Infective Endocarditis in Dogs and Cats: Symptoms, Echocardiography & Treatment [2025]
Infective endocarditis is a bacterial infection of the heart valves that can lead to valve dysfunction. Signs may include fever, a heart murmur and lameness. Treatment usually requires long-term, high-dose antibiotics.
When to See a Vet
Seek Immediate Emergency Care
- •Difficulty breathing or severe respiratory distress — seek emergency care immediately
- •Confusion, brief loss of consciousness, or sudden fainting
- •Sudden weakness in limbs or abrupt inability to walk
Schedule a Clinic Visit Soon (within 24–72 hours)
- •Persistent lethargy or noticeably reduced activity level
- •Fever or body temperature fluctuating for more than one day
- •Intermittent lameness or pain in one or more limbs
01What symptoms suggest something is wrong?
Infective endocarditis often causes both whole-body signs of infection and heart-related signs. Clinical changes can be rapid and may not follow a typical pattern.
- Lethargy and a clear drop in activity, often appearing listless
- Reduced appetite or ongoing refusal to eat, with a noticeable drop in food intake
- Fever or fluctuating body temperature that rises and falls and is hard to stabilise
- Difficulty breathing or obvious panting, with rapid breathing possible even at rest
- Lameness in one or more limbs, intermittent pain or an unsteady gait
- Repeated vomiting or regurgitation; arrange a veterinary consultation if it continues
Seek emergency care immediately if you notice the following symptoms:
- ⚠️ Seek urgent veterinary care for difficulty breathing or severe panting
- ⚠️ Confusion, brief collapse or episodes of unresponsiveness
- ⚠️ Sudden weakness in all four limbs or sudden inability to walk
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02How can I assess abnormalities at home? Key observations and when to seek emergency care
Careful observation and key notes at home can help your vet understand the disease timeline quickly and assess severity.
- Write down when the illness started and the order in which signs appeared
- Take your pet's temperature each day and record the time and reading to track fluctuations
- Watch for changes in energy, sleep and activity tolerance
- Record increases or decreases in food and water intake, as well as any vomiting or diarrhoea
- Use your phone to record short videos of breathing, walking or vomiting to show your vet
- If signs worsen or any warning signs appear, arrange a specialist consultation promptly
03How will the vet diagnose it? Common tests
At the clinic, your vet will use systematic examinations and tests to find the infection source, assess the degree of heart damage and evaluate effects on the rest of the body.
Detailed physical examination, including heart auscultation and assessment of the lungs and whole body
Blood tests, including a complete blood count and organ function testing
Blood culture or other bacterial culture samples to identify the infectious organism
Echocardiography to assess heart valve damage and structural heart abnormalities
PCR testing or cytology to help confirm the source of infection
Advanced imaging such as chest or abdominal imaging or CT when needed
Testing is best arranged at a referral or larger veterinary hospital that can perform blood cultures
04How is it treated and managed after diagnosis? Medication, diet and care
Treatment focuses on controlling infection and supporting organ function. Many pets need long-term follow-up and repeated tests to assess response to treatment.
- Hospitalisation with intravenous fluids and supportive care to maintain fluid and electrolyte balance
- Long-term antibiotics adjusted according to culture results, with regular blood test monitoring
- Oxygen therapy or other supportive treatment when needed to stabilise your pet
- Scheduled rechecks and follow-up imaging or blood tests as directed by your vet
- Dietary adjustment, adequate rest and avoiding overexertion can support recovery
- Regular assessment by a veterinary cardiologist and a long-term follow-up plan are recommended
05What should I prepare before seeing the vet? Key details that help identify the cause
This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.