Sa Medicine Ii -- Infectious Endocarditis

--inflammation of the valve tissue
(usually due to an infectious agent)

>> bacterial endocarditis

>> vegetative endocarditis

>> fungal endocarditis

>> marantic endocarditis (sterile vegetations)

--camelids get mural endocarditis

--vegetations are on the walls, not the valves

--bacteremia
>> normal flora
>> remote inf.

--vegetative lesions
>> high pressure source
>> flow side of valves

>> wide variation of size/shape

--consist of platelets, fibrin, RBCs, WBCs, +/- admixed bacteria

--must have transient or persistent bacteremia

--endothelial injury results in platelet deposition

--bacteremia allows bacterial adhesion/colonization of vegetative lesion

--endothelial integrity

--disturbed blood flow

--bacterial virulence

--host immunity

--dogs, cats, horses, pigs: mitral and aortic valves

--tricuspid and pulmonic valves

--mural endocardium (RV > LV)

--valvular insufficiency

>> volume overload

--myocarditis

>> arrhythmias

--systemic infection

>> sepsis

--septic embolization (target organs)

--immune-mediated disease

>> arthritis, glomerulonephropathy

-- ventricular arrhythmias > SVT > 3rd degree AV node block > atrial fibrillation

--subaortic stenosis

>> jet lesions on endocardial surface

--subaortic stenosis

--immunocompromise (e.g. chemo)

--virulent infections

>> diskospondylitis, prostatitis, pneumonia, UTI, pyoderma

--indwelling catheters >> iatrogenic phlebitis

--staph

--strep

--E. coli

-- corynebacterium spp.

--streptococcus spp.

--actinobacillus spp.

--Bartonella spp.

--other fastidious or slow-growing organisms

--prior antibitic treatment

--deficient blood culture technique

"the great imitator"

--CHF, heart murmur

--weight loss, diarrhea, anorexia

--ocular disease, paresis, seizures

--hematuria, renal failure

--septic arthritis

--medium to large breed dogs

--GSD, Boxers, Goldens, Labs, rottweilers

>> breeds predisposed to subaortic stenosis

--4d anorexia lethargy

--2d intermittent left pelvic limb lameness

--24h respiratory difficulty

--2/6 left basilar diastolic murmur

-- 104.5F

--bounding femoral pulses

>> systolic P inc.

>> diastolic P dec.

--positive echocardiogram

--new valvular insufficiency

--positive blood culture

--fever

--medium to large dog

--SAS

--thromboembolic disease

--immune-med disease

--positive blood culture

--Bartonella serology > 1:1024

--pathology of valve

--two major criteria

--one major and two minor criteria

--isolation of bacteria from valvular lesion

--multiple venipuncture sites

>> 2-3 samples drawn over 3-24h

>> sterile collection

>> anaerobic and aerobic cultures

>> do prior to abx if possible

--antibiotic sensitivity testing

--clinical signs of L CHF

--not uncommon to have signs of ATE/inflammatory arthritis

--grave prognosis, MST of 31 d (one study)

--no

--aminoglycosides (amikacin) or enrofloxacin
+

--penicillin or cephalosporin

--broad spectrum (C&S results)

--long-term: 8-12 wks of treatment

--heart failure treatment (FAD)

--treat arrhythmias, target organ disease

--clavamox and enrofloxacin

--b-lactam

--doxycycline

--azithromycin

--spleen

--kidney

--brain

--heart

--joints

--guarded to poor

--heart failure

>> aortic insufficiency

>> mitral regurgitation

--septic shock

--organ failure

--cardiac arrhythmias

-- >80% mortality (AI >> MR)

--they have mitral regurgitation (not aortic insufficiency) and non-bartonella infections

-- mitral valve MST > Aortic valve MST

--valvular insufficiency

--succumb to infection (sepsis)

--embolization

--arrhythmias

--immune mediated complications
(e.g. IM polyarthritis, glomerulonephritis)

--antibiotics prior to and after dental procedures, urogenital or GI surgery, other surgical procedures or lacerations