Myasthenia gravis towards a safer anesthesia: clinical experience and review of literature

ABSTRACT

Myasthenia gravis is caused by auto antibodies to postsynaptic nicotinic acetylcholine receptors[anti-AChRS] at the neuromuscular junction, causing weakness of skeletal muscles. In addition patients with thymoma-associated MG produce autoantibodies to a variety of neuromuscular antigens, including antibodies to the calcium release channel of the skeletal muscles and antibodies to cytoplasmic filamentous proteins. Some patients with thymoma-associated MG have an inflammatory myopathy of striated and cardiac muscles that may cause heart failure, cardiac arrhythmias, and sudden death. Consequently Myasthenia gravis [MG] is a disease with many implications for the safe administration of anesthesia and involves considerable morbidity and mortality. Thymectomy is a common surgical procedure in patients with myasthenia gravis. We describe an anesthesia technique involving continuation of pre-operative anticholinesterase, use of non-paralyzing technique [i.e. avoidance of muscle relaxants], and use of ultra-short acting anesthetics. This technique was safe and effective in eight patients who underwent trans-sternal thymectomy and were extubated on the table following administration of intravenous anticholinesterase and anticholinergic drugs. None needed post-operative ventilatory assistance. There was no post-operative morbidity or mortality