Abnormal Radiological Findings and a Decreased Carbon Monoxide Transfer Factor Can Persist Long after the Acute Phase of Legionella pneumophila Pneumonia
R. E. Jonkers
()
2
3
4
K. D. Lettinga
1
2
4
T. H. Pels Rijcken
0
2
4
J. M. Prins
1
2
4
C. M. Roos
2
3
4
O. M. van Delden
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2
4
A. Verbon
1
2
4
P. Bresser
2
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H. M. Jansen
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3
4
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Department of Radiology, Academic Medical Center
,
Amsterdam
,
The Netherlands
1
Department of Internal Medicine, Division of Infectious Diseases
,
Tropical Medicine, and AIDS
2
Received 27 June 2003; accepted 7 October 2003; electronically published 17 February 2004. Financial support: Ministry of Health, The Netherlands (grant CSG/PP 1074808). Pulmonology Dept., Academic Medical Center
,
PO Box 22700, 1100 DE Amsterdam
,
The Netherlands
3
Department of Pulmonology
4
We thank Dr. G. J. Weverling, Department of Clinical Epi- demiology and Biostatistics, Academic Medical Center (Am- sterdam, The Netherlands)
,
for statistical advice
Pulmonary abnormalities may persist long after the acute phase of legionnaires disease (LD). In a cohort of 122 survivors of an outbreak of LD, 57% were still experiencing an increased number of symptoms associated with dyspnea at a mean of 16 months after recovery from acute-phase LD. For 86 of these patients, additional evaluation involving high-resolution computed tomography (HRCT) of the lung revealed pulmonary abnormalities in 21 (24%); abnormal HRCT findings generally presented as discrete and multiple radiodensities. Residual pulmonary abnormalities were associated with a mean reduction of 20% in the gas transport capacity of the lung. This latter sign could not be used to explain the increased symptoms of dyspnea reported by patients. Receipt of mechanical ventilation during the acute phase of LD, delayed initiation of adequate antibiotic therapy, and chronic obstructive pulmonary disease were identified as risk factors for the persistence of lung abnormalities.
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In a survey of 31 survivors of the classic 1976 outbreak
of legionnaires disease (LD) in Philadelphia, a
considerable proportion still had respiratory symptoms or a
reduced carbon monoxide diffusion capacity (DLCO)
after a follow-up period of 2 years [1]. Additional
information on the persistence of such pulmonary
symptoms and signs in survivors of LD is scarce. In one
study, abnormal radiological findings were observed for
at least several months after recovery from acute-phase
LD [2]. In 2 small series, analysis of lung biopsy
specimens obtained shortly after acute-phase LD revealed
structural changes and fibrosis of the lung parenchyma
[3, 4]. Taken together, these observations suggest that
residual abnormalities in the lung parenchyma
(hereafter, pulmonary abnormalities) resulting in
functional disturbances may persist long after the clinical
resolution from the acute phase of LD. It is unknown
which factors predispose patients to such long-term
pulmonary abnormalities.
In March 1999, a large outbreak of LD occurred
among individuals who visited a flower exhibition in
The Netherlands [5]. This offered a unique opportunity
to expand the knowledge on the long-term pulmonary
sequelae of LD. We evaluated 122 survivors 1319
months after resolution of the acute phase of LD for
the presence of persistent abnormal radiological and
functional findings and tried to correlate these with
symptoms of shortness of breath. In addition, we tried
to identify risk factors associated with the persistence
of pulmonary abnormalities.
PATIENTS AND METHODS
Patients. After detection of the outbreak, local
municipal health services and hospitals were requested to
report every suspected case of LD. Six months after the
outbreak, 318 patients with suspected LD had been reported.
Written informed consent was obtained from 202 patients or their
relatives; 161 had confirmed or probable LD. Our definitions
of confirmed and probable cases of LD have been described
elsewhere [6]. Eighteen patients died during the acute phase of
the disease, and 1 died shortly thereafter. Of the remaining
survivors, 130 were contacted for our follow-up study 1319
months after the acute phase of the disease, and 122
participated. All participants completed a questionnaire, and 86
consented to visit our hospital for additional radiological
examination and lung function testing. This study was approved by
the medical ethics committee of the Academic Medical Center
in Amsterdam, The Netherlands.
Radiological examination and lung function testing.
Participants were screened for pulmonary abnormalities using
standard chest radiography and tests that measured the vital
capacity (VC), the forced expiratory volume in 1 s (FEV1),
and the single-breath DLCO of the lung (expressed as a
percentage of the predicted value). All chest radiographs were
evaluated by 2 radiologists blinded to the patients medical
records; consensus was required for inclusion of findings in
our analysis. Focal increases in radiodensity anywhere in the
lung parenchyma were considered to be signs of residual
abnormalities. Participants with no abnormal chest radiograph
findings were suspected of having residual p (...truncated)