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Introduction
Infective endocarditis is defined as an inflammatory process of
the endocardium of a valve or chamber, on a septal defect, or the
chordae tendineae, as a result of an infection by bacteria, virus,
fungus or mycobacteria and rickettsias, which in the majority
of cases occurs in people with pre-existing abnormalities of the
cardiovascular system ().
It is responsible for around 0.2 to 0.5% of all pediatric hospital
admissions and is a significant cause of mortality (20-64%) among
children and adolescents despite advances in treatment and prophylaxis
with antimicrobial agents. A number of different factors affect
prognosis, clinical parameters, the type of microorganism involved
and the presence of a prosthetic heart valve ().
In the absence of a previous cardiac lesion the disease is considered
rare in children ().
In adults it is common among intravenous drug users and people more
than fifty years old ().
In children a growing increase in the number of cases have been
reported, principally in newborns and young infants, with a concomitant
change in the bacterial profile. The prevalence of Staphylococcus
aureus and other bacteria which were previously less often identified
with Infective endocarditis ().
In these patients, endocarditis is acute and generally associated
with congenital cardiac defects. Cases of classic subacute endocarditis,
caused by Streptococcus viridans have reduced due to the
reduction in the prevalence of rheumatic fever and its cardiac sequelae.
In addition to the reduction in the number of rheumatic fever cases,
improvements to the care of high risk newborns, an increase in invasive
procedures and early surgical interventions in congenital cardiopathies
have contributed to an increase in the number of patients in this
age group exposed to the risk of Infective endocarditis ().
Although the disease is uncommon, it is serious and is considered
a significant cause of morbidity and mortality in children and therapeutic
success depends upon early and precise diagnosis. Despite authors
having described a number of different diagnosis criteria based
on clinical and pathological parameters, the criteria currently
most accepted are the Duke criteria which include echocardiographic
examination parameters ()
(Table 1). The value of this examination has been questioned, but
its validity has been confirmed if a bidimensional color Doppler
echocardiogram is used and the cardiologist has experience in interpreting
the results. With the publication of new Infective endocarditis
diagnosis criteria by the Endocarditis Service at Duke University,
it is now considered that the two main criteria for certain diagnosis
of Infective endocarditis are multiple positive blood cultures
for typical germs and echocardiogram evidence of myocardial lesions
and/or vegetation growth on heart valves, intramyocardial abscesses,
or recent partial decomposition of a prosthetic valve ().
Table 1 -
Duke criteria for the diagnosis of infective endocarditis (4,7)
The use of echocardiography in adults has confirmed its utility,
especially the transesophageal echocardiogram, since this offers
greatly amplified image observation fields. In children, the transesophageal
echocardiography examination has limited uses for which reason the
transthoracic echocardiogram examination is routinely used ().
As Infective endocarditis in children is a heterogeneous entity,
its management also requires careful criteria based on laboratory
and clinical evidence in addition to the echocardiographic criteria
().
As studies of transthoracic echocardiogram in Infective endocarditis
of children have reported variable results in terms of diagnostic
sensitivity, we propose to describe a series of 28 cases of Infective endocarditis treated at the Nossa Senhora da Glória Children's
Hospital, in Vitória-ES, with emphasis on clinical and laboratory
findings and transthoracic echocardiogram examinations, in order
to verify the characteristics of the disease in our locale.
Patients and Methods
All children, under eighteen, diagnosed with Infective endocarditis,
and interned at the Infectious Diseases Service at the Nossa Senhora
da Glória Children's Hospital, Vitória - Espírito
Santo, during the period between January 1993 and December 2001
were included. The criteria for a diagnosis of Infective endocarditis
were those published by the Duke Endocarditis Service (Duke University,
Durham, North Carolina - USA) (),
in which one of the main diagnosis parameters is the demonstration
of echocardiographic evidence of a myocardial lesion and/or vegetation
on heart valves, intramyocardial abscesses or recent partial decomposition
of a prosthetic valve.
The Nossa Senhora da Glória Children's Hospital is a public
hospital, part of the Espirito Santo state network where its Pediatric
Infectious Diseases and Cardiology Services are centers of excellence,
also caring for patients from the south of the state of Bahia and
the east of the state of Minas Gerais.
Using a specialized pro forma, filled out by the resident
doctors and academics at the Infectious Diseases Service, and revised
by the team doctors, sex, clinical and laboratory findings and the
results from transthoracic echocardiography were recorded for each
of the 28 children who fulfilled the clinical and laboratory criteria
for a diagnosis of Infective endocarditis. All of the laboratory
examinations were performed at the routine hospital laboratory.
In all cases blood cultures were carried by collecting blood (three
samples) under aseptic conditions and were inoculated in aerobic
and anaerobic media, incubated at a temperature of 37 ºC and
tested with an automated system - VITEC SYSTEM ®(BIOLAB).
The study was submitted to and approved by the Committee for Ethics
and research at the Nossa Senhora da Glória Children's Hospital.
Statistical analysis
Statistical analysis was performed using the "SPSS-CDC Inc
for Windows" software program (Statistical Package for the
Social Sciences of Centers Diseases Control - USA. Release 8.0 -
1998). Averages were compared using the paired t test or with
the Wilcoxon test. Proportions were compared with the Yates corrected
Chi-square test, or with Fisher's exact test.
Results
Data on age, sex, clinical and bacteriological characteristics
and the principal echocardiogram findings are shown in Table 2.
The previous cardiopathies observed were 12 congenital cardiopathies
(85.7%) and two rheumatic cardiopathies (14.3%). The most clinical
findings which most often led to a suspicion of Infective endocarditis,
and so resulted in the echocardiogram, were: prolonged fever (100%),
heart murmur (67.9%), dyspnea (57.1%), hepatomegaly (57.1%), vascular
phenomena (32.2%), including small erythematous lesions or painless
hemorrhaging on the palms of the hands or soles of the feet (Janeway
lesions), splenomegaly (28.6%) and small, painful intradermal nodes
on the pads of the fingers (Osler nodes, 7.1%).
Table 2 -
Main demographic, clinical, echocardiographic and laboratorial
data of 28 cases of infective endocarditis, at HINSG, from 1993
to 2001
Blood cultures were positive in 16 (57.1%) of the 28 cases. Community
acquired Staphylococcus aureus was the most frequently isolated
germ (9/16- 56.2%). There was a statistically significant difference
in the frequency of the different types of germ isolated from children
older or younger than 24 months: Staphylococcus aureus was
found in the eight cases which involved children older than 24 months,
without previous cardiac lesions, and in only one of the cases involving
children younger than 24 months. The other seven children with positive
blood culture results were all younger than 24 months old and the
microorganisms isolated from them were: Streptococcus viridans
in two cases (12.5%), Enterobacter sp in four cases (25.5%)
and Candida tropicalis in one case (6.2%).
There was persistent fever, despite antimicrobial treatment, lasting
between 2.5 and 30 days, with a median of 18.0 days. On admission
leukogram had a wide variety of values for total number of leukocytes
(average value of 11,657+7,085 mm3), but with
obvious predominance of young neutrophils in all cases if the average
values were compared on admission and discharge (p < 0.000)
(Table 3). Transthoracic echocardiogram showed endocardiac vegetation
in all cases, especially in the tricuspid (25.0%) and mitral (25.0%)
valves and at the limits of intraventricular communication (28.6%)
(Figure 1). Thirteen (46.4%) children presented concomitant sepsis
and three (10.7%) developed nosocomial infections. There was one
death (3.6% of cases).
Table 3 -
Comparison of hemoglobin, leukocytes and neutrophils values in
rods of 28 cases of infective endocarditis on admission and discharge,
HINSG, 1993-2001
Figure 1 -
Location of the lesions observed on the echocardiogram in 28
cases of infective endocarditis.
Discussion
A number of Pediatric Cardiology Units have reported the observation
that cases of endocarditis infectious are increasing, primarily
among children under two years old, mainly due to the increase in
survival rates among children who have had surgery for cardiopathies
resulting from the improved care afforded by intensive care units
().
Taking into account the fact that in pediatrics Infective endocarditis
is a heterogeneous entity, we must look at all possible criteria,
from laboratory findings, echocardiographic and all criteria already
described as defining clinical criteria of the disease (),
summing up all possible effort in an attempt to achieve a definite
diagnosis with urgency, permitting early and adequate treatment,
thus reducing the mortality of children with endocarditis. Recent
publications demonstrate a significant change in pediatric Infective endocarditis, alterations in prevalence, age distribution and the
microorganisms involved as causative agents ().
Our results, similar to results reported in literature, demonstrate
a changing Infective endocarditis epidemiological profile in our
locale too. Fifty percent of cases occurred in newborns and infants,
and Staphylococcus aureus was frequently isolated from positive
blood cultures. Although blood cultures were only positive in 57.1%
of cases, the results reinforce the idea of the elevated prevalence
of S. aureus as the etiologic agent in acute Infective endocarditis
in our environment. In contrast we do not have an adequate explanation
for the low frequency of positive blood in this series of cases,
bearing in mind that blood samples were collected in a an apparently
adequate manner. It is possible that previous antibiotic use is
the main factor as many patients arrive at the Children's Hospital
having been transferred from other Health Units.
The role of transthoracic echocardiograms as a means of diagnosis
for children with a clinical suspicion of Infective endocarditis
remains controversial and is the cause of disagreement between a
number of authors ().
Some authors consider the method to be of too low a sensitivity
to be a method for diagnosing EI in patients with few of the clinical
criteria of the disease (),
however others believe that the use of echocardiography in the evaluation
of children with a clinical suspicion of endocarditis has ample
applications, primarily because in pediatrics, the transthoracic
echo offers an excellent field ().
In the present study characteristic alterations to the results from
this examination were one of the inclusion criteria. Nevertheless
it is important to remember that cases in which the transthoracic
echocardiogram was negative and which did not meet the criteria
for a diagnosis of Infective endocarditis could still have had
lesions from Infective endocarditis, without obvious evidence,
and were treated as sepsis and excluded from the Infective endocarditis
group.
The microbiology of Infective endocarditis in children has changed
considerably as is reported by a number of authors, with a decrease
in the number of cases due to infections by Streptococcus viridans
and the appearance of new etiological agents which were uncommon
in past decades. An important factor in this change is the increased
survival rate of children with congenital cardiopathies, and another
is the increased incidence of staphylococcal infections ().
We too observed this fact and our results demonstrate that Infective endocarditis was frequent among children less than two years old
and those with congenital cardiopathies. They also demonstrate that
community acquired Staphylococcus aureus was frequently isolated
as an infecting microorganism in children with no previous cardiac
lesions.
Acknowledgements
Thanks to Dr. Alba Lília de Almeida Leite, pediatrician
at the Infectious Diseases Service at the Nossa Senhora da Glória
Children's Hospital, for help with monitoring cases and to Dr. Fausto
Edmundo Lima Pereira, Professor and Doctor at the Infectious Diseases
Center at the Universidade Federal do Espírito Santo, for
help in the final revision of the text and for continuous support
for research and scientific production.
Thanks also to the staff at the Medical Records Storage Service
at HINSG, for their dedication.
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