Mechanism of muscle twitches in hypocalcemia?

[Mohd]

I would expect hypocalcemia to cause decreased ACh at the synaptic junction and therefore lead to weakness . . . . why would twitches occur???

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[SomeDoc]

I would expect hypocalcemia to cause decreased ACh at the synaptic junction and therefore lead to weakness . . . . why would twitches occur???

Remember that membrane potential is around -70mv. When a PT is hypocalcemic, there are less positive ions extracellularly. The result of this is that the membrane potential difference is less negative (IE, in other words, net membrane potential becomes more positive, and closer to the depolarization treshold). As a result, smaller stimuli are needed to elicit muscle twitches. Hope that helps.