Changes

* Paracetamol (acetominophen) - cats have a low level of N-acetyltransferase enzymes, which prevents them from metabolising the drug to non-toxic substances as humans do.  (ref name="ACVIM"> McConkey SE , Cribb A . The molecular mechanism of acetaminophen in dogs and cats. In: Proceedings of the 26th Annual American College of Veterinary Internal Medicine Meeting 2008, pp. 610 – 612 </ref>. They are also relatively deficient in methaemoglobin reductase and methaemoglobinaemia is also a feature of paracetamol toxicity in cats.  

* Paracetamol (acetominophen) - cats have a low level of N-acetyltransferase enzymes, which prevents them from metabolising the drug to non-toxic substances as humans do.  (ref name="ACVIM"> McConkey SE , Cribb A . The molecular mechanism of acetaminophen in dogs and cats. In: Proceedings of the 26th Annual American College of Veterinary Internal Medicine Meeting 2008, pp. 610 – 612 </ref>. They are also relatively deficient in methaemoglobin reductase and methaemoglobinaemia is also a feature of paracetamol toxicity in cats.  

* Diabetes mellitus - there is increased production of radicals resulting from various disease-induced metabolic compromises. Ketoacidotic cats have significantly higher numbers of Heinz bodies than non-ketoacidotic patients. (<ref name="DM"> Christopher M, Broussard J, Peterson M., (1995). '''Heinz body formation

* Diabetes mellitus - there is increased production of radicals resulting from various disease-induced metabolic compromises. Ketoacidotic cats have significantly higher numbers of Heinz bodies than non-ketoacidotic patients. (<ref name="DM"> Christopher M, Broussard J, Peterson M., (1995). '''Heinz body formation associated with ketoacidosis in diabetic cats'''.J Vet Intern Med, Vol 9: p. 24 – 31.</ref>

associated with ketoacidosis in diabetic cats'''.J Vet Intern Med, Vol 9: p. 24 – 31.</ref>

* Hyperthyroidism - one study found increased numbers of Heinz bodies in hyperthyroid cats but patients were not significantly anaemic. (<ref name="Christopher"> Christopher M, (1989). '''Relation of endogenous Heinz bodies to disease and anemia in cats: 120 cases (1978 – 1987)'''. J Am Vet Med Assoc, Vol 194 pp. 1089-1095</ref>

* Hyperthyroidism - one study found increased numbers of Heinz bodies in hyperthyroid cats but patients were not significantly anaemic. (<ref name="Christopher"> Christopher M, (1989). '''Relation of endogenous Heinz bodies to disease and anemia in cats: 120 cases (1978 – 1987)'''. J Am Vet Med Assoc, Vol 194 pp. 1089-1095</ref>

===Horses===

===Horses===

* Dried red maple leaves - contain gallic acid, which may be involved in Heinz body formation.  <ref name="maple>Alward A, Corriher C, Barton M, et al. (2006) Red maple (Acer rubrum) leaf toxicosis in horses: a retrospective study of 32 cases. '''J Vet Intern Med''' 20: 1197 – 1201</ref>

* Dried red maple leaves - contain gallic acid, which may be involved in Heinz body formation.  <ref name="maple">Alward A, Corriher C, Barton M, et al. (2006) Red maple (Acer rubrum) leaf toxicosis in horses: a retrospective study of 32 cases. '''J Vet Intern Med''' 20: 1197 – 1201</ref>

* Garlic - can be used as an antifungal agent in stock feed.

* Garlic - can be used as an antifungal agent in stock feed.

Heinz bodies are frequently missed on routine blood films as they tend not to stain well. However they are easily seen on slides stained with new methylene blue and with Wright-Giemsa stain. <ref name="CVT"></ref>

Heinz bodies are frequently missed on routine blood films as they tend not to stain well. However they are easily seen on slides stained with new methylene blue and with Wright-Giemsa stain. <ref name="CVT"></ref>

Healthy cats may have up to 10% Heinz bodies <ref name="Lab_methods"></ref>

Healthy cats may have up to 10% Heinz bodies <ref name="Lab_methods">Willard and Tvedten (eds) (2012 )'''Clinical diagnosis by laboratory methods Sixth edition''' Elsevier p. 52 </ref> Higher numbers of Heinz bodies may be seen in cats with underlying diseases such as diabetes mellitus, hyperthyroidism and lymphoma but anaemia is not severe in these cases. In contrast, cats suffering from oxidative ingestion will usually have severe anaemia accompanying the Heinz bodies. If a smear is examined more than about 2 days after the oxidative insult, allowing time for a regenerative response to be mounted, reticulocytosis and polychromasia will usually be evident.

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