Secondary haemochromatosis

A gastric mucosa biopsy may facilitate differentiation between HC and secondary haemochromatosis, yet this examination is also regarded as obsolete today. (Iron in macrophages with HC = 0, with secondary HC = ll. )... 

Iron Anaemia Primary and secondary haemochromatosis siderosis, liver cirrhosis... 

Haemochromatosis associated with insulin resistance Secondary iron overload, with increased iron absorption... 

There are several inherited diseases which are associated with the gradual excess accumulation of iron via the gut. Hereditary haemochromatosis is a relatively rare condition in which iron absorption is increased through an unidentified mechanism. This condition usually presents in the fourth or fifth decade of life with the secondary effects of iron overload such as heart failure, liver cirrhosis or sugar diabetes. As the production of red cells is unaffected, the excess iron can be removed slowly by venesecting a unit of blood every week for up to two years. However, in the acute situation, iron chelation may be used to remove toxic low-molecular-weight iron until sufficient negative iron balance has been obtained by venesection. 

Iron absorption may also be increased secondary to chronic haemolysis as in patients with thalassaemia intermedia. In this group of patients, the anaemia is not usually sufficiently severe to necessitate regular blood transfusions as in thalassaemia major, but iron accumulates over many years from increased absorption via the gut. However, unlike haemochromatosis, venesection is not a therapeutic option, and iron chelation is the only effective way to remove the excess iron. 

Method After emptying the bladder, deferoxamine (one vial of 500 mg) is injected (i.m.) and urine is collected for exactly 6 hours with subsequent determination of iron excretion. Iron levels of > 4 mg are considered to be characteristic of primary haemochromatosis, while iron levels of <2 mg are either regarded as normal or caused by secondary haemosiderosis. This test can also be executed as follows 10 mg/kg BW deferoxamine (i.m.) with urine collection for 24 hours, whereby haemochromatosis value is > 10 mg iron and normal value is < 2 mg. 

Haemochromatosis leads to an increase in the density of the liver parenchyma, which correlates with the accumulation of iron. CT scans reveal a remarkably dense and bright liver parenchyma with density values of up to +140 HU (so-called white liver). The deposition of 1 g iron results in a rise in density of 1 HU. (20) CT densitometry clearly facilitates effective control of therapeutic success in this storage disease. It is not possible, however, to differentiate pronounced secondary haemo-siderosis. Hyperdense values are also found in longterm gold therapy, in glycogen thesaurismosis and M. Wilson, or in chronic arsenic poisoning. 

Haemochromatosis (HC) is a hereditary disease (autosomal recessive) affecting the iron metabolism. It refers to pronounced iron deposition, predominantly in the liver (>50% of the total iron in the body), but also in other organs, such as pancreas, spleen, heart, endocrinium, bone marrow, lymph nodes, salivary glands, basal skin layers and gastrointestinal epithelia. In addition to these hereditary (HFE-related) or idiopathic (non-HFE-related) primary forms, there are numerous acquired secondary forms of HC. At first, the cells of the RES become laden with iron. Only when the capacity of the RES is exceeded is there iron deposition in the parenchymal cells this leads to damage of the respective organs, (s. tab 31.17)... 

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