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* '''Methaemoglobinaemia''' formation occurs when the '''iron in the haemoglobin molecule''' is oxidised to the ferric (3+) state. In normal circumstances the methaemoglobin reductase enzyme reduces ferric (3+) back to ferrous (2+) but this system can become overwhelmed in some circumstances.<ref name="CVT"></ref> This is the only form of oxidative damage which is reversible.
* '''Methaemoglobinaemia''' formation occurs when the '''iron in the haemoglobin molecule''' is oxidised to the ferric (3+) state. In normal circumstances the methaemoglobin reductase enzyme reduces ferric (3+) back to ferrous (2+) but this system can become overwhelmed in some circumstances.<ref name="CVT"></ref> This is the only form of oxidative damage which is reversible. Methaemoglobin is a brownish compound formed by the oxidation of iron in haemoglobin from the ferrous to the ferric state. When present in quantity it leads to a muddy cyanotic discolouration of mucous membranes. Usually it accounts for less than 1.1% of haemoglobin. It is increased due to oxidative damage caused by toxins which may also cause Heinz body and eccentrocyte formation. Methaemoglobinaemia results from either increased production due to oxidative injury or decreased reduction of methaemoglobin to Hb. Congenital methaemoglobinaemia has been reported due to deficiency of the RBC enzyme NADH-methaemoglobin reductase. References: [[NationWide Laboratories]]
* Lymphoma - an increased percentage of Heinz bodies has been linked with lymphoma in cats. <ref name="Christopher"></ref>
* Lymphoma - an increased percentage of Heinz bodies has been linked with lymphoma in cats. <ref name="Christopher"></ref>
* Propylene glycol, salmon based diets and Renal failure, possibly due to altered metabolism generating oxidative metabolic intermediates.
===Dogs===
===Dogs===
* In dogs HBs are not normally present. Canine Heinz bodies are often small irregular and multiple.
* Onions/garlic - contain oxidative agents which are active in raw, cooked and dehydrated forms. Heinz body anaemias are most common in small breeds, suggesting a dose relationship and in breeds with naturally high levels of potassium, such as Akitas and Shar-Peis. <ref name="Schalm"></ref>
* Onions/garlic - contain oxidative agents which are active in raw, cooked and dehydrated forms. Heinz body anaemias are most common in small breeds, suggesting a dose relationship and in breeds with naturally high levels of potassium, such as Akitas and Shar-Peis. <ref name="Schalm"></ref>
N-acetylcysteine (Mucomyst) should be given as soon as possible after drug exposure as it is only effective within the first few hours. It is thought to increase glutathione synthesis, which provides more substrate for the detoxification of the reactive metabolite.<ref name="N-acet"> Lauterburg et al (1983) '''Mechanism of Action of N-Acetylcysteine in the Protection Against the Hepatotoxicity of Acetaminophen in Rats In Vivo''' J Clin Invest. April; 71(4): 980–991</ref>
N-acetylcysteine (Mucomyst) should be given as soon as possible after drug exposure as it is only effective within the first few hours. It is thought to increase glutathione synthesis, which provides more substrate for the detoxification of the reactive metabolite.<ref name="N-acet"> Lauterburg et al (1983) '''Mechanism of Action of N-Acetylcysteine in the Protection Against the Hepatotoxicity of Acetaminophen in Rats In Vivo''' J Clin Invest. April; 71(4): 980–991</ref>
== References ==
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[[Category:Anaemia|8]]
[[Category:Anaemia]]