Endocarditis in Dogs
Dr. Arnold Plotnick
Thorough history and physical exam. Although the great diversity of clinical signs in dogs with endocarditis makes it "the great imitator," on occasion, an owner will reveal a history of an event that might have predisposed the dog to endocarditis, such as a recent dental procedure or recent placement of an intravenous catheter. Usually, however, the history is vague and non-specific, such as lethargy and poor appetite. Most dogs have a fever on physical examination. If the dog is already in heart failure, presence of a cough, weakness, and shortness of breath may be present as well. Fever and a heart murmur, especially one that had not been detected on previous examinations, is suggestive of endocarditis.
Cardiac ultrasound. This is an important tool in the diagnosis, as the visualization of vegetations on the mitral and/or aortic valve is highly supportive of a diagnosis. If heart failure is present, ultrasound also helps assess the degree to which the heart is compromised.
Electrocardiography (EKG). EKG analysis detects abnormal heart rhythms in 50 to 75 percent of dogs with endocarditis. Seriously abnormal rhythms carry a poorer prognosis for survival.
Thoracic radiograms. X-rays of the chest help diagnose the heart failure that often develops as a consequence of the malfunctioning, infected valves.
Blood cultures. Isolation and identification of bacteria in the bloodstream strongly support a diagnosis of endocarditis, in conjunction with other diagnostic findings. Positive blood cultures have been reported in about 75 percent of dogs with bacterial endocarditis.
The goals of therapy for bacterial endocarditis are to sterilize the vegetations on the valves, to treat any heart failure or other heart abnormalities such as abnormal rhythms, and to manage any abnormalities that might be affecting other organ systems as a result of the heart valve infection.
Antibiotics. Antibiotics are the mainstay of therapy for endocarditis. Therapy usually lasts for two to six weeks to ensure complete killing of the infecting organism. Initially, they should be given intravenously so that effective blood levels are achieved rapidly. Dogs that respond well are sent home with oral antibiotics.
Anti-arrhythmics. Drugs that control abnormal heart rhythms are used to treat severe or life-threatening abnormal rhythms.
Drugs that treat congestive heart failure (diuretics, cardiac glycosides, vasodilators, angiotensin converting enzyme inhibitors). Heart failure is the most common cause of death in dogs with bacterial endocarditis. Palliation of the clinical signs of heart failure may be achieved using a variety of drugs. The specific drug regimen is tailored to the individual patient.
Treatment for shock. Septic shock is a serious complication that is difficult to treat and carries a poor prognosis for survival. Intravenous fluids, antibiotics, and perhaps a dose of glucocorticoids (this is very controversial) may be given in an attempt to reverse this condition.