TV4101 -SAM - Infective Endocarditis

Signalment

•Medium to large breed dogs

•Very rare in cats

Relation to Congenital HD or MMVD?

•Low incidence in congenital heart disease- Subaortic stenosis and PDA may have associations

•No association with MMVD – even with dental procedures and bacteremia

Pathogenesis?

•Bacteremia - Mouth, GI, UTI, skin or unknown source

Bacteria cannot survive in bloodstream

•Collect in dense capillary beds/end organ systems

•Glomeruli

•Joints

•Brain/meninges

•Heart valves/endocardium

•Pleural surfaces

•Spine

Species differences for predilection sites

Pathogenesis continued

Bacterial and host factors?

•Bacterial factors - Virulence, type, oxygen requirements

•Host factors - Endothelium, immune defences, mucosal defence

The pathogenesis is not clear though because

Little dogs that have damaged heart valves, rotten teeth and Cushing’s disease don’t seem to get IE

Infective Endocarditis DX?

•Can be challenging – no gold standard single test

•Radiographs often unhelpful

•Echocardiography may show hyperechoic nodules on valves

• Aortic – very suspicious – especially if insufficiency

• Mitral – MMVD can look nodular and its common

•Blood culture – skin contaminants, or transient bacteremia may confound results

Usual bacterial suspects?

•Staph spp. (S. aureus, S. intermedius, coagulase-positive and coagulase-negative),

Strep spp. (S. canis, S. bovis, and beta-hemolytic)

Bartonella spp.,

Ecoli,

Pseudomonas aeruginosa, Corynebacterium spp.,

Erysipelothrix rhusiopathiae.

•Bartonella vinsonii and related proteobacteria (B. henselae, B. clarridgeiae, B. washoensis)

• Contentious

• Because of subclinical/asymptomatic infections

Blood culture aspects?

•Bacteremia is transient/episodic – “thunder showers”

•Skin contamination is issue

•Collect 5-10ml per site (3-4 sites) every 30 min to one hour

TX?

•Antibiotics – based on culture ideally

•Treatment for CHF if needed

pROGNOSIS?

•Variable

• Many cases dx in teaching hosp – more severe more complications

•Many are probably rx but never diagnosed?

• Fevers in general practice

•CHF – guarded to poor.

Concerns in animal presenting would be?

•Fever

•Recently acquired murmur

•Tachycardia

Valves affected?

What else can be affected?

Other things that can happen?

•Aortic valve - ~ 50% (better to have this one affected as its less likely to have an insufficiency)

•Mitral valve - ~ 50%

•Tricuspid + pulmonic extremely rare – hypoxia

•Endocardium also can be effected

•Causes valvular leakage

•Systemic inflammatory cascade

Bacterial emboli

• Kidney

• Spleen

What is this?

Infective endocarditis - vegetative cauliflower like lesions on the vavles

CX

Fever and Recently acquired murmur

Other signs are non-specific

Major criteria for Endocarditis?

-ve echocardiogram: Vegetative or eroxive lesion, or abscess

New valvulr insufficiency: >Mild aortic insufficiency without subaortic stenosis or annuloaortic ectasia
Positive blood culture: >2 +ve blood culture, or >3 if common skin contaminant

Minor cirteria

1. Fever

2. Medium-large (>1kg)

3. Subaortic srtenosis

4. Thromboembolic disease

5. 5. immune-mediated disease: polyarthritis glomerulonephritis

6. Positive blood culture metting major critiera listed in this table

   1. Bartonella serology >1 : 1024