Sympathotonic orthostatic hypotension: a report of four cases.

We describe four patients with sympathotonic orthostatic hypotension, a syndrome in which the decrease in blood pressure associated with standing is accompanied by tachycardia. The patients in this series had experienced either a viral infection or rapid weight loss prior to the onset of their orthostatic intolerance. Vasomotor reflexes and norepinephrine production were normal, and analysis of palmar autonomic surface potentials indicated that the sympathetic innervation of the upper extremities was intact. The amplitudes of the plantar autonomic surface potentials, however, were decreased although still within the normal range. The latencies of plantar autonomic surface potentials were slightly prolonged. Although most autonomic function tests are normal in sympathotonic orthostatic hypotension, mild abnormalities in the plantar autonomic surface potentials may indicate a neuropathy that primarily affects low thoracic or lumbar sympathetic neurons.

Effect of the somatostatin analogue SMS-201-995 on the adrenergic response to glucose ingestion in patients with postprandial hypotension.

PURPOSE: The somatostatin analogue SMS-201-995 has recently been introduced as a new therapy for postprandial hypotension in patients with autonomic neuropathy. The present study was performed to determine the effect of SMS-201-995 on the adrenergic response to glucose ingestion in patients with this disorder. PATIENTS AND METHODS: Eleven patients with postprandial hypotension were studied: six with central autonomic dysfunction (multiple system atrophy) and five with peripheral sympathetic dysfunction (progressive autonomic failure). Patients received either a subcutaneous injection of SMS-201-995 or a placebo injection, immediately before administration of a 50-g glucose drink. Each treatment was given on separate, consecutive days in a randomized fashion. RESULTS: Glucose ingestion caused a decrease in blood pressure (from 82 +/- 6 mm Hg to 66 +/- 7 mm Hg, p less than 0.01) and an increase in plasma norepinephrine level (165 +/- 20 pg/mL to 305 +/- 85 pg/mL, p less than 0.01) in five patients with progressive autonomic failure. Administration of SMS-201-995 prevented both the decline in blood pressure and the increase in norepinephrine. By contrast, glucose ingestion elicited no increase in plasma norepinephrine levels despite profound hypotension (average postprandial mean blood pressure, 55 +/- 3 mm Hg) in six patients with multiple system atrophy. Administration of SMS-201-995 prevented postprandial hypotension in these patients, but had no effect on plasma norepinephrine. CONCLUSION: Our data indicate that the pressor effect of SMS-201-995 is independent of the sympathetic nervous system in patients with multiple system atrophy, but may suppress the adrenergic response to glucose ingestion in patients with progressive autonomic failure.

Are there two types of diabetic foot ulcers?

Neurological function was determined in diabetic patients with peripheral vascular disease and foot ulcers (n = 13). This was compared to that of diabetic patients without foot ulcers with (n = 23) and without (n = 13) symptoms of neuropathy. Diabetic patients with typical neuropathic ulcers (n = 13) and age-matched healthy controls (n = 20) were also studied. The beat-to-beat variation with deep breathing was 6.1 +/- 1.0 beats/min in those with peripheral vascular disease and foot ulcers, less than 50% of that of diabetic patients without foot ulcers (p < 0.01) or normal controls (p < 0.005). Autonomic surface potentials in the soles were greatly diminished or absent in nearly all the patients with peripheral vascular disease and ulcers. Quantitative sensory testing revealed profound abnormalities in small fiber (heat and cold sensation) and large fiber (vibration sensation) function in diabetic patients with peripheral vascular disease and foot ulcers. Our results document the presence of advanced autonomic and somatosensory neuropathy in nearly all diabetic patients with peripheral vascular disease and foot ulcers.

Posttraumatic syringomyelia.

Posttraumatic syringomyelia can be a subtle entity initially. Awareness of the early clinical manifestations is a necessary adjunct in preventing the disabling sequela. Four case reports are examined with emphasis on temporal progression of symptoms and the resultant functional loss. The salient clinical features and a description of their pathogenesis are summarized. The presenting symptoms and signs were upper extremity reflex loss, musculoskeletal-type pain, and arm numbness. The functional impairments which resulted included the following: increased assistance with wheelchair mobility, significantly reduced performance of ADL, and loss of walking skill in a previously independent ambulator. Each patient underwent myelography (insufficient alone) as well as contrast CT scanning. Each patient underwent shunting with only one patient benefiting significantly. Syrinx formation must be included in the differential diagnosis of neuromuscular complaints by the spinal cord injured (SCI) population and treated appropriately.

Autonomic surface potential analysis: assessment of reproducibility and sensitivity.

There has been recent interest in measuring sympathetic sudomotor function by autonomic surface potential analysis. The purpose of the present study was to assess factors affecting the reproducibility of the test. We determined the within-day and between-day reproducibility in 24 healthy volunteers. We used an increasing rather than a constant electrical stimulus to minimize habituation. The amplitudes were still highly variable (an average within-day coefficient of variation in the soles of 35%). Habituation did not, however, affect the latencies of the responses, which were much more reproducible (an average within-day coefficient of variation in the soles of 8%). Studies of between-day reproducibility revealed that the mean amplitudes were lower on day 2 vs. day 1 (0.706 +/- 0.10 vs. 0.85 +/- 0.10 mV in the soles, P less than 0.01) but the mean latencies were similar on the different testing days (2.09 +/- .04 seconds for the soles on day 1 vs. 2.16 +/- .05 seconds on day 2). We also assessed the sensitivity of surface potential analysis and report the results of testing 35 patients with far advanced autonomic neuropathy.