Bronchiolitis obliterans organizing pneumonia

Abstracts

Uma paciente 48 anos apresentou-se, assintomática, mas com achado radiológico de condensações alveolares, algumas constituindo nódulos em lobo superior direito, lobo médio e língula com predomínio perihilar. Foi considerado o diagnóstico diferencial de neoplasia, sarcoidose, doenças granulomatosas e tuberculose, entre outras doenças. O diagnóstico de bronquiolite obliterante com pneumonia em organização foi estabelecido através de videotoracoscopia e foi iniciado o tratamento com esteróides. Houve boa evolução com resolução radiológica.

Bronquiolite obliterante; Bronquiolite obliterante com pneumonia em organização

CASE REPORT

Bronchiolitis obliterans organizing pneumonia^*

Gabriela Addor; Andreia Salarini Monteiro; David Henrique Nigri; Wilhermo Torres; Carlos Alberto de Barros Franco

^{Correspondence}

ABSTRACT

48 years-old woman, asymptomatic, presented with radiographic findings of patchy airspace consolidation with nodular opacities in the upper right lobe, middle lobe and lingula. The differential diagnoses of neoplasms, sarcoidosis, granulomatous diseases and tuberculosis were considered. Diagnosis of Bronchiolitis obliterans organizing pneumonia was made by means of videothoracoscopy whereupon treatment with corticosteroids was begun. The patient had a positive evolution with resolution of the radiographic finding.

Key words: bronchiolitis obliterans organizing pneumonia, bronchiolitis obliterans

Acronyms and Abbreviations utilized in this text

BOOP: Brochiolitis obliterans with organizing pneumonia

HRCT: High resolution computerized tomography

BAAR: Alcohol –acid resistant bacillus

COP: Cryptogenic organizing pneumonia

PCR: Polymerase chain reaction

FAN: Antinuclear antibody

ANCA: Anti-Neutrophil Cytoplasmic Antibody

Introduction

Brochiolitis obliterans with organizing pneumonia was described in 1985 by Epier et cols, as a distinct disease with clinical, radiological and prognostic manifestations differing from other pulmonary interstitial diseases. In 1983, Davison et cols, described a similar disease entity they called cryptogenic organizing pneumonia. Bronchiolitis obliterans with organizing pneumonia (BOOP) is characterized by the presence of plugs in the conjunctive tissue within the distal airspaces. It appears predominantly in the alveolar ducts and alveoli and often also impairs the bronchioles ^{(1, 7).} This histo-pathological pattern may be associated with diseases of the conjunctive tissue, vasculitis, infections, pneumonitis by hypersensitivity, obstructive pneumonia, aspiration, addiction to systemic and inhaled drugs or toxins, chronic eosinophylic pneumonia and hematological malignancies or be idiopathic^{,( 8)} . In this last case it is preferably called cryptogenic organizing pneumonia (COP). As the use of the acronym BOOP may bring about a confusion with other diseases of the airways such as constrictive bronchiolitis ⁽¹⁾ and significantly stress the bronchiolar component that may be found in other affections not associated to organizing pneumonia, it has progressively been less used ⁽³⁾ Use of the generic term organizing pneumonia has therefore been proposed, with modifications suitable for each case, for instance organizing pneumonia associated to rheumatoid arthritis, organizing pneumonia associated to viral pneumonia etc. ⁽¹⁾

Case Report

A 48 year old woman, engineer, smoker (25 packs/year) asymptomatic was, submitted to routine chest X-ray which disclosed alveolar infiltrate in the right upper and medium lobes. There was no history of recent infection, use of systemic or inhaled drugs or recent travels.

Denied history of asthma or affection of the sinuses.

Physical exam was normal. High resolution computerized tomography of the chest (HRTC) showed alveolar condensations, some forming nodules in the upper right lobes, medium lobe and lingula, with a perihiliar prevalence (figures 1 and 2).

Spirometry was normal with FEV₁ = 2.58L (91%) and slow VC = 3.68L (107%) 6 minute walk test without changes with initial saturation of O₂ = 98% and final = 97% with a distance of 320 meters covered. Anti HIV not reactive, blood tests, VHS, C reactive protein and serum calcium normal. Serology for collagen diseases and systemic vasculitis (including FAN, ANCA, Anti-DNA, Anti-Sm, Anti-SS-A, Anti-SS-B and rheumatoid factor) were negative. Bronchoscopy with transbronchial biopsy was normal; GRAM and culture for common microbes, BAAR, direct testing for fungi and PCR for Mycobaterium tuberculosis were negative in the bronchoalveolar lavage and the histo-pathological exam was not conclusive. Pulmonary biopsy by videothoracoscopy which was compatible with BOOP was performed (Figure 3). Thereupon prednisone 40mg/day was initiated with a significant improvement at CT scan in 45 days and after 6 months presented only with a discrete infiltrate in ground glass appearance.

Discussion

Idiophatic BOOP is the most common form of BOOP usually occurring between 50 and 70 years of age, most often in non-smokers and without a preference for gender. Its incidence and prevalence still remain undefined ^(1). In general, symptoms are not specific and even absent in 13% of the cases ⁽⁶⁾. This was true of this patient, who due to radiological findings sought a lung specialist. Patients frequently present with cough, dyspneia, and occasionally with constitutional symptoms such as weight loss, myalgia, malaise, prostration and fever. Laboratory tests may show increase of VHS and of the C reactive protein ^(7). Fine dry crepitations and tachypneia are the more common clinical findings. Normally there is no clubbing. Most common radiological findings are uni- or bilateral zones of consolidation. Small nodular opacities may be found in 10 to 50% of the cases. CT scan of the chest disclosed consolidation of the airspace in 90% of the BOOP cases, prevailing in the lower areas and attenuation in ground glass may be detected in 60% of the cases ⁽¹⁾. In15% of the patients we detected multiple nodules ⁽¹⁾.

Diverging from the most common findings in literature, the patient was asymptomatic and the chest X-ray was not usual (infiltrate with nodules predominantly in the upper lobes), leading to search for the following differential diagnoses: sarcoidosis, neoplasias, fungal disease, alveolar proteinosis, Wegener granulomatosis and tuberculosis.

A transbronchial biopsy was performed to collect the histo-pathological specimen required for diagnosis of BOOP. Although the above procedure discloses bronchiolitis obliterans, in most cases it is not suited for ruling out associated lesions. This is not the case of surgical biopsy, considering that the specimen is obtained under direct vision and in larger amounts. The role of transbronchial biopsy for the diagnosis of BOOP is still not well defined ⁽¹⁾. The patient was submitted to transbronchial biopsy which was inconclusive because the specimen did not hold any representative pulmonary component and in this case, pulmonary biopsy by videothoracoscopy was essential for diagnostic definition. Furthermore there was no complication due to this procedure.

Diagnosis of COP is achieved by exclusion of other pathology or aggressive mechanism associates to the picture of BOOP. In the present case, serology tests for collagenosis and systemic vasculitis were negative and surgical biopsy was important to exclude eventually associated infectious diseases or neoplasms.

In their majority, patients have a complete remission with administration of corticoids (prednisone in doses ranging from 0.75 to 1.5 mg/kg as initial dose and gradual tapering off) that must be continued for 6 to 12 months ⁽⁷⁾ A small percentage of patients have spontaneous recovery ⁽⁷⁾ A progression to respiratory failure and death is infrequent. Evolution of diffuse interstitial fibrosis suggests another diagnosis as well as relapse with steroid doses larger than 20 mg ^(8); however there is no relationship between the number of relapses and prognosis ^{(7, 8).} As BOOP is a characteristically benign disease, seldom progressing to respiratory failure and death, a balance between an efficient treatment protocol and minimal side effects is important. There is no consensus in literature about the ideal corticoid dosage. Early treatment seems to avoid relapses ⁽⁸⁾. In this clinical case the use of a small prednisone dose (0.75 mg/kg) was chosen with a gradual tapering off and cessation after 6 months, in view of the good radiological response and absence of relapse to date. The good response may also be attributed to starting treatment at an asymptomatic stage.

Also in the current case the patient presented with an extensive radiological finding with no clinical or laboratory association. Surgical lung biopsy was the only method capable of ascertaining diagnosis. The beginning of treatment at an asymptomatic stage associated to a lower steroid dose, gradually tapered off showed good response without severe side effects or relapses.

References

Submitted for publication on May/8/03,

Accepted after review on August/26/03

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*

Work carried out Escola Médica de Pós-Graduação da PUC-RJ. Disciplina de Pneumologia e na ClÌnica Barros Franco-Consultoria em Aparelho Respiratório

Publication Dates

• Publication in this collection
  08 June 2004
• Date of issue
  Apr 2004

History

• Received
  08 May 2003
• Accepted
  26 Aug 2003