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Recognition of Proximal Bronchiectasis at Bronchoscopy: The Igloo Sign

Ahmad, Kaiser A. MD; Dillard, Thomas A. MD

Bronchoscopic Image

Relatively few recent reports have emphasized findings on visual inspection of the airways at bronchoscopy in patients with bronchiectasis. In some circumstances, however, bronchoscopic findings can expedite the recognition of bronchiectasis and lead to confirmatory studies if indicated. In this report, we describe the dilatation of proximal subsegmental airways in a patient who subsequently proved to have allergic bronchopulmonary aspergillosis (ABPA).

From the Section of Pulmonary/Critical Care Medicine, Department of Medicine, Medical College of Georgia, Augusta, Georgia, USA (Drs. Ahmad and Dillard).

Reprints: Thomas A. Dillard, MD, BBR 5513 Section of Pulmonary/Critical Care Medicine, Medical College of Georgia, Augusta, GA 30907, U.S.A.; (e-mail:

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A 22-year-old man was admitted to his local hospital with a history of cough, production of yellow to green sputum, fever and chills, and weight loss of 10 to 15 pounds in the last month. His chest radiograph initially showed a right lower lobe air fluid level. Plain computed tomographic (CT) scan of the chest from the outside hospital reported a mass-like opacity in the right lung. He improved clinically on antibiotics but developed a new density in the right upper lobe and was transferred to the Medical College of Georgia.

Medical history included an episode 4 years earlier of severe pneumonia complicated by lung abscess in the right lower lobe. He also reported asthma and rhinosinusitis since childhood. Medications on transfer included intravenous ticarcillin/clavulanate and symptomatic analgesia.

Physical examination revealed: blood pressure 149/68 mm Hg; pulse 66 beats/min; respiratory rate of 20 breaths/min, and a temperature of 36.6°C. Oral examination revealed good dentition. Nasal examination revealed decreased patency, mucosal thickening, and a nasal polyp. Chest examination revealed inspiratory squawks bilaterally, best heard anteriorly, and scattered wheezing. Cardiovascular examination revealed regular rate and rhythm without murmur. Abdomen was soft, nontender, and nondistended with no visceromegaly. Extremities revealed no clubbing, cyanosis, or edema. Laboratory studies revealed hemoglobin 12.2 g/dL, platelets 379, white blood count 5.5 with differential count of 45 neutrophils, 30 lymphocytes, 7 monocytes, 15 eosinophils, and 3 basophil. Serum chemistries were normal.

Bronchoscopy revealed dilatation of the subsegmental bronchi in multiple locations, including the right lower lobe (Figs. 1 and 2). Other findings included atrophy of bronchial submucosa as suggested by greater prominence of transverse connective tissue bands in the dilated airways (Fig. 2) and mucus plugging of the right upper lobe. Based on the findings at bronchoscopy, repeat chest CT (Fig. 3) with and without thin sections was obtained. CT showed central and cylindrical bronchiectasis in both upper lobes and right lower lobe, foci of airspace density, ground glass opacity, and adenopathy.







Bronchoalveolar lavage fluid cultures grew Aspergillus fumigatus and Aspergillus flavus at 500 to 1000 colony-forming units (cfu) per milliliter and rare Torulopsis glabarta. Cultures were negative for acid-fast organisms. Bacterial cultures were less than 103/mL. Serologic tests subsequently supported the diagnosis of allergic bronchopulmonary aspergillosis. Total IgE level was 4984 mg/mL (normal, 0-150 mg/mL). Aspergillus-specific IgG and IgE were 104 μg/mL (normal, <29 μg/mL) and 22 KU/L (normal, <0.35 KU/L), respectively. Fungal cultures grew A. fumigatus and A. flavus at 500 to 1000 cfu/mL and rare Torulopsis glabrata.

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Bronchiectasis, or permanent dilatation of bronchi, 1 can result from many causes but most commonly results from chronic or recurrent infections. The present case met nearly all diagnostic criteria for allergic bronchopulmonary aspergillosis (ABPA), a known cause of proximal bronchiectasis.

Few recent reports have described bronchoscopic findings in bronchiectasis. One earlier report 2 described a post-inflammatory bronchiectatic cavity seen by flexible bronchoscopy. The patient, a 55-year-old woman, had presented with cough and hemoptysis and a history of pneumonia 35 years ago. Flexible bronchoscopy showed a post-inflammatory bronchiectatic cavity in the right B3 bronchus. 2

High-resolution CT scanning (HRCT) is the usual imaging modality of choice for evaluating bronchiectasis, and has replaced bronchography and selective bronchography methods for diagnosis. 3 Direct signs of bronchiectasis on HRCT include bronchial dilatation greater than the accompanying pulmonary artery, lack of normal tapering, more than 2 cm after bifurcation, contour abnormalities, and abnormal visibility of airways in peripheral lung zones. Indirect signs include bronchial wall thickening or irregularity, abnormal collections of mucous, and other findings. 3 The presence of multiple signs increases the likelihood of bronchiectasis.

Few of the CT signs can be recognized on bronchoscopy. Lack of tapering of the airways is difficult to detect by bronchoscopy, in part because of distance perspective, the optical illusion of tapering that occurs when looking into the end of any tubular structure. Viewed from the end, tubular structures appear to taper even when they do not.

Occasionally, like in this case, bronchoscopy can recognize dilatation of distal airways in comparison to more proximal airways. We observed an increase of airway caliber when advancing the bronchoscope more distally (Figs. 1 and 2). The first impression at bronchoscopy was loss of the usual “tunnel vision” perspective when entering the bronchiectatic cavity. In our case, we also observed atrophy of submucosal tissue and mucous plugging.

Further development of visual criteria for bronchiectasis at bronchoscopy such as measurement of airway caliber could be helpful. Estimation of airway diameter can be aided by introduction of an instrument of known size such as biopsy forceps. Estimation of airway diameter in the area of concern and proximally could increase suspicion of dilatation.

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1. Barker AF. Bronchiectasis. N Engl J Med. 2002; 346:1383–91.
2. Imamura S, Negro S, Fukuoka M, et al. Postinflammatory bronchiectatic cavity observed by fiberoptic bronchoscopy. Eur Respir J. 1994; 7:1714–5.
3. Webb WR, Muller NL, Naidich DP. High resolution CT of the Lung. Philadelphia: Lippincott Williams and Wilkins, 2001:467–512.

bronchiectasis; fiberoptic bronchoscopy; allergic bronchopulmonary aspergillosis

© 2003 Lippincott Williams & Wilkins, Inc.