<s>[INST] My mother-in-law who is 83 has been having episodes of sudden shaking and total weakness. She has had two falls and broke an ankle. She loses all strength suddenly and doesn t know when it will happen. When she went to the hospital they gave her fluids and tested blood but couldn t find anything. At one point I believe she was told her kidney function is not quite normal. Any ideas....she goes to an array of specialist but know when has an answer for her? [/INST] Hello,Sudden onset of weakness may be due to stroke or essential tremor or delirium or electrolyte imbalance or caffeine or other medications or it ma be a seizure etc. Until examination is done it is difficult to say what it is. Please get it done MRI brain, ECG, serum electrolytes, X-ray of leg and blood sugar levels. Please consult with your neuro-physician he will examine and treat you accordingly.Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Penchila Prasad Kandikattu , Internal Medicine Specialist </s>