A 63-year-old man presents to his primary care physician after his wife noticed that he fainted for no apparent reason.

[answerhappygod]

A 63-year-old man presents to his primary care physician after
his wife noticed that he fainted for no apparent reason. When
questioned by his doctor, the patient also complains of occasional
shaking (tremors) in both arms, although more pronounced on the
right than the left side, recurrent inability to move, especially
initiation of movement, and feeling unsteady on his feet (loss of
balance), all of which he had noticed for about two months. The
primary care physician refers the patient to the local neurologist
for further evaluation and tests. The neurologist observes the
resting tremor in the patient’s arms and unsteadiness in his gait.
He is also able to demonstrate orthostatic hypotension, the most
likely cause of the patient’s fainting spell. The neurologist
orders blood tests to rule out other conditions that could possibly
cause the patient’s symptoms, including cardiac disease. Imaging
studies of the brain (MRI) are performed and exclude a tumor or
stroke.
what do we think is causing this problem?