A 71-year-old man comes to the office due to "strange visions." He lives alone and has not seen a doctor in 30 years. The patient says, "I started seeing children playing in my yard in the evenings about 2 months ago. What's weird is that my closest neighbors are 2 miles away, and I rarely have anyone visit." He says that this was not too disturbing; however, about a month ago, he started seeing animals scampering throughout his house despite not owning any pets, which caused more alarm. The patient is not forgetful and still drives, goes grocery shopping, prepares meals, and takes care of chores around the house. He says his energy is "not what it used to be," and he has lost his balance a few times but has not fallen. The patient also states that he does not like to socialize but adds that he has "always been like that." He is unaware of any medical diagnoses. Temperature is 37.1 C (98.8 F), blood pressure is 138/89 mm Hg, pulse is 78/min, and respirations are 14/min. The patient scores 29 of 30 (normal: ≥26) on the Montreal Cognitive Assessment. Gait is steady but slow. He has a tremor at rest that is most prominent in the right hand. Reflexes are 3+ on the right and 2+ on the left, and there is resistance to passive movement in all limbs that is worse on the right. Which of the following is the most likely diagnosis in this patient?

Question

A 71-year-old man comes to the office due to "strange visions."  He lives alone and has not seen a doctor in 30 years.  The patient says, "I started seeing children playing in my yard in the evenings about 2 months ago.  What's weird is that my closest neighbors are 2 miles away, and I rarely have anyone visit."  He says that this was not too disturbing; however, about a month ago, he started seeing animals scampering throughout his house despite not owning any pets, which caused more alarm.  The patient is not forgetful and still drives, goes grocery shopping, prepares meals, and takes care of chores around the house.  He says his energy is "not what it used to be," and he has lost his balance a few times but has not fallen.  The patient also states that he does not like to socialize but adds that he has "always been like that."  He is unaware of any medical diagnoses.  Temperature is 37.1 C (98.8 F), blood pressure is 138/89 mm Hg, pulse is 78/min, and respirations are 14/min.  The patient scores 29 of 30 (normal: ≥26) on the Montreal Cognitive Assessment.  Gait is steady but slow.  He has a tremor at rest that is most prominent in the right hand.  Reflexes are 3+ on the right and 2+ on the left, and there is resistance to passive movement in all limbs that is worse on the right.  Which of the following is the most likely diagnosis in this patient?

Quizplus · Accepted Answer

11ec25c8_d764_15a5_bc81_47b42c584670_MD0003_00 This patient's bradykinesia, resting tremor, and rigidity are consistent with Parkinson disease (PD). PD frequently presents with asymmetric motor symptoms, as seen in this patient. It is often complicated by psychiatric symptoms, which may include depression and psychosis (eg, hallucinations). As in this patient, when hallucinations are present, they are most often visual. In addition to psychosis due to PD itself, many anti-PD medications may cause or exacerbate psychotic symptoms. Dopamine agonists (eg, pramipexole, ropinirole) are more likely to cause psychosis than levodopa. For patients with PD who develop new or worsening psychotic symptoms, a low-potency, second-generation antipsychotic (eg, quetiapine, pimavanserin) may be used. (Choice A) Brief psychotic disorder has similar criterion symptoms (eg, hallucinations, delusions, disorganization) to schizophrenia but is differentiated based on duration. Brief psychotic disorder is diagnosed when symptoms last ≥1 day but <1 month. This patient's hallucinations are better explained by PD given his neurological findings. (Choice B) Delirium is an acute-onset, fluctuating disorder of disrupted attention and arousal that usually develops in the context of medical illness, pharmacologic intoxication (ie, prescription or illicit drugs), or withdrawal. Although delirium may be associated with hallucinations, this patient's course of symptoms, intact orientation on examination, and neurological symptoms make PD a more likely explanation. (Choice C) Dementia with Lewy bodies presents with dementia plus 2 of the following 4 features: parkinsonism, hallucinations, REM sleep behavior disorder, and fluctuating cognition. This patient does not meet the criteria for dementia because he does not demonstrate cognitive impairment (ie, no forgetfulness, normal Montreal Cognitive Assessment) or associated impairments in activities of daily living (eg, grocery shopping, meal preparation). (Choice D) Major depressive disorder (MDD) with psychotic features is a severe subtype of MDD characterized by prominent mood symptoms followed by the development of delusions and/or hallucinations, typically with depressive themes (eg, guilt, worthlessness, nihilism). This patient has insufficient mood symptoms to diagnose MDD, and his examination findings and visual hallucinations are consistent with PD. (Choice F) Patients with schizotypal personality disorder exhibit a lifelong pattern of odd thinking and behavior, often accompanied by perceptual disturbances that are subthreshold for diagnosing a psychotic disorder. This patient's new onset of visual hallucinations and neurological findings are more consistent with PD. Educational objective: Parkinson disease presents with bradykinesia, resting tremor, and rigidity. It may be complicated by visual hallucinations, which can be treated with a low-potency, second-generation antipsychotic (eg, quetiapine, pimavanserin). References: The psychosis spectrum in Parkinson disease. (http://www.ncbi.nlm.nih.gov/pubmed/28106066)

A 71-Year-Old Man Comes to the Office Due to "Strange