 Micrograph of hemosiderosis. Liver biopsy. Iron stain. |
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| ICD-10 | R79.0 |
|---|---|
| ICD-9 | 790.6 |
| DiseasesDB | 5581 |
| MeSH | D019190 |
In medicine, iron overload (also known as haemochromatosis) indicates accumulation of iron in the body due to any cause.
Contents |
Terminology
Historically, the term "haemochromatosis" was initially used to refer to what is now more specifically called haemochromatosis type 1 (or HFE-related hereditary haemochromatosis). The term is currently used more broadly to refer to any form of iron overload, thus requiring specification of the cause. The term haemosiderosis is used to indicate the pathological effect of iron accumulation in any given organ, which mainly occurs in the form of haemosiderin; sometimes the simpler term siderosis is used in its stead. The terms haemosiderosis and siderosis tend to be used when iron accumulation occurs only in a specific organ (such as the lung) as opposed to the whole body in haemochromatosis.
Clinical presentation
Organs commonly affected by haemochromatosis are the liver, heart and endocrine glands.[1]
Causes
The causes can be distinguished between primary cases (genetically determined) and less frequent secondary cases (acquired during life).[2]
Primary haemochromatosis
The fact that most cases of haemochromatosis were inherited was well known for most of the 20th century, though they were incorrectly assumed to depend on a single gene.[3] The overwhelming majority actually depend on mutations of the HFE gene discovered in 1996, but since then others have been discovered and sometimes are grouped together as "non-classical hereditary haemochromatosis"[4], "non-HFE related hereditary haemochromatosis".[5], or "non-HFE haemochromatosis".[6]
| Description | OMIM | Mutation |
| haemochromatosis type 1: "classical"-haemochromatosis | 235200 | HFE |
| Haemochromatosis type 2A: juvenile haemochromatosis | 602390 | haemojuvelin ("HJV", also known as RGMc and HFE2) |
| Haemochromatosis type 2B: juvenile haemochromatosis | 606464 | hepcidin antimicrobial peptide (HAMP) or HFE2B |
| Haemochromatosis type 3 | 604250 | transferrin receptor-2 (TFR2 or HFE3) |
| Haemochromatosis type 4/ African iron overload |
604653 | ferroportin (SLC11A3/SLC40A1) |
| Neonatal haemochromatosis | 231100 | (unknown) |
| Acaeruloplasminemia (very rare) | 604290 | caeruloplasmin |
| Congenital atransferrinaemia (very rare) | 209300 | transferrin |
| GRACILE syndrome (very rare) | 603358 | BCS1L |
Most types of hereditary haemochromatosis have autosomal recessive inheritance, while type 4 has autosomal dominant inheritance.[7]
Secondary haemochromatosis
- Severe chronic haemolysis of any cause, including intravascular haemolysis and ineffective erythropoiesis (haemolysis within the bone marrow).
- Multiple frequent blood transfusions (either whole blood or just red blood cells), which are usually needed either by individuals with hereditary anaemias (such as beta-thalassemia major, sickle cell anaemia, and Diamond-Blackfan anaemia) or by older patients with severe acquired anaemias such as in myelodysplastic syndromes.
- Excess parenteral iron supplements
- Excess dietary iron
- Some disorders do not normally cause haemochromatosis on their own, but may do so in the presence of other predisposing factors. These include cirrhosis (especially related to alcohol abuse), steatohepatitis of any cause, porphyria cutanea tarda, prolonged haemodialysis, post-portacaval shunting.
Treatment
Routine treatment in an otherwise healthy person consists of regularly scheduled phlebotomies (bloodletting). When first diagnosed, the phlebotomies may be fairly frequent, perhaps as often as once a week, until iron levels can be brought to within normal range. Once iron (Fe) and other markers are within the normal range, phlebotomies may be scheduled every other month or every three months depending upon the patient's rate of iron loading.
For those unable to tolerate routine blood draws, there is a chelating agent available for use. The drug Deferoxamine binds with iron in the blood stream and enhances its elimination via urine and feces. Typical treatment for chronic iron overload requires subcutaneous injection (SQ) over a period of 8-12 hours daily.
See also
References
- ^ Andrews NC (1999). "Disorders of iron metabolism". N. Engl. J. Med. 341 (26): 1986–95. doi:. PMID 10607817.
- ^ Pietrangelo A (May 2003). "Haemochromatosis". Gut 52 Suppl 2: ii23–30. PMID 12651879. PMC 1867747. http://gut.bmj.com/cgi/pmidlookup?view=long&pmid=12651879.
- ^ Cam Patterson; Marschall S. Runge (2006). Principles of molecular medicine. Totowa, NJ: Humana Press. pp. 567. ISBN 1-58829-202-9.
- ^ Mendes AI, Ferro A, Martins R, et al. (March 2009). "Non-classical hereditary haemochromatosis in Portugal: novel mutations identified in iron metabolism-related genes". Ann. haematol. 88 (3): 229–34. doi:. PMID 18762941. http://dx.doi.org/10.1007/s00277-008-0572-y.
- ^ Maddrey, Willis C.; Schiff, Eugene R.; Sorrell, Michael F. (2007). Schiff's diseases of the liver. Hagerstwon, MD: Lippincott Williams & Wilkins. pp. 1048. ISBN 0-7817-6040-2.
- ^ Pietrangelo A (November 2005). "Non-HFE haemochromatosis". Semin. Liver Dis. 25 (4): 450–60. doi:. PMID 16315138.
- ^ Franchini M (March 2006). "Hereditary iron overload: update on pathophysiology, diagnosis, and treatment". Am. J. haematol. 81 (3): 202–9. doi:. PMID 16493621.
External links
- Iron Overload (Texas Medical Center)
- Iron Overload - Hemosiderosis - Hemochromatosis (Merck)
- Iron Overload.org
- haemochromatosis.org
- Haemochromatosis.org.au
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