Thoracic Manifestation of Myeloperoxidase-Antineutrophil Cytoplasmic Antibody (MPO-ANCA)-Related Disease

Interstitial Lung Disease and Anti-Neutrophil Cytoplasmic Antibody–Associated Vasculitis

Interstitial lung disease is a common complication of anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV). It is seen most commonly in microscopic polyangiitis owing to the pathogenic effect of myeloperoxidase in the lung. Oxidative stress, neutrophil elastase release, and expression of inflammatory proteins by neutrophil extracellular traps result in fibroblast proliferation and differentiation and therefore fibrosis. Usually, interstitial pneumonia pattern fibrosis is common and associated with poor survival. Treatment for patients with AAV and interstitial lung disease lacks evidence, and those with vasculitis are treated with immunosuppression, whereas those with progressive fibrosis may well benefit from antifibrotic therapy.

Pulmonary Vasculitides: A Radiological Review Emphasizing Parenchymal HRCT Features

Vasculitides represent a heterogeneous group of immune-mediated disorders, characterized by a systemic inflammatory destructive process of the blood vessels resulting either in ischemia or hemorrhage. The organ involved and vessel size influence the pattern of presentation of the pathology. The lung is commonly involved in systemic vasculitides, with heterogeneous clinical, radiological, and histopathological presentations. Primary vasculitides most commonly associated with lung parenchymal involvement include small-vessel antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitides, such as granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA), and microscopic polyangiitis (MPA). Several studies have reported cases of interstitial lung diseases (ILDs) associated with systemic vasculitis, particularly those positive for ANCA associated vasculitis/vasculitidis: AAV. We have selected from our case series different radiological features of pulmonary vasculitis (i.e., solitary or multiple nodules, cavitary lesions, nodules with centrilobular or peribronchial distribution, airspace consolidations, “crazy paving” appearance, interstitial disease), including cases with interstitial lung alterations. Therefore, the aim of this review is to describe the typical clinical manifestations of vasculitides and their main radiologic features (especially AAV).

Differential diagnoses of COVID-19 pneumonia: the current challenge for the radiologist-a pictorial essay

BACKGROUND

COVID-19 pneumonia represents the most severe pandemic of the twenty-first century and has crucial clinical, social and economical implications. The scientific community has focused attention and resources on clinical and radiological features of COVID-19 pneumonia. Few papers analysing the vast spectrum of differential diagnoses have been published.

MAIN BODY

Complexity of differential diagnosis lays in the evidence of similar radiological findings as ground-glass opacities, crazy paving pattern and consolidations in COVID-19 pneumonia and a multitude of other lung diseases. Differential diagnosis is and will be extremely important during and after the pandemic peak, when there are fewer COVID-19 pneumonia cases. The aim of our pictorial essay is to schematically present COVID-19 pneumonia most frequent differential diagnoses to help the radiologist face the current COVID-19 pneumonia challenge.

CONCLUSIONS

Clinical data, laboratory tests and imaging are pillars of a trident, which allows to reach a correct diagnosis in order to grant an excellent allocation of human and economical resources. The radiologist has a pivotal role in the early diagnosis of COVID-19 pneumonia because he may raise suspicion of the pathology and help to avoid COVID-19 virus spread.

A proposed role of neutrophil extracellular traps and their interplay with fibroblasts in ANCA-associated vasculitis lung fibrosis

ANCA-associated vasculitides (AAV) comprise three diseases: granulomatosis with polyangiitis, microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis. They are characterised by small vessel inflammation and have a broad range of clinical manifestations and multiorgan involvement which endanger the patient's life. An increasingly recognised complication of AAV, especially in MPA is lung fibrosis, for which no clearcut therapy in this context is available. The release of neutrophil extracellular traps (NETs) in these diseases has been related to the development of fibrosis, but the precise mechanisms are not fully unravelled. This review provides an overview of some of the important proteins known to compose NETs, and proposes some mechanisms by which these remarkable components may exert an impact on the different fibroblastic phenotypes leading to lung fibrosis.

Evaluation of poor prognostic factors of respiratory related death in microscopic polyangiitis complicated by interstitial lung disease

The prognosis of microscopic polyangiitis (MPA) with interstitial lung disease (ILD) is significantly worse than that of MPA without ILD. However, the clinical characteristics in MPA-ILD, especially poor prognostic factors, are not elucidated. We evaluated demographic, clinical, laboratory, and radiological findings, treatments, and outcomes of 80 patients with MPA, and investigated prognostic factors of respiratory-related death in patients with myeloperoxidase (MPO)-anti-neutrophil cytoplasmic antibody (ANCA) positive MPA-ILD. Ground-glass opacity and fibrosis were evaluated as scores on high-resolution computed tomography (HRCT). The presence of ILD was consistent with a high risk of respiratory-related death (hazard ratio, 4.8; P = 0.04). Multivariable logistic regression analyses using propensity scoring showed right or left lower lobe fibrosis score to be significantly associated with respiratory-related death (P = 0.0005 and 0.0045, respectively). A right or left lower lobe fibrosis score ≥ 2, indicating the presence of honeycombing at 1 cm above the diaphragm, was determined to be the best cut-off value indicating a poor prognosis. The 5-year survival rate was significantly lower in patients with right or left lower lobe fibrosis score ≥ 2 (survival rates: 37% and 19%, respectively) than those with a score < 2 (71% and 68%, respectively) (P = 0.002 and 0.0007, respectively). These findings suggest that the presence of honeycomb lesions in bilateral lower lobes on chest HRCT was associated with respiratory-related death in patients with MPO-ANCA positive MPA-ILD.

Interstitial lung disease and microscopic polyangiitis in chilean patients

Objective:

To describe the clinical and serological patients characteristics with Microscopic Polyangiitis (MPA) and Interstitial lung disease (ILD).

Methods:

Of all the patients with AAV diagnosed between 2007-2017 at the Hospital Clinico Universidad de Chile, those with MPA and ILD were selected and studied retrospectively.

Results:

All patients were Hispanic; median age at diagnosis 65 years (32-84). 59% were female. All were positive for p-ANCA, 16 patients for MPO. Most common manifestations were constitutional symptoms, weight loss and fever. CT-Scans patterns were Usual Interstitial Pneumonia (UIP) in 10 patients, Nonspecific Interstitial Pneumonia (NSIP) in 6 and fibrosis not UIP or NSIP pattern in 1. In 6 cases, ILD was diagnosed 0.5-14 years before MPA and concomitantly in 11.

Conclusions:

Although infrequent, Microscopic Polyangiitis should be suspected in patients with ILD particularly if extra-pulmonary manifestations that rise the possibility of a systemic illness are present, regardless of the time elapsed between the latter and the diagnosis of this type of lung involvement. (Sarcoidosis Vasc Diffuse Lung Dis 2020; 37 (1): 37-42)

Radiologic and pathologic characteristics of myeloperoxidase-antineutrophil cytoplasmic antibody-associated interstitial lung disease: a retrospective analysis

Background

The association between interstitial lung disease (ILD) and myeloperoxidase (MPO)-antineutrophil cytoplasmic antibodies (ANCAs) has been described, but pathologic characteristics are not well characterized.

Objectives

We assessed the radiologic and pathologic characteristics of ILD in MPO-ANCA-positive patients and the association between ILD and vasculitis, particularly microscopic polyangiitis (MPA).

Methods

We retrospectively searched electronic health records to identify MPO-ANCA-positive patients with ILD who underwent surgical lung biopsy at our institution from January 1997 through August 2017. Demographic, clinical, imaging, and pathologic characteristics were analyzed.

Results

We identified 18 MPO-ANCA-positive patients with ILD. The median (range) age was 58 (43-75) years, and the cohort included 10 men (56%), 10 former smokers (56%), and 11 patients (61%) had clinical evidence of systemic vasculitis (MPA) at the time of diagnosis of ILD. On high-resolution computed tomography, the most common radiologic pattern was "inconsistent with usual interstitial pneumonia" (UIP) (n=14 [78%]); the other 4 patients (22%) fulfilled the radiologic criteria for the UIP pattern. Honeycombing was seen in 15 patients (83%). Ten patients (56%) had the UIP pattern on biopsy: 4 of these patients had additional inflammatory changes that were not typical of UIP (as seen in patients with idiopathic pulmonary fibrosis), and the other 6 patients had other inflammatory patterns or findings. The presence or absence of MPA did not correlate with pathologic findings.

Conclusions

MPO-ANCA-positive patients with ILD do not show the typical UIP pattern as seen in patients with idiopathic pulmonary fibrosis on surgical lung biopsy.

Interstitial Lung Disease and Other Pulmonary Manifestations in Connective Tissue Diseases

Lung involvement in connective tissue diseases is associated with substantial morbidity and mortality, most commonly in the form of interstitial lung disease, and can occur in any of these disorders. Patterns of interstitial lung disease in patients with connective tissue disease are similar to those seen in idiopathic interstitial pneumonias, such as idiopathic pulmonary fibrosis. It may be difficult to distinguish between the 2 ailments, particularly when interstitial lung disease presents before extrapulmonary manifestations of the underlying connective tissue disease. There are important clinical implications in achieving this distinction. Given the complexities inherent in the management of these patients, a multidisciplinary evaluation is needed to optimize the diagnostic process and management strategies. The aim of this article was to summarize an approach to diagnosis and management based on the opinion of experts on this topic.

Pulmonary Involvement in Antineutrophil Cytoplasmic Antibodies (ANCA)-associated Vasculitis: The Influence of ANCA Subtype

OBJECTIVE

To describe pulmonary involvement at time of diagnosis in antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV), as defined by computed tomography (CT).

METHODS

Patients with thoracic CT performed on or after the onset of AAV (n = 140; 75 women; granulomatosis with polyangiitis, n = 79; microscopic polyangiitis MPA, n = 61) followed at a tertiary referral center vasculitis clinic were studied. Radiological patterns of pulmonary involvement were evaluated from the CT studies using a predefined protocol, and compared to proteinase 3 (PR3)-ANCA and myeloperoxidase (MPO)-ANCA specificity.

RESULTS

Of the patients, 77% had an abnormal thoracic CT study. The most common abnormality was nodular disease (24%), of which the majority were peribronchial nodules, followed by bronchiectasis and pleural effusion (19%, each), pulmonary hemorrhage and lymph node enlargement (14%, each), emphysema (13%), and cavitating lesions (11%). Central airways disease and a nodular pattern of pulmonary involvement were more common in PR3-ANCA-positive patients (p < 0.05). Usual interstitial pneumonitis (UIP) and bronchiectasis were more prevalent in MPO-ANCA-positive patients (p < 0.05). Alveolar hemorrhage, pleural effusion, lymph node enlargement, and pulmonary venous congestion were more frequent in MPO-ANCA-positive patients.

CONCLUSION

Pulmonary involvement is frequent and among 140 patients with AAV who underwent a thoracic CT study, almost 80% have pulmonary abnormalities on thoracic CT. Central airway disease occurs exclusively among patients with PR3-ANCA while UIP were mainly seen in those with MPO-ANCA. These findings may have important implications for the investigation, management, and pathogenesis of AAV.

Interstital lung disease in ANCA vasculitis

Anti-neutrophil cytoplasmic antibodies (ANCA) vasculitides are immune-mediated disorders that primarily affect small blood vessels of the airway and kidneys. Lung involvement, one of the hallmarks of microscopic polyangiitis and granulomatosis with polyangiitis, is associated with increased mortality and morbidity. In recent years, several retrospective series and case reports have described the association of interstitial lung disease (ILD) and ANCA vasculitis, particularly those positive for ANCA specific for myeloperoxidase. In the majority of these patients pulmonary fibrosis occurs concurrently or predates the diagnosis of ANCA vasculitis. More importantly, these studies have shown that ILD has an adverse impact on the long-term prognosis of ANCA vasculitis. This review focuses on the main clinical and radiologic features of pulmonary fibrosis associated with anti-neutrophil cytoplasmic antibodies. Major histopathology features, prognosis and therapeutic options are summarized.

Propylthiouracil-Induced Vasculitis With Alveolar Hemorrhage Confirmed by Clinical, Laboratory, Computed Tomography, and Bronchoscopy Findings: A Case Report and Literature Review

INTRODUCTION

Propylthiouracil (PTU) is commonly used to treat hyperthyroidism and can induce antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Although this is a rare side effect, ANCA-associated vasculitis can progress to severe disease if its diagnosis and treatment are delayed, leading to a poor prognosis.

CASE PRESENTATION

A 43-year-old woman with Graves' disease developed pulmonary vasculitis and diffuse alveolar hemorrhage (DAH) associated with ANCA against myeloperoxidase and proteinase-3 that was confirmed by computed tomography (CT) and bronchoscopy and treated with PTU. The symptoms and signs of alveolar hemorrhage were rapidly resolved after PTU withdrawal and treatment with corticosteroids. After 6 months of follow-up, the patient maintained complete ANCA-negative clinical remission status, as confirmed by normal CT and bronchoscopy findings. To our knowledge, this is the first documented case of bronchoscopic comparison of PTU-induced DAH before and after steroid treatment.

CONCLUSIONS

Patients treated with PTU should be closely monitored and followed up, even if the drug has been used for several years. When patients develop progressive dyspnea with alveolar opacities on chest imaging that cannot be explained otherwise, alveolar hemorrhage should be an important differential diagnosis while investigating the case. Early diagnosis and prompt discontinuation of the PTU treatment are essential for improving patient outcomes.

Organizing pneumonia associated with myeloperoxidase anti-neutrophil cytoplasmic antibody

Organizing pneumonia (OP) is a clinicopathological entity that occurs idiopathically or in association with several conditions, but there are few reports about myeloperoxidase anti‐neutrophil cytoplasmic antibody (MPO‐ANCA)‐associated OP. We describe a patient with OP whose clinical conditions improved spontaneously. Moreover, serum MPO‐ANCA titers paralleled the clinical activity of the disease, which disappeared in association with disease quiescence. Based on these findings, a subset of patients may have OP related to MPO‐ANCA. ANCA testing should be considered in the work‐up of patients with suspected OP.

Clinical presentation and long-term outcome of 144 patients with microscopic polyangiitis in a monocentric German cohort

OBJECTIVE

To evaluate the clinical presentation and long-term outcome of a vasculitis centre cohort of patients with microscopic polyangiitis (MPA) with respect to organ manifestations, treatment, chronic damage and mortality.

METHODS

We performed a retrospective chart review at our vasculitis referral centre. MPA patients admitted between 1991 and 2013 classified by a modified European Medicines Agency algorithm were diagnosed and treated according to a standardized interdisciplinary approach.

RESULTS

Comprehensive data from standardized interdisciplinary workups was available for 144 patients (median follow-up 72 months). The overall standardized mortality ratio was 1.40 (95% CI 0.91, 2.07; P = 0.13). We observed a higher mortality [hazard ratio (HR) 4.04 (95% CI 1.21, 13.45), P = 0.02] in 17 patients with MPA-associated fibrosing interstitial lung disease (ILD) and 56 patients with peripheral nervous system involvement [HR 5.26 (95% CI 1.10, 25.14), P = 0.04] at disease onset. One hundred and fifteen patients (79.9%) responded to the initial treatment. Sixty-one (42.3%) achieved complete remission and 54 (37.5%) achieved partial remission. Twenty (13.9%) showed a refractory disease course.

CONCLUSION

MPA patients at our tertiary rheumatology referral centre seemed to have a less severe phenotype resulting in a less severe disease course and better outcome than reported in other cohorts. Fibrosing ILD was significantly associated with mortality in this cohort.

Antineutrophil cytoplasmic antibody-positive conversion and microscopic polyangiitis development in patients with idiopathic pulmonary fibrosis

Background

Increasing evidence indicates that antineutrophil cytoplasmic antibody (ANCA)-positive conversion occurs in patients initially diagnosed with idiopathic pulmonary fibrosis (IPF) and as a result, some of these patients develop microscopic polyangiitis (MPA). However, the incidence density of these patients is not well known.

Objectives

To explore the incidence of ANCA-positive conversion and development of MPA during the disease course in patients with IPF and to evaluate whether corticosteroid therapy reduces MPA development in patients with IPF with myeloperoxidase (MPO)-ANCA positivity at diagnosis or who later acquire MPO-ANCA positivity.

Methods

We retrospectively analysed the medical records of 504 Asian patients with IPF treated at our institution in Saitama, Japan.

Results

Of the 504 patients with IPF, 20 (4.0%) had MPO-ANCA and 16 (3.2%) had PR-3-ANCA when first evaluated. In 264 of 504 patients with IPF, ANCA was measured repeatedly and seroconversion to MPO-ANCA and PR3-ANCA occurred in 15 (5.7%) and 14 (5.3%) patients, respectively, and 9 of 35 patients who were either MPO-ANCA positive at IPF diagnosis or who subsequently seroconverted developed MPA. None of the nine patients who developed MPA had been previously treated with steroids. The incidence of MPA tended to be lower in patients treated than not treated with corticosteroids although this was not statistically significant.

Conclusions

Some patients with IPF with MPO-ANCA positivity at IPF diagnosis or with MPO-ANCA-positive conversion during follow-up developed MPA. Clinical trials to determine whether corticosteroid therapy can reduce MPA development and prolong survival in MPO-ANCA-positive patients with IPF should be considered.

Pulmonary complications of systemic vasculitides

The pulmonary vasculitides are a heterogeneous group of diseases that often occur as a component of systemic vasculitic diseases. Most frequently, pulmonary vasculitis is observed in vasculitic syndromes that preferentially affect small vessels. Pulmonary involvement may develop because the lung has an extensive vascular and microvascular network. Sensitising antigens can easily reach the lung, and there are large numbers of vasoactive and activated immune cells in the lung. A diagnosis often can be made on the basis of clinical presentation and serologic studies, but biopsy of skin, nose, kidney, or lung may be necessary to ascertain the precise syndrome.

Interstitial lung disease and ANCA-associated vasculitis: a retrospective observational cohort study

OBJECTIVES

ANCA-associated vasculitis and interstitial lung disease (ILD) are uncommon conditions. The occurrence of both diseases in the same patient is increasingly recognized. Our aim was to ascertain the characteristics and outcomes of patients with ILD and ANCA-associated vasculitis.

METHODS

A retrospective observational cohort study was performed. Patients who presented to the Hammersmith Hospital, London, with ANCA-associated vasculitis [granulomatosis with polyangiitis (Wegener's), microscopic polyangiitis (MPA) or Churg-Strauss syndrome] who also had ILD were included. Following hospital discharge, all patients were followed up in a multi-disciplinary vasculitis clinic. We recorded patient demographics, diagnostic tests, treatment, complications and mortality.

RESULTS

ILD was observed in 2.7% (n = 14) of our patients with ANCA-associated vasculitis (n = 510); all had MPO-ANCA and a clinical diagnosis of MPA, giving a prevalence of 7.2% in patients with MPA (n = 194). There was no significant difference in survival between patients with MPA and ILD and those with MPA alone.

CONCLUSION

It is important that physicians are aware of this clinical association and the presence of ILD should be considered in all patients with ANCA-associated vasculitis, especially those with MPO-ANCA. The possibility that patients with ILD may subsequently develop features of systemic vasculitis should also be remembered.

Pyrexia of unknown origin and pulmonary fibrosis as a presentation of MPO-ANCA associated vasculitis

The authors report the case of a 72-year-old man presenting with chronic dyspnoea and pyrexia of unknown origin (PUO). After extensive investigation, he was found to have pulmonary fibrosis with usual interstitial pneumonia pattern on high-resolution CT imaging and positive myeloperoxidase antineutrophil cytoplasmic antibodies (MPO-ANCA) with no infectious cause or other evidence of vasculitis organ involvement. His pyrexia and symptoms settled with oral systemic corticosteroid treatment. To the authors' knowledge this is the first case of MPO-ANCA positive vasculitis presenting as PUO and pulmonary fibrosis alone. The authors review the recent literature regarding the association of pulmonary fibrosis with ANCA-positive vasculitides with regards to pathogenesis, prognosis and treatment.

Pulmonary findings in Churg-Strauss syndrome in chest X-rays and high resolution computed tomography at the time of initial diagnosis

Churg-Strauss syndrome (CSS) is a rare, systemic, necrotizing, small- and middle-sized vessel vasculitis which is accompanied by blood eosinophilia, eosinophil infiltration of various tissues, and bronchial asthma. The lungs are the organs most often involved in CSS. The aim of this study was a retrospective evaluation of the pulmonary findings in chest X-rays and high resolution computed tomography (HRCT) in CSS patients at the time of initial diagnosis and to determine their frequency, character, and location. Seventeen CSS patients were studied (12 women; 5 men; aged 29-56 years). In all patients at the time of initial diagnosis, chest X-rays were performed, and in 15 patients, HRCT was performed additionally. The radiological images were evaluated independently by two radiologists who reached a decision by consensus. Out of 17 patients studied, chest X-rays revealed parenchymal abnormalities in 11, pleural effusion in three, and bronchial wall thickening in one. In five patients, no abnormalities in chest X-rays were found. In HRCT, abnormalities were found in all patients (15 patients, 100%). Predominant HRCT findings consisted of: ground-glass opacities and consolidations found in 13 patients (86.7%). Additionally, in four patients, pulmonary micronodules were described; in ten, interlobular septal thickening; in three, linear opacities; in ten, bronchial wall thickening and/or bronchial dilatation; and in three, pleural effusions. Ground-glass opacities and consolidation abnormalities distribution pattern were peripheral in seven and random in six patients. In patients with CSS, the most common pulmonary radiological findings are parenchymal opacities, which may be peripheral or random in distribution. Pathologic changes were found in 70.6% of patient in chest X-rays, and in 100%, when HRCT was performed. These changes are nonspecific; however, they should be not overlooked, as they may help in establishing the diagnosis and suggest the prognosis.

Pulmonary fibrosis-an uncommon manifestation of anti-myeloperoxidase-positive systemic vasculitis?

Small vessel vasculitides such as microscopic polyangiitis and Wegener’s granulomatosis commonly involve the kidney and lung, with alveolar haemorrhage being the commonest manifestation of pulmonary involvement. Here we describe a patient who developed acute renal failure and pulmonary haemorrhage with positive autoantibodies against myeloperoxidase 1 year after a diagnosis of usual interstitial pneumonia had been made and we discuss the uncommon association of pulmonary fibrosis and anti-myeloperoxidase positive vasculitis.

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.

[Imaging procedures in rheumatology: imaging in vasculitis]

In small vessel vasculitides, imaging studies aid in determining disease extent and activity, localization for biopsy, and for disease monitoring. They do not directly delineate the vasculitic lesion. Imaging studies focus on the upper and lower respiratory tract. Cranial magnetic resonance imaging (MRI) shows upper respiratory and retrobulbar granuloma in Wegener's granulomatosis. Furthermore, MRI depicts both mastoiditis and mucosal inflammation of the ear, nose, and throat. It is sensitive but not specific for the detection of cerebral vasculitis. Computed tomography (CT) reliably detects osseous facial lesions. Chest radiography in two planes remains the standard method of investigation for the lower respiratory tract. High-resolution CT aids in detecting further interstitial pathologies. Medium-sized vasculitides frequently occur with aneurysms. The classification criteria for polyarteritis nodosa involve the angiographic detection of visceral aneurysms. Patients with Kawasaki disease may develop coronary aneurysms that may be described by echocardiography or angiography according to diagnostic criteria. In large-vessel vasculitides such as temporal arteritis (giant cell arteritis) and Takayasu arteritis, MRI, MR-angiography, CT, CT-angiography, and duplex sonography delineate characteristic homogenous wall thickening with or without stenoses in the aorta and other arteries. There is a high correlation with angiography and positron emission tomography. Duplex sonography of the temporal arteries has a high sensitivity and specificity for the diagnosis. Data on temporal artery MRI in giant cell arteritis have recently been published.

Bench-to-bedside review: pulmonary-renal syndromes--an update for the intensivist

The term Pulmonary-renal syndrome refers to the combination of diffuse alveolar haemorrhage and rapidly progressive glomerulonephritis. A variety of mechanisms such as those involving antiglomerular basement membrane antibodies, antineutrophil cytoplasm antibodies or immunocomplexes and thrombotic microangiopathy are implicated in the pathogenesis of this syndrome. The underlying pulmonary pathology is small-vessel vasculitis involving arterioles, venules and, frequently, alveolar capillaries. The underlying renal pathology is a form of focal proliferative glomerulonephritis. Immunofluorescence helps to distinguish between antiglomerular basement membrane disease (linear deposition of IgG), lupus and postinfectious glomerulonephritis (granular deposition of immunoglobulin and complement) and necrotizing vasculitis (pauci-immune glomerulonephritis). Patients may present with severe respiratory and/or renal failure and require admission to the intensive care unit. Since the syndrome is characterized by a fulminant course if left untreated, early diagnosis, exclusion of infection, close monitoring of the patient and timely initiation of treatment are crucial for the patient's outcome. Treatment consists of corticosteroids in high doses, and cytotoxic agents coupled with plasma exchange in certain cases. Renal transplantation is the only alternative in end-stage renal disease. Newer immunomodulatory agents such as those causing TNF blockade, B-cell depletion and mycophenolate mofetil could be used in patients with refractory disease.

Increased serum vascular endothelial growth factor levels in microscopic poly angiitis with pulmonary involvement

Microscopic polyangiitis (MPA) is a systemic necrotizing vasculitis that affects small vessels, resulting in a wide spectrum of organ involvement including the lungs. However, there are little serological markers that predict its prognosis or severity of pulmonary involvement. Vascular endothelial growth factor (VEGF) is an angiogenic mediator, which has been reported to be elevated in systemic vasculitis. In this study, we measured serum VEGF levels in 22 MPA patients with pulmonary involvement. We also investigated VEGF expression in pulmonary cells using flow cytometry analysis. We found that serum VEGF levels in MPA patients were significantly higher than those in respiratory or urinary tract infection. The serum VEGF levels decreased in parallel with the improvement of MPA symptoms. The serum VEGF levels in MPA patients who died within 5 years were significantly higher than those who survived more than 5 years. The sensitivity of VEGF levels to distinguish MPA patient with poor prognosis from those with good prognosis was 90.9%, and specificity was 81.8% (cutoff value = 802.5 pg/ml). The serum VEGF levels showed significant positive correlation with the composite physiological index, which indicates the severity of pulmonary lesion. In flow cytometry analysis, CD11b positive bronchoalveolar lavage fluid cells expressed VEGF. Immunohistochemically, alveolar macrophages, tissue infiltrating inflammatory cells and alveolar epithelial cells stained positive for VEGF. Measurement of serum VEGF levels in MPA might become one of the markers for prognosis and the severity of pulmonary involvement in MPA. VEGF might contribute to the development of pulmonary lesion of MPA.

Pulmonary involvement in microscopic polyangiitis

PURPOSE OF REVIEW

Microscopic polyangiitis is a systemic necrotizing vasculitis that affects small vessels, resulting in a wide spectrum of organ involvement including the kidneys and the lungs. This paper reviews recent insights and observations into the pathogenesis, clinical manifestations, and treatment of pulmonary involvement in microscopic polyangiitis.

RECENT FINDINGS

The spectrum of clinical presentations ranges from antecedent interstitial fibrosis to frank hemoptysis secondary to capillaritis. Computerized tomography imaging reveals a variety of pulmonary findings, including ground-glass attenuation, consolidation, thickening of bronchovascular bundles, and honeycombing. Antineutrophil cytoplasmic antibodies are important in diagnosis as well as in the pathogenesis and prognosis of microscopic polyangiitis. There is more evidence to support the various therapeutic modalities currently used in pulmonary manifestations of microscopic polyangiitis, including induction therapy with cyclophosphamide, the use of other novel pharmacologic agents such as the tumor necrosis factor-alpha blockers and rituximab, and nonpharmacologic modalities such as plasmapheresis and ventilatory management.

SUMMARY

The pulmonary manifestations of microscopic polyangiitis are diverse and often difficult to manage; however, as our understanding and experience grows so does our ability to successfully diagnose and treat these patients.