If you have never seen someone have a seizure, count yourself lucky. The single most frightening thing I've witnessed is watching my mom seize in her hospital bed this weekend. It was truly scary. I can't even find words to describe it, just take my word for it.
A bit of advice, if you have an "older" loved one who is having any type of procedure done, have them check their electrolytes with a simple blood test BEFORE and AFTER the procedure. If the levels are low before the procedure, I suggest rescheduling.
While we've been conditioned to believe that a low sodium diet is ideal, sodium is necessary for fluid balance, blood pressure regulation, and normal function of the nervous and muscular systems. Hyponatremia (a low concentration of sodium in the blood) is more common in older adults for many reasons (as outlined here from the Mayo Clinic). The symptoms can include nausea, headache, confusion, seizures, and coma (according to this information from medicinenet).
We've all been told to eat our bananas when we experience muscle spasms. That's because we need more potassium which is responsible for normal cell electrical function. A potassium deficiency (hypokalemia) can cause muscle spasms and heart palpitations (as outlined here from the Mayo Clinic).
Low electrolytes are the most likely cause of my mom's seizures (36 hours post-operative). It is a painfully slow process getting her potassium and sodium levels back to normal. In the meantime, she suffers from nausea, headaches, muscle spasms, disorientation, hallucinations, confusion, not to mention the threat of more seizures. This possibly could have been prevented. If you have a relative going in for any procedure, no matter how minor, please ask the doctors to monitor their electrolytes both before and after the surgery.