Clinical Presentation and Management of Granulomatosis with Polyangiitis (GPA)

Key Clinical Manifestations

• The British Medical Journal recommends that nasal crusting, stuffiness, and epistaxis (nosebleeds) are common presenting symptoms of GPA, often accompanied by scleritis and other ocular manifestations 1, 2
• Chronic rhinosinusitis with possible nasal polyps, otitis media, and hearing loss may occur in patients with GPA 2
• Nasal septal perforation can develop in advanced cases of GPA 2
• Pulmonary infiltrates and nodules are common in GPA, and alveolar hemorrhage can occur in severe cases 1
• Glomerulonephritis is a hallmark feature of GPA, though not always present at initial presentation, and may manifest as proteinuria, hematuria, and varying degrees of kidney failure 1
• Peripheral neuropathy, skin lesions including palpable purpura, arthralgia, and myalgia are common systemic manifestations of GPA 1

Laboratory Findings and Diagnostic Evaluation

• The National Institute of Health recommends that anti-neutrophil cytoplasmic antibodies (ANCA) testing should be performed in all suspected cases of GPA, with PR3-ANCA (c-ANCA) being highly specific to GPA and present in 80-90% of cases 1, 3
• Urinalysis may show hematuria and proteinuria in cases with renal involvement 1

Disease Classification and Assessment

• The European League Against Rheumatism recommends that the Birmingham Vasculitis Activity Score (BVAS) is the primary validated tool for assessing disease activity, and the Five-Factor Score (FFS) predicts mortality risk 4
• BVAS/WG evaluates manifestations across multiple systems including systemic, cutaneous, mucous/ocular, ENT, pulmonary, cardiovascular, gastrointestinal, and renal 4

Treatment Approach

• The American College of Rheumatology recommends that initial therapy includes glucocorticoids combined with either rituximab or cyclophosphamide, and plasma exchange may be considered in cases with pulmonary hemorrhage or severe renal involvement 1, 5
• Options for maintenance therapy include azathioprine, methotrexate, rituximab, or co-trimoxazole 1

Prognosis and Monitoring

• Regular monitoring of ANCA levels is recommended, though decisions should not be based solely on ANCA titers, and monitoring for treatment-related complications is essential 4

Diagnostic Approach and Management of Granulomatosis with Polyangiitis (GPA)

Clinical and Laboratory Findings

• Kidney biopsy typically shows crescentic necrotizing glomerulonephritis, a hallmark feature of GPA, according to the American College of Rheumatology 6
• Complete blood count with differential diagnosis, urinalysis, and inflammatory markers (ESR, CRP) are essential laboratory tests for diagnosing GPA, as recommended by the European League Against Rheumatism 7
• Renal function tests (creatinine, BUN) are crucial for assessing kidney involvement in GPA patients, as suggested by the American College of Rheumatology 7

Diagnostic Evaluation and Disease Assessment

• Biopsy of affected organs is recommended when feasible to confirm diagnosis, according to the European League Against Rheumatism 8
• Pulmonary function tests, electromyography, and nerve conduction studies are necessary for assessing respiratory and neurological involvement in GPA patients, as recommended by the American Thoracic Society 7
• Brain and/or spinal cord MRI is essential for evaluating CNS manifestations in GPA patients, as suggested by the European League Against Rheumatism 7

Differential Diagnosis and Treatment Approach

• Other small-vessel vasculitides, such as microscopic polyangiitis and eosinophilic granulomatosis with polyangiitis, should be considered in the differential diagnosis of GPA, according to the American College of Rheumatology 6
• Treatment decisions should be modified for special populations, including children, elderly, and pregnant women, as recommended by the European League Against Rheumatism 6

Granulomatosis with Polyangiitis Clinical Presentations

Respiratory Tract Manifestations

• Subglottic stenosis develops in 5-23% of treated patients, presenting insidiously with persistent cough, wheezing, and dyspnea that may initially be misdiagnosed as asthma 9
• Cough and hemoptysis occur in >95% of patients with lower respiratory tract disease 9
• Diffuse alveolar hemorrhage can occur in severe cases, manifesting as diffuse alveolar infiltrates on chest imaging 9
• Tracheobronchial stenosis occurs in 15% of patients 9
• Clinical presentation ranges from subacute nonspecific respiratory illness to rapidly progressive respiratory insufficiency 9
• Non-specific systemic symptoms including fever, malaise, and weight loss 9
• Giant cell arteritis can present with chronic cough in patients >50 years old, but typically involves extracranial arteries of the head and neck with temporal artery abnormalities 9
• Lung malignancy should be considered in the differential diagnosis of pulmonary manifestations 9

Differential Diagnoses

• Clinical pitfalls include misdiagnosing subglottic stenosis symptoms as asthma, which can be avoided by investigating abnormal inspiratory and expiratory flow-volume loops 9

Diagnostic and Serologic Criteria for Granulomatosis with Polyangiitis (GPA)

Clinical Presentation

• Upper respiratory tract involvement – Persistent sinus pain, congestion, and epistaxis occur in >90 % of patients with GPA. This high prevalence supports the classic sinusitis presentation as a key diagnostic clue. 10
• Renal involvement – GPA characteristically produces pauci‑immune necrotizing crescentic glomerulonephritis, manifested by proteinuria, hematuria, and red‑cell casts. This histopathologic pattern is a hallmark of the disease. 11

Serologic Markers

• PR3‑ANCA (c‑ANCA) positivity – Detected in 80‑90 % of GPA cases and is highly specific for this vasculitis, making it a pivotal laboratory confirmation when clinical features are present. 10
• Elevated erythrocyte sedimentation rate (ESR) – An ESR of ≈60 mm/hr reflects the active systemic inflammation typical of GPA and can aid in assessing disease activity. 12

Differential Diagnosis

• Excluding Eosinophilic Granulomatosis with Polyangiitis (EGPA) – EGPA requires blood eosinophilia > 10 % and elevated IgE, which are absent in GPA; only 35‑40 % of EGPA patients are ANCA‑positive, and when present it is usually p‑ANCA/MPO rather than c‑ANCA. Additionally, EGPA more frequently involves cardiac disease and gastro‑intestinal symptoms. All these features help differentiate EGPA from GPA. 13
• Excluding Polyarteritis Nodosa (PAN) – PAN is an ANCA‑negative medium‑vessel vasculitis, making it incompatible with the c‑ANCA positivity seen in GPA. 11
• Rheumatoid factor (RF) overlap – A positive RF can occur in ≈5 % of GPA patients with atypical c‑ANCA, but RF alone does not cause the necrotizing glomerulonephritis, severe sinusitis, or pulmonary hemorrhage characteristic of GPA. 10
• Prompt ANCA testing – In patients presenting with chronic rhinosinusitis with epistaxis, systemic constitutional symptoms, and renal abnormalities, ANCA testing should be performed immediately to avoid misdiagnosis and treatment delay. 10

Clinical Features and Diagnostic Approach for Granulomatosis with Polyangiitis (GPA)

Upper Respiratory Tract Manifestations

Diagnostic Evaluation

Serologic Testing

Histologic Confirmation

Integrated Diagnostic Criteria

Saddle‑Nose Deformity in ANCA‑Associated Vasculitis

Pathophysiology

• Necrotizing vasculitis and granulomatous inflammation in granulomatosis with polyangiitis progressively destroy the nasal cartilaginous framework (dorsum and septum), leading to saddle‑nose deformity. 15

Clinical Manifestations

• Patients commonly exhibit chronic rhinosinusitis, friable erythematous mucosa with granulation tissue on nasal endoscopy, and impaired mucociliary clearance as part of the sinonasal disease spectrum. 15

Diagnostic Criteria

• Diagnosis is established by the combination of characteristic clinical features, a positive PR3‑ANCA serology in approximately 80‑90 % of cases, and biopsy evidence of necrotizing vasculitis with granulomatous inflammation. 15

Histologic Sampling Limitations

• Nasal mucosal biopsies often lack sufficient diagnostic hallmarks for granulomatosis with polyangiitis; therefore, tissue should be obtained from other involved organs (e.g., lung or kidney) to achieve definitive histologic confirmation. 15

Classification and Differential Diagnosis of Granulomatosis with Polyangiitis

Classification Criteria (American College of Rheumatology)

• The American College of Rheumatology classification system for granulomatosis with polyangiitis (GPA) requires the presence of any two of the following four features: (1) biopsy‑proven necrotizing granulomatous vasculitis, (2) urinary sediment containing red blood cells or red cell casts, (3) abnormal chest imaging (e.g., nodules, infiltrates, cavitation), and (4) oral or nasal inflammation (e.g., chronic sinusitis, nasal ulceration). These criteria are intended solely for research classification and are not recommended as diagnostic criteria in routine clinical practice. 16

Distinguishing GPA from Other Vasculitides

• In the differential diagnosis of GPA, IgA vasculitis and cryoglobulinemic vasculitis are characterized by immune‑complex deposition on biopsy, whereas GPA demonstrates a pauci‑immune (minimal immune‑deposit) pattern. This histopathologic distinction helps exclude these mimicking conditions. 17

Evidence‑Based Diagnostic Evaluations for Granulomatosis with Polyangiitis (GPA)

Laboratory Assessment

• Measure 24‑hour protein excretion or the urine protein‑to‑creatinine ratio when urinalysis reveals abnormalities to screen for renal involvement. 18

ENT and Upper Airway Evaluation

• Arrange an ENT consultation with nasal endoscopy to identify chronic rhinosinusitis, nasal polyps, and friable erythematous mucosa, which are common in GPA. 18
• Perform audiometry when hearing loss or middle‑ear disease is suspected, as otologic involvement may occur. 18

Pulmonary Assessment

• Conduct pulmonary function testing to detect restrictive or obstructive ventilatory patterns and to assess for subglottic stenosis, a potential airway complication of GPA. 18

Renal Confirmation

• Obtain a kidney biopsy in patients with significant proteinuria (approximately > 1 g/day), glomerular hematuria, or unexplained decline in renal function to confirm pauci‑immune necrotizing crescentic glomerulonephritis. 18

Neurologic Evaluation

• Use electromyography and nerve‑conduction studies when peripheral neuropathy is clinically suspected to document vasculitic nerve injury. 18