Clinical Overview
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder and the most common cause of dementia, affecting approximately 6.7 million Americans aged 65 and older. The 2024 revised diagnostic criteria emphasize a biological definition of AD, incorporating biomarker evidence of amyloid plaques and tau tangles alongside clinical symptoms.
The disease is characterized by progressive cognitive decline, beginning with memory impairment and advancing to affect executive function, language, visuospatial abilities, and behavior. Recent advances in understanding AD pathophysiology have led to the first disease-modifying treatments, marking a paradigm shift from purely symptomatic management to interventions that may slow disease progression.
The 2025 clinical staging framework recognizes three stages: preclinical AD (biomarker positive, cognitively normal), mild cognitive impairment due to AD, and dementia due to AD. Early detection and intervention are increasingly emphasized, with new diagnostic tools including PET imaging and CSF biomarkers becoming more widely available in clinical practice.
Key Symptoms & Presentations
Progressive Memory Loss
Initially affects recent memory and new learning, progressing to remote memory loss. Difficulty remembering names, appointments, and recent conversations becomes increasingly severe.
Executive Dysfunction
Impaired planning, problem-solving, and judgment. Difficulty managing finances, following complex instructions, and making decisions becomes progressively worse.
Language Difficulties
Word-finding problems, reduced vocabulary, and difficulty understanding complex language. Progresses from mild anomia to severe aphasia in advanced stages.
Visuospatial Impairment
Difficulty with spatial relationships, getting lost in familiar places, problems with depth perception, and challenges recognizing faces or objects.
Behavioral and Psychological Symptoms
Agitation, aggression, depression, anxiety, sleep disturbances, wandering, and paranoid ideation. These symptoms significantly impact quality of life and caregiver burden.
Functional Decline
Progressive loss of ability to perform activities of daily living, from complex tasks like driving and managing medications to basic self-care needs.
Disorientation
Confusion about time, place, and eventually person. Patients may not recognize familiar environments or close family members in advanced stages.
Treatment Approaches
Current treatment for Alzheimer’s disease employs a multimodal approach combining pharmacological interventions, non-pharmacological strategies, and comprehensive care planning. The 2024 treatment guidelines emphasize early intervention and personalized care based on disease stage and individual patient factors.
Pharmacological Interventions: Cholinesterase inhibitors (donepezil, rivastigmine) remain first-line treatment for mild to moderate AD, with memantine added for moderate to severe stages. The FDA approval of lecanemab in 2023 represents the first disease-modifying therapy, targeting amyloid plaques in early-stage disease.
Behavioral and Psychological Symptom Management: Depression and anxiety are treated with SSRIs, while agitation may require careful use of antipsychotics or alternative agents. Sleep disturbances benefit from sleep hygiene interventions and, when necessary, targeted medications.
Non-Pharmacological Interventions: Cognitive stimulation, structured activities, music therapy, and environmental modifications play crucial roles in maintaining function and quality of life. Caregiver education and support are essential components of comprehensive care.
Medication Considerations
Cholinesterase Inhibitors:
- Donepezil (Aricept): 5-10 mg/day, approved for all stages of AD. Most commonly prescribed due to once-daily dosing and extensive evidence base
- Rivastigmine (Exelon): 6-12 mg/day oral or transdermal patch. Useful when gastrointestinal side effects limit other options
- Galantamine (Reminyl): 16-32 mg/day, has additional nicotinic receptor modulation properties
NMDA Receptor Antagonist:
- Memantine: 10-20 mg/day, approved for moderate to severe AD. Can be combined with cholinesterase inhibitors
Disease-Modifying Therapy:
- Lecanemab (Leqembi): 10 mg/kg IV every 2 weeks for 18 months. First FDA-approved treatment targeting underlying disease pathology. Requires specialized monitoring for ARIA (amyloid-related imaging abnormalities)
Behavioral Symptom Management:
- Depression: Sertraline, escitalopram, or citalopram preferred due to lower anticholinergic effects
- Agitation: Risperidone or quetiapine used cautiously due to black box warning in dementia
Special Considerations:
- Avoid anticholinergic medications that can worsen cognitive symptoms
- Monitor for drug interactions, especially with multiple comorbid conditions
- Regular assessment of benefits vs. risks, particularly with antipsychotic use
- Consider pharmacogenomic testing for optimal medication selection
Common Comorbidities
Condition
Clinical Considerations
Depression
Present in 40-50% of Alzheimer’s patients. Often underdiagnosed and undertreated. SSRIs preferred due to lower anticholinergic burden. May improve with cholinesterase inhibitor treatment.
Anxiety Disorders
Affects 30-40% of AD patients. May manifest as agitation, restlessness, or excessive worry. Requires careful differential diagnosis from cognitive symptoms and behavioral manifestations of dementia.
Sleep Disorders
Sleep-wake cycle disruption affects 60-70% of AD patients. Includes difficulty falling asleep, frequent awakening, and day-night reversal. Non-pharmacological interventions preferred initially.
Cardiovascular Disease
Vascular risk factors contribute to AD progression. Hypertension, diabetes, and hyperlipidemia require aggressive management. Some cardiovascular medications may affect cognitive function.
Behavioral and Psychological Symptoms of Dementia (BPSD)
Includes agitation, aggression, psychosis, and wandering. Affects 90% of AD patients at some point. Requires comprehensive assessment and multimodal treatment approach including environmental modifications.
