90 Year Old Female With Hypertension And No Other Medical

90 year old female with hypertension and no other medical history, now with a 3-month history of recurrent episodes of dizziness, weakness, headache, feelings of "heat" lasting 30 min to an hour, initially almost daily, now once or twice a week. Extremely debilitating. Initially seemed to correlate with high blood pressure, but not as much recently. Multiple ER visits, one brief hospitalization. Cardiac, neuro, ENT, endocrine work-ups all negative, incl w/u for pheochromocytoma. What might might be some less common things to consider, and could these be panic attacks?