Transcript Document

BAMBINO GESU’
Children Hospital
HealthCare and
Research Institute
Rome - ITALY
Poster Board NUMBER H28
[email protected]
Abstract
Extrapulmonary manifestation of
tuberculosis disease is a rare
event.
In the last three years, at
“Bambino
Gesù”
Children
Hospital, Reference Centre for
Diagnosis
and
Healthcare
of
Mycobacteria
Infection
in
Children,
we
evaluated
the
QuantiFERON TB Gold to assess
the assay performance in extrapulmonary TB diagnosis.
Four
cases
referred
to
TB
meningitis, one occurred in a child
over 5 years and three in children
under 5 years, were investigated
with QFT-G in whole blood. During
the first evaluation, two cases out
of 4 had already QFT-G positive,
one generated an Indeterminate
result and one a Negative result.
These two patients received a
second QFT-G test a few days
later and both resulted QFT-G
Positive
Four cases of pleural TB without
any
pulmonary
lesion
were
collected in this study. Three
cases out of four were strongly
positive
for
INF-
measured
directly on pleural effusion, in one
patient an enough amount of
pleural effusion for QFT-G was not
collected.
One case with peritoneal fluid, as
only evidence of a peritoneal TB
manifestation, was investigated
both in blood and in the pleural
fluid.
QFT-G
performed
in
peripheral blood was negative
while QFT-G was strongly positive
when tested directly on pleural
effusion.
All of these cases were confirmed
as extra-pulmonary TB by culture
isolation
of
Mycobacterium
tuberculosis.
Background and Rationale of the Study
Results
The clinical presentation of TB in
Surveillance of tuberculosis in Europe
children is extremely variable. It
depends by different factors as: the
age, the immunocapability of the host
response and also the TB spread. In
particular Tuberculous meningitis has
high rate of morbidity and mortality.
Demonstration of tubercle bacilli in
cerebrospinal fluid, the only reliable
method of diagnosis, is time consuming
and has a low yield. Pleural or peritoneal tuberculosis presenting with effusions are not
always easy to diagnose because conventional tests for extra-pulmonary TB have
several limitations. Also Nucleid Acid Amplification commercial kits have low and
varying sensitivities, and therefore should not be used for excluding a diagnosis of
tuberculous pleuritis. Moreover, Cutaneous sensitivity to Purified Protein antigen
Derivative is not satisfied.
In recent years, numerous authors studied possible
biochemical markers such as interferon gamma (IFN- ), to improve diagnostic
efficiency.
MENINGITIS
INF- on blood
Patient
Age
1st
evaluation
2nd
evaluation
Culture
Days for
positivization
Identification
13 days
M. tuberculosis
DA
1y 2m
POS
EOA
4y 3m
IND
POS
7 days later
13 days
M. tuberculosis
POS
14 days later
14 days
M. tuberculosis
11 days
M. tuberculosis
GG
16y
NEG
VD
1y 11m
POS
Four children received the finaly diagnosis of tuberculous meningitis
All children had foreign origin (three from Est Europe and one from Africa)
TST was not reactive (negative) in all children
QFT-G was positive during the first evaluation for two children under 2 years of age
Computed Tomography images showed hydrocephalus and basilar meningitis
but without any evidence of tuberculoma
The aims of our study have been:
to apply the new QuantiFeron TB Gold (QFT-G – Cellestis Limited, Carnegie, Victoria,
Australia) both in blood and in pleural or peritoneal effusion to asses the performance of
QFT-G in samples specimens different from blood as marker of TB;
 to test if the new QuantiFeron TB Gold (QFT-G) is able to work in suspected TB
meningitis as rapid tool for TB diagnosis.
Population and Methods
OUR PATIENTS
PLEURAL TB
INF-
Patient
Age
on Blood
Culture
on Pleural
fluid
Days for
positivization
Identification
PERITONEAL TB
INF-
CG
11y 5m
POS
POS
15 days
M. tuberculosis
PM
14y 2m
IND
Not Done
12 days
M. tuberculosis
GSA
16y 7m
IND
POS
15 days
M. tuberculosis
VRN
7y 5m
POS
POS
11 days
M. tuberculosis
Patient
VG
on Blood
on
Peritoneal
fluid
Days for
positivization
Identification
NEG
POS
14 days
M. tuberculosis
Age
12y 1m
Culture
INF- ELISA assay
From
2004
to
2007
we
investigated children admitted
at “Bambino Gesù” Children Hospital
(Rome, Italy) presenting with:
 Signs
or
symtoms
of
meningitis
compatible wich a TB suspected
 Pleural effusion
or
 Peritoneal effusion
In wich any other etiology were found
QuantiFeronTB-Gold Liquid and In Tube version
Step 2 ELISA assay
Step 1 samples collection
The QFT-G was performed
on blood as manufacture
instructions and on body
fluids both whole and after
fluid concentration.
Step 3 Interpretation of INF-γ amount
All specimen fluids (cerebrospinal, pleural and peritoneal) were collected and processed
by using our Mycobacterial TB laboratory protocol
Four children received the finaly diagnosis of pleural tuberculosis and one child
had a peritoneal TB localization
Two children were italian and three had foreign origin (with history of TB
immunization)
Three children received TST (two were TST positive and one TST negative)
fluorescenza
QFT-G was always positive when performed on pleural or peritoneal fluid
 AFB fluorescence Stain
400x
In conclusion, in our experience
QFT-G has revealed as a powerful
tool in a rapid diagnosis of extrapulmonary TB in children.
 Solid and liquid media cultures
Nucleid Acid Amplification (Cobas Amplicore®- Roche) direct on samples
Discussion
Conclusions
Our study was carried out prospectively in a clinical routinely situation during the last three years.
We assessed whether the new Interferon-γ release assay QuantiFERON-Gold could be used in practice in
special setting (as pediatric population) and in extra-pulmonary localization as meningitis, pleural and
peritoneal tuberculosis.
Our results reveal that:
 in pleural and peritoneal effusion, INF-
levels are significantly higher than in whole
blood in tuberculous disease;
 in case of suspected TB meningitis in
children under 2 ys the QFT-G assay gives a
positive results
Computed Tomography images showed a large ammount of effusion in pleural
cavity but without any parenchymal involvement or typical granulomas
Potential limitations of our study
should be:
 the low number of cases may affect
precision
 we did not evaluate children HIV
affected
Tuberculosis is a systemic infection caused by Mycobacterium tuberculosis. It is transmitted by
coughed aerosol and usually presents with respiratory symptoms; however, it can produce disease in
any organ system by haematogenous spread, specially in newborn, children and teen agers. The mean
annual number of cases referred to extra-pulmonary TB cases are approximately unchanged during the
last five years (about 25-30% of all TB cases) in Europe . Extra-pulmonary TB is often diagnosed on the
basis of clinical experience which may lead to diagnostic errors. A correct diagnosis depends on the
possibility of obtaining appropriate specimens for cultures and often requiring invasive procedures and
more sophisticated laboratory techniques.
In conclusion, evaluation of an increase in the IFN- level in the pleural fluid is a good and useful
diagnostic marker of pleural tuberculosis and, in our experience, QFT-G has revealed as a powerful tool
in a rapid diagnosis approach in case of suspected extra-pulmonary TB in children
Acknowledgements
Silvia Gobbi and Eugenia Galeno laboratory technicians – Microbiology Unit – Laboratory Department
Stefania Colafati MD - Radiology Department - for supporting in CT images and interpretation