Chapters 7 - Neurological Disorders 05. Alzheimer's disease

05. Alzheimer's disease

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"I have lost my self!" Auguste D, 1901.

1. General:

Disease Alzheime r [ 69 , 196 , 197 ] is a neurodegenerative disease [ 138 , 198 ] that affects different regions of the brain. This is the main [ 140 , 199 ] cause of dementia [ 197 ] (reduction acquired, progressive, deep and irreversible cognitive functions) in the elderly.

The disease takes its name from Dr. Alois Alzheimer who, in 1907 [ 196 ], described for the first time the anatomical changes observed in the brain of a patient of 51 years, Auguste D [ 201 ].

In 1901 [ 200 ], Dr. Alzheimer ask the patient to tell his name, Auguste tries to remember but can not do it, then she looks up, looks at the doctor and said, "I lost myself" [ 202 ].

2. Pathophysiology:

The neurodegenerative process responsible for the disease is the formation (between neurons) of amyloid plaques [ 113 ] (senile plaques), and within neurons tau protein aggregates that form neurofibrillary tangles [ 196 ].

These two phenomena cause massive neuronal destruction manifested macroscopically by cortical atrophy [ 185 , 196 ].

In patients with Alzheimer's disease, the brain can lose 8-10% of its weight every ten years, against 2% in healthy subjects [ 203 ]. Cortical atrophy is associated with dilation of cerebral ventricles and sulci.

Neuronal loss particularly affects the cholinergic systems [ 80 ] (neocortex, entorhinal cortex, amygdala, hippocampus, basal nucleus of Meynert [ 50 , 119 , 172 ]), noradrenergic (locus coeruleus), serotonergic (raphe nucleus) [ 63 ].

3. Risk factors:

The exact causes of Alzheimer's disease are still unknown [ 39 ], but it is assumed that environmental factors (aluminum and heavy metals including mercury [ 204 ]) and DNA [ 196 , 197 ] contribute. Mutations in at least four genes predisposing to AD were identified.

Among the risk factors for developing Alzheimer's disease are:

  • Age is the most important factor [risk 196 ]. As we age, the natural repair mechanisms of the body are less effective.
  • Cardiovascular Disease: All risk factors for cardiovascular disease [ 204 ] (such as hypertension and hypercholesterolemia) are also risk factors for Alzheimer's disease.
  • Family and genetic background [ 196 , 197 ].
  • The ApoE4 gene [ 197 ].
  • Female [ 196 ].
  • Diabetes [ 205 ].
  • Injuries of the skull [ 196 , 197 , 204 ] ...

4. Clinic:

The first symptom of Alzheimer's disease is the loss of memory of recent events (amnesia) [ 201 ], it is initially manifested by minor distractions that gradually increase with the progression of the disease, while memories former are relatively preserved.

Thereafter, cognitive deficits extend to the areas of language (aphasia) [ 198 ], the organization of movements (apraxia) [ 205 ], visual recognition (visual agnosia) [ 197 ] and executive functions ( such as decision making and planning) [ 206 ], these symptoms reflect in particular the pathological process of degeneration reaching the frontal lobes of the brain.

These psychological changes affect essential human qualities and for this reason Alzheimer's disease is sometimes described as a disease where the victims suffer the loss of qualities that form the essence of human existence.

5. Treatment:

No treatment can cure Alzheimer's disease today [ 206 ], or even stop its evolution. However, some drugs slow evolution mitigating losses of memory, language and reasoning.

5.1. Specific treatments:

These are drugs that are prescribed specifically in Alzheimer's disease [ 207 ]:

  • Acetylcholinesterase inhibitors: They inhibit the degradation of acetylcholine. Thus, they seek to correct the deficit of acetylcholine observed in the brains of people with this disease.
  • NMDA antagonists: Neural receptors N-methyl-D-aspartate (NMDA) receptors play an important role in memory processes.

5.2. Non-specific treatments:

It changes the behavior of the patient without addressing the disease itself [ 206 ].

  • Psychotropic decrease anxiety, aggression or agitation states of patients. Anticholinergics should be avoided because they aggravate the disease.
  • Drugs targeting the risk factors of the disease: some statins, antioxidants (such as vitamin E or melatonin) and anti-inflammatory.

In all cases, the consideration of disruption associated cognitive impairment in personal and social life of patients is essential as well as support for families.

Cognitive rehabilitation techniques and some psychotherapies are often helpful.