Anaemia

Anaemia

Defined as a low red blood cell (RBC) count, decreased amount of haemoglobin and a decreased haematocrit. Not a “diagnosis”, but a sign of underlying pathology. The clinical features of anaemia are due to the reduced oxygen carrying capacity of the blood.

General clinical features of anaemia:
Fatigue, breathlessness and angina on exertion, palpitations, headache, insomnia, throbbing in head and ears, dizziness, tinnitus, parathesia in fingers and toes, angina, pallor of skin, oedema

Classification based on size and changes in RBC’s:
size – microcytic, normocytic, macrocytic
colour (chromic) – normal, hypo (pale), hyper

Three major groups:
Normocytic, normochromic – normal size and colour – eg acute blood loss and anaemia associated with chronic disease, bone marrow failure, renal failure, pregnancy, haemolysis
Macrocytic, normochromic – large size and normal colour – eg vitamin B12 and folic acid deficiencies, alcohol, liver disease, hypothyroidism
Microcytic, hypochromic – small size and decreased haemoglobin (colour is pale) – eg iron deficiency anaemia, thalassaemia, congenital sideroblastic anaemia

Aetiology:
• decrease in haematopoiesis (aplastic anaemia/bone marrow failure; myelofibrosis; leukaemia; multiple myeloma; iron deficiency; vitamin B12 deficiency; folic acid deficiency
• abnormal haematopoiesis (sickle cell anaemia; thalassaemia)
• increased loss/destruction of red blood cells (prolonged menstrual bleeding; peptic ulcer; immune haemolytic anaemia; hypersplenism; malaria)

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