Alzheimer’s Disease

SOURCE

Source: Peron EP, Slattum PW, Powers KE, Hobgood SE. Alzheimer disease. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey L, eds. Pharmacotherapy: A Pathophysiologic Approach. 10th ed. New York, NY: McGraw-Hill; 2017. http://accesspharmacy.mhmedical.com/content.aspx?bookid=1861&sectionid=146062470. Accessed January 20, 2017.

DEFINITION

• Progressive dementia leading to loss of cognitive, analytical, and physical functioning.

ETIOLOGY

• Exact etiology unknown.

• Potential causes include:

  • Genetic factors.

  • Environmental factors.

PATHOPHYSIOLOGY

• Exact pathophysiology of Alzheimer disease (AD) not entirely known, and no cure exists.

• Intracellular neurofibrillary tangles, extracellular neuritic plaques, degeneration of neurons and synapses, cortical atrophy.

• β-Amyloid protein aggregation leading to plaque formation, hyperphosphorylation of tau protein, inflammatory processes, vasculature injury, depletion of neurotrophin and neurotransmitters.

• Loss of cholinergic activity and serotonergic neurons.

• Increased activity of monoamine oxidase type B

• Abnormal glutamate pathways of cortex and limbic structures.

EPIDEMIOLOGY

• Affects approximately 5.3 million Americans.

• Number of AD patients is projected to be 13.8 million by 2050.

• Most cases present in persons over age 65 years, but 4% occur in younger persons.

• AD is the fifth leading cause of death in persons age 65 years and older in the United States.

• Most common form of dementing illness, and the prevalence of AD increases with each decade of life.

• AD accounts for 60% of cases in persons over the age of 65 years.

RISK FACTORS

• Hypertension.

• Increasing age.

• Elevated LDL cholesterol.

• Low HDL cholesterol.

• Diabetes mellitus.

CLINICAL PRESENTATION

SYMPTOMS

• Cognitive.

  • Memory loss (poor recall and losing items)

  • Aphasia (circumlocution and anomia)

  • Apraxia.

  • Agnosia.

  • Disorientation (impaired perception of time and unable to recognize familiar people)

  • Impaired executive function.

• Noncognitive (behavioral)

  • Depression.

  • Psychotic symptoms (hallucinations/delusions)

  • Behavioral disturbances (aggression, hyperactivity, uncooperativeness, wandering, repetitive mannerisms, combativeness)

• Functional.

  • Inability to care for self.

    • Instrumental activities of daily living.

      • Handling finances and organizing medications.

    • Activities of daily living (ADL)

      • Hygiene and dressing.

• Stages.

  • Mild (Mini-Mental Status Examination [MMSE] score 26–21):

    • Difficulty remembering recent events.

    • Declining ability to manage finances, prepare food, and perform other household activities.

    • May get lost while driving.

    • Begin to withdraw from difficult tasks and give up hobbies.

    • May deny memory problems.

  • Moderate (MMSE score 20–10):

    • Requires assistance with ADLs.

    • Frequently disoriented to time. Severely impaired recall for recent events.

    • May forget details of past life and names of family and friends.

    • Functioning may fluctuate.

    • Loses ability to drive safely.

    • Generally denies problems.

    • May become suspicious or tearful. Agitation, paranoia, and delusions are common.

  • Severe (MMSE score 9–0):

    • Loses ability to speak, walk, and feed self.

    • Incontinent of urine and feces.

    • Requires care 24 hours per day, 7 days a week.

DIAGNOSIS

MEANS OF CONFIRMATION AND DIAGNOSIS