A 73-year-old man comes to the office due to increasing forgetfulness over the past 6 months. He says, "My mind used to be quite sharp, but now I can't even concentrate to read a book or newspaper. I'm afraid I'm developing dementia like my father." The patient reports he has been losing sleep and has little energy and motivation. He recently took a leave of absence from work because he could no longer concentrate on details and complete his paperwork. His medical history includes hypertension, hypercholesterolemia, diabetes, benign prostatic hyperplasia, and transient ischemic attack. Family history is significant for hypertension and diabetes (mother) and Alzheimer disease (father). The patient does not smoke and drinks wine only occasionally. Vital signs are unremarkable, and physical examination is normal except for slowed speech and movements. The patient declines to perform a serial sevens assessment and says, "I just can't do it." CT scan of the head is normal. Which of the following is the most likely cause of this patient's cognitive impairment?

Question

A 73-year-old man comes to the office due to increasing forgetfulness over the past 6 months.  He says, "My mind used to be quite sharp, but now I can't even concentrate to read a book or newspaper.  I'm afraid I'm developing dementia like my father."  The patient reports he has been losing sleep and has little energy and motivation.  He recently took a leave of absence from work because he could no longer concentrate on details and complete his paperwork.  His medical history includes hypertension, hypercholesterolemia, diabetes, benign prostatic hyperplasia, and transient ischemic attack.  Family history is significant for hypertension and diabetes (mother) and Alzheimer disease (father).  The patient does not smoke and drinks wine only occasionally.  Vital signs are unremarkable, and physical examination is normal except for slowed speech and movements.  The patient declines to perform a serial sevens assessment and says, "I just can't do it."  CT scan of the head is normal.  Which of the following is the most likely cause of this patient's cognitive impairment?

Quizplus · Accepted Answer

This patient's increasing forgetfulness, low energy and motivation, sleep disturbance, and psychomotor retardation (eg, slowed speech, thinking, movements) are consistent with major depressive disorder (MDD). Older patients who are severely depressed may demonstrate cognitive impairment and slowing rather than depressed mood (previously referred to as pseudodementia). Deficits in attention, concentration, memory, and executive functioning can be seen and are often compounded by poor effort during testing, as seen in this patient. Although these patients are at higher risk for developing dementia later, their depression-related cognitive impairment is potentially reversible and can improve with treatment of the underlying depression. Alzheimer disease can be difficult to differentiate from depression-related cognitive impairment because depression can occur in patients with Alzheimer disease. However, this patient does not have other dementia symptoms, such as apraxia, agnosia, and aphasia (Choice A). Patients with Alzheimer disease are typically less concerned about their memory loss and are brought in for evaluation by family members. In contrast to this patient who shows poor effort, they are more likely to try harder but to give incorrect answers or confabulate to compensate for poor memory on mental status testing. (Choice B) This patient's presentation does not include key features of dementia with Lewy bodies, which include fluctuating cognition, recurrent visual hallucinations, and REM sleep behavior disorder, making this diagnosis less likely. (Choice D) Although normal aging is associated with some cognitive decline, MDD is still more likely in this patient given the presence of associated depressive symptoms (eg, poor sleep, low energy and motivation) that are causing clear functional impairment. (Choice E) Parkinson disease can also present with slow movements and depression. However, patients with parkinsonism usually demonstrate other features, such as rigidity, masked facies, and shuffling gait. This patient's slow movements are caused by psychomotor retardation, one of the diagnostic criteria for MDD. (Choice F) This patient's age and medical history of hypertension, hypercholesterolemia, diabetes, and transient ischemic attack make vascular dementia a plausible diagnosis. However, the normal CT scan findings, normal physical examination, and history of gradual memory loss (as opposed to acute, stepwise onset in vascular dementia) make this diagnosis less likely. Educational objective: In older patients, cognitive impairment caused by depression often mimics other neurocognitive disorders, such as Alzheimer disease. However, it is accompanied by other symptoms of depression and usually improves with treatment of the underlying depressive disorder. References: Diagnosis and treatment of depression and cognitive impairment in late life. (http://www.ncbi.nlm.nih.gov/pubmed/25655026) Cognitive impairment in depression: recent advances and novel treatments. (http://www.ncbi.nlm.nih.gov/pubmed/31190831)

A 73-Year-Old Man Comes to the Office Due to Increasing