Cerebral occlusive vasculopathy in systemic lupus erythematosus and speculation on the part played by complement

Neuropsychiatric lupus

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease. Involvement of the nervous system, either primary or secondary, is common in SLE, and 19 different neuropsychiatric clinical syndromes have been recognised in association with the disease. Several pathophysiological mechanisms have been implicated in the pathogenesis of neuropsychiatric SLE (NPSLE), including vasculopathy, autoantibodies, and cytokine-mediated tissue injury. Careful evaluation of the patient is required to rule out secondary causes before attributing the neurological symptoms to SLE. Treatment depends on the nature and severity of NPSLE syndrome.

The histopathologic associates of neurometabolite abnormalities in fatal neuropsychiatric systemic lupus erythematosus

OBJECTIVE

To determine the histopathologic basis of altered brain neurometabolites in neuropsychiatric systemic lupus erythematosus (NPSLE).

METHODS

Brain neurometabolite concentrations in a 20-voxel area of the brain were determined premortem by magnetic resonance spectroscopy (MRS) in 7 individuals with NPSLE. Absolute concentrations of neurometabolite for N-acetylaspartate (NAA), choline, creatine, and lactate were measured. After the death of the patients, histopathologic changes were determined at autopsy of the brain and were matched voxel-by-voxel with the neurometabolites.

RESULTS

The mean +/- SD absolute concentrations of NAA (9.15 +/- 1.78 mM in patients versus 12.2 +/- 0.8 mM in controls; P < 0.01) and creatine (6.43 +/- 0.16 mM in patients versus 6.90 +/- 0.60 mM in controls; P < 0.003) were significantly reduced and the concentration of choline (2.51 +/- 0.42 mM in patients versus 1.92 +/- 0.32 mM in controls; P < 0.04) was significantly elevated in NPSLE patients as compared with controls. Widespread heterogeneous changes in the histologic features of the brain were present, including microinfarcts, microhemorrhages, bland angiopathy, thrombotic angiopathy with platelet and fibrin thrombi, neuronal necrosis in various states of resolution, reduced numbers of axons and neurons, vacuole and space formation among the fibers, reduced numbers of oligodendrocytes, reactive microglia and astrocytes, lipid-laden macrophages, and cyst formation. Neurometabolite abnormalities were closely associated with underlying histopathologic changes in the brain: 1) elevated choline levels were independently associated with gliosis, vasculopathy, and edema (r = 0.75, P < 0.004 in the multivariate model); 2) reduced creatine levels with reduced neuronal-axonal density and gliosis (r = 0.72, P < 0.002 in the multivariate model); 3) reduced NAA levels with reduced neuronal-axonal density (r = 0.66, P < 0.001 in the multivariate model); and 4) the presence of lactate with necrosis, microhemorrhages, and edema (r = 0.996, P < 0.0001 in the multivariate model).

CONCLUSION

Altered neurometabolites in NPSLE patients, as determined by MRS, are a grave prognostic sign, indicating serious underlying histologic brain injury.

Magnetic resonance imaging and brain histopathology in neuropsychiatric systemic lupus erythematosus

OBJECTIVE

Magnetic resonance imaging (MRI) often demonstrates brain lesions in neuropsychiatric systemic lupus erythematosus (NPSLE). The present study compared postmortem histopathology with premortem MRI in NPSLE.

METHODS

Two hundred subjects with NPSLE were studied prospectively with MRI over a 10-year period during which 22 subjects died. In 14 subjects, a brain autopsy with histopathology, that permitted direct comparison with premortem MRI, was successfully obtained. Surface anatomy was used to determine the approximate location of individual lesions.

RESULTS

Premortem MRI findings in fatal NPSLE were small focal white matter lesions (100%), cortical atrophy (64%), ventricular dilation (57%), cerebral edema (50%), diffuse white matter abnormalities (43%), focal atrophy (36%), cerebral infarction (29%), acute leukoencephalopathy (25%), intracranial hemorrhage (21%), and calcifications (7%). Microscopic findings in fatal NPSLE included global ischemic changes (57%), parenchymal edema (50%), microhemorrhages (43%), glial hyperplasia (43%), diffuse neuronal/axonal loss (36%), resolved cerebral infarction (33%), microthomboemboli (29%), blood vessel remodeling (29%), acute cerebral infarction (14%), acute macrohemorrhages (14%), and resolved intracranial hemorrhages (7%). Cortical atrophy and ventricular dilation seen by MRI accurately predicted brain mass at autopsy (r = -0.72, P = 0.01, and r = -0.77, P = 0.01, respectively). Cerebral autopsy findings, including infarction, cerebral edema, intracranial hemorrhage, calcifications, cysts, and focal atrophy, were also predicted accurately by premortem MRI.

CONCLUSION

Brain lesions in NPSLE detected by MRI accurately represent serious underlying cerebrovascular and parenchymal brain injury on pathology.

Automated T2 quantitation in neuropsychiatric lupus erythematosus: a marker of active disease

Active neuropsychiatric systemic lupus erythematosus (NPSLE) is characterized by brain edema as measured by manual quantitative magnetic resonance (MR) relaxometry. An automated image processing method was developed to segment gray matter (GM), while minimizing the effects of confounding factors, specifically cerebral atrophy and volume averaging artifacts. Twenty patients with SLE (10 major, 10 minor), matched for atrophy, were studied. We compared T2 calculated for GM segmented by manual and automated methods. Both methods demonstrated a marked increase in GM T2 in patients with major NPSLE (P < 0.001), confirming the presence of cerebral edema. The results from each method were highly correlated, (r = 0.64, P = 0.002). The automated method effectively identifies GM, minimizes volume averaging artifacts, and produces results similar to the manual method. This method markedly decreases analysis time and will make quantitative relaxometry a valuable contribution to the clinical management of NPSLE.

Neurometabolite markers of cerebral injury in the antiphospholipid antibody syndrome of systemic lupus erythematosus

BACKGROUND AND PURPOSE

To determine the neurometabolic patterns of brain injury in systemic lupus erythematosus with antiphospholipid antibody syndrome (SLE-aPLS).

METHODS

Forty-nine SLE patients (12 SLE-aPLS) and 23 control subjects were studied using magnetic resonance imaging and spectroscopy. N-Acetylaspartate/creatine (NAA/Cre) and choline/Cre (Cho/Cre) were measured in normal-appearing tissue. IgG and IgM antiphospholipid antibodies (aPL) were measured by enzyme-linked immunosorbent assay.

RESULTS

Stroke, epilepsy, and elevated IgG-aPL were more common in SLE-aPLS patients than in SLE patients (P<0.001). NAA/Cre was lower (P<0.05) and Cho/Cre higher (P<0.001) in SLE-aPLS patients than in SLE patients without aPLS. Regression models showed NAA/Cre was most related to injury seen by imaging (P<0.01), disease duration (P<0. 05), and prior neuropsychiatric SLE (NPSLE) (P=0.07). Reduced NAA/Cre was more closely related to IgG-aPL (P<0.01) than the presence of stroke or aPLS. When adjusted for all factors, Cho/Cre was most associated with the presence of aPLS (P=0.05).

CONCLUSIONS

SLE and SLE-aPLS are actually a clinical continuum describing brain injury in SLE, with SLE-aPLS being characterized by increased aPL, NPSLE, stroke, epilepsy, and disturbed neurochemistry. An elevated IgG-aPL level is a potent risk factor for brain injury as measured by NAA/Cre in SLE that is independent of stroke and aPLS. However, thrombotic phenomena and the presence of aPL (aPLS) are most closely associated with increased Cho/Cre in SLE. These results suggest that aPLs exacerbate SLE, resulting in increased thrombotic and nonthrombotic brain injuries. Spectroscopy detects brain injury in SLE and may permit better understanding of the neurological consequences of SLE and SLE-aPLS.

Systemic lupus erythematosus: immunopathogenesis of neurologic dysfunction

Neurologic complications of systemic lupus erythematosus (neuro-SLE) are common. The most frequent manifestations of neuro-SLE are seizures, encephalopathy, and behavioral changes, but a wide variety of other neurologic abnormalities affecting the central and peripheral nervous system and muscle also occur. Although the prevalence of neuro-SLE is high, the diversity of clinical presentations, the multiple potential etiologies, and the absence of sensitive and specific diagnostic tests render diagnosis difficult. Recent advances in understanding mechanisms of neuronal dysfunction combined with advances in imaging techniques, including functional imaging, should help in diagnosis and management. The mechanisms of neurologic injury can be divided into three broad categories. First, neuronal dysfunction may result from direct effects of the immune system on brain cells such as autoantibody binding to cell surface, immune complex deposition with secondary inflammation, and effects of cytokines. Second, immune- mediated injury to supportive structures such as the vasculature may also affect the nervous system by producing ischemia. Finally, the neuraxis may be affected by any one of several immune and non- immune effects of infection, toxins, and metabolic disturbances.

Aortic root thrombus causing stroke in a patient with systemic lupus erythematosus

We report on a 24 year old woman with systemic lupus erythematosus (SLE) who presented with a cerebrovascular accident affecting her right side. Unusually, this was associated with an aortic root thrombus with absence of any commonly recognised thrombophilic features. Following removal of the thrombus and anticoagulation, she made a good recovery. The relationship between valvular problems and cerebral lesions in SLE is discussed.