ABSTRACT
The neuromuscular junction (NMJ) is uniquely sensitive to the effects of neurotoxins. Unlike the blood-brain barrier that protects the brain and spinal cord and the blood-nerve barrier that protects peripheral nerve, there are no barriers to protect the NMJ from the deleterious effects of these agents. Worldwide, the most common neurotoxicity of the neuromuscular junction results from envenomation. All forms ofNMJ neurotoxicity are characterized by progressive, typically symmetric muscle weakness. Muscles of eye movement or the eyelids are most often involved as are muscles of neck flexion and the pectoral and pelvic girdles. In more severe situations there may be involvement of bulbar and/or respiratory musculature. Cognition and sensation are usually spared unless other elements of the nervous system are simultaneously involved. Muscle stretch reflexes are often preserved or only minimally diminished particularly during the early phases of the illness but may be lost if muscle weakness is severe.
