From the Guidelines
The correct statement about Granulomatosis with Polyangiitis (GPA) is that over 90% have lung infiltrates, which is a characteristic feature of this systemic vasculitis affecting small and medium-sized blood vessels. This is supported by the european position paper on rhinosinusitis and nasal polyps 2020 1.
Key Features of GPA
- Pulmonary involvement is extremely common in GPA, with radiographic abnormalities including nodules, masses, and infiltrates present in the vast majority of patients.
- Septal perforations in GPA, while common, are typically not massive but rather small to moderate in size, as noted in patients with GPA affecting the sinonasal cavity who usually have persistent bleeding, crusting and obstruction, and may develop a septal perforation 1.
- Biopsy findings of non-caseating granulomas can be seen in GPA, but they alone are not diagnostic; the combination of clinical features, positive ANCA serology, necrotizing vasculitis, and granulomatous inflammation on biopsy establish the diagnosis 1.
Diagnostic Considerations
- The presence of anti-neutrophil cytoplasmic antibodies (ANCA) is an important diagnostic marker for GPA when combined with compatible clinical and histopathological findings.
- Nasal biopsies often do not have enough features specific to GPA to confirm the diagnosis, and so biopsies from other involved organs may be required 1.
From the Research
GPA Characteristics
- The statement that over 90% have lung infiltrates is not directly supported by the provided evidence 2, 3, 4, 5.
- Septal perforations in GPA are not typically described as massive in the provided studies 2, 3, 4, 5.
- A biopsy showing non-caseating granulomas is a characteristic feature of GPA, but it is not exclusively diagnostic as similar findings can be seen in other conditions 2, 6, 4, 5.
Diagnostic Features
- GPA is characterized by a necrotizing vasculitis involving small vessels, extensive "geographic" necrosis, and granulomatous inflammation 2.
- The presence of circulating antibodies against cytoplasmic components of neutrophils (ANCAs) plays a role in the pathogenesis of GPA and often correlates with disease activity 2, 3.
- Non-caseating granulomas can be found in GPA, but this feature alone is not sufficient for a definitive diagnosis 6, 4, 5.
Treatment and Manifestations
- Treatment strategies for GPA are evolving, with rituximab showing promise as an effective alternative to cyclophosphamide for inducing remission 2, 4.
- GPA can manifest with various pulmonary symptoms, including diffuse alveolar hemorrhage, which requires aggressive immunosuppression and timely diagnosis for effective management 3.
- The association between GPA and pulmonary emphysema has been observed, suggesting that clinicians should be aware of this potential complication in patients with GPA 5.