WASHINGTON — Treating the HIV infection may ease the symptoms of Parkinson's disease in patients with both conditions, one expert said at the World Parkinson Congress.
Using levodopa to treat Parkinson's symptoms in an HIV-positive individual “may in fact accelerate the HIV infection and it definitely can exacerbate the psychosis that is associated with the infection,” said Dr. Cynthia L. Comella.
Parkinsonism is “increasingly recognized as being one of the neurologic complications of HIV,” said Dr. Comella, a neurologist at Rush University Medical Center in Chicago. As many as 5% of patients with HIV meet U.K. criteria for Parkinson's disease, according to the literature, and an additional 10% exhibit parkinsonian features.
Typically, parkinsonism is seen in HIV patients with the most severe immunosuppression—with CD4 cell counts less than 40, Dr. Comella said.
Parkinsonism associated with HIV is described as symmetric and mostly bradykinetic. Rigidity is also seen, as are early gait and postural instabilities. “Particularly, it's associated with other neurological or psychiatric manifestations, such as associated myoclonus and associated dystonia,” Dr. Comella said.
The etiology of parkinsonism in individuals with HIV arises from two mechanisms: direct HIV infection and opportunistic infections of the basal ganglia. HIV-infected patients are also very susceptible to drug-induced parkinsonism.
“The HIV virus seems to have a propensity to invade the basal ganglia, causing nigral degeneration,” Dr. Comella said.
There is a loss of as much as 25% of nigral neurons, even in asymptomatic patients with HIV. It has also been shown that there is a reduction of dopamine in the cerebral spinal fluid in HIV patients, even in those without neurocognitive deficits.
The highly active antiretroviral drug regimens that are effective against HIV infection are also the most effective treatment for HIV-associated parkinsonism, Dr. Comella said.
In some patients parkinsonian symptoms may resolve with effective treatment of underlying opportunistic infections. The atypical neuroleptics are recommended for psychiatric abnormalities seen in these patients, particularly because these patients are more susceptible to the development of drug-induced parkinsonism with the typical neuroleptics.