Download Document

Dr. Talaat Ali Sabeeh
Al-Jarrah
Pediatric Cardiologist
Infective Endocarditis(IE):
PREVALENCE: IE accounts for 0.5 to 1 of every 1000 hospital
admissions, excluding postoperative endocarditis. The frequency
of IE among children seems to have increased in recent years.
This is due in part to survivors of surgical repair of complex
congenital heart disease and survivors of neonatal intensive care
units, who are at an increased risk for IE.
PATHOGENESIS:
1)Two factors are important in the pathogenesis of IE: a damaged
area of endothelium and bacteremia, even transient.
2)The presence of structural abnormalities of the heart or great
arteries, with a significant pressure gradient or turbulence,
produces endothelial damage that induces thrombus formation
with deposition of sterile clumps of platelet and fibrin
(nonbacterial thrombotic endocarditis), which provides a nidus
for bacteria to adhere leading to vegetation.
3)Almost all patients who develop IE have a history of congenital
or acquired heart disease. Drug addicts may develop IE in the
absence of known cardiac anomalies
Causes:
1)All congenital heart defects, with the exception
of secundum ASD, predispose to IE. More frequently
encountered defects are TOF, VSD,AV disease,TGA,
and systemic-to-pulmonary artery (PA)
shunt(PDA,A-P Window,BT shunt). Rheumatic
valvular disease, particularly MR.prosthetic heart
valve or prosthetic material in the heart are at
particularly high risk for developing IE. Patients
with mitral valve disease (MVP with MR) and those
with hypertrophic obstructive cardiomyopathy
are also vulnerable to IE.
2)Any localized infection (e.g., abscess, osteomyelitis,
pyelonephritis) can seed organisms into the
circulation
MICROBIOLOGY:
In the past, Streptococcus viridians, enterococci,
and Staphylococcus aureus were responsible for
over 90% of the cases,but this decreased to 50% to
60%, with a concomitant increase in cases caused
by fungi and HACEK organisms (Haemophilus,
Actinobacillus, Cardiobacterium, Eikenella, and
Kingella). HACEK organisms are particularly
common in neonates and immunocompromised
children, accounting for 17% to 30% of cases. 4).
Fungal endocarditis (which has a poor prognosis)
may occur in sick neonates, in patients who are
receiving long-term antibiotic or steroid therapy, or
after open-heart surgery
CLINICAL MANIFESTATIONS
History:
1)History of an underlying heart defect.
2)A history of a recent dental procedure or tonsillectomy
is occasionally present, but a history of toothache
(from dental or gingival disease) is more frequent than
a history of a procedure.
3)IE is rare in infancy; at this age, it usually follows openheart surgery.4)The onset is usually insidious with
prolonged low-grade fever and somatic complaints,
including fatigue, weakness, loss of appetite, pallor,
arthralgia, myalgias, weight loss, and diaphoresis
Physical Examination:
1)Heart murmur is universal (100%). The appearance of a new heart murmur
and an increase in the intensity of an existing murmur are important
2)Fever is common (80% to 90%). The temperature fluctuates between
(38.3°C and 39.4°C).
3)Splenomegaly is common (70%).
4)Skin manifestations (50%) (either secondary to microembolization or as an
immunologic phenomenon) may be present in the following
forms:(Petechiae on the skin, mucous membranes, or conjunctivae are the
most frequent skin lesions,Osler's nodes (tender, pea-sized red nodes at
the ends of the fingers or toes) are rare in children,Janeway's lesions
(small, painless, hemorrhagic areas on the palms or soles) are rare, and
Splinter hemorrhages (linear hemorrhagic streaks beneath the nails) are
also rare.
5)Embolic or immunologic phenomena in other organs are present in 50% of
cases,Hematuria and renal failure may occur,Roth's spots (oval, retinal
hemorrhages with pale centers located near the optic disc) occur in less
than 5% of patients.
Also 1-Carious teeth or periodontal or gingival disease is frequently present.
2-Clubbing of fingers without cyanosis develops rarely in more chronic cases.
3-Signs of heart failure may be a complication of IE.
4-C/F in a neonate with IE are nonspecific (respiratory distress, tachycardia)
Laboratory Studies
1-Positive blood cultures are found in more than 90% of
patients in the absence of previous antimicrobial therapy.
Antimicrobial pretreatment reduces the yield of positive
blood culture to 50% to 60%.
2-A complete blood cell count shows anemia, with
hemoglobin levels lower than 12 g/100 mL (present in 80%
of patients), and leukocytosis with a shift to the left.
3-ESR is increased unless there is polycythemia.
4-Microscopic hematuria is found in 30% of patients.
5-Certain echo :(Oscillating intracardiac mass on valve or
supporting structures, in the path of regurgitation jets, or
on implanted material,Abscesses, New partial dehiscence of
prosthetic valve,New valvular regurgitation).
TEE may be superior to TTE in identifying (vegetations on
prosthetic valves, detecting complications of left ventricular
(LV) outflow tract endocarditis (either valvular or
subvalvular), and in detecting aortic root abscess and
involvement of the sinus of Valsalva).
Certain echo features suggest a high-risk case or a need for
surgery:
1-Large vegetations (greatest risk when the vegetation is >10
mm).
2-Severe valvular regurgitation.
3-Abscess cavities.
4-Pseudoaneurysm.
5-Valvular perforation or dehiscence.
6-Decompensated heart failure.
DIAGNOSIS: There are three categories of diagnostic possibilities
using the modified Duke criteria: definite, possible, and rejected
Definition of terms used in the modified duke criteria .
MAJOR CRITERIA
A)Blood culture positive for IE:
1)Typical microorganisms consistent with IE from two separate blood cultures; or
2)Microorganisms consistent with IE from persistently positive blood cultures defined as follows:
at least two positive cultures of blood samples drawn >12 hours apart; or all of three or a
majority of four separate cultures of blood (with first and last samples drawn at least 1 hour
apart)
3)Single positive blood culture for Coxiella burnetii or anti-phase 1 IgG titer >1:800
B)Evidence of endocardial involvement
1) Echocardiogram positive for IE; or
2)Abscess; or
3)New partial dehiscence of prosthetic valve; or
4)New valvular regurgitation (worsening or changing or preexisting murmur not sufficient)
MINOR CRITERIA
1)Predisposition, predisposing heart condition, or injection drug users.
2)Fever, temperature >38°C.
3)Vascular phenomena: major arterial emboli, septic pulmonary infarcts, mycotic aneurysm,
intracranial hemorrhage, conjunctival hemorrhages, and Janeway's lesions
4)Immunologic phenomena: glomerulonephritis, Osler's nodes, Roth's spots, and rheumatoid
factor .
5)Microbiologic evidence: positive blood culture but does not meet a major criterion as noted
above or serologic evidence of active infection with organism consistent with IE
MANAGEMENT
1-Blood cultures are indicated for all patients with fever of
unexplained origin and a pathologic heart murmur, a history
of heart disease, or previous endocarditis.
a)Usually, three blood culture samples are drawn by separate
venipunctures over 24 hours, unless the patient is very ill. In
90% of cases, the causative agent is recovered from the first
two cultures.
b)If there is no growth by the second day of incubation, two
more maybe obtained. There is no value in obtaining more
than five blood cultures over 2 days unless the patient
received prior antibiotic therapy.
c)It is not necessary to obtain the cultures at any particular
phase of the fever cycle.
d)An adequate volume of blood must be obtained; 1 to 3 mL in
infants and young children and 5 to 7 mL in older children are
optimal.
e)Aerobic incubation alone suffices because it is rare for IE to
be due to anaerobic bacteria.
2-It is highly recommended that consultation with a local
infectious disease specialist .
3-Initial empirical therapy is started with the following
antibiotics while awaiting the results of blood
cultures.a)The usual initial regimen is an
antistaphylococcal semisynthetic penicillin (nafcillin,
oxacillin, or methicillin) and an aminoglycoside
(gentamicin). This combination covers against S. viridans,
S. aureus, and gram-negative organisms.
4-The final selection of antibiotics depends on the organism
isolated and the results of an antibiotic sensitivity test.
Streptococcal IE: intravenous (IV) penicillin , 4 weeks.
Staphylococcal IE
1)If methicillin-susceptible staphylococci (MSSA):
is one of the semisynthetic β- lactamase-resistant
penicillins (nafcillin, oxacillin, and methicillin) for a
minimum of 6 weeks (with or without gentamicin for
the first 3 to 5 days).
2). Patients with methicillin-resistant(MRSA) native
valve IE are treated with vancomycin for 6 weeks (with
or without gentamicin for the first 3 to 5 days).
Enterococcus-caused native valve endocarditis usually
requires a combination of IV penicillin or ampicillin
with gentamicin for 4 to 6 weeks. If patients are
allergic to penicillin, vancomycin combined with
gentamicin for 6 weeks is required.
HACEK organisms have begun to become resistant to
ampicillin.Ceftriaxone or another third-generation
cephalosporin alone or ampicillin plus gentamicin for
4 weeks .
Fungal IE :Amphotericin B.
For culture-negative endocarditis:treatment is directed
against staphylococci, streptococci, and the HACEK
organisms using ceftriaxone and gentamicin.
Prosthetic valve endocarditis should be treated for 6
weeks based on the organism isolated and the results of the
sensitivity test.
Operative intervention may be necessary before the
antibiotic therapy is completed if the clinical situation
warrants (such as progressive CHF, significant malfunction
of prosthetic valves, persistently positive blood cultures
after 2 weeks of therapy). Bacteriologic relapse after an
appropriate course of therapy also calls for operative
intervention
PROGNOSIS: overall recovery rate is 80% to 85%; it is
90% or better for S. viridans and enterococci and about
50% for Staphylococcus organisms. Fungal
endocarditis is associated with a very poor outcome
PREVENTION:More important than the diagnosis and
treatment of IE is its prevention. Maintenance of good
oral hygiene is more important than antibiotic
prophylaxis.
Indications and non indications of IE prophylaxis based on cardiac 
lesions
PROPHYLAXIS RECOMMENDED 
High-Risk Category 
1-Prosthetic cardiac valve, including bioprosthesis and homograft valves 
2- Previous bacterial endocarditis3-Complex cyanotic congenital heart defect 
(e.g., single ventricle, transposition of the great arteries, tetralogy of Fallot)
4-Surgically constructed systemic-to-pulmonary artery shunt or conduit 
Moderate-Risk Category 
1-Most other congenital heart defects (e.g., patent ductus arteriosus, 
ventricular septal defect, primum atrial septal defect, coarctation of the aorta,
bicuspid aortic valve)
2-Acquired valvular dysfunction (e.g., rheumatic heart disease, collagen 
vascular disease) 3-Hypertrophic cardiomyopathy4-Mitral valve prolapse with
mitral regurgitation and/or thickened mitral valve leaflets
PROPHYLAXIS NOT RECOMMENDED (Negligible-Risk Category) 
1-Isolated secundum atrial septal defect2-Surgical repair of atrial or ventricular
septal defects or patent ductus arteriosus (without residua beyond 6
months).3-Previous coronary artery bypass surgery.4-Mitral valve prolapse
without mitral regurgitation.5- Innocent heart murmurs.6-Previous Kawasaki
disease without valvular dysfunction7- Previous rheumatic fever without
valvular dysfunction 8-Cardiac pacemakers (intravascular and epicardial) and
implanted defibrillators.
Dental procedures and endocarditis prophylaxis
PROPHYLAXIS RECOMMENDED
1-Dental extraction.2-Periodontal procedures including surgery,
scaling and root planing, probing, and recall maintenance.3Dental implant placement and reimplantation of avulsed teeth
4-Endodontic (root canal) instrumentation or surgery only
beyond the apex .5-Subgingival placement of antibiotic fibers or
strips. 6-Initial placement of orthodontic bands but not brackets
Intraligamentary local anesthetic injections.7-Prophylactic
cleaning of teeth or implants when bleeding is anticipated
PROPHYLAXIS NOT RECOMMENDED
1-Restorative dentistry (operative and prosthodontic) with or
without retraction cord.
2-Local anesthetic injection (non-intraligamentary).3-Intracanal
endodontic treatment; post placement and buildup. 4Placement of rubber dams.5-Postoperative suture removal.6Placement of removable prosthodontic or orthodontic
appliances.7- Taking of oral impressions.8-Fluoride
treatments.9- Taking of oral radiographs.10.Orthodontic
appliance adjustment Shedding of primary teeth