Alzheimer Disease
Alzheimer’s disease is the most common cause of dementia (now called major neurocognitive disorder) affecting as many as 5.8 million Americans in 2020 and this number is expected to triple to nearly 14 million by 2060.
Pathophysiology of Alzheimer’s Disease
Alzheimer’s disease is a neurodegenerative condition that occurs as a result of a buildup of amyloid protein in beta-pleated sheets along with tau protein. Pathology will reveal neuritic plaques, neurofibrillary tangles of tau protein, and extra-cellular deposition of amyloid beta-proteins. The brain in Alzheimer’s disease shows several changes including enlargement of ventricles, shrinkage of cerebral cortex and shrinkage of the hippocampus. One area of the brain that degenerates in Alzheimer’s disease is the nucleus basalis of Meynert and this leads to a deficiency of acetylcholine (ACh).
Presentation of Alzheimer’s Disease
Alzheimer’s disease is typically seen in those over the age of 65. The first symptoms for most is impaired short term memory. Specifically their recent memory. Later immediate recall can be affected. Long-term memory usually remains, and patients can recall their childhood quite well.
Symptoms can include: apraxia, sleep disturbance, seizures, abnormal sense of small, impaired judgement, impaired problem solving, problems with executive function, changes in mood or personality.
Read more about types of memory and memory disorders here.
Diagnosis of Alzheimer’s Disease
Diagnosis is clinical. Confirmation with biopsy of the brain is rarely done. Biopsy would show amyloid plaques and neurofibrillary tangles.
Management of Alzheimer’s Disease
Management involves supportive care and medications to slow the progression. There is no cure at the moment.
- Cholinesterase inhibitors: donepezil, rivastigmine, galantamine
- NMDA receptor antagonist: Memantine
- Antioxidants: Vitamin E
- Selegiline
Disease progression is monitored with the Mini-Mental Status Exam.
Major Neurocognitive Disorder due to Alzheimer’s disease with behavioral disturbance
Major neurocognitive disorder is the new DSM-V term for dementia. These patients have Alzheimer’s disease and a neuropsychiatric disorder (psychosis, delusions, hallucinations, depression). Management includes treating the Alzheimers disease (see above) and the additional neuropsychiatric problem (e.g. SSRIs for depression, atypical antipsychotics for psychosis). Also supportive care is very important – including creating an appropriate environment for the patient and educating/ counselling family members and caregivers. Environmental changes can include: lighting, hearing aids, glasses.
Resources/ Further Reading
CDC – Alzheimer’s disease
Note: Feature Photo by Matthias Zomer from Pexels