ANAEMIA

Classification according to mean cell volume (MCV).

Microcytic, hypochromic	Normocytic, normochromic	Macrocytic
MCV < 80 fl	MCV 80-95 fl	MCV > 95fl
MCH < 27 pg	MCH >26 pg
Iron deficiency	Many haemolytic anaemias	Megaloblastic: vitamin B₁₂ or folate deficiency
Thalassaemia	Secondary anaemia
Anaemia of chronic diseases (some cases)	After acute blood loss	Non-megaloblastic anaemia: alcohol, liver disease, myelodysplasia, aplastic anaemia, etc
Lead Poisoning	Mixed deficiencies
Sideroblastic anaemia (some cases)	Bone marrow failure e.g. post-chemotherapy, infiltration by carcinoma, etc. Renal disease

· An abnormal MCV is a good indicator: low in iron deficiency anaemia of chronic disease, thalassaemia, raised in: megaloblastic anaemia, liver disease, myelodysplasia. Blood film findings may indicate the cause.

Iron deficiency

Chronic inflammation or malignancy

Thalassaemia trait (a or b)

Sideroblastic anaemia

MCV

MCH

MCHC

Serum iron

TIBC

Serum ferritin

Bone marrow iron stores

Erythroblast iron

Haemoglobin electrophoresis

All reduced in relation to severity of anaemia

Reduced

Raised

Reduced

Absent

Normal

Low normal or mild reduction

Reduced

Normal or raised

Present

Absent

Normal

All reduced: very low for degree of anaemia

Normal

Present

Hb. A₂ raised in b form

Very low in congenital type but MCV often raised in acquired type

Raised

Normal

Raised

Present

Ring forms

Normal

For suspected iron deficiency search for a cause of bleeding, see audit on GI investigations for iron deficiency anaemia.

Lab. requests for B12/Folate will be rejected when the FBC is normal (except when neuropathy present)

Haematological advise is always available for other causes. If orthopnoea is present, transfusion is recommended but does carry risks (see Handbook of Transfusion Medicine) and in certain situations e.g. autoimmune haemolytic anaemia, other treatments such steroids may be safer.

In the case of specific haematinic deficiency replacement of the specific haematinic is always the preferred treatment.

PRIMARY BLEEDING DISORDERS

A full history including family history and drug history are an essential pre-requisite. Clinical examination for relevant causes e.g. liver disease is also required.

Standard investigations are FBC, INR and APTT. If the cause is not apparent, haematological advice should be sought.

OVER-ANTICOAGULATION - Haemorrhage

The main adverse effect of all oral anticoagulants is haemorrhage. Checking the INR and omitting doses when appropriate is essential: if the anticoagulant is stopped but not reversed, the INR should be measured 1-2 days later to ensure that it is falling. The following recommendations by the British Society for Haematology are based on the result of the INR and whether there is major or minor bleeding: the recommendations apply to patients taking warfarin:

· Major bleeding-stop warfarin: give phytomenadione (vitamin K₁), 5mg by slow intravenous injection: give fresh frozen plasma 15mL/kg.

· INR >8.0, no bleeding or minor bleeding – stop warfarin, restart when INR <5.0: if there are no other risk factors for bleeding give phytomenadione (vitamin K₁) 0.5mg by slow intravenous injection or 5mg by mouth (for partial reversal of anticoagulation give smaller oral doses of phytomenadione e.g. 0.5-2.5mg): repeat dose of phytomenadione if INR still too high after 24 hours.

· INR 6.0-8.0, no bleeding or minor bleeding – stop warfarin, restart when INR <5.0.

· INR <6.0 but more than 0.5 units above target value – reduce dose or stop warfarin, restart when INR <5.0.

· Unexpected bleeding at therapeutic levels – always investigate possibility of underlying cause e.g. unsuspected renal or gastro-intestinal tract pathology.

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