Question
What are the sympathetic changes that we typically observe after nerve injury?
Answer
Sympathetic loss results in vasomotor, sudomotor, pilomotor, and trophic changes. Vasomotor changes are the first. We will see in a patient with a nerve injury changes in skin temperature, skin color, changes in swelling, and changes in cold intolerance. It becomes very difficult for these people to be out in cold temperatures for long periods of time. I think one of the best quick tricks for cold intolerance is warming packs. If you go to a sporting goods store, they carry these for hunting and other sports. You pop them open and you can put them in your gloves very safely. They can really improve the amount of heat that can be produced within a glove.
Secondly with sudomotor, you see changes in sweat patterns. You will see no sweating or hypohidrosis in denervated areas. So if you have lost sensation, you have also lost the ability to sweat. If you have a partial nerve injury, you can also see hyperhidrosis or excessive sweating.
Pilomotor changes are going be the absence of that gooseflesh response or “goosebumps.”
With trophic changes, you can see changes in skin texture, atrophy of the finger pulps, changes in the nail beds, changes in hair growth, and slower skin healing. All of these are sympathetic effects of nerve injuries that can also be observed. Any of these observations that I make clinically I document in the chart.
Editor’s note: This Ask the Expert was adapted from the course, ‘The Hand 101’ that is available in text and video course formats.
