Peripheral Nerve |
Functional |
Paediatric Neurosurgery |
Hyperhidrosis simply means excessive sweating. Palmar hyperhidrosis therefore refers to excessive sweating in the hands. While everyone perspires to maintain a constant body temperature, the perspiration in palmar hyperhidrosis is far in excess than what normally occurs. It is often associated with sweaty armpits and sometimes sweaty feet. Not only can this be socially embarrasing, it can cause occupational, educational and psychological problems.
The amount of sweating in the palms of the hands is so severe that beads of sweat can often be seen to drip from the affected person's hands. Writing becomes a problem as it would cause ink to smudge. Handling electronic equipment, especially when that is necessary in one's occupation, becomes harzardous. Socially, it can be ackward shaking hands with others as the opposite party may not understand why the affected person's hand is so wet. While such excessive sweating is can be brought on by excercise, stress, emotions and anxiety, it often occurs spontaneously for no apparent reason.
Sweaty palms is more common in hot and humid countries like Singapore.
It is caused by an overactive nervous system. Underlying medical conditions (eg, thyrotoxicosis) can cause this to occur - secondary hyperhidrosis. However, in most instances, the underlying cause is unknown or idiopathic - essential / primary hyperhidrosis.
It is sometimes heriditary but often, no family history is present.
| 1. | Medical - the first line of treatment |
| a. Astringents. These block up the sweat glands with limited and temporary effects. They are suitable for mild cases. | |
| b. Anticholinergics. These reduce secretion but the side effects, like that dry mouth are rather unpleasant. | |
| c. Iontophoresis. This involves placing the hands in a bath of water through which an electric current passes to 'stun' the sweat glands. Its effectiveness wears off in 1-2 weeks. It is therefore time consuming as it has to be repeated regularly. | |
| 2. | Botox injections - multiple injections under the skin of the hands or armpits |
| Botox or Botulinum toxin, affects the ending of nerves that supply the sweat glands. This therefore reduces sweating but the effects last only about 6 months (although longer than Iontophoresis). | |
| 3. | Surgery - Endoscopic Sympathectomy |
| Also known as Thoracoscopic Sympathectomy, surgery is considered only if medical therapy has failed. While it is indeed a minimally invasive procedure, it remains more invasive than medical treatment or Botox injections. The effects however are long term / permanent with very high success rates (for dry hands & armpits). |
Sympathetic chain is cut and disrupted |
You should consider thoracoscopic sympathectomy only if your sweating is excessive, such that it causes you social, occupational, educational or psychological problems and if medical therapy has proven to be ineffective.
The procedure involves disrupting / destroying / cutting or resecting the part of the nerves that supply the sweat glands of the hands, ie, the sympathetic chain at the level of T2. Sometimes, the chain at the level of T3 is also cut, especially if the armpits are involved. Moreover, some surgeons cut the chain at the level of T4 as well, to ensure that the hands are completely dry.
The procedure is performed under general anaesthesia. The anaesthetist ventilates the patient with a special double lumen tube to allow him to collapse the lung on the side that the surgeon is working on - this is to enable the sympathetic chain (which would otherwise be blocked by a normal expanded lung) to be visualised.
A 1.5cm incision is made under the armpit through which an endoscope is inserted. The chain is visualised and then cut at the appropriate level. Some surgeons prefer to use an additional 2nd or 3rd cut through the armpit for the purpose of using extra instruments to push the lung away and resecting the chain. The author favours a single port technique.
When completed, a chest tube is inserted through the incision to allow the unwanted air in the chest cavity to escape through an underwater seal. The anaesthetists then re-inflates the lung and subsequently collapses the other lung for the surgeon to operate on the opposite side. When both chains are resected, the lungs are both fully re-inflated with the help of the 2 chest tubes now present. Before waking the patient up, the chest tubes are usually removed.
The patient is then discharged after 6 - 8 hours or after a period of observation overnight. There is usually a little pain and discomfort on coughing, sneezing or breathing hard. The pain would subside fairly quickly over a few days and the stiches can be removed after 10 to 14 days. The scar or scars are small and hidden under the armpit. This is opposed to open sympathectomy which involves a longer incision, cutting of the muscles and ribs - a more difficult and painful procedure.
| 1. | Compensatory Hyperhidrosis |
| This occurs in 60-70% of cases. Increased sweating in other parts of the body occurs to compensate for loss of sweating in the hands / armpits. This often occurs in the lower back, legs and calves. It is often unpredictable but most patients tolerate it well with 5% of patients finding this severe and regret having had the procedure done | |
| 2. | Gustatory Sweating |
| Occurs in 5-10% of cases and is rarely severe. | |
| 3. | Bleeding from an artery or vein |
| This is rare but if it cannot be controlled, the operation is converted into an open thoracotomy. | |
| 4. | Injury to the nerve under the rib |
| This can cause chronic post-operative pain. | |
| 5. | Horner's Syndrome |
| This is rare (1%) and it results in a drooping eyelid, constricted pupils and decreased sweating on the same side of the face | |
| 6. | Pneumothorax |
| Air stuck in the chest cavity may necessitate re-inesrtion of the chest-tube. | |
| 7. | Systemic complications |
| These include chest infections, heart abnormalities, urine infections, deep vein thrombosis and other general complications associated with general anaesthesia. |