Mitral stenosis with bacterial myocarditis in a cat.

An eleven-year-old female Japanese mongrel cat was referred to the Tottori University Veterinary Teaching Hospital for assessment of acute paresis and dyspnea. Two-dimensional echocardiography showed a hydropericardium. The mitral valve leaflets were thickened, the separation of the right and left leaflets was not complete. Treatments with intravenous fluids of lactate Ringer solution, furosemide, urokinase, antibiotics were initiated, but did not improve the respiratory failure. The cat died 10 days later. From pathological and microbiological examinations, this was an unusual case diagnosed as acquired mitral stenosis associated with congenital malformation of the mitral valve complex, and accompanied by secondary infectious myocarditis with Streptococcus canis.