RESUMEN
OBJECTIVE: Unilateral onset of parkinsonism due to nigrostriatal damage of the contralateral hemisphere is frequent in Parkinson disease (PD). There is evidence for a left-hemispheric bias of motor asymmetry in right-handed patients with PD indicating a hemispheric dominance. Isolated REM sleep behavior disorder (IRBD) constitutes the prodromal stage of PD and other synucleinopathies. To test the hypothesis that right-handed patients with IRBD exhibit left-hemispheric predominance of subclinical nigrostriatal dysfunction, we evaluated this aspect using neuroimaging instruments. METHODS: In 167 right-handed patients with IRBD without parkinsonism, we evaluated in each hemisphere the integrity of the striatal dopaminergic terminals by dopamine transporter (DAT)-SPECT and the substantia nigra echogenicity by transcranial sonography. RESULTS: DAT-SPECT showed lower specific binding ratio (SBR) in the left striatum and left caudate nucleus than in the right striatum and right caudate nucleus. The percentage of patients with lower SBR was greater in the left striatum and left caudate nucleus than in the right striatum and right caudate nucleus. In those who developed a synucleinopathy in <5 years from DAT-SPECT, there was a lower SBR in the left putamen and left caudate nucleus than in the right putamen and right caudate nucleus. Substantia nigra echogenic size was greater in the left than in the right side in patients with hyperechogenicity and among individuals who phenoconverted in <5 years from transcranial sonography. CONCLUSION: Right-handed patients with IRBD exhibit left-hemispheric predominance of subclinical nigrostriatal dysfunction. In premotor PD, the neurodegenerative process begins asymmetrically, initially impairing the nigrostriatal system of the dominant hemisphere.
Asunto(s)
Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/farmacología , Dopamina/metabolismo , Enfermedad de Parkinson/fisiopatología , Trastorno de la Conducta del Sueño REM/fisiopatología , Adulto , Anciano , Cuerpo Estriado/metabolismo , Cuerpo Estriado/fisiopatología , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/metabolismo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neuroimagen/métodos , Enfermedad de Parkinson/metabolismo , Putamen/diagnóstico por imagen , Trastorno de la Conducta del Sueño REM/diagnóstico , Trastorno de la Conducta del Sueño REM/metabolismo , Sustancia Negra/diagnóstico por imagen , Sustancia Negra/fisiopatología , Ultrasonografía Doppler Transcraneal/métodosRESUMEN
OBJECTIVE: Giant cell arteritis (GCA) may involve the aorta. Retrospective studies have demonstrated a higher prevalence of aortic aneurysm among patients with GCA compared with the general population. We investigated the prevalence of aortic aneurysm in a cohort of patients with biopsy-proven GCA using a defined protocol and assessed whether persisting low-grade disease activity is associated with higher risk of developing aortic aneurysm. METHODS: Fifty-four patients with GCA (14 men and 40 women) were cross-sectionally evaluated after a median followup of 5.4 years (range 4.0-10.5 years). The screening protocol included a chest radiograph, abdominal ultrasonography scan, and computed tomography scan when aortic aneurysm was suspected or changes with respect to the baseline chest radiograph were observed. Clinical and laboratory data, corticosteroid requirements, and relapses were prospectively recorded. RESULTS: Twelve patients (22.2%) had significant aortic structural damage (aneurysm/dilatation), 5 of them candidates for surgical repair. Aortic aneurysm/dilatation was more frequent among men (50%) than women (12.5%; relative risk 3.5, 95% confidence interval 1.53-8.01, P = 0.007). At the time of screening, patients with aneurysm/dilatation had lower serum acute-phase reactants, lower relapse rate, and needed shorter periods to withdraw prednisone than patients without aortic structural damage. CONCLUSION: There is a substantial risk of developing aortic aneurysm/dilatation among patients with GCA. Our data do not support that aneurysm formation mainly results from persistent detectable disease activity. Additional factors including characteristics of the initial injury or the target tissue may also determine susceptibility to aortic aneurysm/dilatation.