Infective Endocarditis
Introduction
Infectious clinical syndrome spans a continuum
between acute and subacute presentations
 Acute endocarditis- febrile illness, rapid damage
to cardiac structures and seeding of extracardiac
sites hematogenously, death within weeks (6
wks).
 Subacute endocarditis-Follows an indolent course,
rarely metastatic infection, slowly damages heart
if occurs at all, gradual progression unless
complicated by embolic event or ruptured
mycotic aneurysm
Brief Pathophysiology
 Infectious syndrome with a lot of causative
pathogens. Consult Harrison’s for full list (Native
Endocarditis, Prosthetic, IV drug user)
 Acute Endocarditis
1. Staph aureus
2. B-hemolytic streptococci
3. pneumococci
 Subacute endocarditis
1. Strep viridans
2. Enterococci
3. Coagulase negative Staph aureus
4. HACEK
(Haemophilus,
Actinobacillus,
Cardiobacterium, Eikenella, Kingella)
 Endothelial injury [site of impact of high pressure
jets or low-pressure side of a cardiac lesion]
causes aberrant flow allowing:
o Direct infection
o Nonbacterial
thrombotic
endocarditis=
Development of uninfected platelet-fibrin
thrombus that is later infected during a
transient bacteremia
 Vegetation-prototypic lesion = platelets + fibrin+
microcolony of organisms and scant inflammatory
cells
Differentials
 Signs and symptoms of IE are non-specific and
highly variable. Why?
o A predisposition to IE are valvular defectsvariable cardiac manifestations may be due to IE
or the predisposing valvular defect example:
murmurs may be due to a congenital VSD or
rheumatic heart disease which predisposes the
patient to IE or can be caused by IE.
o Embolic events are a complication of IE. It can
throw emboli anywhere in the body causing
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events such as stroke, MI, infarction of
extremities, bowels, spleen, kidneys.
o Metastatic infection-hematogenous spread may
result in focal infections at other sites which
include skin, brain, kidneys, spleen, skeletal
system. It is possible to form abscesses and
meningitis.
The most common symptom is fever. So
differentials will include ALL febrile illnesses. Since
infective endocarditis can be caused by
bacteremia of a host of pathogens and has
variable symptoms and signs as stated earlier its
diagnosis is not based on ruling out other diseases
but of RULING IN infective endocarditis. (IE can
exist with other diseases)
Manifestations include: fever, chills and sweats,
anorexia, weight loss, malaise, myalgias,
arthralgias, back pain, murmurs, heart blocks,
heart failure symptoms, arterial emboli,
splenomegaly, clubbin, neurologic manifestations,
peripheral manifestations, petechiae.
Roth’s spots-oval retinal hemorrhages with pale
centers
Janeway
lesions-small
erythematous
or
hemorrhagic, macular nontender lesions on palms
and soles due to septic embolic events
Osler’s nodes-small tender, subcutaneous nodules
in pulp of digits or proximally in fingers lasting for
hours or days.
Subungual hemorrhages
Diagnosis
When do we suspect IE?
Suspect IE in all febrile patients with:
1. Valvular abnormalities, prosthetic valves
2. Congenital heart disease
3. IV drug abuser
4. Bacteremia with pathogens typical of IE
5. Unexplained arterial emboli
6. Progressive valvular incompetence (new or
worsening murmur)
Diagnosis is based on Duke’s criteria:
DEFINITE endocarditis
o 2 major criteria
o 1 major + 3 minor criteria
o 5 minor criteria
POSSIBLE endocarditis
o 1 major +1 minor criteria
o 3 minor criteria
DUKES criteria
Major
1. Positive Blood culture
a. Typical microorganism in 2 separate cultures
b. Persistently positive blood culture
i. Blood cultures drawn 12 hours apart
ii. All 3 or majority of 4 or more separate blood
cultures with 1st and last drawn at least 1 hour
apart
iii. Exception: Coxiella burnetii-single positive
blood culture or elevated IgG antibody titer
2. Evidence of Endocardial involvement
a. Positive echocardiogram
i. Oscillating intracardiac mass on valve or
supporting structures in the absence of an
alternative anatomic explanation (vegetation)
ii. Abscess
iii. New partial dehiscence of prosthetic valve
b. New valvular regurgitation
Minor
1. Predisposition: heart condition or IV drug user
2. Fever >38.0oC
3. Vascular phenomena: major arterial emboli,
septic pulmonary infarcts, mycotic aneurysm,
intracranial
hemorrhage,
conjuntival
hemorrhage, Janeway lesions
4. Immunologic phenomena: glomerulonephritis,
Osler’s nodes, Roth’s spots, Rheumatoid factor
5. Microbiologic evidence: Positive blood culture
not meeting major criteria or serologic evidence
of active infection with organism consistent with
IE
Mnemonic for Dukes criteria (original ito by Joguel)
BE Vv’s FIMP (Read: Be VV’s PIMP!!!)
Major criteria: BE= Blood culture + Endocardial
involvement
Minor Criteria
Vv’s FIMP= Vascular + Fever + Immunologic +
Microbiologic + Predisposition
Plan
Diagnostics
 Blood Culture, 2-D echo (for Duke’s criteria)
o Note Transthoracic echo (TTE) is
less
sensitive
than
Transesophageal echo (TEE)
 CBC with PC with DC- elevated WBC with
neutrophilic predominance, may have anemia
 Crea- kidney function test: involvement of kidney
or Gentamicin nephrotoxicity (may be elevated)
 Chest radiograph- Heart enlargements (heart
defects)
 ECG- detect heart blocks, MI, chamber
enlargements
 Other labs: ESR, C-reactive protein, rheumatoid
factor, circulating immune complex titers are all
elevated
IVF: No particular fluid needed. PNSS 1L x 12-24
hours to keep vein open (KVO). Choice of fluids may
depend on other comorbidities
Diet: Diet as tolerated
Monitor: VS q1-4 hours with TEMP
Admit to Ward or Micu-depending on the patient
Treatment
Ideally, treatment with antibiotics is culture guided.
Consult Harrison’s for specific regimen for each
pathogen. There are SEVERAL.  But….
Empiric treatment (from Med Blue book):
Acute Bacterial Endocarditis (including IV drug user)=
main target Staph. aureus
1. Oxacillin 2g IV q4 or Vancomycin 500mg IV
q6 or 1 gm q 12 (1 gm in 250 mL D5W
infused slowly over 1 hour q 12) for 4 weeks
2. + Gentamicin 100-200 mg IV (2mg/kg), then
80 mg (1-1.5mg/kg) IV q8 for 3-5 days
Note: may change regimen once with
culture and sensitivity results.
Subacute Bacterial Endocarditis= main target Strep
viridans, Enterococci
1. Penicillin G 2-4 M units (12-24 M units/day)
IV q4 for 4 weeks or Ampicillin 2 g
(12g/day) q4 [high or low dose penicillin
depends on microorganism and clinical
course. High dose=toxic patients] If culture
negative use Ceftriaxone 2 g IV OD for 4
weeks
2. + Gentamicin 80mg (1-1.5 mg/kg) IV q8 x 2
weeks
Expected clinical course:
 Defervescence after 3-7 days
 Repeat blood C/S 2 and 4 weeks after end
of treatment to detect relapse