Autoimmune Haemolytic Anaemia

This patient presented with anaemia and a rised bilirubin. The platelet and neutrophil count is normal (this is important!).

The red cells are dimorphic, with some red cells appearing normal and some which are spherocytes. Spherocytes are cells which have lost their central pallor. The cause of this here is that antibody coating the red cell has changed the membrane charge and this has allowed the membrane in the middle of the cell (which would normally be stuck together) to dissociate. This is different to the cause of irregularly contracted cells in Hb C disease or microspherocytes in burns.

The remaining red cells show some mild nonspefici abnormlities such as the occasional stomatocyte, but there is no evidence of either haemoglobinopathy or enzyme deficiency. The main differential would be of a membrane disorder but in this case the positive DAT, normal MCHC (this is usually raised in Hereditary Spherocytosis) and the acute onset would be clues.

The platelets in this film are not normal - they are rather large and show anisocytosis. This is important because it hints there may be increased immune clearance. The combination of autoimmune haemolysis and autoimmune thrombocytopenia is called Evans Syndrome. In this case the platelet count is normal so it is hard to call the ITP but the size on the film is a significant finding. 

The white cell series is reactive with both neutrophils and lymphocytes showing change although numbers are not increased.

The final diagnosis needs the laboratory testing as suggested above but the film gives us a strong hint.