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Hemochromatosis Jennifer Nnamdi 1414 MD4
Table of Content. Introduction Causes Signs and symptoms Diagnosis Prevention Treatment References
Introduction Hemochromatosis is also referred to as iron overload, this means accumulation of iron in the body. This action is genetic and the excess iron if left untreated, can damage joints, organs, and eventually be fatal.
Iron is an essential nutrient found in many foods. Iron carries oxygen (in hemoglobin) to all parts of the body. Normally, humans absorb about 8-10% of the iron in foods that they eat. People with hemochromatosis (too much iron) can absorb four times more iron than normal. Mismanaged iron in the brain has been observed in autopsies of people with neurodegenerative diseases: Alzheimer's, early onset Parkinson's, epilepsy, multiple sclerosis, and Huntington's disease
Caucasians are the people most at risk for the classic type of hemochromatosis. More than one million Americans have the genes for this type. However, there are other gene combinations that result in hemochromatosis regardless of a person's ethnicity. It is estimated that as much as or more than 16 million Americans have some degree of elevated iron and are at risk for the same diseases that occur in people with the untreated classic type: bone and joint disease, cirrhosis, liver cancer, diabetes, hypothyroidism, hypogonadism, infertility, impotence, depression, or premature death due to liver or heart failure.
There are several types of hemochromatosis. Hemochromatosis type 1: It is also called Classic Hemochromatosis (HHC), there is a mutation in HFE gene. This is the leading cause of iron overload disease. People with HHC absorb extra amounts of iron from the daily diet. Hemochromatosis type 2: it is also know as juvenile hemochromatosis Hemochromatosis type 2a: Mutation in hemojuvelin also known as RGMc and HFE2 Hemochromatosis type 2b: Mutation in hepcidin antimicrobial peptide HAMP or HFE2B Hemochromatosis type 3: Mutation in transferrin receptor 2 or HFE3
Hemochromatosis type 4: Mutation in ferroportin SLC11A3/SLC40A1 Neonatal hemochromatosis: Etiology unknown The remaining types of hemochromatosis are very rare Over time, these excesses build up in major organs such as the heart, liver, pancreas, joints, and pituitary. If the extra iron is not removed, these organs can become diseased. Untreated hemochromatosis can be fatal. Most types of hemochromatosis have autosomal recessive inheritance except type 4 which has autosomal dominant inheritance
Causes Primary hemochromatosis It is caused by defects (mutations) in the HFE gene. HFE has many purposes, but one important role is that it helps to control the amount of iron that is absorbed from food. There are several known mutations in the HFE gene, but presently testing for only three is available: C282Y, H63D, and S65C. Everyone inherits two copies of HFE, one from Mom and one from Dad. When a person has one mutated copy, he or she is called a carrier or heterozygote. When a person has two of the same mutated copies, he or she is called a homozygote. When a person has two different – but mutated – copies, he or she is called a compound heterozygote. What is most important is that you know which gene combination causes the greatest known risk of loading iron.
Causes Secondary hemochromatosis This is an acquired form of hemochromatosis, it is mainly due to other blood related disorders. Sometimes, it can occur in people with long term alcoholism and other health related issues It could be due to severe chronic hemolysis of any cause, including intravascular hemolysis and ineffective erythropoiesis (hemolysis 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 anemia (such as beta-thalassaemia major, sickle cell anemia, and Diamond–Blackfan anemia) or by older patients with severe acquired anemia such as in myelodysplastic syndromes
Excess parenteral iron supplements, such as what can acutely happen in iron poisoning Excess dietary iron Some disorders do not normally cause hemochromatosis 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 hemodialysis, and post- portacaval shunting
Signs and Symptoms Chronic fatigue and joint pain are the most common complaints of people with hemochromatosis. For this reason, the complete diagnosis is often delayed because these two symptoms are commonly seen in other diseases. Pain in the knuckles of the pointer and middle finger, collectively called “The Iron Fist,” is the only sign or symptom specific to hemochromatosis. However, not everyone with HHC experiences the Iron Fist. Lack of energy Abdominal pain Memory fog Loss of sex drive (Testicular failure)
Signs and symptoms Heart flutters Irregular heart beat (Cardiomyopathy) Cirrhosis of the liver Diabetes due to pancreatic islet cell failure Arthritis (calcium pyrophosphate deposition in joints) Slate grey discoloration of the skin Joint pain and bone pain
Diagnosis There are 3 tests that together make up the Iron Panel Test. These tests are the Serum Ferritin, Total Iron Binding Capacity, and Serum Iron. These tests need to be taken as a panel, not independently, to receive a comprehensive and accurate assessment of a potential Hemochromatosis diagnosis. SERUM IRON (SI) This test is best conducted after fasting for at least three hours. Also, iron or Vitamin C supplements should be discontinued at least three days before taking the test. Do not discontinue other medication unless your doctor tells you to.
Diagnosis SERUM FERRITIN (SF) This test measure the amount of iron contained or stored in the body. Serum ferritin reference ranges are different for adults and children. For adults, the ideal range is ng/ml. TOTAL IRON BINDING CAPACITY (TIBC) This test tells how well your body can bind to iron. Serum iron divided by TIBC x 100% gives you important information about the transferrin-iron saturation percentage (TS%). TS% is usually %; in some people with iron overload, the TS% is very high. There are other types of iron overload where the TS% is normal. In the past, liver biopsy was widely used to diagnose hemochromatosis. Today, liver biopsy is not necessary to diagnose the inherited form of HHC. DNA tests are available to determine if a person has genetic hemochromatosis.
Prevention Screening family members of a person diagnosed with hemochromatosis may detect the disease early so that treatment can be started before organ damage has occurred in other affected relatives.
Treatment It is very important to get iron levels down to normal. Therapeutic blood removal, or phlebotomy, is the most common means of iron reduction. Therapeutic phlebotomy (TP) is the same as regular blood donation but TP requires a doctor’s order (prescription). Regular blood donation can be done every 8 weeks. A person with severe iron overload may need to give blood as much as 8 times in a single month! The goal is to bring blood ferritin levels to an ideal range of ng/mL. Depending on the amount of iron overload at the time of diagnosis, reaching normal levels can require several phlebotomies. Serum ferritin drops about 30ng/mL with each full unit (500cc) of blood removed. When ferritin falls more rapidly following a phlebotomy, there is likely some other reason for the fast rate other than the blood donation. These reasons are specific to the individual but can include the presence of inflammation, changes in alcohol consumption, or changes to medication.
Treatment Once iron levels reach normal, a person can begin maintenance therapy, which involves making a blood donation every 2 to 4 months for life. Some people may need to give blood more or less depending on what they eat and how quickly their body absorbs iron. The TS% and serum ferritin tests can be done periodically to help determine how often blood should be removed. When hemochromatosis is diagnosed early and treated before organs are damaged, a person can live a normal life expectancy. For people who have the disease at the time of diagnosis, life expectancy may be shortened depending upon the disease. If a person is diagnosed and treated before serum ferritin is above 1,000ng/mL the risk of cirrhosis or liver cancer is less than 1%.
References Bacon BR, Adams PC, Kowdley KV, et al. Diagnosis and management of hemochromatosis: 2011 practice guideline by the American Association for the Study of Liver Diseases forms