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A Case of Progressive Panlobular Emphysema in an Adult Nonsmoker With Normal A1AT Levels FREE TO VIEW

Michael McMahon, MD; Nikunj Bhatt, MD
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Walter Reed National Military Medical Center, Silver Spring, MD


Chest. 2015;148(4_MeetingAbstracts):514A. doi:10.1378/chest.2265755
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Abstract

SESSION TITLE: Imaging Student/Resident Case Report Posters

SESSION TYPE: Student/Resident Case Report Poster

PRESENTED ON: Tuesday, October 27, 2015 at 01:30 PM - 02:30 PM

INTRODUCTION: Radiographic evidence of basilar panlobular emphysema is intimately linked to the diagnosis of alpha-1 antitrypsin deficiency (A1ATD) in adults. We present a rare case of progressive panlobular emphysema in a non-smoking patient with a normal A1AT level.

CASE PRESENTATION: A 65-year old woman, with a previous diagnosis of asthma, presented to the clinic with a one year history of progressive dyspnea on exertion and exercise intolerance. She denied any smoking history and denied any significant exposures. The patient had a complicated medical history including papillary thyroid cancer (status post resection), Addison’s disease (on hydrocortisone, fludrocortisones), peripartum cardiomyopathy (with normalization of cardiac function), and premature ovarian failure. Incidentally, the patient also had a positive SSA, low complement 3 and 4 levels, and a positive anti-phospholipid antibody. Examination of the lungs demonstrated decreased breath sounds at the bases bilaterally and normal lung sounds in the upper lobes. A high-resolution CT confirmed panlobular basilar emphysematous changes (see image 1). A V/Q scan was low probability for having a pulmonary embolism. Pulmonary function testing showed a moderately severe obstructive pattern with a moderately reduced DLCO without a bronchodilator response. A cardiopulmonary exercise test also confirmed expiratory flow limitation and dynamic hyperinflation. An extensive workup that including A1AT quantitative testing on two separate occasions were normal and initial A1AT phenotype testing was negative for the PI*Z and PI*S alleles, and was reported as a “normal” Pi*M phenotype. Additionally, bronchoscopy with bronchoalveolar lavage, transbronchial biopsy, and bronchial brushings were unrevealing.

DISCUSSION: The patient’s normal A1AT levels in the setting of panlobular emphysema suggests an A1ATD dysfunction. Other known causes including smoking, congenital lobar emphysema, and drug-induced causes were unlikely in this patient. While the underlying etiology remains unknown, several hypotheses can be considered. The similar radiography appearance to A1ATD suggest that the patient may have a subtype mutation of the A1AT that lead to a qualitative defect in this protein. Alternatively, another factor may be inhibiting A1AT’s activity.

CONCLUSIONS: We present a rare case of basilar panlobular emphysema without evidence of an exposure history or A1ATD. Our case highlights the need to better understand the underlying pathophysiology of panlobular emphysema.

Reference #1: Stoller JK, Aboussouan LS. Alpha1-antitrypsin deficiency. Lancet 2005; 365:2225.

DISCLOSURE: The following authors have nothing to disclose: Michael McMahon, Nikunj Bhatt

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