Lewy body dementia US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Lewy body dementia. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Lewy body dementia US Medical PG Question 1: A 61-year-old woman presents to her primary care doctor with her son who reports that his mother is not acting like herself. She has gotten lost while driving several times in the past 2 months and appears to be talking to herself frequently. Of note, the patient’s husband died from a stroke 4 months ago. The patient reports feeling sad and guilty for causing so much trouble for her son. Her appetite has decreased since her husband died. On examination, she is oriented to person, place, and time. She is inattentive, and her speech is disorganized. She shakes her hand throughout the exam without realizing it. Her gait is slow and appears unstable. This patient’s condition would most likely benefit from which of the following medications?
- A. Bromocriptine
- B. Rivastigmine (Correct Answer)
- C. Reserpine
- D. Selegiline
- E. Levodopa
Lewy body dementia Explanation: ***Rivastigmine***
- The patient's symptoms of progressive cognitive decline (getting lost while driving, talking to herself), inattention, disorganized speech, and motor symptoms (hand tremor, unstable gait) suggest **Dementia with Lewy Bodies (DLB)**.
- Key features supporting DLB over depression with pseudodementia: **involuntary hand tremor**, **unstable gait**, **visual hallucinations** (talking to herself), and **disorganized speech** occurring with cognitive decline.
- **Rivastigmine**, a cholinesterase inhibitor, is a first-line treatment for the cognitive and behavioral symptoms in DLB and is FDA-approved for this indication.
- While bereavement-related depression is present, the prominent motor and cognitive features indicate an underlying neurodegenerative process.
*Bromocriptine*
- This is a **dopamine agonist** typically used for Parkinson's disease, hyperprolactinemia, and acromegaly.
- While Parkinsonian features are present in DLB, dopamine agonists can worsen **psychotic symptoms** (hallucinations) common in DLB, making them unsuitable as first-line treatment.
*Reserpine*
- **Reserpine** depletes catecholamines and serotonin and is primarily used as an antihypertensive.
- Its use in dementia is not indicated and could exacerbate mood, cognitive issues, and Parkinsonian symptoms due to its dopamine-depleting effects.
- This medication is rarely used in modern practice.
*Selegiline*
- **Selegiline** is a **monoamine oxidase-B (MAO-B) inhibitor** used in Parkinson's disease to reduce dopamine breakdown.
- While it may help with motor symptoms, its benefit in DLB is less established compared to cholinesterase inhibitors.
- The prominent **cognitive and behavioral symptoms** in this patient make cholinesterase inhibition the priority.
*Levodopa*
- **Levodopa** is a dopamine precursor and the most effective medication for motor symptoms of Parkinson's disease.
- In DLB, while it can improve motor symptoms, it can significantly worsen **psychotic symptoms** (hallucinations, delusions) and cognitive fluctuations.
- Given the prominent non-motor symptoms and existing hallucinations, levodopa is not first-line therapy for this patient.
Lewy body dementia US Medical PG Question 2: A 70-year-old woman is brought to the office after her nurse noticed her being apathetic, easily distracted, and starting to urinate in bed. Her medical history is relevant for hypertension, under control with medication. Physical examination reveals a blood pressure of 138/76 mm Hg, a heart rate of 70/min, and a respiratory rate 14/min and regular. On neurological examination, she has a broad-based shuffling gait, and increased muscle tone in her limbs that is reduced by distracting the patient. There is decreased coordination with exaggerated deep tendon reflexes, decreased attention and concentration, and postural tremor. Which of the following additional features would be expected to find in this patient?
- A. Degeneration of the substantia nigra pars compacta
- B. Caudate head atrophy
- C. Accumulation of Lewy bodies in cortical cells
- D. Dilation of the ventricular system (Correct Answer)
- E. Accumulation of amyloid plaques and neurofibrillary tangles in the cerebral cortex
Lewy body dementia Explanation: ***Dilation of the ventricular system***
- The patient presents with a classic triad of **gait apraxia** (broad-based, shuffling gait), **dementia** (apathy, distractibility, decreased attention and concentration), and **urinary incontinence**, which are the hallmark symptoms of **Normal Pressure Hydrocephalus (NPH)**. NPH is characterized by **ventricular dilation without increased intracranial pressure**.
- Other features like **increased muscle tone that reduces with distraction** (frontal release sign), **exaggerated deep tendon reflexes**, and **postural tremor** further support the diagnosis of NPH, as these are often seen due to involvement of frontal lobe pathways secondary to ventricular enlargement.
*Degeneration of the substantia nigra pars compacta*
- This is characteristic of **Parkinson's disease**, which typically presents with a rest tremor, bradykinesia, rigidity, and postural instability, but not typically with prominent early dementia and urinary incontinence in this combined clinical picture.
- While Parkinson's can cause gait disturbance, the specific combination of symptoms (dementia, incontinence, and gait apraxia) points away from primary Parkinson's as the most likely diagnosis.
*Caudate head atrophy*
- **Caudate head atrophy** is a hallmark finding in **Huntington's disease**, which is characterized by chorea, psychiatric symptoms, and progressive cognitive decline.
- The patient's symptoms, particularly the broad-based shuffling gait and urinary incontinence, are inconsistent with the typical presentation of Huntington's disease.
*Accumulation of Lewy bodies in cortical cells*
- This is a pathological feature of **Lewy body dementia (LBD)**. While LBD presents with dementia and Parkinsonian features, it also typically includes **recurrent visual hallucinations** and **fluctuations in attention and alertness**, which are not specified in this patient's presentation.
- The patient's dominant features of gait apraxia and urinary incontinence along with dementia are more indicative of NPH.
*Accumulation of amyloid plaques and neurofibrillary tangles in the cerebral cortex*
- These are the pathological hallmarks of **Alzheimer's disease**, which primarily presents with progressive memory loss, executive dysfunction, and other cognitive deficits.
- While dementia is a feature in this patient, the prominent gait disturbance and urinary incontinence are not typical early or dominant features of Alzheimer's disease.
Lewy body dementia US Medical PG Question 3: A 72-year-old woman comes to the physician because she is seeing things that she knows are not there. Sometimes she sees a dog in her kitchen and at other times she sees a stranger in her garden, both of which no one else can see. She also reports a lack of motivation to do daily tasks for the past week. Three years ago, she was diagnosed with Parkinson disease and was started on levodopa and carbidopa. Her younger brother has schizophrenia. The patient also takes levothyroxine for hypothyroidism. She used to drink a bottle of wine every day, but she stopped drinking alcohol 2 months ago. Neurologic examination shows a mild resting tremor of the hands and bradykinesia. Her thought process is organized and logical. Which of the following is the most likely underlying cause of this patient's symptoms?
- A. Alcohol withdrawal
- B. Adverse effect of medication (Correct Answer)
- C. Major depressive disorder
- D. Schizophrenia
- E. Poorly controlled hypothyroidism
Lewy body dementia Explanation: ***Adverse effect of medication***
- The patient's **visual hallucinations** and **apathy** are consistent with **dopaminergic medication-induced psychosis**, a common complication of **levodopa/carbidopa** in Parkinson's disease, especially in older patients.
- The hallucinations are typically **well-formed**, non-threatening, and the patient often retains insight into their unreality, as described ("she knows are not there").
*Alcohol withdrawal*
- **Alcohol withdrawal hallucinations** typically occur within 12-48 hours of cessation and are primarily visual, but often accompanied by autonomic instability (tremors, sweating, tachycardia) which is not mentioned here.
- Given she stopped drinking 2 months ago, acute withdrawal symptoms would have resolved much earlier.
*Major depressive disorder*
- While **apathy** and lack of motivation can be symptoms of depression, the prominent **visual hallucinations** are not typical of major depressive disorder without psychotic features (which would then be a specified subtype).
- Her thought process is described as **organized and logical**, making a primary thought disorder secondary to depression less likely.
*Schizophrenia*
- Schizophrenia typically presents in **early adulthood** (late teens to early 30s) and involves persistent psychosis, disorganized thought, and functional decline, which is not consistent with this patient's age of symptom onset or preserved thought process.
- The family history of schizophrenia is a risk factor, but the clinical presentation—especially the patient's insight into the hallucinations—is more indicative of a medication-induced effect or other organic cause in an older person.
*Poorly controlled hypothyroidism*
- **Hypothyroidism** can cause cognitive slowing, depression, and in severe cases, myxedema madness with psychotic symptoms, but her symptoms primarily manifest as formed visual hallucinations.
- There is no clinical or lab evidence provided to suggest her hypothyroidism is poorly controlled or severe enough to cause such distinct hallucinations.
Lewy body dementia US Medical PG Question 4: A 45-year-old man is brought to the hospital by his daughter with complaints of wide-based gait. His daughter reveals that he was sitting silently in the examination chair with a blank face. In addition, he was frequently talking to the empty chairs and told that his friends are sitting there. He has been forgetting many small things recently. On physical examination, fine movements are seen at resting condition that disappears when he is asked to drink water. A stepwise slowness in movement is also seen in his upper limb. Which of the following is most likely to be observed in the histological specimen of this patient?
- A. Spongiform changes in cortex
- B. Neuritic plaques in cortex
- C. Lewy bodies in affected neurons (Correct Answer)
- D. Tau protein aggregates in cortex
- E. Neurofibrillary tangles in hippocampus
Lewy body dementia Explanation: ***Lewy bodies in affected neurons***
- The patient's symptoms of **wide-based gait**, **cognitive decline** (forgetting things, talking to empty chairs), **psychotic features** (visual hallucinations), and **motor symptoms** (resting tremor, bradykinesia) are highly suggestive of **Lewy body dementia** (LBD).
- **Lewy bodies**, which are abnormal aggregates of **alpha-synuclein protein**, are the characteristic histological finding in neurons of individuals with LBD, found in both **cortical areas** (defining feature of LBD) and **substantia nigra**.
- The presence of early prominent visual hallucinations with parkinsonism and cognitive fluctuations is pathognomonic for Lewy body dementia.
*Spongiform changes in cortex*
- This finding is characteristic of **prion diseases**, such as **Creutzfeldt-Jakob disease** (CJD), which typically present with rapidly progressive dementia and myoclonus.
- While CJD involves cognitive decline, the presence of resting tremor, visual hallucinations, and a more gradual progression with parkinsonian features makes spongiform changes unlikely.
*Neuritic plaques in cortex*
- **Neuritic plaques**, composed of **amyloid-beta protein**, are a hallmark of **Alzheimer's disease**.
- Although Alzheimer's disease causes cognitive decline, the prominent early motor symptoms (resting tremor, wide-based gait, bradykinesia) and early visual hallucinations are not typical features of Alzheimer's disease.
*Tau protein aggregates in cortex*
- **Tau protein aggregates** (neurofibrillary tangles) are another key histological feature of **Alzheimer's disease** and certain **tauopathies** like **frontotemporal dementia** and **progressive supranuclear palsy**.
- While associated with dementia, they do not explain the unique combination of early parkinsonian motor features and prominent visual hallucinations seen in this patient.
*Neurofibrillary tangles in hippocampus*
- **Neurofibrillary tangles** composed of hyperphosphorylated **tau protein** in the hippocampus are characteristic of **Alzheimer's disease** and correlate with memory impairment.
- However, Alzheimer's disease does not typically present with early parkinsonism, resting tremor, or prominent visual hallucinations as seen in this patient with Lewy body dementia.
Lewy body dementia US Medical PG Question 5: A 65-year-old man was picked up by the security personnel for voiding urine and defecating at an inappropriate place in the community. On questioning, he was making offensive remarks and behaving inappropriately. On physical examination, the physician observed signs of cognitive impairment and amnesia. Initial urine drug screen is negative for any drugs of abuse. Which is the most likely pathological finding present in this patient?
- A. Drug abuse
- B. Amyloid plaques
- C. Lewy bodies
- D. Pick bodies (Correct Answer)
- E. PrPSC Sheets
Lewy body dementia Explanation: ***Pick bodies***
- The patient presents with **disinhibition** (inappropriate voiding, defecating in public), **offensive remarks**, and **inappropriate behavior**, which are hallmarks of **frontotemporal dementia (FTD)**, specifically the behavioral variant.
- **Pick bodies** are aggregates of **tau protein** found in neurons of the frontal and temporal lobes, characteristic of Pick's disease, a subtype of FTD.
- Behavioral variant FTD characteristically presents with **personality changes**, **loss of social awareness**, and **executive dysfunction** before significant memory impairment.
*Drug abuse*
- While drug abuse can lead to inappropriate behavior and neuropsychiatric symptoms, the **negative urine drug screen** makes this diagnosis unlikely.
- Drug abuse typically doesn't present with the progressive cognitive decline and specific behavioral pattern seen here.
*Amyloid plaques*
- **Amyloid plaques** (along with neurofibrillary tangles) are characteristic pathological findings in **Alzheimer's disease**, which typically presents with **memory impairment** as the predominant initial symptom.
- Although Alzheimer's disease can lead to behavioral changes in later stages, the **prominent early disinhibition** and preserved memory (relative to behavioral changes) are more typical of FTD than Alzheimer's.
*Lewy bodies*
- **Lewy bodies** are associated with **dementia with Lewy bodies (DLB)** and **Parkinson's disease dementia**.
- DLB is characterized by **fluctuating cognition**, **visual hallucinations**, and **parkinsonism** (rigidity, bradykinesia), which are not the predominant features in this patient's presentation.
*PrPSC Sheets*
- **PrPSC sheets** refer to the misfolded prion protein found in **prion diseases** such as Creutzfeldt-Jakob disease (CJD).
- CJD typically manifests with **rapidly progressive dementia** (over weeks to months), **myoclonus**, and **cerebellar signs**, with a much faster progression than the clinical picture suggested here.
Lewy body dementia US Medical PG Question 6: A 76-year-old man is brought to his geriatrician by his daughter, who reports that he has been "losing his memory." While the patient previously performed all household duties by himself, he has recently had several bills that were unpaid. He also called his daughter on several occasions after getting lost while driving and having "accidents" before getting to the toilet. On exam, the patient is conversant and alert to person, place, and time, though his gait is wide-based and slow. Which of the following diagnostic procedures would be most appropriate to confirm the suspected diagnosis in this patient?
- A. Warfarin
- B. Donepezil
- C. Carbidopa/Levodopa
- D. Memantine
- E. Lumbar puncture (Correct Answer)
Lewy body dementia Explanation: ***Lumbar puncture***
- The patient's symptoms of **cognitive decline**, **gait disturbance**, and **urinary incontinence** (losing control before reaching the toilet) represent the classic triad of **Normal Pressure Hydrocephalus (NPH)**.
- **Lumbar puncture** with removal of CSF (30-50 mL) serves as both a **diagnostic and therapeutic test** (tap test); transient improvement in symptoms, especially gait, strongly supports the diagnosis of NPH.
- This is the only **diagnostic procedure** among the options; the others are medications/treatments.
*Warfarin*
- This is an **anticoagulant medication** (not a diagnostic procedure) used to prevent blood clots in atrial fibrillation or venous thromboembolism.
- Has no role in diagnosing or treating NPH, which involves CSF dynamics, not coagulation.
*Donepezil*
- **Donepezil** is an **acetylcholinesterase inhibitor medication** (not a diagnostic procedure) used to treat Alzheimer's disease symptoms.
- While the patient has cognitive decline, the classic NPH triad (cognitive, gait, incontinence) distinguishes this from typical Alzheimer's dementia.
- This is a treatment option, not a diagnostic test.
*Carbidopa/Levodopa*
- This **medication combination** (not a diagnostic procedure) is the primary treatment for **Parkinson's disease**, replacing dopamine.
- While Parkinson's causes gait issues, it doesn't typically present with this specific triad, and parkinsonian gait differs from NPH's magnetic/apraxic gait.
- This is a treatment, not a diagnostic procedure.
*Memantine*
- **Memantine** is an **NMDA receptor antagonist medication** (not a diagnostic procedure) used in moderate to severe Alzheimer's disease.
- Like donepezil, this treats dementia symptoms but is not a diagnostic test for NPH.
Lewy body dementia US Medical PG Question 7: A 77-year-old woman is brought to her primary care provider by her daughter with behavioral changes and an abnormally bad memory for the past few months. The patient’s daughter says she sometimes gets angry and aggressive while at other times she seems lost and stares at her surroundings. Her daughter also reports that she has seen her mother talking to empty chairs. The patient says she sleeps well during the night but still feels sleepy throughout the day. She has no problems getting dressed and maintaining her one bedroom apartment. Past medical history is significant for mild depression and mild osteoporosis. Current medications include escitalopram, alendronic acid, and a multivitamin. The patient is afebrile, and her vital signs are within normal limits. On physical examination, the patient is alert and oriented and sitting comfortably in her chair. A mild left-hand tremor is noted. Muscle strength is 5 out of 5 in the upper and lower extremities bilaterally, but muscle tone is slightly increased. She can perform repetitive alternating movements albeit slowly. She walks with a narrow gait and has mild difficulty turning. Which of the following is the most likely diagnosis in this patient?
- A. Lewy body dementia (Correct Answer)
- B. Alzheimer's disease
- C. Serotonin syndrome
- D. Frontotemporal dementia
- E. Delirium
Lewy body dementia Explanation: ***Lewy body dementia***
- This patient exhibits **fluctuating cognition** (being lost and staring, behavioral changes), **recurrent visual hallucinations** (talking to empty chairs), and spontaneous motor features of **parkinsonism** (mild left-hand tremor, increased muscle tone, slow alternating movements, narrow gait, difficulty turning), all core features of Lewy body dementia.
- The **insidious onset** and progressive decline over months, along with the symptom triad, fit the diagnostic criteria for Lewy body dementia.
*Alzheimer's disease*
- While Alzheimer's involves memory loss and cognitive decline, it is not typically associated with **prominent early visual hallucinations** or **parkinsonian features** at presentation.
- Alzheimer's disease often presents with **memory impairment as the most prominent early symptom**, often preceding other cognitive deficits by years.
*Serotonin syndrome*
- This is an acute drug reaction characterized by a triad of **mental status changes**, **autonomic hyperactivity**, and **neuromuscular abnormalities**, usually developing rapidly after medication changes affecting serotonin levels.
- The patient's symptoms have been present for months, the vital signs are stable, and her medications (escitalopram) have been stable, making an **acute syndrome** like serotonin syndrome unlikely.
*Frontotemporal dementia*
- This type of dementia primarily affects personality, behavior, and language, with **prominent disinhibition or apathy**.
- While behavioral changes are present, the patient's prominent **visual hallucinations** and **parkinsonian features** are not characteristic of frontotemporal dementia.
*Delirium*
- Delirium is characterized by an **acute onset** and fluctuating course of attention and awareness, often triggered by an underlying medical condition, medication, or infection.
- The patient's symptoms have progressed over **several months**, rather than hours or days, and she is afebrile with stable vital signs, making delirium less likely.
Lewy body dementia US Medical PG Question 8: A 72-year-old woman is brought to the physician by her son for an evaluation of cognitive decline. Her son reports that she has had increased difficulty finding her way back home for the last several months, despite having lived in the same city for 40 years. He also reports that his mother has been unable to recall the names of her relatives and been increasingly forgetting important family gatherings such as her grandchildren's birthdays over the last few years. The patient has hypertension and type 2 diabetes mellitus. She does not smoke or drink alcohol. Her current medications include enalapril and metformin. Her temperature is 37°C (98.6°F), pulse is 70/min, and blood pressure is 140/80 mm Hg. She is confused and oriented only to person and place. She recalls 2 out of 3 words immediately and 1 out of 3 after 5 minutes. Her gait and muscle strength are normal. Deep tendon reflexes are 2+ bilaterally. The remainder of the examination shows no abnormalities. Further evaluation is most likely to reveal which of the following findings?
- A. Generalized cerebral atrophy (Correct Answer)
- B. Myoclonic movements
- C. Hallucinations
- D. Urinary incontinence
- E. Resting tremor
Lewy body dementia Explanation: ***Generalized cerebral atrophy***
- The patient's symptoms of progressive **cognitive decline**, including difficulty with navigation and memory, are classic signs of **Alzheimer's disease**.
- **Generalized cerebral atrophy**, particularly of the **hippocampus** and **temporal lobes**, is a hallmark pathological finding in Alzheimer's disease due to neuronal loss and synaptic dysfunction.
*Myoclonic movements*
- **Myoclonic movements** are sudden, brief, involuntary muscle jerks, most commonly associated with **Creutzfeldt-Jakob disease** or certain types of dementia with Lewy bodies, which are not suggested by the patient's presentation.
- While some rare forms of early-onset Alzheimer's can have atypical features, myoclonus is not a typical or early finding in the more common late-onset presentation described.
*Hallucinations*
- **Hallucinations**, particularly visual hallucinations, are frequently seen in **dementia with Lewy bodies** and **Parkinson's disease dementia**, often preceding or co-occurring with cognitive decline.
- While hallucinations can occur in late-stage Alzheimer's, they are not a prominent or early feature differentiating it from other dementias.
*Urinary incontinence*
- **Urinary incontinence** can be a symptom of various conditions, including **normal pressure hydrocephalus (NPH)**, which presents with a triad of gait instability, dementia, and urinary incontinence.
- In Alzheimer's disease, incontinence typically appears in the **later stages**, after significant cognitive impairment and functional decline have occurred.
*Resting tremor*
- A **resting tremor** is a characteristic symptom of **Parkinson's disease** and is often seen in **Parkinson's disease dementia** or **dementia with Lewy bodies**.
- The patient's neurological examination, including normal gait and muscle strength, does not suggest Parkinsonian features.
Lewy body dementia US Medical PG Question 9: A 68-year-old man seeks evaluation by a physician with complaints of worsening forgetfulness and confusion for 1 year. According to his wife, he has always been in good health and is generally very happy; however, he has started to forget important things. He recently had his driving license revoked because of multiple tickets, but he cannot recall having done anything wrong. This morning, he neglected to put on his socks and was quite agitated when she pointed this out to him. He denies having a depressed mood, sleep problems, or loss of interest. He occasionally has a glass of wine with dinner and has never smoked or used recreational drugs. His medical history and family medical history are unremarkable. His pulse is 68/min, respirations are 14/min, and blood pressure is 130/84 mm Hg. Except for a mini-mental state examination (MMSE) score of 20/30, the remainder of the physical examination is unremarkable. Imaging studies, including a chest X-ray and CT of the brain, reveal no pathologic findings. An electrocardiogram (ECG) is also normal. Laboratory testing showed the following:
Serum glucose (fasting) 76 mg/dL
Serum electrolytes:
Sodium 140 mEq/L
Potassium 4.1 mEq/L
Chloride 100 mEq/L
Serum creatinine 0.9 mg/dL
Blood urea nitrogen 11 mg/dL
Cholesterol, total: 180 mg/dL
HDL-cholesterol 45 mg/dL
LDL-cholesterol 75 mg/dL
Triglycerides 135 mg/dL
Hemoglobin (Hb%) 16 g/dL
Mean corpuscular volume (MCV) 85 fL
Reticulocyte count 0.9%
Erythrocyte count 5 million/mm³
Thyroid-stimulating hormone 3.5 µU/mL
Urinalysis
Glucose Negative
Ketones Negative
Leucocytes Negative
Nitrite Negative
RBCs Negative
Casts Negative
Which of the following is the most likely diagnosis?
- A. Alzheimer’s dementia (Correct Answer)
- B. Creutzfeldt-Jakob disease
- C. Lewy body dementia
- D. Parkinson’s disease
- E. Vascular dementia
Lewy body dementia Explanation: ***Alzheimer’s dementia***
- The patient presents with **progressive memory loss** and **confusion** that has worsened over a year, along with **agitational behavior** and difficulty with daily tasks (neglecting to put on socks), which are classic symptoms of Alzheimer's dementia.
- The **MMSE score of 20/30** indicates cognitive impairment, and the absence of other neurological findings or clear vascular risk factors supports this diagnosis.
*Creutzfeldt-Jakob disease*
- This is a rare, rapidly progressive, and fatal neurodegenerative disease that typically presents with **rapidly progressive dementia**, **myoclonus**, and other neurological signs, which are not described in this case.
- The patient's symptoms have progressed over a year, which is not as rapid as the typical course of CJD.
*Lewy body dementia*
- Characterized by **fluctuating cognition**, **recurrent visual hallucinations**, and **spontaneous parkinsonism**, which are not reported in this patient.
- While agitation can occur, the core features of Lewy body dementia are absent.
*Parkinson’s disease*
- Primarily a **movement disorder** characterized by **bradykinesia**, **rigidity**, **tremor**, and **postural instability**. While dementia can occur in later stages (Parkinson's disease dementia), the initial presentation in this patient is predominantly cognitive decline without prominent motor symptoms.
- The patient's physical examination is "unremarkable," suggesting an absence of parkinsonian motor signs.
*Vascular dementia*
- Typically associated with a history of **stroke** or significant **vascular risk factors** (e.g., uncontrolled hypertension, diabetes) and often presents with a **step-wise decline** in cognitive function.
- This patient has a largely unremarkable medical history, controlled blood pressure, and normal cholesterol, and a CT scan showed no pathological findings (e.g., infarcts), making vascular dementia less likely.
Lewy body dementia US Medical PG Question 10: A 68-year-old man, accompanied by his wife, presents to his physician with cognitive decline and hallucinations. The patient’s wife tells that his cognitive impairment progressed gradually over the past 6 years, and first began with problems counting and attention. The hallucinations began approximately a year ago. The patient describes them as realistic and non-frightening; most often, he sees his cat accompanying him everywhere he goes. The patient’s wife also notes frequent episodes of staring spells in her husband and prolonged daytime napping. The blood pressure is 130/80 mm Hg with the orthostatic change to 110/60 mm Hg, heart rate is 75/min, respiratory rate is 13/min, and the temperature is 36.6°C (97.8°F). The patient is alert and responsive, but he is disoriented to time and place. He is pale and hypomimic. The cardiac, lung, and abdominal examinations are within normal limits for the patient’s age. The neurological examination is significant for a bilateral symmetrical cogwheel rigidity in the upper extremities. What would you most likely see on additional radiological investigations?
- A. Multiple lacunar infarcts on MRI
- B. Marked hippocampal atrophy on MRI
- C. Hypoperfusion and hypometabolism in frontal lobes on SPECT
- D. Decreased perfusion and dopaminergic activity in occipital lobes on PET (Correct Answer)
- E. Pontine 'hot-cross bun' sign on MRI
Lewy body dementia Explanation: ***Decreased perfusion and dopaminergic activity in occipital lobes on PET***
- This finding is characteristic of **dementia with Lewy bodies (DLB)**, which is strongly suggested by the patient's presentation with **cognitive fluctuations**, **visual hallucinations** (non-frightening, realistic), **parkinsonism** (cogwheel rigidity), and **REM sleep behavior disorder** (daytime napping/staring spells could be a manifestation). PET scans in DLB often show reduced occipital lobe uptake.
- The combination of **parkinsonism** (cogwheel rigidity) and **visual hallucinations** preceding or appearing early in the course of cognitive decline is a hallmark of DLB, which differentiates it from other dementias.
*Multiple lacunar infarcts on MRI*
- While lacunar infarcts can cause cognitive decline (**vascular dementia**), the clinical picture of prominent, well-formed visual hallucinations, parkinsonism, and cognitive fluctuations is less typical for purely vascular dementia.
- Vascular dementia usually presents with a step-wise decline in cognition and focal neurological deficits, which are not the primary features here.
*Marked hippocampal atrophy on MRI*
- **Hippocampal atrophy** is a hallmark of **Alzheimer's disease**, which typically presents with insidious memory loss as the primary symptom.
- The prominent early visual hallucinations and parkinsonism are not typical initial features of Alzheimer's disease.
*Hypoperfusion and hypometabolism in frontal lobes on SPECT*
- **Frontal lobe hypoperfusion/hypometabolism** on SPECT/PET is characteristic of **frontotemporal dementia (FTD)**.
- FTD typically presents with early behavioral changes or language deficits, not prominent visual hallucinations, parkinsonism, or significant cognitive fluctuations in the way seen in this patient.
*Pontine 'hot-cross bun' sign on MRI*
- The **'hot-cross bun' sign** on MRI is pathognomonic for **multiple system atrophy (MSA)**, specifically the **MSA-C subtype (cerebellar)**.
- While MSA can cause parkinsonism and autonomic dysfunction, it typically does not feature prominent visual hallucinations or significant cognitive decline as early and striking features as seen in this patient.
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