Neuropsychiatric Involvement in Systemic
Lupus Erythematosus


By Hanna Ainiala
January 2012
Tampere University Press
Distributed by Coronet Books Inc.

ISBN: 9789514486135
130 pages

$87.50 Paper original


Systemic lupus erythematosus (SLE) is an autoimmune disease affecting multiple organ systems. Neuropsychiatric (NP) manifestations are a major cause of morbidity and mortality in patients with SLE. The prevalence of NPSLE ranges widely reflecting variable diagnostic criteria and differences in selection of patients for study. The pathogenesis of NPSLE is still unclear. This study was done to describe the prevalence of NP syndromes in a Finnish population of patients with SLE and classify them according to the American College of Rheumatology (ACR) nomenclature and case definitions for NPSLE; to assess the validity of the ACR nomenclature system; to evaluate whether serum matrix metalloproteinase-9 (MMP-9) levels are associated with NP manifestations and to evaluate the volumetric brain magnetic resonance imaging (MRI) findings in SLE patients.

The study group consisted of 46 SLE patients and an equal amount of matched controls. A complete medical history was obtained from all and a clinical neurological examination was performed by the same neurologist. All past and present NP syndromes were listed and classified according to the ACR nomenclature and case definitions. Individual disease activity and an accumulated NP abnormality were assessed by using standardized scores. A cumulative lifetime dose of glucucorticoids was derived from the medical records. Laboratory tests including anticardiolipin antibodies and a quantification of immunoreactive MMP-9 were done for all. A battery of standardized neuropsychological tests and a clinical interview by the psychologist were performed in order to detect a possible cognitive deficit, depression or anxiety disorder. Cerebral MRI was done for all study subjects. Volumetric measures of cerebral atrophy as well as T1- and T2-weighted lesions were obtained.

At least one NP syndrome was identified in 91% of SLE patients in this population-based study. Cognitive dysfunction was the most frequent single manifestation followed by headache and mood disorder. When mild NP syndromes (mild cognitive deficit, headache, mild depression, anxiety and polyneuropathy with normal ENMG findings) were excluded, the prevalence of NPSLE dropped to 46%.

All NPSLE syndromes were more frequent among SLE patients than controls. However, most syndromes were also found among controls, which resulted in low specificity. To improve the criteria we constructed revised criteria based on objective findings only. We entirely excluded mild NP syndromes and with this modification, the proportion of controls fulfilling at least 1 of the criteria was substantially lower (7% versus 54%).

No significant difference was found in serum MMP-9 levels between the overall group of SLE patients and controls. However, patients with at least one NP manifestation had significantly higher MMP-9 concentrations than SLE patients without NP syndromes. Among SLE patients, those with cognitive deficits had significantly higher MMP-9 concentrations than did those with normal cognitive function. Furthermore, serum MMP-9 levels correlated positively with the volumes of T1- and T2-weighted lesions in the brain MRI.

Compared with controls, SLE patients had increased volumes of both T1- and T2-weighted lesions and increased cerebral atrophy in brain MRI. Cerebral atrophy was associated with cognitive dysfunction, epileptic seizures and cerebrovascular disease; T1-weighted lesions with epileptic seizures and T2-weighted lesions with cognitive dysfunction. A positive correlation was found between a cumulative dose of glucocorticoids and cerebral atrophy in SLE patients.

As a summary, the prevalence of NPSLE in a population-based sample of SLE patients was 91% by using ACR nomenclature and case definitions, and 46% when our revised criteria based on neurologic injury and exclucion of mild NP syndromes, was used. ACR criteria for NPSLE were not able to differentiate SLE patients from controls. In cerebral MRI, brain atrophy, cerebrovascular and demyelinating lesions were more common in patients with SLE than in general population, and associated with certain NP manifestations. Elevated levels of serum MMP-9 in patients with SLE may indicate NP involvement, especially cognitive dysfunction.

 

Acta Universitatis Tamperensis No. 1672

 

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