Delirium vs. Dementia
Delirium: acute onset, fluctuating course, impaired attention and consciousness, reversible; Dementia: insidious onset, chronic, intact attention early on.
Alzheimer Disease
Extracellular amyloid-beta senile plaques and intracellular hyperphosphorylated tau neurofibrillary tangles; APOE epsilon-4 allele; temporoparietal atrophy.
Lewy Body Dementia
Visual hallucinations, fluctuating cognition, spontaneous Parkinsonism, and extreme neuroleptic sensitivity; alpha-synuclein cortical inclusions.
Normal Pressure Hydrocephalus
Triad of 'Wet, Wacky, and Wobbly' (Urinary incontinence, Cognitive decline, Magnetic gait apraxia); ventriculomegaly on CT/MRI; improves post-LP.
Dementia Subtypes Differential Matrix
| Dementia Type | Pathology & Neuroimaging | Clinical Presentation Hallmark | Pharmacologic Management |
|---|---|---|---|
| Alzheimer Disease (AD) | Extracellular Amyloid-beta plaques and intracellular hyperphosphorylated Tau neurofibrillary tangles; hippocampal and temporoparietal atrophy | Early, prominent short-term memory impairment (anterograde amnesia) with preserved remote memory; progressive loss of executive function | Cholinesterase inhibitors (Donepezil, Rivastigmine, Galantamine); NMDA receptor antagonist (Memantine) |
| Vascular Dementia | Large vessel atherothrombosis or small vessel lacunar infarcts; subcortical white matter ischemic changes | Stepwise cognitive deterioration temporally linked to previous transient ischemic attacks or strokes; focal neurologic deficits | Control cardiovascular risk factors (antihypertensives, statins, antiplatelet therapy); smoking cessation |
| Dementia with Lewy Bodies (DLB) | Cortical cytoplasmic alpha-synuclein Lewy bodies | Visual hallucinations (well-formed people/animals), spontaneous Parkinsonism, fluctuating alertness/attention, REM sleep behavior disorder | Cholinesterase inhibitors (Donepezil); AVOID typical antipsychotics (severe neuroleptic hypersensitivity) |
| Frontotemporal Dementia (Pick Disease) | Intracellular aggregates of hyperphosphorylated tau (Pick bodies) or TDP-43; focal frontal and temporal lobar atrophy | Early personality and behavioral changes (disinhibition, apathy, hyperorality), loss of empathy, followed by expressive progressive aphasia; memory spared early | Supportive care; SSRIs for compulsive behaviors; atypical antipsychotics used with extreme caution |
OMM Board Correlate: Cranial Fluctuation & Autonomic Calming
- CV4 for Autonomic Agitation: In hospitalized geriatric patients with hyperactive delirium, the CV4 technique (compression of fourth ventricle) induces a systemic still point, slows sympathetic arousal, and lowers heart rate.
- Normal Pressure Hydrocephalus Mechanism: Impaired CSF resorption at arachnoid granulations into the superior sagittal sinus elevates intraventricular volume without substantial opening pressure elevations. Suboccipital and venous sinus drainage techniques encourage cranial venous return.
Board Traps & Common Distractors
- In patients with Dementia with Lewy Bodies (DLB), NEVER administer typical first-generation antipsychotics (Haloperidol); extreme neuroleptic sensitivity can precipitate irreversible extrapyramidal rigidity, acute sedation, and death.
- Always rule out reversible causes of cognitive decline before diagnosing primary dementia: obtain serum Vitamin B12, TSH (hypothyroidism), RPR (neurosyphilis), and non-contrast head CT (subdural hematoma or NPH).
- Delirium is a medical emergency signifying acute underlying illness (urinary tract infection, pneumonia, electrolyte disturbance, medication toxicity); physical restraints exacerbate delirium and increase fall mortality.