The gadolinium-enhanced coronal and axial T1-weighted images show the extent of diffuse dural thickening along the falx cerebri around the right lobe and extending through the tentorium cerebelli bilaterally. These findings along with the patient’s clinical manifestations are consistent with hypertrophic pachymeningitis.
A rare manifestation associated with several rheumatologic diseases, pachymeningitis is characterized by chronic, inflammatory thickening of the dura. The pia and arachnoid also are involved, creating a thick membrane held together with fibrous adhesions.1
The clinical features of pachymeningitis include headache, vision loss, diplopia, papilledema, cranial nerve involvement, ataxia, and seizures. The ESR may be elevated, with elevated protein levels and lymphocytosis in the CSF.2
The differential diagnosis for pachymeningitis is broad, including hematological disease, infection, migraine, malignancy, and iatrogenic drug-induced disease. Given the patient’s serological test results in the setting of an acute inflammatory symmetrical polyarticular arthritis and pachymeningitis, the 2 leading diagnoses were RA and Wegener granulomatosis (WG).
Twenty cases of rheumatoid pachymeningitis have been reported, and they typically have been associated with long-standing disease; seropositivity; erosive, extra-articular features; and rheumatoid nodules in the dura.3 In all cases, the rheumatoid factor and the ESR were elevated. The typical presentation included cranial nerve involvement or headache. Rheumatoid nodules of the dura were found in all autopsy diagnoses, but only rarely with dural biopsy; if present, they were visible on MRI.
Pachymeningitis is found in up to 7% of patients who have WG.4 Typically, there is a male predominance, with limited involvement and only 6 months of active disease before diagnosis. The clinical presentation is chronic headache on nonfocal physical examination. Both positive MRI findings and positive dural biopsy results are 100% sensitive for diagnosis. WG and RA may coexist, although that situation was described in only 6 cases from 1966 to 2003.5
Biopsy of our patient’s dura demonstrated perivascular lymphoplasmacytic infiltration and granulomatous inflammation accompanied by leukocytoclastic debris and necrosis (photomicrographs, hematoxylin and eosin stain) that were most consistent with a small-vessel vasculitis. The only primary systemic vasculitis with an extravascular inflammatory component is WG. Recent data show that within the granulomatous lesions of WG, there is evidence of lymphatic follicles that may lead to elevated levels of inflammatory markers, such as anti-PR3.6 Given the biopsy results and the patient’s presentation, duration of disease in the setting of chronic headache responsive to corticosteroids, and elevated levels of anti-PR3 antibodies, our final diagnosis was WG with pachymeningitis.
Our patient received induction therapy that included a 3-month course of oral cyclophosphamide(Drug information on cyclophosphamide) with high-dose corticosteroids that were tapered slowly. Daily single-strength trimethoprim(Drug information on trimethoprim)/sulfamethoxazole also was provided.
With this regimen, the patient reported resolution of his symptoms, including headache; his ESR was 17 mm/h and his c-ANCA level was lower than 6 U/mL. The patient has remained stable on a maintenance regimen of methotrexate(Drug information on methotrexate), 25 mg/wk, injected subcutaneously.
This case was presented by Jefferson Roberts, MD, an attending rheumatologist at Walter Reed Army Medical Center in Washington, DC, and Alana Wade, a third-year medical student at the Uniformed Services University of Health Sciences in Bethesda, Maryland.