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Anathesia

What cautions does My Docter need to take when they put Me under anethisia to break up My kidnystones?

Type of Myotonia: mc

Country: USA

Re: Anathesia

Hello,

I found out accidentally that I have myotonia. I was injured and sent for a nerve and EMG study or I would have never known... I recently had ankle surgery because of this injury and I informed ALL doctors involved about the myotonia. I noticed they added a warming blanket on top of me during this surgery to keep me extra warm in the operating room because cold can trigger muscle stiffness. Also certain types of anaesthesia can be harmful from what I have read about myotonia. I would discuss all this with your doctor as soon as possible before any surgery. Have a great day and all the best.

Gia

Type of Myotonia: Not sure

Country: United States

Re: Anathesia

Leroy:

If you don't know which type of myotonia you have then they might want to treat you the same way they would treat someone who is susceptible to malignant hyperthermia.

I have been told that people with confirmed chloride channel myotonia, such as Thomsen MC or Becker MC, need to avoid succinylcholine and similar depolarizing muscle relaxants. It is also called suxamethonium and goes by a few different brand names. It's used in the intubation process to paralyze your throat muscles so your body doesn't fight the ventilation tube. An anesthesiologist that I had told me that he couldn't give me the antidotes to the succinylcholine alternatives as well so I would have to be on a ventilator until the succinylcholine alternative just wore off....I'm not sure where he got that from but I wasn't in a position to doubt him and didn't want to be on a ventilator for 6 hours, so we went with spinal anesthesia combined with an amnesiac called Versed instead of general anesthesia and completely avoided any MC related hassle. It also probably saved me a few thousand dollars.


Type of Myotonia: Becker

Country: USA

Re: Anesthesia Protocols

Leroy, this is a good article to print out for your doctor. It mentions myotonia on the second page:

Coping with Anesthesia

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Here is a protoco written up by the anesthesiologist of one of our forum members:

There are several concerns when anesthetizing patients with myotonia congentia. First off there appears to be an increased risk of developing malignant hyperthemia (MH) which is a very dangerous and often fatal anesthetic complication induced by depolorazing neuromuscular blockers like succinylcholine and by the inhalational anesthetics. The inhereited predispostion to developing MH is heterogeneous. There is a defect in ca++ influx into unrestrained muscle contraction. MH is linked to a defect in the muscle sarcolemyma ryanodine receptor. This of course is not the same defect as that seen in myotonia congentia. It appears that many causes of intraoperative muscle rigidity in patients with myotonia are misdiagnosed as MH. It is a little unclear if the risk for MH is increased but for now it is best to assume that it is increased and to have the anesthesiologist deliver what is called a non-triggering anesthetic. This can be easily done.

Patients with myotonia are at increased risk of developing masseter muscle spasm of the jaw and this can lead to inability of the anesthesiologist to manage the patients airway and will often lead to cancellation of the case before it gets started. Masseter muscle spasm is often associated with MH but is also seen in myotonia leading to some confusion in making the proper diagnosis in this emergency situation. Masseter spasm is seen most commonly afer succinylcholine administration.

Besides the risk of MH. Patients with both types of Myotonia should never be given the depoloraizing muscle relaxants like Succinylcholine. This causes sustained muscle contraction instead of the expected relaxation and can lead to the inability to intubate or ventilate the patient, which could be fatal. Also patients with myotonia who are given Succinylcholine may have a massive release of potasium leading to cardiac arrest. Prolonged surgeries leading to muscle compression or the administration of Succinylcholine may lead to post-operative muscle breakdown in the form of rhabdomyolysis which can also cause acute renal failure and death.

Patients with myotonia also run the risk of having prolonged weakness afer surgery which may increase there need for prolonged ventilation and endotracheal intubation. This may be caused by the neuromuscular blocking agents or by the inhalational anesthetics.

Patients with myotonia are also at increased risk of pulmonary aspiration and postop pneumonia.

Regional anesthetic techniques like spinal or epidural anesthesia, should be safe in patients with myotonia. Local anesthetics can also be used.

In summary, before your child has anesthesia, you should talk to the anesthesiologist and explain his disorder and make a plan for a non-triggering anesthetic which will avoid most of the problems listed above and can be readily delivered.

Preparation of the operating room anesthesial machine and preparation of the anesthsiologist are very important in anesthetizing these patients.

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This is the protocol that I have written up based on communication with several anesthesiologists who are experts in surgery for patients with myotonia congenita. It was reviewed by the head of obstetric anesthesia for Brigham and Women's Hospital.

Check pseudocholinesterase levels before surgery to determine risk from anesthetics and depolarizing agents - if low use extreme caution

Make sure filter medium and tubes have not been contaminated with inhalation anesthetics; evacuate operating room air thoroughly before patient enters

Warm IV fluids and operating table if possible. Keep warm blankets on patient during the surgery to avoid triggering myotonia from chilling.

Anesthetics/Analgesics: Propofol, Fentanyl and Versed

Paralyzing Agent: Vecuronium (NO succinylcholine)

Local - Bupivacaine, no vasoconstrictors (no Lidocaine); epinephrine will trigger myotonia

IV saline only - no potassium added. Glucose/dextrose slow drip to avoid blood sugar elevation

Monitor potassium levels throughout surgery - cardiac arrest from hyperkalemia is a bigger risk than malignant hyperthermia



Type of Myotonia: Thomsen's

Country: USA