Anesthesia in Neuromuscular disorders/mentions CMT

[Guest guest]

Danita, this might be of some help to you and your anestheologist -

although it is 2 years old. It mentions CMT. ~ G)

Abstract from Anasthesiol Intensivmed Notfallmed Schmerzther. 2002

Mar;37(3):125-37.

(original article in German)

Anesthesia in neuromuscular disorders. Part 2: specific disorders]

Baur CP, Schara U, Schlecht R, Georgieff M, Lehmann-Horn F.

Universitatsklinik fur Anasthesiologie der Universitat Ulm, Germany.

The neuromuscular disorders described are divided into four groups:

motoneuron diseases, peripheral neuropathies, disturbances of

neuromuscular transmission and myopathies. In motoneuron diseases

problems mainly result from respiratory insufficiency and the

predisposition for aspiration caused by progressive muscular weakness.

Depolarising muscle relaxants may elicit myotonic reaction and massive

hyperkalemia. In contrast to non-depolarising muscle relaxants there may

be an extreme hypersensitivity. In peripheral neuropathies the cardiac

function is often limited whereby dysautonomia may enhance

cardiovascular instability. The negative inotropic effect of anaesthetic

agents must be observed with care and patients with higher degree of AV

blocks may need a cardiac pacemaker during general anaesthesia.

The Charcot-Marie-Tooth-Syndrome is characterized with a high

sensitivity to thiopental. Disturbances of neuromuscular transmission

frequently cause respiratory problems The fluctuating weakness of bulbar

and respiratory muscles may impair swallowing and can lead to recurrent

aspirations. Due to the reduced number of acetylcholine receptors the

sensitivity to non-depolarizing muscle relaxants is elevated and the

response to succinylcholine is reduced. Drugs reducing neuromuscular

transmission such as antibiotics and beta-blockers may enhance these

symptoms and should be avoided.

In progressive muscular dystrophies the anaesthetic risk is mainly

dependent on cardiac and respiratory impairment. Administration of

succinylcholine leads to the risk of

hyperkalmic cardiac arrest. Patients with metabolic myopathies are also

at risk due to the involvement of cardiac muscle but respiratory

problems are less frequent. Muscle metabolism should be supported by

administration of substrates depending on the underlying disorder.

In membrane disorders muscle rigidity (myotonic reactions) or weakness

may lead to respiratory insufficiency. In addition to the depolarising

muscle relaxants also anticholinesterase drugs, hypothermia and

dyskalaemia can evoke myotonic reactions.