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Post-micturitional hypotension in patients with multiple system atrophy
T Uchiyama1, R Sakakibara, M Asahina
1Department of Neurology, Chiba University Graduate School of Medicine, Chuo-ku, Chiba 260-8670, Japan. uchiyama@faculty.chiba-u.jp
Journal of Neurology, Neurosurgery, and Psychiatry
|January 18, 2005
Summary
Multiple system atrophy (MSA) patients experience post-micturition syncope due to autonomic dysfunction. This study investigated hemodynamic changes during micturition, revealing significant blood pressure drops and abnormal straining contribute to fainting episodes.
Area of Science:
- Neurology
- Cardiology
- Urology
Background:
- Patients with multiple system atrophy (MSA) can experience syncope or pre-syncope after urination.
- The underlying mechanism for these episodes requires further investigation.
Purpose of the Study:
- To investigate the hemodynamic changes associated with micturition in MSA patients.
- To clarify the mechanism of post-micturition syncope in MSA.
Main Methods:
- Studied 25 probable MSA patients and 16 healthy controls.
- Monitored blood pressure and heart rate during water cystometry, Valsalva maneuver, and head-up tilt testing.
- Measured plasma noradrenaline and calculated heart rate variability (coefficient of variance of RR intervals).
Main Results:
- MSA patients exhibited lower baseline blood pressure and attenuated hemodynamic responses during bladder filling compared to controls.
- Post-voiding, MSA patients showed a prolonged and significant drop in blood pressure (mean systolic reduction -15.2 mm Hg), leading to hypotension (-29.0 mm Hg compared to controls).
- Greater blood pressure falls were observed in patients with syncope/pre-syncope and those experiencing abdominal straining during voiding.
Conclusions:
- Post-micturition hypotension in MSA is likely caused by generalized autonomic dysfunction.
- Abnormal abdominal straining during voiding exacerbates hypotension and contributes to syncope in MSA patients.