Neurocognitive Disorders (Dementia, Delirium, Alzheimer's) MCQs

Psychiatry · 26 free questions with answers & explanations.

1. An 82-year-old man undergoes hip replacement surgery. On the second post-operative night, he becomes confused, agitated, and believes nurses are trying to harm him. He has fluctuating consciousness and picks at his IV line. The next morning he is lucid and cooperative. What feature best distinguishes delirium from dementia?
2. A 72-year-old woman with progressive memory loss for three years is brought by her family. She cannot recall her grandchildren's names, gets lost in her own neighbourhood, and has difficulty with word-finding. MMSE score is 16/30. MRI shows bilateral hippocampal and entorhinal cortex atrophy. Her condition is most strongly associated with accumulation of which pathological protein?
3. A 72-year-old man with Lewy Body Dementia (LBD) develops agitation. His physician considers prescribing haloperidol. What is the critical contraindication specific to LBD?
4. In DSM-5, which of the following correctly distinguishes Mild Neurocognitive Disorder (NCD) from Major NCD?
5. A 68-year-old man develops subacute cognitive decline over 3 months with myoclonus, cerebellar ataxia, visual disturbances, and pyramidal signs. EEG shows periodic sharp wave complexes. What is the most likely diagnosis?
6. A 78-year-old man with Lewy body dementia develops worsening agitation and visual hallucinations. A junior resident prescribes haloperidol 2 mg IM. Three hours later the patient develops severe rigidity, obtundation, and autonomic instability. The most likely explanation is:
7. A 72-year-old woman post-hip replacement surgery develops acute onset fluctuating confusion, inattention, and visual hallucinations on day 2. Her MMSE score fluctuates between 16 and 24 within hours. The single most important reversible cause to exclude FIRST is:
8. Memantine, used in moderate-to-severe Alzheimer's disease, exerts its mechanism by:
9. An 80-year-old man with well-controlled hypertension develops fluctuating consciousness, visual hallucinations, and severe attention deficits over 2 days following hip replacement surgery. He was oriented before surgery. Vitals show mild tachycardia. His son reports his father was 'perfectly fine' before surgery. What is the MOST likely diagnosis?
10. A 70-year-old man presents with a 2-year history of progressive memory loss, word-finding difficulty, and inability to manage finances. MMSE is 19/30. MRI shows hippocampal and medial temporal lobe atrophy. CSF shows decreased Abeta-42, increased total tau and phospho-tau. Which of the following biomarker patterns is MOST consistent with Alzheimer's disease?
11. A 73-year-old man with a history of multiple lacunar infarcts presents with stepwise cognitive decline, prominent executive dysfunction, and gait apraxia. His MMSE is 22/30. What type of dementia does this MOST likely represent, and which neuroimaging finding would be MOST supportive?
12. A 68-year-old woman with probable Alzheimer's dementia develops severe agitation at night ('sundowning'). Her family asks about medication. Which class of medication has a BLACK BOX WARNING for increased mortality in elderly patients with dementia-related psychosis?
13. An 80-year-old hospitalised man develops acute confusion, visual hallucinations, sleep-wake cycle reversal, and fluctuating attention 2 days post-hip replacement. He has no prior cognitive complaints. EEG shows diffuse slowing. What EEG finding, when present, most specifically differentiates delirium tremens from other causes of delirium?
14. A 72-year-old man develops progressive dementia, prominent visual hallucinations of children and animals, marked day-to-day fluctuations in cognition, and REM sleep behaviour disorder. He falls after starting haloperidol for the hallucinations. What is the diagnosis, and what is the critical management implication of the fall?
15. In Alzheimer's disease, memantine acts on which receptor system, and in which cognitive domain does it have the strongest evidence for benefit compared with AChEIs?
16. A 70-year-old man develops fluctuating cognition, recurrent visual hallucinations of small animals, mild parkinsonism, and REM sleep behaviour disorder. His symptoms are exacerbated by low-dose haloperidol given for the hallucinations, causing severe rigidity. The most likely diagnosis is:
17. Which of the following best characterises the mechanism of action of memantine in Alzheimer's Disease?
18. In DSM-5, delirium due to alcohol withdrawal is distinguished from other causes of delirium by which feature?
19. In the pathophysiology of Alzheimer's Disease, which form of amyloid-beta (Aβ) is currently considered most neurotoxic?
20. A 75-year-old patient with Alzheimer's disease is on donepezil 10 mg/day. He develops intolerable gastrointestinal side effects. Which mechanism of action explains both the therapeutic benefit and the GI adverse effects of donepezil?
21. A 70-year-old man with Alzheimer's disease has behavioural and psychological symptoms of dementia (BPSD) — agitation, aggression, and sleep disturbance — causing significant caregiver distress. First-line management should be:
22. Which biomarker combination in CSF is currently the best-validated diagnostic indicator of Alzheimer's disease pathology, used in research and pre-dementia clinical staging?
23. Which of the following CSF biomarker profiles is MOST consistent with a diagnosis of Alzheimer's disease?
24. An 80-year-old man develops acute confusion, disorientation, and auditory hallucinations following hip replacement surgery. His serum sodium is 125 mEq/L. The MOST appropriate immediate intervention is:
25. A 70-year-old man has progressive memory loss, apathy, and word-finding difficulty. MRI shows bilateral hippocampal and entorhinal cortex atrophy. PET scan shows hypometabolism in the posterior temporoparietal regions. CSF shows reduced Abeta-42 and elevated p-tau. These findings are MOST consistent with:
26. Memantine is used in moderate to severe Alzheimer's disease. Its mechanism of action is: