These morphologic changes are most frequently seen in dogs and cats, where they are of diagnostic relevance. AcanthocytesĪcanthocytes (or spur cells) are spherical cells with blunt-tipped or club-shaped spicules of different lengths projecting from their surface at irregular intervals. Evaluation for significant shape abnormalities requires a well-made blood film prepared from fresh blood, so that artifactive shape changes are not superimposed upon any of potential pathologic significance. In all cases, the fullest interpretation of red blood cell changes can be made only in light of the other parameters of the hemogram, along with pertinent clinical, historical, and laboratory findings. certain species of goats, young calves).Īcanthocyte seen with electron microscopy In other instances, many poikilocytes may be an expected or “normal” finding (e.g. zinc in dogs, acetaminophen in cats, red maple leaf in horses) should be instituted in such patients. For instance, many eccentrocytes and Heinz bodies in an anemic animal indicate oxidant injury and a search for an oxidant (e.g. The presence of moderate or many misshapen cells is likely to be of more clinical relevance and can actually yield clues as to the cause of anemia in affected animals. Testing for this hemostastic disorder could be considered, depending on what is wrong with the dog. For instance, a few schistocytes in a sick dog with thrombocytopenia should raise suspicion of fragmentation injury, secondary to disseminated intravascular coagulation (DIC). However, in some situations, low numbers can be helpful. Low numbers of misshapen red blood cells can be seen in blood from clinically normal or ill animals and may not be of diagnostic relevance. The diagnostic relevance of poikilocytes is number-, shape- and context-dependent. These situations include physiologic poikilocytosis of goats and young ruminants, chemotherapy-induced poikilocytosis (see image right) and poikilocytosis in cats with liver disease. However, in some situations, there are so many red blood cell shapes or there are some shapes that defy description that the generic term poikilocytosis suffices and provides the same information as identifying each red blood cell shape individually. acanthocyte, keratocytes, echinocytes, and the generic term of poikilocytosis or poikilocytes should be avoided. Wherever possible, the red blood cell shape should be identified specifically, e.g. We can subclassify poikilocytes by specific shape changes, some of which have fairly unique diagnostic significance, while other forms are quite non-specific. The term “poikilocyte” is a generic or umbrella term to describe erythrocytes with abnormal shape.
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