Review Question - QID 220754

This patient, who presents with delusions and hallucinations in the setting of Parkinson disease treatment most likely has Parkinson disease psychosis. This manifestation should be treated with an antipsychotic medication such as pimavanserin.

Patients with an underlying history of Parkinson disease can experience visual hallucinations and paranoid delusions in a manifestation known as Parkinson disease psychosis (PDP). PDP is a common non-motor symptom of Parkinson disease, affecting up to 50% of patients. It is characterized by hallucinations, delusions, and illusions. Patients who are taking levodopa can be at a higher risk of this manifestation. The most appropriate treatment for PDP is the use of atypical antipsychotic medications, such as quetiapine, clozapine, or pimavanserin. These medications have demonstrated efficacy in reducing psychotic symptoms in Parkinson disease patients without worsening motor symptoms. It is important to carefully select the specific atypical antipsychotic based on the patient's overall medical condition and potential drug interactions.

Schneider et. al review the presentation and management of Parkinson disease psychosis. They discuss how the mainstay of management is atypical antipsychotics such as pimavanserin, quetiapine, and clozapine. They recommend using pimavanserin because this is a novel medication that is specifically approved for Parkinson disease psychosis.

Figure/Illustration A is a brain MRI that demonstrates no significant mass effect with preserved central ventricles (red circle). These findings are consistent with Parkinson disease psychosis rather than an infection or hydrocephalus.

Incorrect Answers:
Answer 1: Deep brain stimulation therapy is a surgical treatment option for advanced Parkinson disease to improve motor symptoms. It is not indicated for the treatment of PDP, which primarily involves managing psychiatric symptoms. Deep brain stimulation does not have a significant effect on these psychiatric symptoms.

Answer 2: Increasing levodopa/carbidopa therapy and observing the patient would not address the psychotic symptoms of PDP. Levodopa, the mainstay of Parkinson disease treatment, primarily targets motor symptoms and is a possible cause of psychosis. Increasing this medication may therefore increase the severity of these symptoms.

Answer 4: Rivastigmine is a cholinesterase inhibitor that can be used in the treatment of Alzheimer disease. This disease can also rarely present with delusions and hallucinations in the late stages of the disease, but would not be likely in the absence of significant memory symptoms.

Answer 5: Trihexyphenidyl is an anticholinergic medication that can be used to manage motor symptoms in patients with Parkinson disease. It would not be recommended in the treatment for PDP. Anticholinergics may worsen cognitive impairment, psychosis, and other psychiatric manifestations of Parkinson disease.

Bullet Summary:
The most appropriate treatment for Parkinson disease psychosis is an atypical antipsychotic medication such as pimavanserin.