DOENÇA DE ALZHEIMER EXPLICADA: DIAGNÓSTICO, SINTOMAS E TRATAMENTO ATUAL (AULA COMPLETA)

Introduction to Alzheimer's Disease

Overview and Historical Context

• The speaker introduces the topic of Alzheimer's disease, emphasizing its richness and complexity, and invites questions after the lecture.

• Alzheimer’s disease was first described by Alois Alzheimer in 1906 during his study of a patient named Auguste Deter, who exhibited unusual symptoms.

• Auguste presented with delirium, memory deficits, disorientation, and loss of autonomy; these symptoms prompted Alzheimer’s interest in her case.

• Upon her death, Alzheimer conducted an autopsy revealing pathological changes in her brain: amyloid plaques and neurofibrillary tangles.

Epidemiology of Alzheimer's Disease

• Alzheimer's is the most common form of dementia among the elderly; its prevalence significantly increases with age.

• In Brazil, approximately 55.1% of dementia cases in individuals over 65 are attributed to Alzheimer's disease.

• Prevalence rates rise dramatically from 0.16% for ages 65–69 to 23.4% for those over 85 years old.

Risk Factors for Alzheimer's Disease

Identified Risk Factors

• Advanced age is a primary risk factor; chronic cerebral perfusion alterations also contribute through conditions like microangiopathy and strokes.

• Genetic factors include mutations such as APOE ε4 allele; environmental stressors like pollution and toxins also play a role.

Protective Factors

• Protective factors against Alzheimer’s include higher education levels, intellectual activities, physical exercise, and Mediterranean diet adherence.

Cognitive Reserve Concept

Understanding Cognitive Reserve

• Cognitive reserve refers to the brain's ability to utilize alternative cognitive strategies to compensate for pathological changes associated with Alzheimer’s.

• Individuals with higher educational attainment have more stable neural networks that can delay symptom onset despite underlying pathology.

Genetic Insights into Alzheimer's Disease

Genetic Contributions

• Most cases of Alzheimer’s are sporadic; familial forms account for about 5%, often linked to autosomal dominant inheritance patterns.

• Familial cases typically involve mutations on chromosomes 1, 14, or 21 leading to early-onset symptoms before age 65.

Key Genes Involved

• The gene encoding amyloid precursor protein (APP), located on chromosome 21, is crucial in familial Alzheimer’s development due to trisomy effects.

Pathophysiology of Alzheimer's Disease

Neuropathological Changes

• Microscopic examination reveals neuronal loss along with beta-amyloid peptide deposits forming neuritic plaques and neurofibrillary tangles containing hyperphosphorylated tau protein.

Amyloid Cascade Hypothesis

• The amyloid cascade hypothesis posits that beta-amyloid accumulation triggers subsequent pathological events leading to clinical manifestations of Alzheimer’s.

Clinical Presentation

Symptoms Overview

• Early symptoms include significant memory loss affecting daily life activities; patients may forget recent events or personal information.

Behavioral Changes

• As the disease progresses , behavioral issues such as depression , anxiety , irritability , impulsivity , hallucinations , personality changes emerge .

Motor Symptoms

• Patients may experience motor difficulties including weakness , falls , tremors , coordination problems alongside sleep disturbances .

Clinical Approach

Diagnostic Considerations

• A thorough clinical assessment should exclude reversible causes of cognitive decline while considering comorbidities .

• Neurocognitive tests help quantify cognitive impairment severity ; laboratory tests assess potential underlying conditions contributing to dementia-like symptoms .

Understanding Brain Imaging and Its Role in Diagnosing Dementia

Importance of Brain Imaging

• White areas visible on MRI indicate potential brain atrophy, which can be crucial for diagnosing vascular diseases that may predispose to dementia.

• MRI assists in differentiating microhemorrhages and conditions like hydrocephalus; small spots suggestive of microhemorrhages may indicate underlying vascular issues such as amyloid angiopathy.

Advanced Cases of Microhemorrhages

• In advanced cases, MRI shows extensive cortical microbleeds, indicating a more severe condition affecting brain function.

Criteria for Alzheimer's Diagnosis

• Dementia is characterized by memory loss and cognitive skill impairment (e.g., apraxia, agnosia), leading to social and occupational dysfunction. It's essential to rule out delirium caused by infections or tumors.

• Typical Alzheimer’s progression is gradual with documented cognitive decline through neuropsychological tests like Mini-Mental State Examination (MMSE) or MoCA.

Diagnostic Support from Imaging

• Imaging exams support diagnostic hypotheses; biomarkers like beta-amyloid levels can clarify uncertain diagnoses, especially in early-onset Alzheimer’s cases.

Advanced Imaging Techniques

• PET scans assess cerebral metabolism while SPECT evaluates perfusion; both are valuable but costly tools for understanding brain functionality in Alzheimer’s patients.

Conclusion and Reflection

• The discussion emphasized the clinical picture and pathophysiology of Alzheimer's disease, concluding with a reminder about the importance of care: "Cure sometimes, help often, console always."