Unrecognized Charcot-Marie-Tooth disease: diagnostic difficulties in the assessment of recovery from paralysis

[Neuromuscular monitoring in patients with neuromuscular diseases. Options and needs]

The management of general anaesthesia in patients with neuromuscular disorders remains challenging. The underlying causes and clinical presentations of these rare heterogeneous diseases are highly variable and the only common feature is usually skeletal muscle weakness. The appropriate choice and dosage of muscle relaxants are important and an adequate monitoring of the neuromuscular blockade is obligatory. Neuromuscular monitoring can be complicated because of disease-induced alterations in neurophysiology; however, continuous monitoring of the neuromuscular blockade should be realized to accurately determine the recovery from the blockade. These patients very often have an increased risk for postoperative pulmonary complications, which increases further if a residual neuromuscular blockade is present.

Onset and duration of mivacurium-induced neuromuscular blockade in children with Charcot-Marie-Tooth disease. A case series with five children

BACKGROUND

The Charcot-Marie-Tooth (CMT) disorders are a group of hereditary motor and sensory neuropathies characterized clinically by peripheral muscle wasting and weakness. We hypothesized that unknown involvement of the muscle used for monitoring neuromuscular block may account for the conflicting reports about the effect of nondepolarizing neuromuscular agents in these patients. The aim of this study was to compare onset and recovery from mivacurium-induced neuromuscular block on the adductor pollicis and orbicularis oculi muscles.

METHODS

We used mivacurium 0.2 mg.kg(-1) in five children (aged 7-12 years) with CMT type I undergoing propofol-fentanyl-oxygen-air anesthesia for orthopedic surgery. Using acceleromyography, neuromuscular transmission was monitored in parallel in the eye and thumb muscles, and onset and duration times were recorded.

RESULTS

Following bolus administration of 0.2 mg.kg(-1) of mivacurium the onset time ranged between 135 and 240 s and 75 and 165 s in the eye and in the thumb, respectively. The recovery time varied between 5.3 and 16 min and 6 and 31.3 min in the eye and in the thumb, respectively.

CONCLUSIONS

In our small series of patients with CMT the clinical duration of mivacurium-induced neuromuscular block was similar to data known from children without neuromuscular disease.