Pyruvate Kinase Deficiency post Splenectomy

This blood film shows all the features of pyruvate kinase deficiency, a hereditary enzymopathy, and those of a patient post splenectomy. 

There are two main red cell enzymopathies which can be diagnosed on a blood film - PK deficiency and G6PD deficiency. These two look markedly different, and should never be listed on a differential together. To say this implies you know little about the morphology of one, or both or these conditions. 

PK deficiency causes numerous echinocytes, or burr cells. In PK deficiency, a lack of the PK enzyme blocks glycolysis, causing a severe shortage of cellular ATP. This energy failure stops the sodium-potassium pumps from working, disrupting ion and water balance and altering the cell membrane to form spikes.

Splenic macrophages recognises these cells as being abnormal, and try to remove them from the peripheral circulation. This causes anaemia, driving reticulocytosis. This process is therefore a form of congenital haemolysis. In individuals who suffer from sever anaemia, splenectomy used to be a treatment as removing the splenic macrophages means the echinocytes return to a normal life span in the peripheral blood. In practice, this doesn't always work - these cells aren't particularly healthy with no intracellular ATP. Nowadays, we tend to use other treatments rather than splenectomy.

Post splenectomy, you see all the changes associated with lack of splenic macrophage function. In the peripheral blood there are Howell-Jolly bodies, thrombocytosis, pappenheimer bodies, spherocytes and reactive lymphocytes.

Despite the alarming looking film, this patient is actually quite well. They need to take prophylactiv vaccination and antibiotics because of the hyposplenism (although some centres are challenging the role of antibiotics - so don't quote me on that!).