AAV That Involves Central Nervous System Linked to More Active Disease, Chinese Study Suggests

In people with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), central nervous system involvement is associated with more active disease and peripheral nervous system involvement, a recent Chinese study suggests.

The study, “Central nervous system involvement in patients with antineutrophil cytoplasmic antibody–associated vasculitis: a study of 29 cases in a single Chinese center,” was published in Clinical Rheumatology.

The nervous system can be broadly divided into two parts: the central nervous system (CNS) includes the brain and spinal cord, while the peripheral nervous system (PNS) encompasses all parts of the nervous system elsewhere in the body.

As many as half of the people with AAV experience symptoms related to the nervous system, but this usually involves only the PNS. CNS involvement in AAV is relatively rare, estimated to affect less than 15% of AAV patients.

In the study, researchers analyzed clinical data for 434 people with AAV who were diagnosed at Peking University First Hospital in China between 2005 and 2018. The study population included 199 males and 235 females; the average age at diagnosis was 63.4 years.

According to specific AAV types, there were 325 cases of microscopic polyangiitis (MPA), 83 of granulomatosis with polyangiitis (GPA), and 26 of renal-limited vasculitis.

In total, 29 people in the study population had evidence of CNS involvement. The average age at diagnosis and sex ratio in this group did not differ significantly from the overall population, and there were 25 cases of MPA and four of GPA.

“To the best of our knowledge, this is by far the largest series of AAV patients with CNS involvement,” the researchers wrote.

Most commonly, CNS involvement manifested as muscle weakness and/or sensory impairment; other reported symptoms included persistent headaches, lower body paralysis (paraplegia), and diabetes insipidus.

Patients who had AAV with CNS involvement had significantly higher scores (23.5) than those without CNS involvement (18.8) on the Birmingham Vasculitis Activity Score, which measures vasculitis-associated disease activity. Additionally, a significantly higher percentage of those with CNS involvement also had PNS involvement (58.6% vs. 14.6% of those without CNS involvement), and a significantly higher percentage were smokers (34.5% vs. 8.1%).

The survival rate did not differ significantly based on CNS involvement.

The patients with CNS involvement underwent magnetic resonance imaging of the brain. It was determined that most of them (24 out of 29, or 82.8%) had ischemic lesions — that is, areas where a lack of oxygen led to the death of brain cells.

These patients received standard of care immunosuppressive therapies, which most commonly involved cyclophosphamide and glucocorticoids as induction therapy, often with the addition of methylprednisolone pulse therapy, then azathioprine (Azasan) as a maintenance treatment.

With a median follow-up time of just over two years, 11 people were in complete remission, while 18 were in partial remission.

All but one of the 24 people with ischemic lesions responded to treatment, which included the lessening of symptoms such as headache. The exception was an individual with a prior history of heart disease, who died of a heart attack shortly after being diagnosed with CNS involvement.

“Whether CNS lesions bring obvious effect on the survival of AAV patients remains to be evaluated by further study with larger sample size and longer follow-up,” the authors wrote.

“In conclusion, CNS involvement in Chinese patients with AAV was mainly manifested as cerebral ischemic lesions,” they added. “Compared with patients without CNS involvement, patients with CNS manifestations had a significantly more active disease of AAV and higher proportion of peripheral nervous system involvement.”