Irreversible causes
Alzheimer’s Disease
Mild Cognitive Impairment (MCI)
Vascular (multi-infarct) dementia
Mixed Dementia
Dementia with Lewy Bodies (Lewy body dementia)
Parkinson’s Disease
Frontotemporal Dementia
Creutzfeldt-Jakob Disease (Prion disease)
Progressive supranuclear palsy
Huntington’s Disease
Wernicke-Korsakoff Syndrome, Alcohol
Progressive multifocal leukoencephalopathy
Reversible causes
Pseudodementia (depression)
Medications (e.g antihistamines, anticholinergics, sedatives, antipsychotics, opioids)
Vitamin B12 deficiency
Thiamine deficiency
Niacin deficiency
Hypothyroidism, Hyperthyroidism
Hypercalcemia, hyperparathyroidism
Hypoglycemia
Neurosyphilis
HIV-associated dementia
Delirium
Anoxia
Normal pressure hydrocephalus
Head injury, subdural hematoma
Transient global amnesia
Brain tumor (space-occupying lesion)
Structural brain disease
Dementia pugilistica
Corticobasal degeneration
Paraneoplastic syndrome
Whipple’s disease
Uremic or hepatic encephalopathy
Wilson’s disease
Sleep apnea
Chronic meningitis
Thinking through the Differential Diagnosis
Dementia can be divided into reversible and irreversible causes.
Further Reading
https://www.alz.org/professionals_and_researchers_13507.asp
Drugs Aging. 1994 Dec;5(6):431-45. Differential diagnosis of dementia, delirium, and depression. Implications for drug therapy. https://www.ncbi.nlm.nih.gov/pubmed/7858369
Am Fam Physician. 2011 Oct 15;84(8):895-902. Evaluation of Suspected Dementia. https://www.aafp.org/afp/2011/1015/p895.html