Cognitive Impairment Seen in Childhood CNS Vasculitis
Patients with childhood primary angiitis of the central nervous system are at elevated risk for poor cognitive outcome, and the risk is highest by far in the subgroup with small-vessel disease presenting with seizures.
In the years since use of immunosuppressive therapy has become common, mortality among affected children has lessened. “Most children survive. However, in day-to-day clinical practice, it’s our observation that what matters most to parents of these children is their long-term cognitive outcome. Parents ask us, ‘Will our child attend a regular school? Will our child achieve the same levels of academic performance and social and vocational accomplishments as their siblings?’ ” observed Dr. Peter Gowdie of the University of Toronto Hospital for Sick Children.
He and his coinvestigators sought answers to these questions in their single-center, retrospective, cohort study involving 63 patients with childhood primary angiitis of the CNS (cPACNS) without known premorbid cognitive deficits. Nineteen children had the small-vessel subtype, which is angiography negative and requires brain biopsy for diagnosis. Forty-four had large-vessel disease, which is identifiable on angiography and for which brain biopsy is therefore not indicated.
The median age at diagnosis was 8.1 years, with a median time to cognitive testing of 14.8 months.
Patients with large- and small-vessel cPACNS differed in several key ways in terms of clinical presentation, as previously noted in other studies.
Neurocognitive testing was carried out using the Wechsler Intelligence Scale for Children (WISC), a comprehensive battery of 10 subtests assessing a variety of domains.
Scores of 85-115 on the full scale IQ portion of the WISC are considered within average range. The majority of children with small-vessel cPACNS – 53% to be exact – scored below 85, which indicates global cognitive impairment. This was twice the rate seen in children with large-vessel disease. The mean full-scale IQ score in patients with small-vessel cPACNS was 82, compared with 97 in those with large-vessel disease.
The specific cognitive domains where patients with small-vessel disease were disadvantaged were verbal comprehension, with a mean score of 91 compared with 101 in youngsters with large-vessel disease; processing speed, where the difference in mean scores was 83 versus 96; and working memory, on which patients with small-vessel cPACNS had an average score of 81 compared with 96 in those with large-vessel disease.
“Neurocognitive testing is helpful in determining the cognitive burden of cPACNS. Characterization of the cognitive deficits may be helpful in tailoring early rehabilitation interventions,” the rheumatologist said.
Patients with large-vessel cPACNS and no seizures had an average Full Scale IQ score of 99. IQ scores were slightly but not significantly lower in those with large-vessel disease who presented with seizures as well as in those with small-vessel disease and no seizures. However, the mean full-scale IQ score was 79 in patients with small-vessel cPACNS who presented with seizures.
Dr. Gowdie reported having no financial conflicts of interest.