Anaesthetics – general or local – are powerful drugs that have a particular effect on your nervous system and muscles. Because CMT is a condition that affects part of your nervous system, you need to take special care that the anaesthetist understands well in advance of any operation that you have CMT. This holds true even if you only have mild symptoms, no symptoms at all or have a family history of CMT.
By telling the anaesthetist about your condition well in advance, he or she can work out with you what type of pain relief is best for you. The anaesthetist may also want to check your respiratory function before the operation. As an extra precaution you will probably be asked to stay in hospital longer than usual after the operation, which is why people with CMT should not be admitted for day treatment.
In theory, local anaesthetics (which work directly on the nerve fibres) will be affected by CMT. There have been reports of greater sensitivity to local anaesthetics in people with CMT, namely the anaesthetic lasting longer and having a more intense effect. Also, in current practice, local anaesthetics are injected around nerves after locating them using nerve stimulators. This technique may need to be modified or may not work at all on nerves that have been significantly affected by neuropathy. However, spinal or epidural anaesthesia have been reported as successful techniques.
If general anaesthesia is used, non-depolarising muscle relaxants (as opposed to depolarising) are likely to have a prolonged effect on people with CMT. The effect would be to prolong an anaesthetic since someone with CMT would need to be kept anaesthetised until the relaxant wears off or can be reversed. Depolarising muscle relaxants should be avoided but inhalational anaesthetics are safe.
It is extremely important that your surgeon and anaesthetist are informed if you have HNPP as being in one position for a long time under anaesthesia must be avoided.
Questions to ask before surgery: