Approach Considerations
Relevant laboratory tests and findings include the following:
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CBC count with differential - To check for anemia and thrombocytopenia
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Total and direct bilirubin levels - Elevated
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Reticulocyte count - To check for any signs of hemolysis
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Glucose level - Infants with neonatal hemochromatosis can present with hypoglycemia
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Albumin level - May be low, which accounts for the infants' edema
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Urinalysis - To check for causes of oliguria and any renal involvement
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BUN and creatinine levels - To evaluate renal function
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Prothrombin time (PT), activated partial thromboplastin time (aPTT), and fibrin split products - To rule out any hemorrhagic causes
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Transferrin level - Low but hypersaturated (one of the most common findings)
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Serum ferritin levels - Elevated
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Total iron-binding capacity - Low
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Cytoferrin level - Markedly elevated
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Lactic acid dehydrogenase (LDH) level - Markedly elevated
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Aminotransferases level - Mildly elevated
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Iron levels - Usually in the reference range
MRI and Ultrasound
Imaging studies include MRI and ultrasonography. MRI is the most helpful study in the diagnosis of neonatal hemochromatosis. [9]
Ultrasonography demonstrates patency of the ductus venosum; this is because of liver injury and, thus, portocaval shunting occurs.
MRI can be used to detect increased levels of iron in the liver compared with levels in normal tissues and can be used to document any areas of siderosis of the pancreas and myocardium. Absence of siderosis of the spleen may also be observed.
MRI of infants in utero has not demonstrated any siderosis or signs of neonatal hemochromatosis.
Biopsy
Liver biopsy is not easily performed in these infants because of the increased tendency of bleeding, but it is helpful in aiding in the diagnosis.
Another option is to perform a punch biopsy of the oral mucosa. This area is used because of the presence of the small salivary glands. Punch biopsy is performed by using 3-mm punch biopsy of the mucosa of the lower lip, and bleeding can be controlled. Salivary glands are siderotic if neonatal hemochromatosis is present.
Histologic Findings
Microscopic examination of the liver reveals that the hepatocytes have giant-cell transformation or pseudoacinar transformation with bile plugs, or no hepatocytes are present at all. Also, the hepatocytes may show siderosis, while Kupffer cells are spared. Scarring may be present from macrophages, which contain high levels of stainable iron. The bile duct is proliferated. The spleen, lymph nodes, and bone marrow contain a small amount of stainable iron. The placenta is not siderotic, and villitis has not been reported.
