These medications help increase the concentration of dopamine in the brain. Patients who can't maintain adequate symptom control with medications may be candidates for neurosurgical procedures, such as pallidotomy, thalamotomy and deep brain stimulation. These avenues carry slight risks of bleeding, stroke or perioperative infection, so these treatment options aren't preferred early in the course of the disease when medications can be highly effective. At autopsy, JP patients have preserved, nondegenerated cells in the substantia nigra. The cells, however, lack the pigment neuromelanin.
Pigment is formed within nigral cells as a by-product of dopamine metabolism.
This neuromelanin is absent at birth for all people, but accumulates later. In most people, the nigral cells are fully pigmented by age 16. As nigral cells idle in people with Parkinson's, neuromelanin is released, removed and eventually disappears. This differs from typical Parkinson's of YOPD, in which tyrosine hydroxylase is reduced equally in the nigra and the striatum. This differs from adult-onset Parkinson's patients, whose symptoms begin asymmetrically, usually in the hands.