Alzheimer's Disease: Brain Disorder and Dementia

Alzheimer's Disease

• Alzheimer's disease is a brain disorder that gets worse over time, characterized by changes in the brain that lead to the deposit of proteins, causing brain shrinkage and eventual death.
• It is the most common cause of dementia, a gradual deterioration in memory, thinking ability, behavioral and social skills.

Genetic Basis

• Alzheimer's disease can be classified into two main types: Early-Onset Alzheimer's Disease (EOAD) and Late-Onset Alzheimer's Disease (LOAD).
• EOAD is characterized by mutations in three key genes: APP (Amyloid Precursor Protein), PSEN1 (Presenilin 1), and PSEN2 (Presenilin 2), which affect the gamma-secretase complex and increase amyloid-beta production.
• LOAD is influenced by multiple genes and interactions with environmental factors, with the most significant genetic risk factor being the APOE ε4 allele.

Pathophysiology

• Abnormal processing of APP by beta and gamma-secretases produces amyloid-beta peptides, which aggregate to form extracellular amyloid plaques.
• Hyperphosphorylation of tau protein leads to the formation of intracellular neurofibrillary tangles, disrupting normal function of microtubules in neurons.
• Amyloid plaques and tau tangles disrupt synaptic function, leading to a loss of synapses and neurons.
• Chronic activation of the immune system in the brain contributes to neuroinflammation, exacerbating neuronal damage and disease progression.

Epidemiology

• Alzheimer's disease affects approximately 5-10% of individuals over the age of 65, with the prevalence increasing with age.
• It is the 5th leading cause of death in adults over 65 years of age, and the 6th leading cause of death overall.
• Demographic factors that contribute to the risk of Alzheimer's disease include age, genetics, gender, and geographic variations.

Clinical Manifestations

• Cognitive decline, memory impairment, and behavioral changes are common symptoms of Alzheimer's disease.
• Poor oral hygiene, dry mouth, mouth ulcers, and gingival hyperplasia are common dental manifestations of the disease.

Diagnosis and Treatment Options

• Alzheimer's disease can be diagnosed definitively only by autopsy, but clinical suspicion can be confirmed using biomarkers and neuroimaging such as MRI, CT, and PET scans.
• Treatment options include pharmacological interventions such as cholinesterase inhibitors, and non-pharmacological interventions such as cognitive therapy, physical exercise, and lifestyle modifications.

Dental Management

• Behavioral challenges and difficulty in cooperating during dental treatments due to cognitive impairment and behavioral issues are common in individuals with Alzheimer's disease.
• Dental management should focus on addressing the unique challenges of the disease, including poor oral hygiene, dry mouth, and other oral health issues.