doctors have not identified the cause of her symptoms

[f3456]

Patient Case:

A 76-year-old female began experiencing symptoms four or five years ago. Occasionally, while walking, she suddenly feels unsteady, as if she is about to fall. During these episodes, she does not feel dizzy, her legs do not feel weak, and she does not experience cold sweats, tremors, palpitations, hunger, fatigue, vision impairment, or confusion. When she stops walking, the unsteadiness disappears. This sensation does not occur when she rides an electric bike or sits in a car. The episodes do not happen daily, have no specific time pattern, and there were even periods of three to four months without symptoms. However, in the past two years, the frequency of these symptoms has increased.

Additionally, over the past few years, she has occasionally experienced another symptom: in the morning, her vision becomes slightly dark and blurry. This symptom lasts for about 20 minutes to an hour and occurs with long intervals between episodes. The two symptoms have never occurred simultaneously.

Various examinations show that all organ functions are generally normal. Brain CT shows mild atrophy, carotid arteries are free of plaques, heart and lung CT scans are mostly normal, there is no evidence of ear stones, and vestibular function tests show no issues. Her static blood pressure and blood sugar levels are normal, lipid levels are generally normal, and the levels of calcium, phosphorus, potassium, and sodium in her blood are within normal ranges.

Additional Test Results:

CT scan shows cerebral arteriosclerosis and multiple ischemic lacunar infarcts in the brain.

MRI indicates chronic ischemic-hypoxic changes in the periventricular white matter of the frontal lobe and brain atrophy.

Echocardiogram shows rheumatic heart valve disease and mild pulmonary hypertension.

In summary, doctors have not identified the cause of her symptoms and are unsure how to treat her. What is your analysis, diagnosis, and recommendation?