Multiple system atrophy

2 They defined the full syndrome comprising of orthostatic hypotension, urinary and rectal incontinence, loss of sweating, iris atrophy, external ocular palsies, rigidity, tremor, loss of associated movements, impotence, atonic bladder, loss of rectal sphincter tone, fasciculations, wasting of distal muscles, evidence of a neuropathic lesion in the electromyogram suggesting involvement of the anterior horn cells, and the finding of a neuropathic lesion in the muscle biopsy. Plasma noradrenaline, an index of peripheral sympathetic activity, is often normal in patients with MSA, reflecting intact peripheral sympathetic neurones, but abnormally low in patients with pure autonomic failure, indicating abnormal peripheral sympathetic neurones. 16 However, the distinction on the basis of plasma noradrenaline has been unreliable. 17 Kaufmann et altherefore proposed that plasma arginine vasopressin (AVP) measurements in upright tilt are a more sensitive way to differentiate the two conditions. 18 In patients with MSA upright tilt produced a marked fall in blood pressure, but plasma AVP increased only slightly and inappropriately for the degree of hypotension. (A) false: the plasma noradrenaline concentrations are normal or slightly raised in MSA patients differentiating it from pure autonomic failure in which the plasma noradrenaline concentrations are usually 1ow; (B) false: magnetic resonance imaging may show altered signal in striatum, particularly in putamen, thus differentiating it from idiopathic Parkinson's disease; (C) false: electrophysiological monitoring of individual motor units from the striated component of urethral sphincter has shown consistent abnormalities in MSA patients and is highly specific; (D) true; (E) true.