A 75-year-old man is brought to the office by his wife due to worsening psychosis. The patient has a history of Parkinson disease treated with carbidopa-levodopa and pramipexole. Dosages of both medications were increased 6 months ago to target worsening tremor and bradykinesia, resulting in significant improvement in motor symptoms. However, over the ensuing months, the patient began experiencing paranoia and hallucinations. He has been verbally assaultive toward the mail carrier, claiming that she is stealing from him. The patient has also been observed talking to himself and is often distracted by visual stimuli that are invisible to others. Dose reduction of his antiparkinson medications resulted in significant rebound motor symptoms, requiring resumption of the prereduction doses. Temperature is 36.7 C (98 F), blood pressure is 118/82 mm Hg, and pulse is 62/min. The patient appears suspicious of the examiner and mumbles to himself throughout the examination. Mild rigidity, tremor, and gait instability are present. Which of the following is the most appropriate next step in management of this patient?

Question

A 75-year-old man is brought to the office by his wife due to worsening psychosis.  The patient has a history of Parkinson disease treated with carbidopa-levodopa and pramipexole.  Dosages of both medications were increased 6 months ago to target worsening tremor and bradykinesia, resulting in significant improvement in motor symptoms.  However, over the ensuing months, the patient began experiencing paranoia and hallucinations.  He has been verbally assaultive toward the mail carrier, claiming that she is stealing from him.  The patient has also been observed talking to himself and is often distracted by visual stimuli that are invisible to others.  Dose reduction of his antiparkinson medications resulted in significant rebound motor symptoms, requiring resumption of the prereduction doses.  Temperature is 36.7 C (98 F), blood pressure is 118/82 mm Hg, and pulse is 62/min.  The patient appears suspicious of the examiner and mumbles to himself throughout the examination.  Mild rigidity, tremor, and gait instability are present.  Which of the following is the most appropriate next step in management of this patient?

Quizplus · Accepted Answer

Psychotic symptoms, most commonly visual hallucinations and paranoid delusions, are a frequent complication of Parkinson disease (PD). They tend to worsen as the underlying disease process progresses and are the strongest predictor of nursing home placement. Although PD psychosis can occur as a result of the underlying disease process, the risk increases in patients treated with dopaminergic medications. Dopamine agonists (eg, pramipexole, ropinirole) are associated with a greater risk of psychosis than the dopamine precursor and gold-standard antiparkinson medication, carbidopa-levodopa. Treatment of PD psychosis may involve a dose reduction of antiparkinson medication, medication substitution, and/or the addition of a low-potency antipsychotic medication. When antiparkinson medication adjustments fail, as in this patient, a trial of an antipsychotic is warranted. Low-potency antipsychotics with minimal dopamine-2 receptor antagonism such as quetiapine, clozapine, or pimavanserin are preferred. Antipsychotics with more potent dopamine-2 receptor antagonism (eg, haloperidol, risperidone) should be avoided as these medications have the highest risk of extrapyramidal symptoms and will worsen Parkinson motor symptoms (Choices B and D). (Choices A and E) Amantadine (an antiviral) and selegiline (a monoamine oxidase inhibitor) are both dopaminergic agents used in the treatment of PD. These drugs would be of little use in this patient given that they are inferior to pramipexole as antiparkinson agents and are also associated with psychosis due to their dopaminergic activity. Educational objective: Psychosis is common in Parkinson disease, occurring at a higher rate in those treated with dopamine agonists than in those treated with carbidopa-levodopa. Psychotic symptoms can be treated with antiparkinson medication dose reduction and/or the addition of a low-potency antipsychotic (eg, quetiapine, pimavanserin). References: The psychosis spectrum in Parkinson disease. (http://www.ncbi.nlm.nih.gov/pubmed/28106066) Psychosis in Parkinson's disease: epidemiology, pathophysiology, and management. (http://www.ncbi.nlm.nih.gov/pubmed/27312429)

A 75-Year-Old Man Is Brought to the Office by His