Respiratory bronchiolitis, a common finding
in cigarette smokers (smoker’s bronchiolitis), may on rare occasions
present as interstitial lung disease (RB-ILD).
Respiratory
bronchiolitis associated with interstitial lung disease (RB-ILD),
first was described by Niewoehner et al in an autopsy study of cigarette
smokers who died from non pulmonary causes in 1974.
The clinical
presentation resembles those of patients with other interstitial lung
diseases - cough and dyspnea, with coarse rales on physical examination.
Diffuse fine
reticulonodular interstitial opacities are found on chest radiograph,
usually with normal-appearing lung volumes.
Bronchial wall
thickening, prominence of peribronchovascular interstitium, small regular
and irregular opacities, and small peripheral ring shadows are distinctive
features.
Pulmonary function
testing may be normal but usually demonstrates mild to moderate
restriction and normal or slightly reduced diffusing capacity. A mixed
obstructive-restrictive pattern is common.
Histologically it is characterized by patchy and non-uniform
accumulation of finely pigmented tan brown macrophages within membranous,
terminal and respiratory bronchioles and also within immediately adjacent
alveoli, and sometimes in the interstitial tissues, associated with mild
interstitial fibrosis, which is limited to the peribronchiolar tissues.
Respiratory
bronchiolitis-associated interstitial lung disease is a distinct
clinical syndrome found in current or former cigarette smokers. The
disease often is confused with other interstitial lung diseases,
especially idiopathic pulmonary fibrosis. The clinical presentation
resembles those of patients with other interstitial lung
diseases--cough and dyspnea, with coarse rales on physical
examination. Diffuse fine reticulonodular interstitial opacities are
found on chest radiograph, usually with normal-appearing lung volumes.
Bronchial wall thickening, prominence of peribronchovascular
interstitium, small regular and irregular opacities, and small
peripheral ring shadows are distinctive features. Pulmonary function
testing may be normal but usually demonstrates mild to moderate
restriction and normal or slightly reduced diffusing capacity. A mixed
obstructive-restrictive pattern is common. Respiratory bronchiolitis-associated
interstitial lung disease is characterized histologically by an
inflammatory process involving the membranous and respiratory
bronchioles. The pathologic findings are dominated by the finding of
tan-brown pigmented macrophages within respiratory bronchioles and
neighboring alveolar ducts and alveoli. The pulmonary parenchyma away
from the airway usually is normal or may demonstrate mild
hyperinflation. The clinical course and prognosis of respiratory
bronchiolitis-associated interstitial lung disease are unknown. Most
patients respond favorably to corticosteroids, with documented
improvement in lung function and chest radiographs. Smoking appears to
play a role in the pathogenesis, so smoking cessation is important in
the resolution of this syndrome.
Respiratory
bronchiolitis-associated interstitial lung disease (RB-ILD) designates
interstitial lung changes in smokers, characterized histologically by
bronchiolocentric accumulation of pigmented alveolar macrophages and
fibrotic or cellular inflammatory changes of pulmonary interstitium.
The definition is nearly identical to that of condensate pneumopathy,
smoker's pneumopathy or smoker's lung, defined by accumulation of
pigmented alveolar macrophages with bland alveoloseptal or
peribronchial fibrosis and cellular inflammation of the bronchial
wall. In addition to respiratory bronchiolitis, which is found in
nearly all smokers, RB-ILD comprises a broad spectrum of varying
degrees of the interstitial reaction to the exogenous injury of
inhalation smoking with gradual transition to desquamative
interstitial pneumonia (DIP). In most cases RB-ILD manifestations are
subclinical and detected coincidentally. Radiographic features are
reticulonodular and ground glass opacities of the lung. The high
resolution computed tomography reveals centrilobular nodules, ground
glass opacities, thickening of bronchial walls, and in some cases a
reticular pattern. Mild emphysema is frequent. Lung function analysis
reveals only minor restrictive or obstructive defects in most cases,
often combined with hyperinflation. CO diffusing capacity is slightly
to moderately impaired. Pronounced interstitial lung diseases with
serious restrictive defects and arterial hypoxemia have been reported
infrequently. In differential diagnosis smoking related interstitial
lung diseases (DIP, Langerhans cell histiocytosis, idiopathic
pulmonary fibrosis) and other interstitial lung diseases have to be
excluded. In most cases diagnosis can be achieved by bronchoalveolar
lavage and transbronchial lung biopsy. In cases of pronounced
interstitial lung disease or assumption of an additional interstitial
lung disease besides RB-ILD a thoracoscopic or open lung biopsy can be
necessary. RB-ILD has a favourable prognosis. After smoking cessation
lung changes are reversible. Corticosteroid therapy is not necessary.
A fatal outcome of RB-ILD has not been reported. Follow-up
examinations are advisable in order to preclude other interstitial
lung diseases. RB-ILD seems to be more frequent than it is assumed at
present. The clinical picture is masked in most cases by the
concomitant smoking induced chronic bronchitis. Thus only pronounced
cases with structural changes and resulting differential diagnostic
problems are diagnosed.
Unlike typical cases of DIP, the disease process is centri-lobular in
distribution, sparing the periphery of the secondary lobules.
Iron stain
shows very fine cytoplasmic positivity within the pigmented macrophages,
unlike the coarse positivity of hemosiderin granules.
The differential diagnosis of RB-ILD includes
small airways disease that may occur in
asbestosis
, Langerhans cell
histiocytosis (LCH), and DIP. Unlike asbestosis, no asbestos bodies are
seen and the macrophages are finely pigmented in RB-ILD. In LCH the
stellate bronchiolocentric fibrosis and the presence
of S-100 positive cells are diagnostic.
UIP can be ruled out by the lack
of the characteristic temporal and spatial heterogeneity.
The distinction
from DIP may be difficult because of overlapping histological changes in
some cases.
However, such distinction may be of little clinical
significance as both diseases more or less share similar presentations and
courses.
In differential
diagnosis smoking related interstitial lung diseases (desquamative
interstitial pneumonia , Langerhans cell histiocytosis , idiopathic
pulmonary fibrosis) and other interstitial lung diseases have to be
excluded). It has been suggested that RD-ILD and DIP may represent
different stages of the same disease.
Long-term prognosis
is good with cessation of smoking, in combination or not with
corticosteroid therapy.
Respiratory
bronchiolitis associated with interstitial lung disease (RB-ILD),
first described by Niewoehner et al in an autopsy study of cigarette
smokers who died from non pulmonary causes in 1974, is a rare entity
that should be distinguished from the other interstitial lung diseases
and in particular from desquamative interstitial pneumonia, although
the two conditions share a similar histopathological pattern. RB-ILD
is clearly connected with tobacco smoking and has been inserted in the
"smoking related interstitial lung diseases" together with DIP and
Cell histiocytosis of Langerhans; it may also be associated with
occupational exposure to machine fumes. The following is a case report
of a patient with both smoking and occupational exposure.
Respiratory
bronchiolitis associated with interstitial lung disease and
desquamative interstitial pneumonia.Clin
Chest Med. 2004 Dec;25(4):717-26, vi.
This article
explores issues of the diagnosis and management of respiratory
bronchiolitis, respiratory bronchiolitis-associated interstitial lung
disease, and desquamative interstitial pneumonia. These three diseases
have common and overlapping features and sometimes are viewed as a
continuum of smoking-induced disease, rather than as distinct and
separate entities.
Respiratory bronchiolitis associated interstitial
lung disease (RB-ILD): a case of an acute presentation.Thorax.
2004 Oct;59(10):910-1.
Respiratory
bronchiolitis associated interstitial lung disease (RB-ILD) is a
recently described clinicopathological entity that occurs almost
exclusively in current heavy cigarette smokers. Few cases have been
reported in the literature and no studies have been carried out on the
effect of treatment, which currently consists of smoking cessation
with or without corticosteroids. We report the first case of an acute
presentation of histologically proven RB-ILD in a young cigarette
smoker whose diagnosis and management proved to be difficult. Smoking
cessation alone was found to be inadequate so management was combined
with corticosteroid therapy.
Respiratory
bronchiolitis-associated interstitial lung disease: radiologic
features with clinical and pathologic correlation.J
Comput Assist Tomogr. 2002
Jan-Feb;26(1):13-20.
PURPOSE: The
purpose of this work was to describe the radiographic and CT findings
in patients with respiratory bronchiolitis-associated interstitial
lung disease (RB-ILD) and to correlate them with clinical,
physiologic, and pathologic features. METHOD: RB-ILD was proved
pathologically in all 21 patients. Sixteen (76%) patients were current
smokers, and five (24%) patients were ex-smokers. The mean cigarette
consumption was 38.7 pack-years. Chest radiographs and CT scans were
semiquantitatively analyzed and correlated with clinical findings,
physiologic measures, and a pathologic score of disease extent.
RESULTS: The major radiographic findings were bronchial wall
thickening in 16 patients (76%) and ground-glass opacity in 12
patients (57%). The predominant initial CT findings were central
bronchial wall thickening (proximal to subsegmental bronchi) in 19
patients (90%), peripheral bronchial wall thickening (distal to
subsegmental bronchi) in 18 patients (86%), centrilobular nodules in
15 patients (71%), and ground-glass opacity in 14 patients (67%), None
of these CT findings had a significant zonal predominance. Other
findings were upper lung predominant centrilobular emphysema (57%) and
patchy areas of hypoattenuation (38%) with a lower lung predominance.
Radiologic findings were similar in both current and ex-smokers. The
amount of ground-glass opacity correlated inversely with arterial
oxygen saturation ( r = -0.67, p = 0.04), and the areas of
hypoattenuation correlated with alveolar-arterial oxygen gradient ( r
= 0.56, p = 0.04). The extent of centrilobular nodules correlated with
the extent of macrophages in respiratory bronchioles ( r = 0.53, p =
0.03) and with chronic inflammation of respiratory bronchioles ( r =
0.57, p = 0.02). The extent of ground-glass opacity correlated with
the amount of macrophage accumulation in the alveoli and alveolar
ducts ( r = 0.56, p < 0.01 and r = 0.54, p = 0.04, respectively). At
follow-up CT after steroid treatment and smoking cessation, in nine
patients, the extent of bronchial wall thickening, centrilobular
nodules, and ground-glass opacity had decreased, but the areas of
hypoattenuation had increased (p < 0.05). CONCLUSION: The CT findings
of RB-ILD are centrilobular nodules, ground-glass opacity, and air
trapping. These radiologic features, in patients with a history of
heavy cigarette smoking, may differentiate RB-ILD from other
interstitial lung diseases.
Respiratory
bronchiolitis with diffuse interstitial lung disease.Rev
Mal Respir. 2001 Apr;18(2):201-4.
Respiratory
bronchiolitis-associated interstitial lung disease (RB-ILD) is a
disease that exclusively affects cigarette smokers. Long-term
prognosis is good with cessation of smoking, in combination or not
with corticosteroid therapy. We report here the case of a 50-year-old
patient with RB-IL diagnosed on lung biopsy. Despite corticosteroid
and cyclophosphamide therapy, no functional or radiological
improvement was obtained. In contrast, cessation of smoking was
associated with the disappearance of the infiltrative opacities.
Clinical and radiological parameters remained stable during follow-up
(13 years) while a moderate obstructive pattern appeared.
Respiratory
bronchiolitis associated interstitial lung disease is an uncommon
condition in current or ex-smokers. The presentation is non-specific,
but haemoptysis is uncommonly reported in this condition. We report
the case of a 25-year-old woman who presented with significant
haemoptysis, dyspnoea, reduced transfer factor and normal clinical
examination. In addition, a Medline literature search was performed to
review the clinical features and prognosis of this disease. Other
causes of haemoptysis were excluded with extensive investigation. The
diagnosis was made on thoracoscopic lung biopsy. The patient had
significant postoperative complications of prolonged air leak and
hydropneumothorax requiring further surgery and prolonged hospital
stay. Advice regarding smoking cessation was given. Her pulmonary
physiology remains abnormal on follow up but symptoms have improved.
Respiratory bronchiolitis-ILD may present with normal examination and
radiology. Haemoptysis in this case may have been associated with the
underlying disease but could have been incidental. Diagnosis, in
general, requires lung biopsy. As in this patient, lung function does
not appear to improve significantly on follow up.
