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File:IPLab5Hemochromatosis11.jpg|This is a histologic section of pancreas from this case stained for iron (Prussian blue). Note the accumulation of iron in the parenchymal cells (1). There is also iron in the pancreatic islets (2).
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== Study Questions ==
* <spoiler text="What is the clinical triad associated with hemochromatosis?">Diabetes mellitus, skin pigmentation, and hepatic fibrosis.</spoiler>
* <spoiler text="What are the two main types of hemochromatosis?">Primary or idiopathic hemochromatosis (also called hereditary hemochromatosis - HHC) is an autosomal recessive heritable disorder. The hemochromatosis gene is located on the short arm of chromosome 6, and the associated HLA haplotypes include A3 in 70% of hemochromatosis patients with fewer numbers of patients expressing B7, B14, or Bw35. Males are affected more than females (5 to 7:1) but this earlier and more severe clinical presentation in males is partly due to physiologic iron loss (menstruation, pregnancy) in females which delays iron accumulation. Even though the gene has been isolated and many aspects of the disease are known; the exact mechanism responsible for iron overload in primary hemochromatosis is not known.
The second type of hemochromatosis where the source of iron overload can be explained is called secondary hemochromatosis. Severe anemias due to ineffective erythropoiesis are the most common causes of secondary hemochromatosis. In these anemias the excess iron accumulation results from transfusions and also from compensatory increases in iron absorption. Alcoholic liver disease is also associated with increased iron accumulation in liver cells. Other more obtuse causes of iron overload leading to secondary hemochromatosis include: transfusions of packed RBCs, iron-dextran injections, and long term hemodialysis.</spoiler>
* <spoiler text="Compare and contrast the pathogenesis and clinical features of hemochromatosis and Wilson’s disease.">Hereditary hemochromatosis is an autosomal recessive disorder which results in increased iron absorption and iron induced parenchymal tissue damage. The exact mechanism of this functional defect is unknown. The iron overload leads to ferritin and hemosiderin in the parenchymal tissues of the body; primarily the liver, pancreas, myocardium, endocrine glands, and joints. Iron is a direct hepatotoxin and results in micronodular cirrhosis. Tissue damage and fibrosis is also evident in the pancreas, heart, and endocrine organs. The "bronze diabetes" of hemochromatosis is produced by excess melanin in the skin and by accumulation of hemosiderin in the dermal appendages. The diabetes is caused by destruction of pancreatic islets. Hemosiderin in the joint synovial lining leads to acute synovitis.
Wilson's Disease is also an autosomal recessive disorder that results in the accumulation of toxic levels of copper. Like hemochromatosis, the gene defect has been localized but the exact nature of the genetic defect is unknown. In this disorder, copper absorption and transport to the liver are normal; however, the copper does not get back into the circulation as ceruloplasmin and copper excretion into bile is severely impaired. The accumulation of copper leads primarily to liver, brain and eye damage. The liver develops fatty change and nuclear vacuolization in the setting of acute or chronic hepatitis which later progresses to cirrhosis. Neurologic manifestations include toxic neuronal injury primarily in the basal ganglia. Accumulation of copper in the cornea results in the formation of Kayser-Fleischer rings.</spoiler>
{{IPLab 5}}
[[Category: IPLab:Lab 5]]