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From the Departments of Radiology (Dr. Choi), Internal Medicine (Dr. Lee), and Pathology (Dr. Myoung), Dankook University College of Medicine, Choongnam, Korea; Department of Radiology (Drs. Im and Han), Seoul National University, College of Medicine, Seoul, Korea; and Department of Radiology (Dr. Kim), Chungnam National University Hospital, Taejon, Korea.
Currently at Samsung Medical Center, Seoul, Korea.
Correspondence to: Young Hi Choi, MD, Department of Radiology, Dankook University College of Medicine, 29 Anseodong, Cheonan, Choongnam, 330715, Korea; e-mail: choiyh{at}anseo.dankook.ac.kr
| Abstract |
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Design: We used retrospective analysis to review and characterize the radiographic, thin-section CT, and clinical findings of CSS.
Patients: The study involved nine patients with CSS. The patients included four men and five women, whose ages ranged from 18 to 60 years (median, 35 years). Thin-section CT scans and chest radiographs were retrospectively analyzed by three radiologists in consensus. Clinical data were obtained by chart review. Histologic samples were available in eight patients.
Results: All patients had a history of asthma averaging 28 months (range, 4 to 72 months) prior to the initial symptom of vasculitis and marked peripheral blood eosinophilia (mean peak count, 8,726/µL; range, 3,000 to 32,000/µL; mean differential count, 41%; range, 19 to 67%). All patients had systemic vasculitis involving the lung and two to four extrapulmonary organs, most commonly the nervous system (n = 8) and skin (n = 7). Chest radiographs showed bilateral nonsegmental consolidation (n = 5), reticulonodular opacities (n = 3), bronchial wall thickening (n = 3), and multiple nodules (n = 1). The most common thin-section CT findings included bilateral ground-glass opacity (n = 9); airspace consolidation (n = 5), predominantly subpleural and surrounded by the ground-glass opacity; centrilobular nodules mostly within the ground-glass opacity (n = 8); bronchial wall thickening (n = 7); and increased vessel caliber (n = 5). Other findings were hyperinflation (n = 4), larger nodules (n = 4), interlobular septal thickening (n = 2), hilar or mediastinal lymph node enlargement (n = 4), pleural effusion (n = 2), and pericardial effusion (n = 2).
Conclusions: In CSS, thoracic organs are invariably involved with additional diverse manifestations. The possibility of CSS should be raised in patients with a history of asthma and hypereosinophilia who present with thin-section CT findings of bilateral subpleural consolidation with lobular distribution, centrilobular nodules (especially within the ground-glass opacity) or multiple nodules, especially in association with bronchial wall thickening.
Key Words: angiitis asthma Churg-Strauss syndrome CT granulomatosis hypereosinophilia lung abnormalities radiography
| Introduction |
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Clinically, there are three distinct phases: (1) a prodromal phase that may persist for many years, consisting of asthma, often preceded by allergic rhinitis; (2) a second phase of marked peripheral blood eosinophilia and eosinophilic tissue infiltrates resembling Löfflers syndrome, or chronic eosinophilic pneumonia, which may recur over a period of years; and (3) a third, life-threatening vasculitic phase.7 Although CSS can be readily diagnosed on clinical grounds, histologic confirmation should always be sought by biopsy of involved skin, nerve, and/or lung. Corticosteroid therapy has dramatically improved the prognosis of this disease, and long-term remission is a realistic expectation.6 7 8 11 It is important, therefore, to separate CSS from other necrotizing systemic vasculitides because Wegeners granulomatosis and, to a lesser extent, polyarteritis often require treatment with cytotoxic agents, whereas corticosteroids alone are effective in CSS.7 8
Radiographically, the pulmonary abnormalities are variable,6 7 12 13 14 with fleeting infiltrates occurring most frequently.6 14 As there have been only anecdotal reports on CT findings of CSS in the literature,15 16 17 18 we present the clinical, radiographic, and thin-section CT findings of nine patients with the histologic diagnosis of CSS collected from six institutes during a 12-year period to better characterize the radiologic findings of this rare disease entity. We also review the pertinent literature.
| Materials and Methods |
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The clinical findings were obtained by means of chart review and included allergic history (asthma, allergic rhinitis, or other allergic tendency); symptoms and signs of vasculitic skin rash or mononeuritis multiplex; laboratory findings including peak eosinophil count in peripheral blood; the organs involved in vasculitis; treatment; and outcome.
In all patients, both chest radiographs and thin-section CT scans of the lung were obtained. The CT scanning was performed with scanners from different manufacturers. CT scans were obtained with 1.5- to 2-mm collimation at 10-mm intervals from apices to lung bases. The scanning parameters were 140 peak kilovolt, 170 mA, and 2 s exposure. The scans were reconstructed with a highspatial frequency algorithm. Both mediastinal (width 450; level 35) and lung window (width 1,500; level -700) images were obtained. All scans were obtained in inspiration with the patient in supine position. Contrast medium was not administered.
The radiographs and thin-section CT scans were reviewed by three radiologists (Y.H.C., J.-G.I., B.K.H.), and decisions were reached by consensus. Images demonstrating abnormalities at presentation and during follow-up were reviewed. The radiographic findings were evaluated for the presence and location of parenchymal abnormalities, such as patchy consolidation, reticulonodular opacities, nodules, bronchial wall thickening, septal lines, presence of mediastinal widening, hilar enlargement, pleural effusion, and cardiomegaly. The CT scans were analyzed specifically for the presence, pattern, and distribution of pulmonary abnormalities, as well as the presence of bronchial wall thickening, cardiomegaly, pleural effusion, and hilar or mediastinal lymph node enlargement.
| Results |
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A rapid initial response to treatment with prednisolone or prednisone (20 to 60 mg/d) was observed in all except one case. Azathioprine and cyclophosphamide were introduced in three cases when incomplete remission or relapse followed early reduction in the steroid dose. CSS was not fatal in any patients.
Radiologic Findings
The most common radiographic findings were bilateral multifocal
consolidation: patchy nonsegmental consolidation (Fig 1
, top, A) in five patients and multiple nodules in
one patient. Four out of six had the lower lung zone predilection (Fig 2
, top, A). Diffuse reticulonodular opacities and
bronchial wall thickening were each observed in three patients. Patient
2, who showed patchy right lower lung consolidation, also showed
diffuse reticulonodular opacities, bronchial wall thickening, increased
cardiac size compared with previous film, bilateral hilar lymph node
enlargement, and small bilateral pleural effusions (Fig 3
, top, A). Open thoracotomy and biopsy of the
right lower lobe revealed findings of eosinophilic pneumonia and
asthmatic bronchitis with eosinophil infiltration and vasculitis in
pleura and pericardium. In patient 4, diffuse ill-defined multifocal
distribution of the ground-glass opacity was associated with the
reticulonodular opacities and bronchial wall thickening (Fig 4
, top, A). He had associated multiple aneurysms
involving medium-sized arteries of both kidneys and the liver (Fig 4
,
bottom, B). Patient 5 showed diffuse reticular
opacities, septal lines, and bronchial wall thickening (Fig 5
). This patient also had left hilar enlargement. Patient 9 showed
multiple variable-sized nodules in both lung zones. The upper and lower
lungs were evenly affected. She had mediastinal lymph node enlargement.
Thoracoscopic biopsy of the nodular lesion of the lung revealed a
granulomatous lesion and necrotizing vasculitis with eosinophil
infiltration.
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| Discussion |
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The etiology of CSS is still unknown, but an allergic or immune pathogenesis for the disease was suggested by the presence of asthma, eosinophilia, and elevated levels of serum IgE in some cases.6 20 21 22 Asthma is the central feature of CSS, but is unusual in Wegeners granulomatosis and polyarteritis nodosa. Relatively late age of onset (mean, 32 years) distinguishes the asthma of CSS from asthma in the general population. Asthma preceded the development of systemic vasculitis by up to 6 years in this series and 30 years in literature review.6 Chronic respiratory infection associated with bronchiectasis may antedate the vasculitic illness by many years.7 23 As in our series, allergic rhinitis and pansinusitis may represent the initial phase of the syndrome.7
Although peripheral blood eosinophilia is a hallmark of CSS, patients with eosinophilic tissue infiltration in the absence of peripheral blood eosinophilia have been reported.7 While asthma is often accompanied by eosinophilia that seldom exceeds 0.8 x 109/L,7 the eosinophilia is generally of a much higher order in CSS: all the patients in our series had peak counts of > 3 x 109/L. The significance of the eosinophilia of CSS is unknown. Eosinophils may play a protective role by their capacity for phagocytosis or be directly responsible for tissue damage.7 Chronic eosinophilic pneumonia is commonly associated with asthma and tissue eosinophilia, but it does not show granulomatous arteritis and is not associated with extrapulmonary lesions.24 Hypereosinophilic syndrome is characterized by eosinophilia of > 1.5 x 109/L persisting for > 6 months.7
Thoracic manifestations with transient pulmonary infiltrates are a central feature of CSS and antedated the systemic vasculitis in 40% of cases.7 Less common intrathoracic manifestations include pleural effusions (29%) containing a large number of eosinophils25 or pericardial effusion.7 Hilar lymphadenopathy15 with other pulmonary infiltrates is infrequent and thought to represent reactive hyperplasia. The heart is a primary target organ in CSS. Cardiac disease accounts for 48% of deaths attributed to CSS,7 including acute pericarditis, constrictive pericarditis, cardiac failure, and myocardial infarction.1 2 7 Delayed treatment can lead to myocardial infarction and intractable cardiac failure.7 In our series, two patients showed pericardial effusion.
Extrathoracic manifestations of CSS include diverse GI involvement of both eosinophilic gastroenteritis and polyarteritis nodosa. Submucosal infiltrates of eosinophils can produce obstructive nodular masses, and mucosal involvement may result in diarrhea and bleeding.7 Skin rash is one of the most common features of the vasculitic phase of CSS, reflecting involvement of smaller vessels. In contrast to the respiratory tract and GI manifestations of CSS, involvement of skin is generally restricted to the vasculitic component of the syndrome. One or more of the following skin lesions were seen in 70% of all cases7 : purpura, macular or papular erythematous rash, urticaria, and subcutaneous nodules. Neuropathy with the typical lesion of mononeuritis multiplex was found in 75%. Cranial nerve palsies are infrequent, but we had one case with facial nerve palsy. Renal involvement is infrequent; the characteristic lesion is a focal segmental glomerulonephritis.1 7 The generally benign nature of the renal disease in CSS distinguishes it from the other necrotizing vasculitides. Myalgia and joint pain occurred because of vasculitic involvement of muscles and joints.
Radiologic Findings
The radiologic appearance of CSS is variable, with 27 to 93%
showing any abnormalities on chest radiographs in the
literature.1
7
12
13
14
In a large series of 154 cases
reported by Lanham et al,7
nonsegmental airspace disease
was reported to be present in 72% and transient Löfflers
pneumonia in 40%. In our series, we found abnormalities on chest
radiographs in all cases; patchy multifocal peripheral consolidation
(67%) was the most common finding. Although the infiltrates in the
prodromal and the vasculitic phase of the disease may be similar
radiologically, the histologic picture in the former is usually that of
extensive eosinophilic infiltration of alveoli and interstitium,
whereas in the latter, necrotizing vasculitis and granulomas are
seen.23
However, in the lung, extravascular granulomas may
be infrequent, and the presence of vasculitis is essential for
diagnosis.26
Multiple nodular lesions with rare cavitation
or diffuse interstitial pattern were also reported.15
18
On thin-section CT, the parenchymal abnormal findings of CSS could be classified into three patterns in our series. The first pattern is subpleural consolidation with lobular distribution. The consolidation proved to be mainly hemorrhagic necrosis. The peripheral location and lobular distribution of the consolidation implies that the lesion is due to vasculitis involving small and medium-sized arteries. The second pattern is centrilobular perivascular densities. In one case of CSS, Buschman et al16 reported the finding of stellate arteries larger than accompanying bronchi, interlobular septal thickening, and widely scattered patchy and indistinct opacities. Connolly et al17 reported the finding of fluffy perivascular opacities in a child with CSS. In our series, we found diffusely scattered centrilobular nodules < 5 mm in diameter, especially within the ground-glass opacity lesion, in 89% of the patients. Along with the increased caliber of peripheral small arterioles with perivascular fluffy opacities (observed in 34% of the cases), this could reflect the pulmonary vasculitis and perivascular cellular infiltration. The third pattern is multiple larger nodules, which we found in 44% of our patients. In our series, there was no cavitation of the nodules, which is quite rare in the literature search.15 18 A halo of ground-glass opacity (halo sign) that surrounded the consolidation or nodule was found in four out of seven patients in our series. In one patient in whom adequate tissue was available, the halo sign corresponded to interstitial infiltration of eosinophils and giant cells that surrounded a central core of hemorrhagic necrosis and granuloma.
Bronchial wall thickening, with or without bronchial dilatation, and hyperinflation are likely to be related to asthma, which is an essential component of CSS. Bronchial wall thickening and bronchial dilatation are common CT findings in asthmatic patients.27 28 Bronchial wall thickening is thought to be the only finding that could differentiate CSS from other pulmonary infiltrates with eosinophilia.
Interlobular septal thickening may reflect the interstitial pulmonary edema attributed to the cardiac and pericardial involvement of CSS, with associated findings of pericardial effusion and increased caliber of vessels. As there was no associated sign of cardiac involvement in one patient, cellular infiltration and accumulation of water could be the cause of the septal thickening.
Differentiation of CSS from chronic eosinophilic pneumonia is necessary in patients with hypereosinophilia and pulmonary abnormality. CT findings of chronic eosinophilic pneumonia are characterized by the presence of homogeneous peripheral airspace consolidation that responds promptly to corticosteroid therapy, whereas in CSS, peripheral consolidation has a tendency toward lobular distribution and frequent association of centrilobular nodules within the ground-glass opacity.
Radiologic differentiation of CSS from other pulmonary angiitis and granulomatosis groups might be possible in some cases. Solitary or multiple parenchymal nodules with frequent cavitation or associated consolidation are the most common findings in Wegeners granulomatosis,29 30 lymphomatoid granulomatosis,31 and necrotizing sarcoid granulomatosis32 ; in CSS, on the other hand, the most common finding is peripheral consolidation, and multiple nodules are rather infrequent.18 In bronchocentric granulomatosis, the most common finding is consolidation, atelectasis, or less confluent pneumonic infiltration involving less than a lobe (73%), reflecting bronchocentricity of the lesion.33 Although the radiologic patterns will suggest the diagnosis of CSS, the specific diagnosis must rely on clinical, immunologic, and pathologic evidence.
In our study, the overall prevalence of abnormal findings on CT was 100%, a rate somewhat higher than the 88% reported in a previous study using CT.18 The difference may be attributed to the difference in the inclusion criteria for CSS. In addition, CT is superior to radiographs for detecting minor abnormalities such as bronchial wall thickening or small lymph node enlargement. This study has limitations to characterize the clinical and CT findings of CSS thoroughly, including only a small number of cases. As lung biopsy was performed in only two cases, we could not correlate each CT finding with pathologic findings.
In summary, CSS invariably involves the thorax, and thoracic manifestations are multiple and varied. Pulmonary parenchymal involvement is the most typical expression, and cardiac involvement is not uncommon. Radiographically, it usually appears as bilateral nonsegmental consolidation or reticulonodular opacities. The most common thin-section CT findings include subpleural consolidation with lobular distribution, centrilobular nodules, bronchial wall thickening, and increased vessel caliber. Less common findings include hyperinflation, mediastinal or hilar lymphadenopathy, and pleural or pericardial effusion. Although not specific, thin-section CT findings including bronchial wall thickening in a patient with hypereosinophilia and history of asthma should raise the possibility of CSS, and the diagnosis could be more confident when the patient has an associated skin lesion or mononeuritis multiplex.
| Acknowledgements |
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| Footnotes |
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Presented at Thoracic Imaging 1997, presented by the American College of Radiology and the Society of Thoracic Radiology, Naples, FL, January 19, 1997.
Received for publication January 27, 1999. Accepted for publication August 20, 1999.
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