A 70-year-old retired professor is brought by his family because of gradual memory loss over 3 years. He initially forgot names and appointments, then became unable to recall recent events, and now cannot recognize close family members. He gets lost in familiar neighborhoods. His mood is stable and he has no focal neurological deficits. MRI shows bilateral hippocampal and entorhinal cortical atrophy. What is the most likely diagnosis, and which neurotransmitter deficit is most prominent?

• A Vascular dementia — dopamine deficit
• B Lewy body dementia — serotonin deficit
• C Frontotemporal dementia — norepinephrine deficit
• D Alzheimer's disease — acetylcholine deficit ✓

Explanation

Alzheimer's disease is the most common cause of dementia, characterized by insidious onset and gradual progressive decline beginning with episodic memory, reflecting early hippocampal and entorhinal involvement. The basal nucleus of Meynert (in the substantia innominata) is the major source of cortical cholinergic innervation and undergoes significant neuronal loss in Alzheimer's disease, resulting in marked acetylcholine deficiency. This is the basis for cholinesterase inhibitor therapy (donepezil, rivastigmine, galantamine). Lewy body dementia features visual hallucinations, fluctuating cognition, and parkinsonism with alpha-synuclein pathology.

Reference: Kaplan & Sadock's Synopsis of Psychiatry, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.