MD Central Nervous System Disorders 3 — Questions and Answers
Question 1: A 60-year-old presents with resting tremor, bradykinesia, and cogwheel rigidity. He also has orthostatic hypotension, REM sleep behavior disorder, and anosmia. What is the unifying diagnosis?
- Essential tremor
- Parkinson disease (Correct answer)
- Multiple system atrophy
- Drug-induced parkinsonism
Correct answer: Parkinson disease
The combination of motor parkinsonism with autonomic dysfunction, REM sleep behavior disorder, and anosmia is characteristic of Parkinson disease.
Question 2: Which medication mechanism is responsible for neuroleptic malignant syndrome?
- Serotonin receptor agonism
- Dopamine receptor blockade (Correct answer)
- GABA receptor inhibition
- Acetylcholine receptor blockade
Correct answer: Dopamine receptor blockade
Neuroleptic malignant syndrome results from dopamine receptor blockade by antipsychotics, causing hyperthermia, rigidity, and autonomic instability.
Question 3: A 25-year-old woman presents with new-onset focal-onset impaired awareness seizures. MRI shows a unilateral medial temporal sclerosis. What is the most likely seizure type?
- Absence epilepsy
- Mesial temporal lobe epilepsy (Correct answer)
- Juvenile myoclonic epilepsy
- Lennox-Gastaut syndrome
Correct answer: Mesial temporal lobe epilepsy
Hippocampal sclerosis is the hallmark of mesial temporal lobe epilepsy, the most common focal epilepsy syndrome in adults.
Question 4: A patient with schizophrenia on haloperidol develops involuntary repetitive movements of the face, tongue, and extremities after 3 years of treatment. What is this condition?
- Acute dystonia
- Tardive dyskinesia (Correct answer)
- Akathisia
- Parkinsonism
Correct answer: Tardive dyskinesia
Tardive dyskinesia is a late-onset movement disorder from prolonged dopamine receptor blockade, typically presenting with oro-facial dyskinesias.
Question 5: A 40-year-old presents with behavioral disinhibition, hyperphagia, and executive dysfunction with preserved memory. MRI shows frontal and anterior temporal atrophy. What is the diagnosis?
- Alzheimer disease
- Frontotemporal dementia (Correct answer)
- Huntington disease
- Creutzfeldt-Jakob disease
Correct answer: Frontotemporal dementia
Behavioral variant frontotemporal dementia is characterized by frontal lobe disinhibition, hyperphagia, and executive dysfunction with relatively preserved memory.
Question 6: Which investigation is most specific for diagnosing herpes simplex encephalitis?
- MRI FLAIR signal in temporal lobes
- CSF HSV PCR (Correct answer)
- EEG showing periodic lateralized epileptiform discharges
- Serum HSV antibody titer
Correct answer: CSF HSV PCR
CSF HSV PCR has high sensitivity and specificity (>95%) and is the gold standard for diagnosing herpes simplex encephalitis.
Question 7: A 50-year-old presents with rapidly progressive dementia, myoclonus, and periodic sharp wave complexes on EEG. CSF 14-3-3 protein is elevated. MRI shows cortical ribboning on DWI. What is the diagnosis?
- Anti-NMDA receptor encephalitis
- Creutzfeldt-Jakob disease (Correct answer)
- Hashimoto encephalopathy
- Viral encephalitis
Correct answer: Creutzfeldt-Jakob disease
Rapidly progressive dementia with myoclonus, periodic EEG complexes, CSF 14-3-3, and DWI cortical ribboning is classic for Creutzfeldt-Jakob disease.
MD Central Nervous System Disorders 3
A 60-year-old presents with resting tremor, bradykinesia, and cogwheel rigidity.
He also has orthostatic hypotension, REM sleep behavior disorder, and anosmia.
What is the unifying diagnosis?