Stefanía Rossi

Objectives The pathogenetic hypotheses of Raynaud’s phenomenon include increased activation of sympathetic noradrenergic nerves controlling muscle tone of digit arteriolar walls. Because acral sympathetic fibres contain vasoactive adrenergic and cholinergic fibres for sweat glands, we tested cholinergic sympathetic fibre function in primary Raynaud’s phenomenon (PRP) patients by sympathetic skin response (SSR). Methods Twenty-six consecutive patients (19 women, 7 men, mean age 37.8 years) with PRP were enroled prospectively. SSR was obtained by random electrical stimulation of the left ulnar nerve at the wrist recording from the palm (PSSR), third (M3SSR) and fifth fingers (U5SSR) on the right side. For each subject latency of shortest response, area of largest response and grand mean latencies and areas of 12 consecutive responses were calculated. The differences between patients and a control group (15 women, 6 men, mean age 38.9 years) were calculated. SSR habituation was also compared between patients and controls. Results PSSRs were recorded in all patients and no difference in any PSSR parameter was found between patients and controls. U5SSRs and M3SSRs were absent in two patients. Grand mean area and mean of largest M3SSRs and U5SSRs were significantly lower in patients than in controls. Grand mean latency and mean of shortest M3SSRs and U5SSRs were significantly slower in patients than in controls. M3 and U5SSRs habituated less in patients than in controls. Interpretation Dysregulation of cholinergic sympathetic fibres innervating the fingers was found in PRP. Abnormal peripheral mechanisms may be the cause. Since SSR habituation was also not normal, even central mechanisms may be implicated.

To compare the prevalence of diabetes in a consecutive sample of patients with ulnar neuropathy at the elbow (UNE) with that in patients with carpal tunnel syndrome (CTS) and to assess differences in demographic, clinical, and electrophysiologic findings between diabetic, idiopathic, and posttraumatic UNE. Six thousand eight hundred seventy-one and 434 consecutive patients diagnosed with CTS and UNE, respectively, were admitted to an outpatient electromyography service between 1995 and 2006. Twenty-six UNE and 452 CTS patients also had diabetes. Prevalence of diabetes in UNE was 6.0% and did not differ from that in CTS (6.6%); there were more male diabetic UNE patients (61.5%) than diabetic CTS patients (35.8%). There was no difference in occupation, duration of symptoms, association with CTS, polyneuropathy, and many neurographic findings of the ulnar, median, and radial nerves between diabetic and idiopathic or posttraumatic UNE patients when UNE groups were matched by sex and age, except for differences in sensory action potential amplitudes of diabetics vs. the other two groups. The prevalence of diabetes is the same in UNE and CTS patients. The patients with UNE and diabetes are clinically and electrophysiologically indistinguishable from other groups of UNE patients, except for a reduction in sensory action potential amplitudes in the diabetic UNE group, presumably owing to diabetic polyneuropathy. Subjects with UNE and diabetes could therefore be treated in the same way as patients with idiopathic forms.