Alzheimer’s disease is an acquired disorder of cognitive and behavioural impairment that markedly interferes with social and occupational functioning. Alzheimer’s leads to progressive deficits in language, memory, comprehension, attention, judgment, and reasoning. It is the most common cause of cognitive decline in adults.

What Is Alzheimer’s Disease? 

Alzheimer’s disease is a progressive condition that leads to dementia and loss of cognitive abilities in adults. It is the most common cause of dementia, representing 60 to 80 percent of dementia cases. Other types of dementia include vascular dementia, frontotemporal dementia, and Lewy body dementia (disease associated with abnormal deposits of a protein called alpha-synuclein in the brain)

Alzheimer’s is most often diagnosed in adults 65 years and older, though it can begin at younger ages. Alzheimer’s disease is incurable. The symptoms are progressive and ultimately lead to death.

Who Gets Alzheimer’s Disease?

The Alzheimer’s Society of Canada estimates that 597,000 adults aged 65 and older were living with Alzheimer’s and other forms of dementia in 2020. That number is projected to rise to 955,900 by 2030. Women account for nearly 62 percent of dementia cases in Canada, with men accounting for 38 percent of cases. 

Worldwide, over 58 million people are affected by dementia. Alzheimer’s Disease International estimates that in 2020, dementia affected 12.7 million residents of Europe, 29.2 million residents of Asia, 5.3 million residents of Africa, and 11.4 million residents of North and South America. 

Causes of Alzheimer’s Disease

Alzheimer’s is a type of neurological disease characterized by gradual and progressive neuronal cell death, typically beginning in the entorhinal cortex in the hippocampus. The damage is caused by the accumulation of abnormal neuritic plaques and neurofibrillary tangles.

The plaques, called beta-amyloid plaques, form microscopic lesions that contribute to brain cell damage. The neurofibrillary tangles may be a complication of the proliferation of beta-amyloid proteins. The presence of excessive beta-amyloid leads to hyperphosphorylation of a protein called tau. This causes the tangling of structures in nerve cells. 

Both plaques and tangles are present in individuals with Alzheimer’s. However, neurofibrillary tangles are more strongly correlated with symptoms and diagnosis of Alzheimer’s than plaques. Beta-amyloid plaques can be present in individuals who do not have dementia. 

There is no known trigger for Alzheimer’s. Evidence suggests there is a genetic component. Researchers have isolated two different genes that may be predictive of the development of Alzheimer’s: risk genes and deterministic genes.  People with a parent or sibling with Alzheimer’s have a greater risk of developing the condition.

Other factors that may also play a role in developing Alzheimer’s include:

• Age
• Traumatic head injury 
• Depression
• Cardiovascular disease 
• Cerebrovascular disease 
• Higher parental age
• Tobacco use

Treatment for Alzheimer’s Disease

There is no cure for Alzheimer’s, however, there are four medications approved by Health Canada to treat dementia. These drugs do not cure the disease but can temporarily improve memory and focus: 

• Aricept™ (brand name) or Donepezil (generic name)
• Exelon™ (brand name) or Rivastigmine (generic name)
• Reminyl ER™ (brand name) or Galantamine (generic name)
• Ebixa® (brand name) or Memantine (generic name)

Symptoms of Alzheimer’s Disease

The earliest symptoms of Alzheimer’s include memory loss and confusion. Over time, symptoms will worsen. Additional symptoms may emerge, including:

• Disorientation 
• Mood changes
• Behaviour changes
• Increasing confusion about events, time, and place
• Unfounded suspicions about family, friends, and caregivers
• Worsening memory loss and behaviour changes 
• Difficulty speaking, swallowing, and walking

Early Signs and Indications for Referral

The earliest signs of Alzheimer’s are confusion and memory loss. Alzheimer’s affects learning, so individuals may have trouble remembering new information while retaining older memories. Confusion and mood swings are also characteristics of early dementia.

Formal diagnosis requires referral to a neurologist. The specialist can perform clinical evaluation, testing to rule out other diagnoses, and brain imaging studies to confirm the presence of beta-amyloid plaques.

Understanding the signs of Alzheimer’s and other types of dementia can help primary care providers better treat older adults. Join the MDBriefCase community for free to stay current on clinical guidelines.