The symptoms of severe hypocalcemia can be remembered with the mnemonic 'CATS go numb': Convulsions, Arrhythmias, Tetany and numbness of hands, feet and lips.
[symptoma.com]
Symptoms include numbness and/or tingling of the hands, feet, or lips, muscle cramps, muscle spasms, seizures, facial twitching, muscle weakness, lightheadedness, and slow
[medicinenet.com]