Page 66 - Essential Haematology

52 / Chapter 4 Iron overload

Table 4.3 Assessment of iron overload.

Assessment of iron stores
Serum ferritin
Serum iron and percentage saturation of transferrin (iron - binding capacity)
Serum non - transferrin bound iron
Bone marrow biopsy (Perls ’ stain) for reticuloendothelial stores
Liver biopsy (parenchymal and reticuloendothelial stores)
Liver CT scan or MRI
Cardiac MRI (T2 * technique)
Deferoxamine or deferiprone urine iron excretion test (chelatable iron)
Repeated phlebotomy until iron defi ciency occurs
Assessment of tissue damage caused by iron overload
Cardiac Clinical; chest X - ray; ECG; 24 - hour monitor; echocardiography; radionuclide (MUGA)
scan to check left ventricular ejection fraction at rest and with stress
Liver Liver function tests; liver biopsy; CT scan or MRI
Endocrine Clinical examination (growth and sexual development); glucose tolerance test; pituitary
gonadotrophin release tests; thyroid, parathyroid, gonadal, adrenal function, growth
hormone assays; radiology for bone age; isotopic bone density study

CT, computed tomography; ECG, electrocardiography; MRI, magnetic resonance imaging; MUGA, multiple
gated acquisition.

small proportion of those homozygous for the
mutation present with clinical features of the disease
and these usually show a serum ferritin > 1000 μ g/L.
A second mutation resulting in a histidine to aspar-
tic acid substitution H63D is found with the
C282Y mutation in approximately 5% of patients
but homozygotes for the H63D mutation do not
have the disease.
Serum hepcidin levels are low in patients
with mutated HFE because HFE is involved in
hepcidin synthesis or secretion (see Fig. 3.4 ).
Low serum hepcidin levels lead to high levels
of ferroportin on the basolateral surface of the
Figure 4.1 Liver biopsy. Iron loading of hepatic duodenal enterocyte and so lead to increased iron

parenchymal cells (Perls ’ stain). (Courtesy of absorption and increased release of iron from
Professor A.P. Dhillon) macrophages.