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| − | ==Inflammatory-Myocarditis== | + | ==Inflammatory-[[Myocarditis]]== |
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| − | Most often due to an infective agent. In most cases myocarditis is a result of a generalised infection, myocarditis is rarely an isolated primary condition.
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| − | Classified as:
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| − | ===Acute Suppurative===
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| − | Follows from the dissemination of septic emboli form suppurative foci therefore always follows pyaemia. Original septic foci may be:
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| − | *Joint ill.
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| − | *Umbilical abcess.
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| − | *Metritis.
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| − | *Mastitis.
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| − | *Valvular endocarditis.
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| − | May also be a result of extension from the endocarium or pericardium.
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| − | ===Acute non-suppurative===
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| − | [[Image:parvovirus dog.jpg|right|thumb|125px|<small><center>'''Parvovirus (dog)'''. Courtesy of T. Scase</center></small>]]
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| − | Usually results from a septicaemia or viraemia E.g [[Parvoviridae|Parvovirus]] infection in puppies.
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| − | Also includes:
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| − | *Foot and Mouth Disease.
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| − | *Leptospirosis.
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| − | *Pasteurellosis.
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| − | '''''Parvovirus Infection of puppies''''':
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| − | Parvovirus affects rapidly dividing cells which are found in the GI tract, and in the growing pup, the myocardium. Myocardial cells divide up to approximately 2 weeks of age and so this is when the infection has an effect although clinical signs may not become apparent until later in life.
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| − | [[Image:Parvovirus myocarditis.jpg|right|thumb|125px|<small><center>'''Parvoviral Myocarditis'''. Courtesy of A. Jefferies</center></small>]]
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| − | Two cardiac syndromes exist:
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| − | *'''Sudden death, 3-8 weeks:''' Cardiac failure with pulmonary oedema etc. Histologically see multifocal myocardial necrosis due to viral replication within the myocardium. May see large basophilic intranuclear inclusion bodies.
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| − | *'''Puppies >8 weeks:''' See dyspoea, weakness, collapse and death within 24 hours. In this case cardiac failure occurs due to myocardial fibrosis.
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| − | ===Chronic===
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| − | Myofibrils replaced by fibrous tissue during healing. May be a sequale of previous acute myocarditis.
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| − | ===Parasites===
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| − | Parasites also may cause myocarditis. parasitic larvae may encyst in the myocardium, including:
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| − | *Cysticercosis.
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| − | *Sarcocystis.
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| − | *[[Tissue_cyst-forming_coccidia|Toxoplasmosis]].
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| | ==Vascular pathology== | | ==Vascular pathology== |