The effect of a balanced liquid meal on supine and postural blood pressure (BP) responses was investigated in three groups of patients with chronic autonomic failure; 10 with associated neurological impairment (multiple system atrophy (MSA), Shy-Drager syndrome) and seven without (of which five had pure autonomic failure (PAF); and two had a deficiency of the enzyme dopamine beta hydroxylase, DBHdeficiency). All had marked postural hypotension. Subjects with normal autonomic function were also studied. In MSA and PAF food lowered supine BP substantially, with a more rapid and greater fall in PAF. After food, the levels of BP reached were considerably lower because of the reduced supine BP and many had to be returned to the horizontal position earlier than before. Ingestion of a similar volume of water alone had no effect in MSA or PAF. In DBH deficiency, food had variable but minimal effects on BP while supine and during head-up tilt. In subjects with normal autonomic function food did not affect BP. The BP responses to food thus varied in the three groups with chronic autonomic failure. The influence of food on both supine and postural BP therefore should be considered in the clinical and laboratory assessment of autonomic dysfunction and in relation to therapeutic approaches, designed to alleviate postural hypotension.Postural hypotension is a cardinal manifestation of autonomic failure and a fall of 20 mm Hg systolic (or less in the presence of symptoms) requires further investigation, whereas a minimal fall often excludes auto-

No abstract

The effects of the somatostatin analogue, octreotide on postural hypotension have been compared with placebo, before and after food ingestion in two groups with primary autonomic failure; patients with pure autonomic failure, and patients with additional neurological involvement as part of multiple system atrophy. After placebo, supine blood pressure was unchanged, but after octreotide, it rose in both groups. Octreotide reduced pre-prandial postural and supine post-prandial hypotension in both pure autonomic failure and multiple system atrophy patients. Postural hypotension post-prandially was considerably worse after placebo; this was reduced after octreotide. Plasma noradrenaline and adrenaline levels remained unchanged. Plasma glucose levels rose higher and faster after placebo. Insulin levels were similar in both groups at rest, but rose higher in patients with pure autonomic failure after placebo. After octreotide, the insulin response in both groups was suppressed. We conclude that octreotide prevents post-prandial hypotension in both groups with primary autonomic failure and additionally reduces postural hypotension both before and after food ingestion. The greater rise in insulin levels in patients with pure autonomic failure suggests that insulin may be a contributing factor to the more severe post-prandial hypotension observed in this group of patients.