Clinical Pearls & Morning Reports
Published September 14, 2022
The differential diagnosis for pachymeningitis includes primary vasculitis syndromes, nonvasculitic chronic inflammatory disease, infection, and cancer. Read the NEJM Case Records of the Massachusetts General Hospital here.
Q: What percentage of temporal artery biopsies demonstrating vasculitis are due to a disease other than giant-cell arteritis?
A: Although giant-cell arteritis is by far the most common form of vasculitis to affect the temporal artery, in up to 6% of temporal artery biopsies that confirm the presence of vasculitis, the vasculitis is due to a form other than giant-cell arteritis.
Q: Is pachymeningitis a known feature of IgG4-related disease?
A: IgG4-related disease has a diverse range of clinical presentations, and histologic features include dense, storiform fibrosis with IgG4+ plasma cells and obliterative venulitis. Circulating IgG4 levels are often elevated. Pachymeningitis is a known feature of IgG4-related disease. Patients with IgG4-related disease typically have a good response to prednisone.
A: GPA has been defined as a necrotizing, granulomatous inflammation of small and medium-sized blood vessels of the respiratory tract that often also affects the kidneys. The absence of findings in the lungs and kidneys is unusual, but such cases occur. Presentations that are limited to the head and neck, including hypertrophic pachymeningitis, are well described in patients with GPA. GPA is closely associated with one of two autoantibodies directed against neutrophil cytoplasmic antigens: either proteinase 3 or myeloperoxidase. GPA is initially responsive to glucocorticoids, but remission requires treatment with either the cytotoxic drug cyclophosphamide or the B-cell–depleting antibody rituximab.
A: Infiltrations of IgG4+ plasma cells are often detected in GPA. Although IgG4-related disease can be associated with vasculitis in both small and large vessels, necrotizing small-vessel vasculitis is not a feature of IgG4-related disease. Giant cells and neutrophilic microabscesses are not features of IgG4-related disease. Diffuse inflammation with giant cells and neutrophilic microabscesses are features of GPA. Many case reports have suggested diagnostic overlap between antineutrophil cytoplasmic antibody-associated vasculitis and IgG4-related disease, but systematic observational studies have been able to differentiate between the diseases. When features of both diseases occur simultaneously, it is more likely that the true diagnosis is one or the other, rather than the presence of both diseases in the same patient.