title: Pleuroparenchymal fibroelastosis: Distinct pulmonary physiological features in nine patients.
abstract: BACKGROUND
  Pleuroparenchymal fibroelastosis (PPFE) is a rare idiopathic interstitial pneumonia defined by pleural and subpleural parenchymal fibrosis predominantly in the upper lobes. Although the radiological and pathological characteristics of PPFE have become increasingly recognized, its pulmonary physiological features are not well understood.
  
  
  METHODS
  We reviewed nine patients with radiologically and histologically proven PPFE, and evaluated pulmonary physiological data.
  
  
  RESULTS
  Of the nine patients, six were male and three were female. The median age at presentation was 61 years. Common symptoms were dyspnea on exertion, weight loss, and nonproductive cough. Recurrent pneumothorax was found in eight patients and pneumonia in four. Median pulmonary function test results were as follows: forced vital capacity, 55.4% predicted; total lung capacity (TLC), 67.1% predicted; residual volume (RV), 102.3% predicted; and RV/TLC, 143.6% predicted. RV/TLC was increased without evidence of small airway disease according to clinico-radiologic-pathologic evaluation. The median partial pressure of oxygen in arterial blood and the alveolar-arterial gradient of oxygen were within normal limits, although there was a slightly elevated partial pressure of carbon dioxide in arterial blood (PaCO2). PPFE progressed in all patients despite treatment with pirfenidone, corticosteroids, and immunosuppressive agents. Seven patients died during the follow-up, five because of hypercapnic respiratory failure.
  
  
  CONCLUSIONS
  PPFE is characterized by severe mechanical restriction with high RV/TLC, causing increased PaCO2 and eventual hypercapnic respiratory failure. These physiological findings may be useful as an adjunct in the diagnosis of PPFE.
authors.affiliation: Department of Respiratory Medicine, Cellular Transplantation Biology, Kanazawa University Graduate School of Medicine, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan. Electronic address: swatanabe@staff.kanazawa-u.ac.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Watanabe
authors.affiliation: Department of Respiratory Medicine, Cellular Transplantation Biology, Kanazawa University Graduate School of Medicine, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan; Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, Vienna 1090 Austria. Electronic address: yuwaseda@gmail.com.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Waseda
authors.affiliation: Department of Respiratory Medicine, Cellular Transplantation Biology, Kanazawa University Graduate School of Medicine, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan. Electronic address: hmurakami@staff.kanazawa-u.ac.jp.
authors.forename: Hazuki
authors.initials: H
authors.lastname: Takato
authors.affiliation: Department of Respiratory Medicine, Komatsu Municipal Hospital, Ho-60, Mukaimoto-ori-machi, Komatsu 923-8560, Japan. Electronic address: manutsuma@gmail.com.
authors.forename: Ryo
authors.initials: R
authors.lastname: Matsunuma
authors.affiliation: Department of Radiology, Kinki Central Hospital of Mutual Aid Association of Public School Teachers, 3-1 Kurumazuka, Itami, Hyogo 664-8533, Japan. Electronic address: johkoht@aol.com.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Johkoh
authors.affiliation: Department of Radiology, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501, Japan. Electronic address: egashira@cc.saga-u.ac.jp.
authors.forename: Ryoko
authors.initials: R
authors.lastname: Egashira
authors.affiliation: Division of Diagnostic Pathology, Saitama Prefectural Cardiovascular and Respiratory Center, 1696 Itai, Kumagaya City, Saitama 360-0105, Japan. Electronic address: kawabata.yoshinori@pref.saitama.lg.jp.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kawabata
authors.affiliation: Section of Diagnostic Pathology, Kanazawa University Graduate School of Medicine, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan. Electronic address: h-ikeda@med.kanazawa-u.ac.jp.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Ikeda
authors.affiliation: Department of Respiratory Medicine, Kanazawa Municipal Hospital, 3-7-3, Heiwa-machi, Kanazawa, Ishikawa 921-8105, Japan. Electronic address: myasui0827@yahoo.co.jp.
authors.forename: Masahide
authors.initials: M
authors.lastname: Yasui
authors.affiliation: Department of Respiratory Medicine, National Hospital Organization Nanao Hospital, 3-1, Mattoumachi-hachibu, Nanao, Ishikawa, Japan. Electronic address: fujimura@nanao.hosp.go.jp.
authors.forename: Masaki
authors.initials: M
authors.lastname: Fujimura
authors.affiliation: Department of Respiratory Medicine, Cellular Transplantation Biology, Kanazawa University Graduate School of Medicine, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan. Electronic address: k-kasa@staff.kanazawa-u.ac.jp.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kasahara
mesh_terms: D000328:Adult; D000368:Aged; D004417:Dyspnea / Q000209:etiology; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000209:etiology; D054988:Idiopathic Interstitial Pneumonias / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000503:physiopathology; D008168:Lung / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011030:Pneumothorax / Q000209:etiology; D012008:Recurrence; D012129:Respiratory Function Tests; D012131:Respiratory Insufficiency / Q000209:etiology; D012143:Respiratory Physiological Phenomena; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Interstitial lung disease; PPFE; Pleuroparenchymal fibroelastosis; Rare idiopathic interstitial pneumonias