[123 I-MIBG myocardial sympathetic innervation scintigraphy and Parkinson's disease. Preliminary results]

Orthostatic hypotension as an early finding in Parkinson's disease

Patients with Parkinson's disease (PD) commonly have clinically significant orthostatic hypotension (OH). In such patients PD+OH might be confused with multiple system atrophy (MSA), in which OH is a frequent finding, or with pure autonomic failure (PAF), if OH preceded clinical manifestations of the movement disorder. This study addressed whether OH can occur as an early finding in PD+OH. Historical data were analyzed from 35 patients with PD+OH evaluated at the NIH. OH was considered early if the patient had OH before, concurrent with, or starting within 1 year after onset of a symptomatic movement disorder. MSA was excluded by myocardial 6-[(18)F]fluorodopamine-derived radioactivity more than 2 standard deviations below the normal mean. Among the 35 PD+OH patients, 21 (60 %) had documentation of OH as an early finding. In 4 such patients, OH had preceded parkinsonism, and in 4 others, OH had dominated the early clinical picture, even after cessation of levodopa treatment for the movement disorder. In PD, OH can occur early in the disease, occasionally preceding or overshadowing the movement disorder.

Alteración precoz de la función adrenérgica cardíaca en los parkinsonismos con cuerpos de Lewy

BACKGROUND

123I-metaiodobenzylguanidine (123I-MIBG) myocardial scintigraphy is clinically used to estimate myocardial sympathetic damage in some forms of heart disease, autonomic nerve disturbance in diabetic neuropathy, and disturbance of the autonomic nervous system in neurodegenerative disease. In the present study, examinations were performed to clarify the rate and characteristics of cardiac sympathetic disturbance in Parkinson's disease (PD) and usefulness of 123I-MIBG myocardial scintigraphy to differentiate PD from the Lewy Body Disease (LBD).

MATERIAL AND METHODS

108 subjects were studied. There were 70 patients with PD, 21 patients with LBD, and 17 age-matched normal subjects without neurological disease. The clinical parameters evaluated were severity of the process (measured by Hoehn and Yahr Scale), vegetative manifestations, development time and use of medication taken. Myocardial adrenergic function was analyzed by imaging with 123I-MIBG. Early (15 min) and delayed (4 h) images of the thorax in the anterior view were obtained after injection of 123I-MIBG (111 MBq). The qualitative and semiquantitative 123I-MIBG uptake was quantified by calculating a heart-to-mediastinum ratio (HMR) and analyzed in a blind manner.

RESULTS

The mean H/M ratio in patients with PD and LBD was significantly lower than in controls (p < 0.05). This is independent of development time, process severity, use of medication or vegetative manifestations. The HMR obtained in LBD patients is less clear than in PD.

CONCLUSION

123I-MIBG myocardial scintigraphy might detect early disturbances of the sympathetic nervous system in PD and LBD.