Pulmonary vasculitis: the spectrum of radiological findings

Myeloperoxidase and associated lung disease: Review of the latest developments

Myeloperoxidase (MPO) anti-neutrophil cytoplasmic antibodies (ANCA) are often detected in association with a variety of lung pathologies, the most common being interstitial lung disease (ILD). A growing cohort of patients are being diagnosed with MPO-ANCA in the context of ILD without ANCA-associated vasculitis. Clinically and radiologically, there is little to differentiate this cohort from MPO-ANCA-negative ILD patients; however, the pathophysiology is likely different and different treatments are likely required. We present here a brief summary of the proposed pathophysiology of MPO-ANCA-positive ILD, and a more detailed review of the latest evidence on management, including monitoring for development of ANCA-associated vasculitis, immunosuppression, anti-fibrotics, and novel agents that have yet to be trialled in human experiments.

Biomarkers in ANCA-Associated Vasculitis: Potential Pitfalls and Future Prospects

Over the past 3 decades, significant advancements in the understanding of the pathophysiology of ANCA-associated vasculitis has led to the development of a multitude of potential candidate biomarkers. Accompanied by the advent of increasingly effective therapeutic strategies, the need for a dependable biomarker to help determine the extent of disease activity and risk of relapse is ever present. Implementation of such a biomarker would enable tailored therapy, optimizing disease control while helping to mitigate unnecessary exposure to therapy and potential treatment-related damage. Although far from perfect, ANCA serology and B-cell population are the two main staple biomarker tools widely used in practice to help supplement clinical assessment. Over recent years, the application and progress of more novel biomarker tools have arisen in both organ-limited and multisystem disease, including genomics, urinary proteins, degradation products of the alternative complement system, cytokines, metabolomics, and biospectroscopy. Validation studies and clinical translation of these tools are required, with serial assessment of disease activity and determination of therapy according to biomarker status correlated with patient outcomes.

A Suspected Case of an Alveolar Haemorrhage Caused by Dasatinib

A 39-year-old man treated with dasatinib for chronic myelogenous leukaemia presented to our hospital with haemoptysis, coughing, and dyspnoea. Chest radiography and computed tomography revealed ground-glass opacities and a crazy-paving pattern. Bronchoalveolar lavage was not performed due to serious hypoxemia and bleeding. Significant bleeding from the peripheral bronchi led to a diagnosis of an alveolar haemorrhage. Dasatinib-induced alveolar haemorrhaging was suspected based on the clinical findings. His condition improved immediately after dasatinib withdrawal and initiation of steroid therapy. Reports of alveolar haemorrhaging induced by dasatinib are rare. As such, this is considered an important case.

Primary Pulmonary Lymphoid Lesions: Radiologic and Pathologic Findings

The pulmonary lymphoid system is complex and is composed of two compartments: the pulmonary lymphatics and the bronchus-associated lymphoid tissue (BALT). Additional important cells that function in the pulmonary lymphoid system include dendritic cells, Langherhans cells, macrophages, and plasma cells. An appreciation of the normal lymphoid anatomy of the lung as well as its immunology is helpful in understanding the radiologic and pathologic findings of the primary pulmonary lymphoid lesions. Primary lymphoid lesions of the lung arise from the BALT and are uncommon. However, they are increasingly recognized within the growing number of posttransplant patients as well as other patients who are receiving immunosuppressive therapies. Primary lymphoid lesions encompass a wide range of benign and malignant lesions. Benign lymphoid lesions of the lung include reactive lymphoid hyperplasia, follicular bronchiolitis, lymphoid interstitial pneumonia, and nodular lymphoid hyperplasia. Malignant lymphoid lesions of the lung include low-grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT), other non-Hodgkin lymphomas, and Hodgkin lymphoma. Last, a miscellaneous group of primary lymphoid lesions includes lymphomatoid granulomatosis, posttransplant lymphoproliferative disorders, acquired immunodeficiency syndrome (AIDS)-related lymphoma, and intravascular lymphoma/lymphomatosis. These lesions are best evaluated with multidetector chest computed tomography. The radiologic findings of the primary lymphoid lesions are often nonspecific and are best interpreted in correlation with clinical data and pathologic findings. The purpose of this article is to review pulmonary lymphoid anatomy as well as the most common primary pulmonary lymphoid disorders.

Pulmonary manifestations of granulomatosis with polyangiitis

OBJECTIVE

To describe the clinical and laboratory data, with special emphasis on thoracic imaging findings, in 14 patients with a definitive diagnosis of granulomatosis with polyangiitis (GPA).

METHODS

The clinical and tomographic data of 14 patients with a definitive diagnosis of GPA are presented. Patients with thoracic manifestations suggestive of GPA were evaluated in 3 hospitals from 2000 to 2012. All patients had a sputum analysis and bronchoalveolar lavage for bacterial, mycobacterial and fungal stains and cultures; antineutrophil cytoplasmic antibodies, antinuclear-antibodies, rheumatoid factor, and a biopsy of involved organs.

RESULTS

A total of 13 patients had at least two organs involved. The most frequent thoracic findings were pulmonary nodules, ground glass opacities and patches of consolidation; other abnormalities were tracheal stenosis, diffuse alveolar hemorrhage, lung masses with organized pneumonia. More than three-quarters (78%) of patients had positive antineutrophil cytoplasmic antibodies (ANCA). Ten patients had respiratory tissue biopsy (8 open lung, one tracheal, and one nasal). In 4 patients the diagnosis was made with the classic organ involvement in GPA, positive ANCA, and renal or skin biopsy, and response to treatment on follow-up. At 6-12 months all patients showed clinical and radiological improvement, with 54% showing a recurrence of disease.

DISCUSSION

The majority of thoracic findings described in GPA are presented in this study. A complete diagnostic approach with invasive diagnostic procedures to rule out other more prevalent respiratory diseases with similar thoracic manifestations must be performed. The positivity of ANCA in this study was high, and the recurrence of the disease was frequent.

Role of imaging in the diagnosis of large and medium-sized vessel vasculitis

In large-vessel vasculitis, imaging studies are useful to document temporal artery involvement and crucial to show large-vessel involvement. Color Doppler sonography, magnetic resonance, and computed tomography show early vasculitic lesions. Angiography delineates later vascular complications well. Color Doppler sonography, magnetic resonance angiography, and computed tomography angiography can also be used to show vascular luminal changes. Positron emission tomography is very sensitive in detecting large-vessel inflammation. Imaging procedures can also be used to monitor the course of large-vessel vasculitis. In medium-vessel vasculitis, imaging studies can be used to show both vascular changes and internal organ changes.

A practical approach to high-resolution CT of diffuse lung disease

Diffuse lung disease presents a variety of high-resolution CT findings reflecting its complex pathology, and provides diagnostic challenge to radiologists. Frequent modification of detailed pathological classification makes it difficult to keep up with the latest understanding. In this review, we describe a practical approach to high-resolution CT diagnosis of diffuse lung disease, emphasizing (1) analysis of "distribution" of the abnormalities, (2) interpretation of "pattern" in relation to distribution, (3) utilization of associated imaging findings and clinical information, and (4) chronicity of the findings. This practical approach will help radiologists establish a way to interpret high-resolution CT, leading to pin-point diagnosis or narrower differential diagnoses of diffuse lung diseases.

Wegener's granulomatosis: a review of clinical features and an update in diagnosis and treatment

Wegener's granulomatosis (WG) is an idiopathic, systemic inflammatory disease characterized by necrotizing granulomatous inflammation and pauci-immune small-vessel vasculitis of upper and lower respiratory tract and kidneys. The condition affects both genders equally, although some inconsistent gender differences have been observed. The aetiology of WG remains unknown although a number of exogenous factors have been suggested to be of aetiological relevance. Most clinical characteristics of this disease are non-specific, making clinical diagnosis challenging. Histopathological examination of lesional and peritoneal tissue is not pathognomonic, but is an essential investigation to confirm the presence of disease and exclude other disorders. At present, despite the increasingly wide range of potential therapies, cyclophosphamide plus corticosteroids remain the most recognized and effective means of inducing and sustaining remission of WG.

Pulmonary affectation of vasculitis

Respiratory tract affectation is frequent in some types of vasculitis, fundamentally in those associated with anti-neutrophil cytoplasmic antibodies (ANCA). The clinical, radiological and histopathological presentation is also heterogeneous and conditions the evolution. It is therefore necessary to establish an early diagnosis based on the symptoms because, thanks to new treatments, and despite them being potentially serious diseases, their prognosis has improved considerably in recent years. The present paper updates the diagnosis and the new therapeutic options for pulmonary vasculitis.

Imaging of pulmonary vasculitis

The presence of pulmonary vasculitis can be suggested by a clinical presentation that includes diffuse pulmonary hemorrhage, acute glomerulonephritis, chronic refractory sinusitis or rhinorrhea, imaging findings of nodules or cavities, mononeuritis multiplex, multisystemic disease, and palpable purpura. Serologic tests, including the use of cytoplasmic antineutrophil cytoplasmic antibody (ANCA) and perinuclear ANCA, are performed for the differential diagnosis of the diseases. A positive cytoplasmic ANCA test result is specific enough to make a diagnosis of ANCA-associated granulomatous vasculitis if the clinical features are typical. Perinuclear ANCA positivity raises the possibility of Churg-Strauss syndrome or microscopic polyangiitis. Imaging findings of pulmonary vasculitis are diverse and often poorly specific. The use of a pattern-based approach to the imaging findings may help narrow the differential diagnosis of various pulmonary vasculitides. Integration of clinical, laboratory, and imaging findings is mandatory for making a reasonably specific diagnosis.

Pulmonary function and high‐resolution CT findings five years after disease onset in patients with Wegener's granulomatosis

OBJECTIVE

Although pulmonary involvement is common in Wegener's granulomatosis (WG), little is known about the pulmonary outcome. We evaluated the relationship between clinical disease characteristics and pulmonary function and high-resolution computed tomography (HRCT) findings after disease duration of 5 years.

METHODS

A pulmonary function test (PFT) and pulmonary HRCT were performed in 41 patients from a population-based register of WG. Clinical predictors for abnormal PFT and HRCT were tested by logistic regression.

RESULTS

Previous WG-related lung involvement (PLI) had occurred in 80% of patients, but only 24% of patients still reported pulmonary symptoms at the research visit. One-third of patients had abnormal PFT findings, with reduced alveolar diffusion by KCO (transfer coefficient) being most common (24%). The number of PLI episodes was associated with reduced KCO and reduced FEV1% (forced expiratory volume in 1 s as a percentage of forced vital capacity) (overall presence 10%). Reduced KCO was also associated with disease duration. Reduced total lung capacity (TLC) (overall presence 8%) was only related to prior WG-related lung nodules. Pulmonary HRCT was abnormal in 80%, but with more severe abnormalities in only 30%. Pleural thickening and parenchymal bands were associated with PLI. None of the treatment variables was associated with the PFT or HRCT findings.

CONCLUSION

Five years after disease onset a quarter of the WG patients reported pulmonary symptoms, had severe abnormalities on HRCT, and abnormal PFT. The correlation between these abnormalities was poor, but the number of pulmonary involvements was a risk factor for reduced gas diffusion, obstructive lung disease, parenchymal bands, and pleural thickening. Treatment variables had no discernible negative pulmonary effects.

Role of imaging in vasculitis and connective tissue diseases

Imaging techniques play a pivotal role in securing the diagnosis of large vessel vasculitis, and in demonstrating internal organ involvement in connective tissue diseases. In large vessel vasculitis, angiography is useful in demonstrating vessel stenoses or aneurysms. However, angiography is unable to reveal initial lesions such as vessel wall oedema and thickening, and is thus not useful to make an early diagnosis. In contrast, colour Doppler ultrasonography, computerized tomography angiography, and magnetic resonance imaging/angiography are able to delineate both the vessel wall and the lumen. Therefore, they may show vessel wall alterations when the lumen is still unaffected on angiography. 18fluorodeoxyglucose positron emission tomography does not visualize the vessel wall, but is very sensitive in revealing inflamed vessels. All of these investigations have also been used to follow up patients over time and to monitor response to treatment. In connective tissue diseases, imaging techniques are particularly useful to study internal organs, especially the brain and lung. Magnetic resonance imaging is the investigation of choice to detect and monitor brain disease, while computerized tomography is the best procedure for lung disease. However, since most imaging findings are not entirely specific for any given condition, it is important to interpret the results of imaging in the broader clinical context.

Atypical bronchial thickening and ulceration: a rare radiological finding in Wegener's granulomatosis

We report the case of a 55-year-old male patient who presented with non-specific pulmonary symptoms (cough, haemoptysis, fever up to 39 degrees C, night sweats and weight loss). After empirical antibiotic therapy prescribed by his primary care physician, the patient showed no improvement in symptoms. Laboratory findings were: elevated C-reactive protein and C-ANCA, leukocytosis and thrombocytosis, and anaemia. Chest radiography showed disseminated nodules bilaterally. On multidetector-row computed tomography (MDCT), the bronchial walls showed a significant thickening and extensive peribronchiolar consolidations. Bronchoscopy revealed diffuse erythema of the tracheobronchial mucosa with diffusely scattered white plaques. Histopathology described a multifocal ulcerative bronchitis with underlying chronic bronchitis. These findings in combination with the laboratory data lead to the diagnosis of Wegener's granulomatosis. Consequently, we started with an immunosuppressive therapy. Chest radiography after 10 days showed marked resolution of the infiltrates. Within 1 month, the patient became asymptomatic.

Respiratory system involvement in antineutrophil cytoplasmic-associated systemic vasculitides: clinical, pathological, radiological and therapeutic considerations

Wegener's granulomatosis (WG), microscopic polyangiitis (MPA) and Churg- Strauss syndrome (CSS) are small-vessel vasculitides that, because of their frequent association with antineutrophil cytoplasmic antibodies (ANCA), are usually referred to as ANCA-associated systemic vasculitides (AASV). The diagnosis of AASV is made on the basis of clinical findings, biopsy of an involved organ and the presence of ANCA in the serum. Lung disease is a very common and important clinical feature of AASV. In WG, almost all patients have either upper airway or lower respiratory tract disease. Solitary or multiple nodules, frequently cavitated, and masses are the most common findings on chest radiography. Asthma is a cardinal symptom of CSS, often preceded by allergic rhinitis. Pulmonary transient and patchy alveolar infiltrates are the most common radiographic findings. In MPA, diffuse alveolar haemorrhage as a result of alveolar capillaritis is the most frequent manifestation of respiratory involvement, and is clinically expressed as haemoptysis, respiratory distress and anaemia. However, diffuse alveolar haemorrhage may also be subclinical and should be suspected when a chest radiograph demonstrates new unexplained bilateral alveolar infiltrates in the context of falling haemoglobin levels. Normal and high-resolution CT have a higher sensitivity than chest radiography for demonstrating airway, parenchymal and pleural lesions. However, many of these radiological findings are nonspecific and, therefore, their interpretation must take into account all clinical, laboratory and pathological data. Therapy of AASV is commonly divided into two phases: an initial 'remission induction' phase, in which more intensive immunosuppressant therapy is used to control disease activity, and a 'maintenance' phase, which uses less intensive therapy, for maintaining disease remission while lowering the risk of adverse effects of immunosuppressant drugs. In patients with AASV refractory to standard therapy with corticosteroids and oral cyclophosphamide, new therapeutic options are now available. Recurrence of pulmonary symptoms suggesting a flare indicates the need for a careful search for an opportunistic lung infection or iatrogenic pulmonary complications. In conclusion, involvement of the respiratory system is a very common and important organ manifestation of AASV. Respiratory system involvement comprises a wide spectrum of clinical features and radiological findings, and because of its frequency and prognostic significance, a complete assessment of the respiratory system should be included in the work-up of all patients with AASV.

[Pulmonary imaging in ANCA-associated vasculitides]

Imaging of ANCA-associated vasculitides principally shows nonsystematized alveolar opacities, predominantly central, that suggest alveolar hemorrhage, as well as uni- or multifocal alveolar opacities of variable interpretation, and nodules, including cavitary nodules. Other signs, observed more rarely on imaging, are interstitial lung diseases, tracheobronchial involvement, and pulmonary hypertension. The principal pulmonary signs of Wegener's granulomatosis are nodules and masses, sometimes cavitary, and areas of airspace consolidation that may or may not suggest diffuse alveolar hemorrhage. Except when the latter is present, the lesions correspond to necrotizing granulomatosis or organized pneumonia. The most frequent pulmonary signs of Churg-Strauss syndrome on computed tomography are ground glass areas or parenchymal consolidation in dispersed bands or with a predominantly subpleural distribution that expresses eosinophilic interstitial and alveolar infiltration. Alveolar hemorrhage is the most common expression of microscopic polyangiitis.

Small-vessel diseases of the lung: CT-pathologic correlates

Diseases that primarily affect the small vessels of the lung are difficult to diagnose. Many conditions are characterized by involvement of small pulmonary vessels, and pathologically they can be conveniently divided into occluding and inflammatory types. The former, typified by chronic pulmonary thromboembolism and primary pulmonary hypertension, are relatively cryptic in terms of imaging. In contrast, inflammatory vasculitides, which often cause pulmonary hemorrhage and infarction, result in florid but nonspecific radiographic abnormalities. The spectrum of thin-section computed tomographic abnormalities encountered in the inflammatory vasculitides is wide: For example, in Wegener granulomatosis the pattern ranges from cavitating nodules to lobar consolidation to ground-glass opacity. This review highlights some of the less obvious imaging manifestations of occlusive and inflammatory diseases of the small pulmonary vessels.