What is the diagnostic approach for pulmonary vasculitis?

From the Guidelines

The diagnostic approach for pulmonary vasculitis should prioritize a combination of clinical suspicion, physical examination, bronchoscopy, and radiological findings, with high-resolution CT scanning being the investigation of choice, as it can suggest the presence of PVOD with findings such as subpleural thickened septal lines and centrilobular ground-glass opacities 1.

Clinical Evaluation

The diagnostic process begins with a thorough clinical evaluation, including a detailed history and physical examination. Patients with pulmonary vasculitis often present with non-specific symptoms such as dyspnea on exertion, fatigue, and in some cases, hemoptysis. Physical examination findings may include digital clubbing and bi-basal crackles on lung auscultation, which are unusual in other forms of pulmonary arterial hypertension (PAH) 1.

Laboratory and Imaging Tests

Laboratory testing should include a complete blood count, comprehensive metabolic panel, inflammatory markers (ESR, CRP), urinalysis, and autoantibody testing specific to vasculitis syndromes. However, the provided evidence does not emphasize the role of these tests in the diagnosis of pulmonary vasculitis. Instead, it highlights the importance of radiological findings, particularly those obtained through high-resolution CT scanning, which can reveal characteristic changes such as Kerley B lines, peripheral interstitial infiltrate, subpleural thickened septal lines, and centrilobular ground-glass opacities 1.

Diagnostic Approach

Given the information from the study published in the European Respiratory Journal 1, the focus should be on clinical presentation and high-resolution CT findings to establish a diagnosis of pulmonary vasculitis, specifically PVOD, with a high probability. This approach may avoid the need for lung biopsy in most cases, which is considered the gold standard for confirmation but carries significant risks.

Key Findings

Key radiological findings that suggest PVOD include:

• Subpleural thickened septal lines
• Centrilobular ground-glass opacities
• Mediastinal lymphadenopathy These findings, in combination with clinical suspicion and physical examination results, can guide the diagnostic approach for pulmonary vasculitis, prioritizing the identification of PVOD as outlined in the guidelines for the diagnosis and treatment of pulmonary hypertension 1.

From the Research

Diagnostic Approach for Pulmonary Vasculitis

The diagnostic approach for pulmonary vasculitis involves a combination of clinical, laboratory, and imaging findings.

• The most common approach to classify vasculitis is according to etiology, dividing them into primary and secondary, with a further sub-classification of primary vasculitis based on the size of the affected vessels (large, medium, and small) 2.
• Radiological presentation is not pathognomonic, but may vary between diseases, with main findings using high-resolution computed tomography (HRCT) including small vessel wall thickening, nodular lesions, cavitary lesions, reticular opacities, ground-glass opacities (GGO), consolidations, interlobular septal thickening, tracheobronchial stenosis, and aneurysmal dilatation of pulmonary arteries, with or without pleural effusion 2.
• 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 can suggest the presence of pulmonary vasculitis 3.
• Serologic tests, including the use of cytoplasmic antineutrophil cytoplasmic antibody (ANCA) and perinuclear ANCA, are performed for the differential diagnosis of the diseases 3, 4.
• A positive cytoplasmic ANCA test result is specific enough to make a diagnosis of ANCA-associated granulomatous vasculitis if the clinical features are typical, while perinuclear ANCA positivity raises the possibility of Churg-Strauss syndrome or microscopic polyangiitis 3.
• Integration of clinical, laboratory, and imaging findings is mandatory for making a reasonably specific diagnosis 3, 5.
• The use of a pattern-based approach to the imaging findings may help narrow the differential diagnosis of various pulmonary vasculitides 3.
• A complete patient history should be obtained and a physical examination performed, with initial laboratory evaluation including inflammation markers, renal and liver function tests, and the determination of ANCA 4.
• New developments in ANCA testing result in tests with excellent predictive value for the diagnosis of AAV-related pulmonary vasculitis, and ANCA should be tested with these tests of the so-called second (capture ELISA) or third (anchor ELISA) generation 4.
• In patients who are ANCA negative, a simple algorithm is presented based on laboratory evaluation of autoantibodies and 18F-FDG-PET-CT scanning, which may be useful for accelerating the diagnostic process needed to make a diagnosis of pulmonary vasculitis, or alternatively, to quickly exclude such a diagnosis 4.
• Clinical examination of other systems and organs involved in the pathological process, including the skin and kidneys, as well as the detection of autoantibodies can improve approaches to early diagnosis and treatment of vasculitis 6.