delirium (Parkinson’s disease)

An episode of an alteration in the level of consciousness characterized by marked mental confusion, fluctuations between decreased arousal (stupor) and agitation, and disorientation. In Parkinson’s disease, delirium tends to be more common in those who are elderly and who also have dementia. It often is generated by anti-parkinson’s medications, particularly anticholinergic medications and dopamine agonist medications, although Levodopa, selegiline, amantadine, and many other medications can be causes. Delirium also is a symptom of cognitive impairment that may or may not be a consequence of the Parkinson’s. It is more likely if Alzheimer’s disease is also present or if there is a history of alcoholism or drug abuse. Even fairly minor infections or mild problems with the body’s steady state, like dehydration, may cause delirium in individuals with dementia, but delirium should always be evaluated. Potentially life-threatening situations such as bleeding or infection in the brain, which are particular risks if there has been any surgical treatment of Parkinson’s, and stroke also cause delirium. it is essential to identify the cause of delirium promptly; diagnostic imaging such as computed tomography (CT) scan or magnetic resonance imaging (MRI), and in some cases spinal tap to examine the fluid around the brain, can usually diagnose or rule out the critical causes.

During an episode of delirium, confusion and disorientation can be severe; the person does not recognize people, places, and events that should be familiar. Episodes may last hours or days. Delirium can cause a person to behave unpredictably, with wide and sudden swings in mood and actions. Sometimes behavior is angry and violent, without apparent provocation. Delirium and psychosis often appear in tandem, and determining whether they are related to the Parkinson’s or are symptoms of other conditions such as Alzheimer’s disease, other age-related dementia, or psychiatric illness such as schizophrenia can be a clinical challenge.

Because anti-Parkinson’s medications are often the culprit when delirium is manifested in a person with Parkinson’s, the first treatment approach is adjustment of their dosages. Levodopa tends to be a safer choice than dopamine agonists and anti-cholinergics, and has a much higher potential symptomatic benefit though similar delirium risk to amantadine and selegiline, hence demented patients are typically taken off of the other agents and maintained on the maximum dose of levodopa they can tolerate without developing delirium or psychosis. Sometimes taking smaller doses more frequently is enough of an adjustment to end the delirium, or manipulations across the spectrum of anti-Parkinson’s medications may be required to find the adjustments that relieve the Parkinson’s symptoms without causing delirium. Generally, if changes in the drug regimen end the delirium, the doctor can reasonably conclude that the anti-Parkinson’s drugs induced the delirium and any related symptoms such as hallucinations, delusions, or psychosis.

Other drugs known to cause delirium and related psychotic symptoms in people with Parkinson’s disease are muscle relaxants and antispasmotic drugs, tricyclic antidepressant medications, narcotic pain reliever drugs, benzodiazepines, and over-the-counter cold and flu products.

Delirium that continues despite efforts to adjust the anti-Parkinson’s medication regimen requires evaluation and treatment. Doctors often prescribe the atypical antipsychotic drug quetiapine, commonly available in the United States as the brand name product Seroquel, for this purpose. Quetiapine affects the brain’s dopamine receptors differently than do conventional antipsychotic medications and seems to calm psychotic symptoms without interfering with the actions of anti-Parkinson’s medications. clozapine is another good choice for treating psychosis and delirium in people with Parkinson’s, but it requires close monitoring of white blood cell counts as it can adversely affect them.

Next post:

Previous post: