|
|
||||||||
Guest Access | Sign In via User Name/Password |
|||||||||
* From the Departments of Pediatrics (Drs. C. K. Kim and S. W. Kim) and Radiology (Dr. J. S. Kim), Inje University Sanggye Paik Hospital, Seoul, South Korea; the Department of Pediatrics and Clinical Research Institute (Dr. Koh), Seoul National University Hospital, Seoul, South Korea; the Department of Pediatrics (Dr. Cohen), Washington University Hospital, St. Louis, MO; and the Department of Pediatrics (Drs. Deterding and White), University of Colorado Health Sciences Center, Denver, CO.
Correspondence to: Young Yull Koh, MD, Department of Pediatrics, Seoul National University Hospital, 28 Yongon-dong, Chongno-gu, Seoul 110744, Korea; e-mail: kohyy{at}plaza.snu.ac.kr
| Abstract |
|---|
|
|
|---|
Design: We extracted specific information regarding predisposing factors, symptoms and signs, diagnostic studies, treatment, and outcome from the medical records of 31 children who received diagnoses of BO at four university medical centers in Korea and the United States in the 1990s.
Results: The large number of Asian children reflects a clustering of cases in Korea due to adenovirus and Mycoplasma pneumoniae epidemics. The characteristic diagnostic features of BO were present in 29 of 30 high-resolution CT (HRCT) studies. Seven of nine children who underwent biopsies had histologic confirmations of BO. In two patients whose biopsy results were nondiagnostic, the diagnosis was established by HRCT together with pulmonary function testing results that were consistent with nonreversible small airways obstruction. Fifteen children (48.4%) had evidence of hypoxemia. At present, all but one are alive. Patients with elevated severity-of-illness scores were observed to have increased likelihoods of lung transplantation or death.
Conclusions: We conclude that BO has a good overall prognosis and that the mortality rate has declined over the past decade. This could be related primarily to the use of HRCT for accurate diagnosis and the availability of pediatric lung transplantation. BO cases in Korea were associated with infectious epidemics, whereas those in United States had variable predisposing factors.
Key Words: bronchiolitis obliterans infectious epidemic Korea mortality United States 1990s
| Introduction |
|---|
|
|
|---|
Our current knowledge of pediatric BO, excluding lung and bone marrow transplantation patients, is based largely on case reports8 and a few small series of patients in the older literature.1 5 In these reports, diagnoses were made largely by bronchogram, ventilation-perfusion scan, and examination of lung tissue from a biopsy or autopsy. In these older cases, the mortality rate was high.
The relatively recent application of high-resolution CT (HRCT) scanning of the chest to children with respiratory disease has enhanced the ability of clinicians to diagnose BO noninvasively.9 Also, the development of pediatric lung transplantation has given some children with end-stage lung disease including BO a potential opportunity for prolonged survival. The purpose of this report was to review recent experiences with BO in children with regard to clinical presentation, etiology, current approaches to diagnosis, treatment (including transplantation), and outcome and to compare the etiology, severity, and prognosis of BO in patients in a developing country (Korea) and a developed country (the United States).
| Materials and Methods |
|---|
|
|
|---|
Patients were included in the study if they had compatible clinical presentations and/or predisposing factors and at least one diagnostic study that had been indicative of BO. Predisposing factors included the following: (1) infectious disease agents, such as adenovirus, influenza virus, and M pneumoniae, that had been identified by culture, serology, and/or polymerase chain reaction (PCR); (2) a history of aspiration or toxic inhalation; (3) the presence of a skin rash that was consistent with Stevens-Johnson syndrome; (4) aspiration diagnosed by a barium swallow procedure, the presence of lipid-laden macrophages, or other studies; and (5) positive antinuclear antibodies or related autoantibodies. The adenovirus serotype was identified by the hemagglutination inhibition assay and was confirmed by a neutralization assay with type-specific reference antisera.10 The serologic diagnosis of Mycoplasma infection was based on the demonstration of a fourfold or greater increase in the titer of antimycoplasma antibodies in the sera of patients with acute disease and in those who were convalescing.
Diagnostic studies included the following: (1) a chest roentgenogram demonstrating unilateral hyperlucent lung (ie, Swyer-James syndrome)11 ; (2) HRCT demonstrating a unilateral hyperlucent lung and/or a combination of geographic hyperlucency, central bronchiectasis, and vascular attenuation12 ; or (3) a diagnostic lung biopsy. In some patients, the diagnosis of BO was supported by characteristic abnormalities of matched patchy defects in ventilation and perfusion by scintigraphy and/or pulmonary function tests (PFTs) showing severe small airways obstruction that was either irreversible or incompletely reversible with bronchodilator therapy. To narrow the focus of this study, we excluded both patients with BO that was related to lung or bone marrow transplantation and patients with BO who had organizing pneumonia.
In those patients meeting the entry criteria, we extracted specific information from the medical records regarding clinical presentation, predisposing factors, physical examination, diagnostic studies, treatment, and outcome, and this information was entered into a database. A severity-of-illness score (1, asymptomatic; 2, symptomatic with normal oxygen saturation while breathing room air under all conditions; 3, symptomatic with normal oxygen saturation while breathing room air, but abnormal oxygen saturation [ie, < 92% at sea level and < 90% in Denver, CO, at elevation 1,700 m] during sleep or exercise; 4, symptomatic with abnormal resting oxygen saturation [ie, < 92% at sea level and < 90% in Denver, CO, at elevation 1,700 m] while breathing room air; and 5, symptomatic with pulmonary hypertension)13 was assigned to each patient based on the available information in the record at the time of the initial diagnostic workup.
| Results |
|---|
|
|
|---|
|
|
|
|
|
10% following salbutamol inhalation,
although all patients continued to have a severe obstructive pattern on
PFT results after bronchodilator therapy.
|
Etiology
The etiology of BO in this series, based on clinical presentation
and diagnostic studies, is presented in Table 4
. In most cases, an infectious cause was found, with adenovirus alone
identified most often. Adenovirus was identified by the culturing of
nasopharyngeal secretions or tracheal aspirates in 12 patients, by
testing the sera from patients with acute disease and from those who
were convalescing in 5 patients, and by PCR of lung tissue in 1
patient. Two patients were identified by both culture and
serology. M pneumoniae was identified by serology in eight
patients, by PCR as well as serology in one patient, and by PCR of BAL
fluid in one patient. Two patients had evidence of coinfection with
adenovirus and M pneumoniae, although it could not be
determined whether these infectious agents had an additive or
synergistic role. Two patients developed BO following Stevens-Johnson
syndrome. In four patients, no discernable etiology could be determined
despite extensive evaluation.
|
Severity and Outcome
Fifteen children had evidence of hypoxemia demonstrated by pulse
oximetry and/or arterial blood gas levels. Of these 15 patients, 7 had
arterial oxygen desaturation with exercise or during sleep and 6 showed
oxygen desaturation at rest. Two patients had evidence of pulmonary
hypertension by ECG or echocardiogram.
Patients have been observed from 1 to 10 years after the onset of symptoms. At the current time, all patients but one are alive. The mortality rate was comparable between patients in Korea and in the United States (0% and 6.7%, respectively). One patient who received high-dose corticosteroid therapy died of disseminated varicella while awaiting lung transplantation. Three children in the United States underwent successful transplantation procedures and are currently alive 1 to 6 years after receiving the transplants. These children showed increases in pulmonary function near that predicted for healthy children after lung transplantation. The severity-of-illness score at the time of the initial diagnostic workup compared to outcome is presented in Table 5 . As expected, the data indicated that patients with more severe disease initially were more likely to require tranplantation or to die.
|
| Discussion |
|---|
|
|
|---|
To our knowledge, this is the largest series of pediatric BO patients reported to date. In contrast to older studies that utilized bronchography, ventilation-perfusion scans, and lung biopsies for diagnosis, this study demonstrates that HRCT has improved the early diagnostic approach to BO in that it is a reasonably accurate diagnostic tool. This may negate the need for bronchography and/or lung biopsy in many cases.14 In fact, the diagnosis of BO may have been missed by lung biopsy due to sampling error, as previously reported.15 In this study, BO was diagnosed with confidence in two children who had undergone nondiagnostic lung biopsies, based on PFT results indicating minimally reversible airways obstruction and characteristic HRCT findings.
The course of patients with BO varies from mild, asthma-like symptoms to rapidly progressive deterioration and death. Our experience that patients with this disease have a good overall prognosis and a relatively low mortality rate is different from that reported by Hardy et al1 This is due in large part to a difference in the way the cases were identified. In the study by Hardy et al,1 approximately half the cases were discovered by reviewing autopsy records. In contrast, most cases in our study were identified through the use of HRCT, which is a highly sensitive diagnostic study of small airway lesions.12 The less severe nature of BO in our series, therefore, may have been in part due to the inclusion of mildly affected patients who otherwise would have been considered as having a sequela of adenovirus or Mycoplasma infection rather than having BO. Pediatric lung transplantation is now an available option for patients who are estimated to have a life expectancy of < 1 year.16 Without a lung transplant, three patients in our population may not have survived, which would have increased the mortality rate. Our data indicate that BO in children is not as lethal as has been reported previously. Even if our observation may not be representative of BO in general, our study helps to illustrate the fact that BO, a primarily pathologic diagnosis, has diverse clinical manifestations and that the prognosis of BO is variable.
The role of adenovirus,3
M
pneumoniae,17
and other infectious
agents5
in the development of chronic lung disease
including BO in children is well-documented. Patients with severe
adenovirus pneumonia have been shown to have immune complexes
containing adenovirus antigen in the lung,18
as well as
increased serum levels of interleukin-6, interleukin-8, and tumor
necrosis factor-
.19
These studies suggest that abnormal
or excessive host immunologic and inflammatory responses may be
important in the development of chronic lung disease from adenovirus
infection.
Little is known about host factors that predispose the patient to BO. The maternal antibody may be protective, because the disease characteristically occurs in infants > 6 months of age. Of interest is the ethnic trend seen in BO patients. Two ethnically distinct populations of children, Polynesian children in New Zealand and Native Americans in central Canada, have been reported to be particularly susceptible to BO, suggesting that genetic or environmental factors may be important.20 Our study evaluated a population of children with BO of different ethnicities and geographic origins. BO cases in Korea were associated with infectious epidemics, whereas those in United States had variable predisposing factors. However, our findings indicate a number of similarities in the results of HRCT scans and PFTs regardless of the etiology of BO or the ethnic/geographic origin of the patient.
PFTs continue to be an important diagnostic tool in patients with BO. The results of PFTs in patients with BO characteristically show irreversible obstructive lung disease in infants21 as well as older children.14 The midexpiratory phase of forced expiratory flow (FEF2575) is a measure of small airways disease, and a marked decrease (ie, < 30% of predicted) is a particularly sensitive indicator of BO.22 A severe obstructive process with air trapping and a decrease in the FEF2575 level were documented in the 14 patients who were able to perform PFTs in our series. Arterial oxygen saturation can be used to grade the severity of the disease.13 Fifteen children (48.4%) had evidence of hypoxemia, suggesting that early diagnosis and treatment are potentially important to prevent secondary pulmonary hypertension.
No universally accepted protocol has been established for the treatment of BO. The use of corticosteroid therapy in the early phase of the illness in an attempt to modify the fibroblastic response has been proposed.23 In our study, a beneficial clinical response was suggested in 11 of the 17 patients (64.7%) following systemic oral corticosteroid therapy. Some patients required maintenance therapy for months or years. Four of 11 patients who benefited from the use of corticosteroids, and 5 of 6 patients who did not, could perform PFTs. Two of the former four patients and none of the latter five patients demonstrated an immediate bronchodilator response following salbutamol inhalation. Although it is difficult to determine with certainty from this small number of patients, bronchodilator responsiveness seems to be a guideline for long-term corticosteroid treatment. The use of bronchodilators is controversial because, in theory, the patients should not show improvement in fixed airway obstruction. In this study, only 3 of 14 patients with PFT data demonstrated a bronchodilator response. However, eight of those patients showed a beneficial clinical response while being treated with bronchodilators. Patients with fixed airflow obstruction, like some emphysema patients, show clinical symptomatic benefits from the repeated use of bronchodilators.24 Therefore, the decision of whether or not to prescribe bronchodilators should not be based on the one-time response to bronchodilators seen in PFTs. In those severely affected patients who are not expected to survive, lung transplantation may be a successful treatment option.
| Footnotes |
|---|
This study was supported in part by a Clinician Scientist Grant awarded in 1998 to Dr. Chang Keun Kim by Inje University, Korea, and by a year 1999 Brain Korea 21 project for Medicine, Dentistry, and Pharmacy.
Received for publication October 13, 2000. Accepted for publication May 4, 2001.
| References |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
Y. Y. Koh, D. E. Jung, J. Y. Koh, J. Y. Kim, Y. Yoo, and C. K. Kim Bronchoalveolar Cellularity and Interleukin-8 Levels in Measles Bronchiolitis Obliterans Chest, May 1, 2007; 131(5): 1454 - 1460. [Abstract] [Full Text] [PDF] |
||||
![]() |
K J Smith and L L Fan Insights into post-infectious bronchiolitis obliterans in children. Thorax, June 1, 2006; 61(6): 462 - 463. [Full Text] [PDF] |
||||
![]() |
A J Colom, A M Teper, W M Vollmer, and G B Diette Risk factors for the development of bronchiolitis obliterans in children with bronchiolitis Thorax, June 1, 2006; 61(6): 503 - 506. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Yoo, J. Yu, D. K. Kim, S. H. Choi, C. K. Kim, and Y. Y. Koh Methacholine and adenosine 5'-monophosphate challenges in children with post-infectious bronchiolitis obliterans Eur. Respir. J., January 1, 2006; 27(1): 36 - 41. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. J. Fullmer, L. L. Fan, M. K. Dishop, C. Rodgers, and R. Krance Successful Treatment of Bronchiolitis Obliterans in a Bone Marrow Transplant Patient With Tumor Necrosis Factor-{alpha} Blockade Pediatrics, September 1, 2005; 116(3): 767 - 770. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. H. Ryu, J. L. Myers, and S. J. Swensen Bronchiolar Disorders Am. J. Respir. Crit. Care Med., December 1, 2003; 168(11): 1277 - 1292. [Abstract] [Full Text] [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |