function in asymptomatic subjects with hereditary hemochromatosis. Am J Cardiol. Oxidative stress in asymptomatic subjects with hereditary hemochromatosis.
Am J Hematol. Iron-overload cardiomyopathy: pathophysiology, diagnosis, and treatment. J Card Fail. Iron in the heart. Etiology and clinical significance. Am J Med. Long-term survival in patients with hereditary hemochromatosis. Excess alcohol greatly increases the prevalence of cirrhosis in hereditary hemochromatosis. Diagnosis and management of hemochromatosis: practice guideline by the American Association for the Study of Liver Diseases.
Nemeth E, Ganz T. The role of hepcidin in iron metabolism. Acta Haematol. A novel MHC class I-like gene is mutated in patients with hereditary haemochromatosis. Nat Genet. European Association for the Study of the Liver. J Hepatol. Hereditary hemochromatosis: time for targeted screening. Ann Intern Med. Iron Disorders Institute. Accessed November 18, Online Mendelian Inheritance in Man gene database. Accessed April 5, Iron-overload-related disease in HFE hereditary hemochromatosis.
A survey of 2, patients with hemochromatosis: symptoms and response to treatment. Association between iron overload and osteoporosis in patients with hereditary hemochromatosis. Osteoporos Int. Bone mineral density in men with genetic hemochromatosis and HFE gene mutation. Centers for Disease Control and Prevention. Hemochromatosis iron storage disease.
Testing protocol. Biological variability of transferrin saturation and unsaturated iron-binding capacity. Diagnosis of hemochromatosis in young subjects: predictive accuracy of biochemical screening tests. Noninvasive prediction of fibrosis in CY homozygous hemochromatosis. HFE genotype in patients with hemochromatosis and other liver diseases. Serum ferritin level predicts advanced hepatic fibrosis among U. Noninvasive prediction of cirrhosis in CY-linked hemochromatosis.
Hereditary hemochromatosis: update for Phlebotomy treatment. Garrison C. Iron avidity: update on report. Iron Disorders Institute nanograms: December Food and Drug Administration. Guidance for industry: variances for blood collection from individuals with hereditary hemochromatosis.
August American Red Cross. Eligibility criteria by alphabetical listing. Ashrafian H. Hepcidin: the missing link between hemochromatosis and infections. Infect Immun. American Academy of Family Physicians. What should you know? Screening for hereditary hemochromatosis: a systematic review for the U.
Phenotypic expression of hereditary hemochromatosis: what have we learned from the population studies? Curr Gastroenterol Rep.
Expert Rev Hematol. Management of hepatocellular carcinoma: an update. Reversibility of hepatic fibrosis in treated genetic hemochromatosis: a study of 36 cases. Long-term survival analysis in hereditary hemochromatosis. This content is owned by the AAFP.
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Contact afpserv aafp. Want to use this article elsewhere? Get Permissions. Read the Issue. Sign Up Now. Next: Guillain-Barre Syndrome. Feb 1, Issue. Hereditary Hemochromatosis. A 14 — Serum ferritin levels should guide phlebotomy frequency, with a goal of 50 to ng per mL Enlarge Print Table 1.
Table 1. Enlarge Print Table 2. Hereditary Hemochromatosis Subtype Classification System Type 1—classical HFE gene mutations resulting in a cysteine-to-tyrosine substitution at amino acid CY or an aspartate-to-histidine substitution at amino acid 63 H63D Type 2—nonclassical also known as juvenile hemochromatosis resulting from mutations in iron regulatory protein, hemojuvelin HJV gene Type 3—nonclassical resulting from mutations in the transferrin receptor protein 2 TFR2 gene Type 4—nonclassical resulting from mutations in the iron exporter, ferroportin SLC40A1 gene note : Type 4 is the only type that is inherited as an autosomal dominant condition; types 1 through 3 are inherited as autosomal recessive conditions.
Table 2. Enlarge Print Table 3. Table 3. Diagnosis of Hereditary Hemochromatosis in Adults Figure 1. Management of Homozygous Hereditary Hemochromatosis Figure 2. Enlarge Print Table 4. Table 4. Iron poisoning in children is almost always acute, occurring in children who ingest their parents' iron supplements. In some cases, acute iron poisoning can be fatal. A person who has mutations in the HFE gene is diagnosed with hereditary hemochromatosis.
However, while many people who have hemochromatosis will have no symptoms for their entire life, others will start to develop symptoms such as joint pain, abdominal pain, and weakness in their 30's or 40's. Men are affected more often than women because women lose blood during their reproductive years through menstruation.
Iron overload may also occur in people who have hemosiderosis and in those who have had repeated transfusions. This may occur with sickle cell anemia, thalassemia major, or other forms of anemia. The iron from each transfused unit of blood stays in the body, eventually causing a large buildup in the tissues. Some persons with alcoholism and with chronic liver disease also develop iron overload. Recent blood transfusions can affect test results as can iron injections or transfused iron.
Multiple blood transfusions can sometimes lead to iron overload. However, the tests are usually not used to assess these conditions. TIBC measures the total amount of iron that can be bound by proteins in the blood. Since transferrin is the primary iron-binding protein, the TIBC test is a good indirect measurement of transferrin availability—the amount of transferrin that is available to bind to iron.
In healthy individuals, transferrin is one-third saturated with iron. This means that there is about two-thirds held in reserve.
In iron deficiency, all of the stored iron is used and the body tries to compensate by producing more transferrin to increase iron transport. While the serum iron level continues to decrease, the transferrin level increases.
Thus, the amount of transferrin available to bind iron TIBC increases and the amount of transferrin saturated with iron i. Transferrin is a protein that may decrease during any inflammatory process and is referred to as a negative acute phase reactant. Chronic inflammation, infections, and malignancies may cause changes in transferrin levels. Yes, there are numerous causes of anemia.
However, iron deficiency is one of the most common. If iron tests rule out iron deficiency, another source for the anemia must be found. See the article on Anemia for more on this.
Devkota, B. Iron-Binding Capacity. Medscape Drugs and Diseases. Accessed on May Paruthi, S. Transferrin Saturation. Harper, J. Iron Deficiency Anemia. Transferrin, Serum. Mayo Clinic Mayo Medical Laboratories. Nader Rifai. Pg Wintrobe's Clinical Hematology.
Corbett, JV. Stamford, Conn. Frey, Rebecca J. Iron Tests. Practice guideline development task force of the College of American Pathologists.
Boston University Medical Center. Community Outreach Health Information System. Lyon, Elaine and Frank, Elizabeth L. Clinical Chemistry Jul Pagana, K. Pp Clarke, W. Pp 43, Wu, A. Louis, MO. Dugdale III, D. Updated February Total Iron Binding Capacity.
MedlinePlus Medical Encyclopedia [On-line information]. Accessed June Modified March About Iron. Iron Disorders Institute [On-line information]. Updated August Dietary Supplement Fact Sheet: Iron.
Rathz, D. Toxicity, Iron. Chen, Y. Updated April Philadelphia: , Pg Gersten, T. Updated February 8. Total iron binding capacity. Accessed April Updated October 4. Medscape Reference [On-line information].
Update March. Yamanishi, H. Clinical Chemistry v 49 1 [On-line information]. S6 Pagana, K. Also Known As.
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