Page 309 - Concise Pathology for Exam Preparation ( PDFDrive )

294 SECTION II Diseases of Organ Systems

(d) Cytoplasmic maturation lags behind that of the nucleus (due to delayed haemoglo-
binization)
(e) Prussian blue stain shows decreased iron stores
5. Iron studies
(a) Decreased serum iron
(b) Percentage saturation , 16%
(c) Serum ferritin , 12 mcg/L (most useful)
(d) Serum transferrin receptor fragments assay (sTFR) by immunological methods
demonstrates an increased value in IDA
(e) Erythrocyte ferritin is decreased in iron deficiency and free erythrocyte zinc proto-
porphyrin (FEP) levels are increased in disorders of haem synthesis including iron
deficiency. Normally protoporphyrin binds iron to form haem in erythroid precur-
sors. In IDA protoporphyrin fails to bind iron and its levels increase. In thalassemia
FEP levels are normal.

Differential Diagnosis

• Heterozygous form of b-thalassaemia/b-thalassaemia trait
• RBC count normal to increased (decreased in iron-deficiency anaemia)
• MCV and MCH disproportionately lower than degree of anaemia
• RDW normal in thalassaemia (increased in iron-deficiency anaemia)
• Target cells abundant (few in iron-deficiency anaemia)
• Basophilic stippling and nucleated RBCs commonly seen (not seen or rare in iron
deficiency)
• Normal iron studies (deranged values in iron deficiency)
• Increased HbF (normal in iron deficiency)
• Anaemia of chronic disorders
• Serum iron decreased
• Serum ferritin normal or increased (decreased in iron deficiency)
• TIBC normal or decreased (increased in iron deficiency)
• Percentage saturation decreased to normal (decreased in iron deficiency)
• Sideroblastic anaemia
• Serum iron normal or increased (decreased in iron deficiency)
• Serum ferritin normal or increased (decreased in iron deficiency)
• TIBC normal (increased in iron deficiency)
• Percentage saturation normal or increased (decreased in iron deficiency)

Q. Write briefly on sideroblastic anaemias.

Ans. The sideroblastic anaemias are inherited or acquired disorders characterized by:
• Refractory anaemia with a variable number of hypochromic red cells in peripheral smear
• Excess of iron and ring sideroblasts in the marrow

Classification

1. Hereditary sideroblastic 2. Acquired sideroblastic anaemia
anaemia (a) Idiopathic or primary (a type of myelodysplasia):
X-linked disorder (i) Refractory anaemia with ring sideroblasts
(ii) Refractory anaemia with ring sideroblasts and
thrombocytosis
(iii) Refractory anaemia with multilineage dysplasia
and ring sideroblasts
(b) Secondary, which may be due to:
(i) Drugs, eg, isoniazid, alcohol abuse and lead toxicity
(ii) Haematological disorders, eg, acute leukaemia,
lymphoma, haemolytic anaemia, myelofibrosis
and polycythaemia vera
(iii) Others, eg, hypothermia, rheumatoid arthritis
and carcinoma

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