excess of iron deposition

HAEMOCHROMATOSIS

Introduction:

Haemochromatosis is an excess of iron deposition within the body particularly in the parenchymal cells of organs. The organs which are mainly affected by this overload include the liver, pancreas, pituitary gland and the heart (Robbins et al 2005, Mohan 2005, Govan 2005 and National Digestive Disease Clearing House). This pathological condition is an inherited disorder and is homozygous recessive basically (Robbins et al 2005). This name was designated for this disorder in 1935 by Sheldon. (Barton et al 2000). This disorder is differentiated from hemosiderosis which is also the accumulation of iron but there is no damage to the cells. On the other haemochromatosis is a condition in which there is an iron overload which is mostly associated with damage to the cells (Chatterjea et al 2007).

This condition is more common in males than in females. This is because females lose iron from the body during menstruation and pregnancy which accounts for delayed accumulation of iron in the body. Males suffer 5 to 7 times more than females from this condition (Robbins et al 2005 and Sfeir et al 2009). This is condition is also more prevalent in whites as compared to the African Americans and it also the most common autosomal recessive disorder (Drobnik et al 2009). It is estimated that the hereditary from of this condition affects 1.5 to 3 people out of 1000 (Durupt S et al 2000) and it effects the whites in a greater proportion that is 1 out of 200 to 400 (Drobnik et al 2009).

Haemochromatosis is classified into two main types. This includes primary haemochromatosis and secondary hameochromatosis. The primary condition is also known as idiopathic or hereditary haemochromatosis. The secondary haemochromatosis results from conditions apart from the genetic mutations (Robbins et al 2005, Chatterjea et al 2007, Lang et al 2005 and Mohan 2005). This condition if left untreated can also be fatal and out of 10000 deaths it is estimated that approximately 1.7 deaths are due to Haemochromatosis. Also it can be more lethal for the people above the age of 50 years as well as in neonates (Sfeir at al 2009).

Etiology:

Hereditary Haemochromatosis occurs when there is mutation in the HFE gene which is found on the 6p21.3 chromosome. This gene codes for a molecule which is a HLA class I like molecule and this molecule is basically involved in the absorption of iron from the small intestine. The mutation that mostly occurs on this gene is known as C282Y (Murray at al 2006, Philpott 2002, Ganong 2005 and Fletcher et al 2002). This mutation accounts for 6.4 to 9.5% mutations in the Northern European whites (Kim WR et al 2002). The HFE gene is mainly expressed in the intestinal epithelial cells (Philpott 2002 and Pietrangelo 2002). After mutation the regulation of iron absorption is lost and this leads to an accumulation of iron at the rate of 0.5 to 1.0 gram per year. This is the reason why the disease mainly expresses itself at a later age because 20 gram or iron overload is required for the disease expression (Robbins et al 2005). Other mutations in the genes which code for the proteins hemojuvelin, hepcidin, transferring receptor 2 and ferroproetin can also lead to haemochromatosis (Murray et al 2006).

Secondary haemochromatosis occurs due to many reasons. This includes a rise in the iron content due to blood transfusions which are given to patients suffering from myeloperoxidase syndromes, to patients who are on continuous hemodialysis as well as in leukemias and aplastic anemias. Chronic damage to the liver by alcoholism and porphyria cutanea tarda can also lead to acquired haemochromatosis. Another cause can be the disturbance in the synthesis of red blood cells as occurs in Beta Thalassemia and deficiency of pyruvate kinase (Lang 2000 and Robbins et al 2005). In sub- Saharan Africa iron overload occurs because of increased intake of alcohol and usage of steel crockery. This overload is suspected to be because of a genetic predisposition as well(Moham 2005 and Moyo VM et al 1998). This is referred to as Bantu siderosis (Vasudevam et al 2007).

Presentation:

The disease affects mainly the skin, causes damage to the pancreas, liver, heart and it leads to pathologies of joints and gonadal dysfunction (Mohan et al 2005). Iron accumulates in organs in the form of hemosiderin and ferritin. These pigments accumulate in liver cells giving it a golden yellow color and causing fibrosis of the liver. As the disease progresses it causes cirrhosis of the liver and it turns brown in color (Robbins et al 2005). The iron accumulation damages the pancreas and then it causes fibrosis and eventually irreversible cell damage which can lead to diabetes mellitus (Mohan 2005). This condition is referred to as bronze diabetes in association with the skin pigmentation. The skin pigmentation appears as a slate grey color of the ski due to the deposition of iron and melanin production also rises (Murray et al 2006). Cardiac problems and arrhythmias also result and there is enlargement of the heart. The risk of carcinomas of the liver rises by 200 times. A condition known as pseudo-gout also results with inflammation of the joints and damage to the cartilage (Robbins et al 2005). Damage to the pituitary gland and haemochromatosis in the testes leads to hypogonadism (Greenspan 2002).

Investigation (laboratory diagnosis):

The patients present with pain in the abdomen, an enlarged liver can be palpated and the pigmentation of the skin due to increased melanin as well as the stale brown color due to increased iron can be seen. Irregularities in the menstrual cycle in the females and loss of sexual function in males should be asked for (Robbins et al 2005). Patients can also present with osteoporosis and pain in the joints (Greenspan et al 2001).

Liver and tissue biopsy of affected tissues is important to determine it (Mohan 2005). The hepatic tissues can be stained with a Prussian blue stain and the tissues acquire a blue color on staining. The other affected tissues also show a similar effect that is they also stain blue with the Prussian blue stain. The iron content in the liver tissue can also be measured. In a normal liver sample which has not been fixed, the tissue contains iron in an amount of 1000 microgram per gram dry weight of liver. This level is raised to as high as 10,000 microgram in patients who are suffering from primary haemochromatosis. Levels may shoot up to even higher values greater than 22,000 microgram in the case of the fibrosis and cirrhosis of the liver. Thus these different values can also help in the assessment of damage (Robbins et al 2005).

The laboratory tests include the estimation of the red blood cells as well as the level of hemoglobin. The total amount of iron present in the plasma should also be tested along with the total iron binding capacity (TIBC). The percentage of iron saturation of transferring should also be checked (Murray et al 2006). The percentage of transferring saturation above 62 % is suggestive of haemochromatosis (Chatterjea et al 2007). Radioimmunoassay is used to check for the ferritin concentration which is present in the plasma. The blood glucose levels can also be measured to confirm the presence of diabetes which occurs due to the damage to the pancreas (Murray et al 2006). Chelating agents can also be used for the determination of the amount or iron. Desferroxamine is an example of an iron chelator (Mohan 2005).

The assessment of the condition of the patient is important and blood disorders, transfusions and alcoholism is necessary to be determined to reach to a conclusion. The family screening of patients with this disease also needs to be done as this can help in early intervention and cure. Genetic screening can also be done for the HFE gene (Robbins et al 2005).

The levels of the sex hormones, ACTH and other hormones of the pituitary can also be assessed to check for the pituitary insufficiency due to damage to the gland that occurs due to the disease (Greenspan et al 2001). The levels of vitamin C can also be assessed because iron leads to an increased breakdown of the vitamin (Lang et al 2005). MRI and CT scans can also be performed for diagnosing the condition (Sfeir et al 2009). Carriers for the mutated gene should also be checked because though they do have increased iron but the levels are not as raised as that with the homozygous recessive condition (Robbins et al 2005).

Conclusion:

Haemochromatosis is a condition which is curable and early diagnosis and determination of the condition can be life saving as well as it can also increase the life expectancy of the patients. This pathological condition is a very common autosomal recessive disorder which can be fatal mainly because of cardiac and liver complications (Robbins et al). Early intervention can also prevent the irreversible damage that occurs to the liver, joints, pancreas and other tissues and it can also reduce the severity of the symptoms. The treatment for the condition is not very complicated and phlebotomy is the procedure that is used. It just involves the removal of blood from the patients every year or every 2 or 3 months depending upon the condition of the patient. The aggravating factors should also be withdrawn which include alcohol or foods which burden the liver (National Digestive Disease Clearing House). The intake of vitamin C should also be stopped because it boosts the absorption of iron from the gastrointestinal tract (National Heart Lung and Blood Institute). Thus this condition should not be overlooked and since proper cure and treatment is available, the opportunity should be availed.

Conclusion:

Haemochromatosis is a condition which is curable and early diagnosis and determination of the condition can be life saving as well as it can also increase the life expectancy of the patients. This pathological condition is a very common autosomal recessive disorder which can be fatal mainly because of cardiac and liver complications (Robbins et al). Early intervention can also prevent the irreversible damage that occurs to the liver, joints, pancreas and other tissues and it can also reduce the severity of the symptoms. The treatment for the condition is not very complicated and phlebotomy is the procedure that is used. It just involves the removal of blood from the patients every year or every 2 or 3 months depending upon the condition of the patient. The aggravating factors should also be withdrawn which include alcohol or foods which burden the liver (National Digestive Disease Clearing House). The intake of vitamin C should also be stopped because it boosts the absorption of iron from the gastrointestinal tract (National Heart Lung and Blood Institute). Thus this condition should not be overlooked and since proper cure and treatment is available, the opportunity should be availed.

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