Iron overload
From Wikipedia, the free encyclopedia
 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 indicates accumulation of iron in the body due to any cause.
Contents |
[edit] Terminology
[edit] Haemochromatosis or haemosiderosis
Historically, the term haemochromatosis was initially used to refer to what is now more specifically called haemochromatosis type 1 (or HFE-related hereditary haemochromatosis). Currently, haemochromatosis (without further specification) is mostly defined as iron overload with a hereditary/primary cause,[1][2] or originating from a metabolic disorder.[3] However, the term is currently also used more broadly to refer to any form of iron overload, thus requiring specification of the cause, for example hereditary haemochromatosis.
The term haemosiderosis is generally used to indicate the pathological effect of iron accumulation in any given organ, which mainly occurs in the form of haemosiderin.[4][5] Sometimes, the simpler term siderosis is used instead.
Other definitions distinguishing haemochromatosis or haemosiderosis that are occasionally used include:
- Haemosiderosis is hemochromatosis caused by excessive blood transfusions, that is, haemosiderosis is a form of secondary haemochromatosis.[6][7]
- Haemosiderosis is hemosiderin deposition within cells, while hemochromatosis is hemosiderin within cells AND interstitium.[8]
- Haemosiderosis is iron overload that does not cause tissue damage,[9] while haemochromatosis does.[10]
- 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.
- Hemosiderosis is arbitrarily differentiated from hemochromatosis by the reversible nature of the iron accumulation in the reticuloendothelial system.[11]
[edit] Clinical presentation
Organs commonly affected by haemochromatosis are the liver, heart and endocrine glands.[12]
[edit] Causes
The causes can be distinguished between primary cases (hereditary or genetically determined) and less frequent secondary cases (acquired during life).[13]
[edit] 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.[14] 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"[15], "non-HFE related hereditary haemochromatosis".[16], or "non-HFE haemochromatosis".[17]
| 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.[18]
[edit] 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.
[edit] Prognosis
A third of those untreated develop hepatocellular carcinoma.[19]
[edit] 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.
[edit] See also
[edit] References
- ^ thefreedictionary.com > hemochromatosis, citing:
- The American Heritage Medical Dictionary, 2004 by Houghton Mifflin Company
- McGraw-Hill Concise Dictionary of Modern Medicine. 2002
- ^ Merriam-Webster's Medical Dictionary > hemochromatosis Retrieved on Dec 11, 2009
- ^ thefreedictionary.com, citing:
- Dorland's Medical Dictionary for Health Consumers, 2007
- Mosby's Medical Dictionary, 8th edition. 2009
- Jonas: Mosby's Dictionary of Complementary and Alternative Medicine. 2005,
- ^ Merriam-Webster's Medical Dictionary > hemosideroses Retrieved on Dec 11, 2009
- ^ thefreedictionary.com > hemosiderosis, citing:
- The American Heritage Medical Dictionary, 2004 by Houghton Mifflin Company
- Mosby's Medical Dictionary, 8th edition.
- ^ eMedicine Specialties > Radiology > Gastrointestinal > Hemochromatosis Author: Sandor Joffe, MD. Updated: May 8, 2009
- ^ thefreedictionary.com > hemosiderosis, citing:
- Gale Encyclopedia of Medicine. Copyright 2008
- ^ Notecards on radiology gamuts, diseases, anatomy 2002, Charles E. Kahn, Jr., MD. Medical College of Wisconsin
- ^ thefreedictionary.com > hemosiderosis, citing:
- Dorland's Medical Dictionary for Health Consumers, 2007
- Mosby's Dental Dictionary, 2nd edition.
- Saunders Comprehensive Veterinary Dictionary, 3 ed. 2007
- ^ The HealthScout Network > Health Encyclopedia > Diseases and Conditions > Hemochromatosis Retrieved on Dec 11, 2009
- ^ thefreedictionary.com > hemosiderosis, citing:
- McGraw-Hill Concise Dictionary of Modern Medicine. 2002
- ^ 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.
- ^ McLean, David I.; Harley A. Haynes (2003). "Chapter 184: Cutaneous Manifestations of Internal Malignant Disease: Cutaneous Paraneoplastic Syndromes". in Freedberg et al. Fitzpatrick's Dermatology in General Medicine. (6th ed.). McGraw-Hill. ISBN 0-07-138067-1.
[edit] External links
- Iron Overload (Texas Medical Center)
- Iron Overload - Hemosiderosis - Hemochromatosis (Merck)
- Iron Overload.org
- haemochromatosis.org
- Haemochromatosis.org.au
- Iron Overload Support Forums
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