Macrocytic Anaemia

Macrocytic Anaemia

·        = MCV > 96 fl

Causes

·        New born 

·        ¯B12/folate

·        Alcoholism (most common cause but usually mild)

·        Liver disease

·        Primary marrow disorders

·        Drugs

·        Malaria

·        Idiopathic/others

Megaloblastic Anaemia

·        Is NOT the same as macrocytic anaemia

·        Causes:

o   ¯Folate (comes from veges) 

o   ¯B12 (comes from meat)

o   Drugs that interfere with B12 metabolism

·        Leads to defective DNA synthesis and delayed maturation of the nucleus cf. cytoplasm.

·        Big red cells and hyper-segmented neutrophils (>= 6 segments)

·        Clinical features:

o   Anaemia 

o   Infection (¯neutrophil function)

o   Jaundice (­bilirubin)

o   Purpura 

o   Malabsorption (¯gut lining)

·        Lab features: 

o  MCV > 95 fl

o  Oval macrocytes 

o  ¯WBC and ¯platelets

·        Investigations: blood film and B12/folate levels.  Serum folate is useless – folate is stored in RBCs

·        If low B12:

o  Also have symmetrical peripheral neuropathy

o  Could be diet: if ¯¯animal products 

o  Could be malabsorption: pernicious anaemia. Check intrinsic factor antibodies against gastric parietal cells. Schilling test for absorption 

·        If low folate:

o  Not eating enough veges (e.g. living on tea and toast)

o  Exclude malabsorption (e.g. Ceoliac Disease)

o  Review drugs