Melanie B. Peachell, MD; Nestor L. Muller, MD, PhD

Disclosures

Semin Respir Crit Care Med. 2004;25(5) 

In This Article

Wegener's Granulomatosis

Wegener's Granulomatosis (WG) is a systemic granulomatous inflammatory process with variable clinical expression. It classically involves the upper and lower respiratory tracts and kidneys. In some patients it can be manifested primarily or exclusively in the respiratory tract, a form known as limited (nonrenal) WG. The characteristic pathological findings of WG include necrotizing granulomata of the respiratory tract, necrotizing vasculitis affecting medium to small pulmonary arteries and veins, and a focal glomerulonephritis.[1]

The most common radiological manifestation of pulmonary WG consists of multiple nodules.[2,3,4] The nodules range from 0.3 to 10 cm in diameter and are usually bilateral.[5] The nodules may be smooth or spiculated; ~50% eventually demonstrate cavitation.[6] The cavities typically have thick walls and shaggy, irregular inner borders[7] (Fig. 1). As the disease progresses, the nodules tend to increase in size and number.[8] CT is superior to chest radiographs in demonstrating the presence and number of nodules and presence of cavitation.[6] Cavitation usually occurs in nodules > 2cm in diameter.[6] In one review of the CT findings in 30 patients, 27 (90%) had nodules or masses; cavitation of one or more of the nodules was present in 13 (48%) of these 27 patients.[4] The nodules ranged from 1 to 32 in number (mean 8) and had a predominantly subpleural or peribronchial distribution.[4]

Wegener's granulomatosis. (A) Computed tomographic (CT) scan at the level of the upper lobes shows bilateral noncavitating nodules (arrows) in the apical regions of both lungs and a cavitating nodule in the left apex. (B) CT scan at the level of main stem bronchi shows multiple cavitating and noncavitating nodules mainly in the subpleural and peribronchovascular regions. The patient was a 50-year-old man.

Another common radiological finding is the presence of areas of air space consolidation or ground-glass opacities[7] (Fig. 2). These are seen in ~50% of patients.[7] Several patterns of distribution of the areas of consolidation and ground-glass opacification have been described, including diffuse, wedge-shaped pleural based, peribronchial, and patchy[7,9] (Fig. 3). Diffuse consolidation or ground-glass attenuation is seen in ~8% of patients and usually reflects the presence of diffuse pulmonary hemorrhage.[5] The areas of consolidation may be seen in association with pulmonary nodules or as an isolated finding; in ~15% of patients cavitation is evident radiologically within the areas of consolidation.[5] Occasionally, foci of calcification may be seen within areas of consolidation and nodules.[7]

Wegener's granulomatosis. Computed tomographic scan image at the level of the right main pulmonary artery shows poorly defined bilateral ground glass opacities and a cavitating nodule (arrow) in the right middle lobe. The ground-glass opacities were due to diffuse pulmonary hemorrhage. The patient was a 53-year-old man.

Wegener's granulomatosis. Computed tomographic scan image at the level of the inferior pulmonary veins shows bilateral areas of consolidation in a peribronchovascular distribution. The patient was a 35-year-old woman.

Tracheobronchial involvement occurs in ~30 to 50% of patients with WG.[4,5] Rarely, tracheobronchial abnormalities may be the only site of involvement or be the presenting abnormality in WG.[10,11] The most common manifestations are tracheobronchitis, tracheal or bronchial stenosis, and subglottic stenosis.[5,12] The stenosis tends to be focal and most commonly involves the main bronchi followed by the trachea, bronchus intermedius, and lower lobar bronchi.[5] CT demonstrates thickening of the airway wall and associated luminal narrowing.[7,13] The severity and extent of airway narrowing are best evaluated using multiplanar and three-dimensional reconstructions of spiral CT scans performed using thin sections.[7,13] Bronchial narrowing and obstruction may result in distal atelectasis. Bronchiectasis may occur with or without associated parenchymal manifestations of WG.[8] Less common findings include intra- and extraluminal soft tissue masses and calcification of the tracheal rings.[4,10]

Pleural effusions are seen in ~12 to 25% of patients and may be unilateral or bilateral, small or large.[2,3,4,5,14] Other pleural abnormalities that can rarely be seen include unilateral or bilateral pleural thickening, pneumothorax, hydropneumothorax, or pyopneumothorax.[3,7,6] Mediastinal lymph node enlargement is evident on CT in 20% of patients.[4]

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