Anaemia in clinical practice by Professor C.K. Bodhinayake

Source: Newsletter of the College of General Dental Practitioners of Sri Lanka

Anaemia is present when haemoglobin (Hb) content is below the expected values for the age and sex.The cut off values defined by the WHO for men, non-pregnant women and pregnant women are 13, 12 and 11g/dL respectively. In children the cut off values are even lower (6-5 yrs 11g, 5-11 yrs 11.5g and 12-14 yrs 12 g).
Anemia could result from a variety of causes which include reduction of Hb synthesis (Iron, B12, folate deficiency, Bone marrow disorders) or excessive blood loss through bleeding or hemolysis. Anemia is classified according to the size of red blood cells (RBC) into Microcytic Normocytic or Macrocytic
anaemia for the purpose of investigations. Mean cell volume (MCV) of a normal RBC is 80-100 fl.The three commonest causes of anaemia in clinical practice are iron deficiency, anemia of chronic disease and thalassemia.

Clinical recognition of anaemia

Loss of energy, palpitations, breathlessness and headache, particularly with exertion, and leg pain are common symptoms of anaemia.
Pica, which means craving for items like raw rice or clay, is only associated with iron deficiency and is a useful symptom to discriminate iron deficiency from other anaemias. History of menorrhagia or bleeding hemorrhoids suggest blood loss leading to iron deficiency. Family history of low Hb in siblings and consanguinity directs toward thalassemia or other hereditary causes of anaemia. Presence of concomitant medical problems such as long standing diabetes, hypertension, kidney, joint or respiratory disease may point towards the diagnosis of anemia of chronic disease.

Physical examination

A common observation in anemia is the pallor of skin and mucosa. Glossitis leading to a smooth and shiny tongue and angular stomatitis suggests iron deficiency. In iron deficiency, the nails are flat or spoon shaped. Nails may also be brittle, and excessive hair loss may be present. Petichiae in mucosae
and skin, fever, oral ulcers suggest thrombocytopenia and neutropenia together with anaemia and points towards bone marrow failure. In advanced leukaemia, gum infiltration and hemorrhagic lesions on the oral cavity are seen.

Beta thalassemia major leads to marrow expansion and altered facies such as frontal bossing and malar prominence. It is important to note that in Sri Lanka, minor forms of thalassemia with mild anaemia are commoner, and are generally passed unnoticed or confused with iron deficiency.
Presence of hypertension together with anaemia suggest chronic renal disease which is also common in clinical practice.

Investigations

A full blood count (FBC) confirms the presence of anaemia, the type of anaemia according to the size of RBCs, as described earlier and the state of white blood cells (WBC) and platelets. Blood film is an essential initial investigation, which is complementary to the FBC and will show the cell morphology clearly. When Hb, WBC and platelets are all reduced which is known as pancytopenia, bone marrow failure is indicated.

Mean cell volume(MCV) is used to classify anemia into different types and further investigations can be planned accordingly. Iron deficiency is confirmed by the presence of microcytic RBC, and low serum ferritin levels. Thalassemia is differentiated from iron deficiency by normal or high serum ferritin despite the presence of microcytic RBC. Anaemia of chronic disease is increasingly common in adullts and is distinguished by the presence of normocytic RBC, with normal or elevated ferritin. In addition to the three common types of anaemia which need to be readily recognized by the clinician, there are other less common aetiologies which need further evaluation beyond office practice.