Doctor Answers (1) on Sudden rage
I understand your predicament. Most patients with such behavioral disturbances lack insight to their illness, therefore, they themselves will never admit to having a problem, neither will they seek or agree for treatment. But tretament is essential.
So what you need to do is take her to a Psychiatric hospital under some pretext. Her condition needs to be evaluated in detail, as she is old. There are always chances of organic or physical brain abnormalities in this age, like dementia, electrolyte disturbances which might lead to such behavior, for which a MRI might be necessary. Once that is ruled out, other psychiatruc causes can be looked for.
Therefore, get her to a Psychiatric set up at the earliest. Do not tell her that you are taking her to a Psychiatric facility. Keep family members along, who might have to stay with her, if she needs hospitalization. You might have to admit her against wish, if the need be. Or, if her condition is treatable on an OPD basis, the doctors might give you medications that could be given spuriously.