Hyperhydrosis is the medical term for excessive sweating. Why some people sweat more than others is unknown although some medical conditions such as an overactive thyroid gland can be the cause. Commonly the hands, armpits and feet are the most affected areas. Simple treatments such as roll on antiperspirants can help and a technique of electrolysis (iontophoresis) can also be useful. In severe cases however these treatments may fail to control the sweating. The side effects of tablets (beta blockers, probanthine) often limit the benefit of this form of treatment. For difficult persistent hyperhidrosis a surgical technique to remove the nerve supply to the sweat glands, SYMPATHECTOMY can be used.
What is the Sympathetic Nerve ?
There are a number of nerves in the body that control automatic functions: "we don't need to think about these functions". For example, if we run for a bus, we automatically breathe harder and our heart beats faster to provide the oxygen to the muscles running for the bus. In a similar way there are nerves which make us sweat in order to lose heat. These nerves are part of the sympathetic nervous system. Dividing (cutting) these nerves is called a sympathectomy.
What does Sympathectomy involve?
Sweating in the hand, arm and face/scalp is controlled by a sympathetic nerve in the lower neck and upper chest. With modern “keyhole” instruments and cameras this nerve can be seen and divided. This is called a cervical sympathectomy. Under a general anaesthetic through a small 1 cm incision a tube containing a camera is introduced into the chest between 2 ribs just below the armpit. The lung prevents a good view of the nerve so the anaesthetist reduces the breathing on this side and the lung becomes less inflated. Now that the nerve can be seen, a second instrument is introduced through another small hole and used to divide the nerve. The lung is then re-expanded, the instruments removed, and the skin closed with dissolvable sutures. The operation takes 20 minutes per side on average. Normal activities are resumed in 1 – 2 weeks.
Sweating in the feet can be treated by destroying the sympathetic nerve supply at the back of the abdomen (Lumbar Sympathectomy). This is usually done with an injection or cauterisation under a local anaesthetic, day procedure.
What are the Complications? (specific to sympathectomy)
Cervical Sympathectomy : The commonest change after the operation is some extra sweating on the lower abdomen, back, or thighs (Compensatory Sweating). In 10 – 20% of cases this may be severe enough to be a problem but in the majority of cases it is mild. The hands may initially be dry and require some moisturiser. Failure of the lung to re-expand requiring a chest drain is rare (< 1%). The eyelid on the same side as the treated hand may droop slightly (Horners Syndrome). This occurs temporarily in 1% of cases but is permanent in only 0.1%. It is rare for the operation to be unsuccessful for hand sweating but it is less reliable for armpit sweating.
Lumbar Sympathectomy : Compensatory sweating can occur after this procedure as above. In men, after a bilateral procedure, fertility can be affected in 20 -30% of cases.
For more information visit the section at the Circulation Foundation