116 of 126
Even in non-Raynaud’s people, the body responds to cold by activating the sympathetic nervous system.
Fingers and toes only have α-receptors – which means they can only vasoconstrict in the presence of NE.
In healthy people, get moderate vasoconstriction in fingers and toes – in Raynaud’s patients, get severe vasoconstriction (in cold environment or when under emotional stress).
Possible mechanisms for overactive/severe vasoconstriction in Primary Raynaud’s:
Exaggerated sympathetic discharge in response to cold
Heightened vascular sensitivity to adrenergic stimuli
Excessive release of vasoconstrictor stimuli (serotonin, thromboxane, endothelin)
Possible mechanisms for overactive/severe vasoconstriction in Secondary Raynaud’s:
With connective tissue diseases or arterial occlusive diseases, digital lumen is largely obstructed by sclerosis or inflammation Æ higher susceptibility to sympathetically mediated vasoconstriction.
Avoid cold places.
Wear warm clothing.
If have to be in cold place, use insulated gloves or footwear.
Some success in preventing vasospasm with drugs that relax vascular tone…
calcium channel blockers