Early in the disease course, a presumptive diagnosis of myasthenia gravis is supported by a test dose of edrophonium chloride (Tensilon), an acetylcholinesterase inhibitor characterized by very rapid onset (30-45…
Myasthenia gravis is seen in all age groups, with a bimodal distribution, affecting younger adults in their 20s and 30s (with a female predominance) and older adults in their 60s…
The nicotinic AChR contains five subunits arranged radially around a transmembrane ion channel. Antibodies generated in myasthenia gravis are primarily directed against the AChR alpha subunit. These antibodies may bind…
This technique is performed to specifically stress the safety factor by rapidly mobilizing and releasing multiple stores of ACh. With a 2-to 5-Hz RMNS, fewer stores of ACh are released,…
Alpha bungarotoxin has another use. Because it binds to tightly to the AChR, it provides a means of seeing each muscle fiber’s postsynaptic site. This is accomplished by tagging bungarotoxin…
The structure of the neuromuscular junction explains why it is so powerful. An axonal branch terminates in a branched structure that is laden with mitochondria, synaptic vesicles, and a number…
The presynaptic nerve terminal is the site of synthesis, release, and reuptake of the neurotransmitter acetylcholine (ACh), the chemical responsible for neuromuscular transmission. Acetylcholine is synthesized in the peripheral nerve…
Spinal Muscular Atrophy Type I (Werdnig-Hoffmann Disease). In the healthy newborn infant, the purposeless movements of the extremities are associated with a well-defined muscular tone, despite the lack of coordinated…
Respiratory failure is the cause of death in most patients. Early in the course of the illness, the patient should be warned against the use of respiratory depressants such as…
TREATMENT To date, riluzole is the sole Food and Drug Administration (FDA)-approved drug for the treatment of ALS. Several randomized trials have demonstrated that riluzole prolongs the life of ALS…
