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Sympathetic skin response in primary Raynaud's phenomenon
Mauro Mondelli1, Renato de Stefano, Stefania Rossi
1EMG Service, Local Health Unit, Siena, Italy. m.mondelli@usl7.toscana.it
Summary
Primary Raynaud's phenomenon (PRP) patients show impaired cholinergic sympathetic nerve function in the fingers, indicated by abnormal sympathetic skin responses (SSR). Both peripheral and central mechanisms may contribute to this condition.
Area of Science:
- Neuroscience
- Physiology
- Dermatology
Background:
- Raynaud's phenomenon (RP) is hypothesized to involve overactive sympathetic nerves affecting digit arteries.
- Acral sympathetic fibers innervate blood vessels and sweat glands, suggesting a role in RP pathogenesis.
Purpose of the Study:
- To investigate cholinergic sympathetic fiber function in primary Raynaud's phenomenon (PRP) using sympathetic skin response (SSR).
Main Methods:
- Twenty-six PRP patients underwent SSR testing via electrical stimulation of the ulnar nerve.
- Recordings were taken from the palm (PSSR), third (M3SSR), and fifth fingers (U5SSR).
- SSR parameters (latency, area) and habituation were compared to 15 healthy controls.
Main Results:
- Palm SSR (PSSR) showed no differences between PRP patients and controls.
- Fifth finger (U5SSR) and third finger (M3SSR) responses were absent in two patients.
- PRP patients exhibited significantly lower U5SSR and M3SSR amplitudes and slower latencies compared to controls.
- SSR habituation was reduced in PRP patients.
Conclusions:
- Dysregulation of cholinergic sympathetic innervation to the fingers is evident in PRP.
- Abnormal peripheral mechanisms are likely involved in PRP.
- Altered SSR habituation suggests potential involvement of central nervous system mechanisms in PRP.
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