Elsevier

Respiratory Investigation

Volume 50, Issue 3, September 2012, Pages 88-97
Respiratory Investigation

Original article
Rapid decrease in forced vital capacity in patients with idiopathic pulmonary upper lobe fibrosis

https://doi.org/10.1016/j.resinv.2012.06.003Get rights and content

Abstract

Background

We are occasionally presented with patients with unclassifiable interstitial pneumonia of unknown etiology. Idiopathic pulmonary upper lobe fibrosis (IPUF) does not fit any of the currently defined subsets of idiopathic interstitial pneumonias (IIPs). This study was performed to examine clinical, functional, and pathological characteristics of IPUF.

Methods

We present 9 cases of histologically confirmed IPUF. The clinical and histological characteristics of the 9 patients were evaluated. The baseline respiratory function of all patients was measured. There were 7 patients whose forced vital capacity (FVC) had been monitored for at least a year who were selected to quantify the yearly decline in FVC.

Results

All patients were slender, with a body mass index of 16.0–19.8 kg/m2. Seven patients had a history of pneumothorax. Six patients died 1.8 to 5.7 years after the onset of the first symptoms. Fundamental histological features were intraalveolar collagen deposition and densely packed elastic fibers in the subpleural areas. These findings are the same as those seen in pleuroparenchymal fibroelastosis. However, the visceral pleura was thickened with dense collagen in only 2 patients, and pleural thickening was localized, if present, in the remaining 7 patients. Ventilatory impairment was also a characteristic. The time course decline of FVC was rapid and almost linear. The median yearly decline in FVC was −20.3% (range, −7.7% to −26.5%), which was more rapid than that reported for chronic fibrosing interstitial pneumonias such as idiopathic pulmonary fibrosis.

Conclusions

IPUF is a unique pulmonary fibrosis that results in rapid deterioration of ventilatory function and poor prognosis.

Introduction

We occasionally encounter patients with pulmonary fibrosis/interstitial pneumonia of unknown etiology that does not fit any of the currently defined subsets of idiopathic interstitial pneumonia (IIP) [1].

Although pulmonary upper lobe fibrosis of unknown etiology has been reported in the past, it is not recognized by current classification systems as a discrete class of IIP. The condition has been described by a variety of terms, including idiopathic progressive pulmonary fibrosis [2], pulmonary upper lobe fibrocystic changes [3], pulmonary apical fibrocystic disease [4], idiopathic progressive pleuropulmonary fibrosis [5], idiopathic pulmonary upper lobe fibrosis (IPUF) [6], [7], [8], [9], [10], [11], marked pulmonary fibrosis in the upper lobe [12], marked pulmonary fibrosis in the upper lung field [13], (idiopathic) pleuroparenchymal fibroelastosis (IPPFE, PPFE) [14], [15], [16], [17], and upper lobe-dominant pulmonary fibrosis [18]. The clinical and pathological characteristics of the cases reported by these authors include upper lobe-predominant pulmonary fibrosis with a chronic progressive course and no known cause for the fibrosis [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], a history of recurrent pneumothorax [6], [7], [8], [9], [10], [12], [13], [15], and marked weight loss [2], [5], [6], [7], [8], [9], [10], [11], [12], [13]. Although not all the patients described in previous reports had identical conditions, they had many pathological and clinical variables in common.

Of the reports mentioned above, those of Amitani et al. [6] and Frankel et al. [14] are key studies of the clinical and histological characteristics of pulmonary upper lobe fibrosis of unknown etiology. The patients in these 2 studies had similar clinical and histological characteristics, but there were some differences, which will be discussed in a subsequent section.

In this report, we adopt the term “idiopathic pulmonary upper lobe fibrosis” (IPUF), which was first used by Amitani et al. [6], and present 9 cases of IPUF with clinical and pathological characteristics and long-term follow-up data on respiratory function, which may be helpful for understanding the natural course of the disease.

Section snippets

Patient selection

We reviewed the medical files of all patients admitted to the departments of respiratory medicine at Fukuoka University Hospital, Fukuoka University Chikushi Hospital, National Hospital Organization Omuta National Hospital, and National Hospital Organization Fukuoka Higashi Medical Center from 2000 to 2010, and selected records of patients who had undergone a surgical lung biopsy or an autopsy. After reviewing the pathological and clinical information on these patients, we identified 9 patients

Patient characteristics

Enrolled patients consisted of 5 females and 4 males. Their age at the first visit to our hospital ranged from 43 to 81 years. Seven of the patients (patients 2–6, 8, and 9) had never smoked, and patients 1 and 7 had stopped smoking 3 and 7 years previously. Seven of the 9 patients had a history of pneumothorax, and 3 of the 7 patients with pneumothorax had a recurrent pneumothorax that had been treated by tube thoracostomy. Steroids were administered to 5 patients, but without benefit. All

Discussion

We present 9 patients with IPUF. By examining the biopsy or autopsy specimens obtained from the patients, we have identified the following common pathological findings: (1) densely packed elastic fibers, a result of the gathering of collapsed alveoli in the subpleural areas of the upper lobes (elastosis), associated with the deposition of mature collagen filling the alveolar lumens (intraalveolar fibrosis); (2) abrupt transitions from the subpleural fibrotic areas to less-involved pulmonary

Conflict of interest

Authors have no potential conflict of interest.

Acknowledgments

This study was partly supported by a Grant to the Diffuse Lung Diseases Research Group from the Ministry of Health, Labor and Welfare, Japan.

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    1

    Present address: Department of Respiratory Medicine, Fukuoka University Chikushi Hospital, Fukuoka 814-0180, Japan.

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