Carlos Ballario and Maria Eugenia Ferri

Dementias are by definition acquired disorders of the central nervous system, which alter intellectual abilities and which compromise at least three of the following cognitive functions: memory, language, visuospatial abilities, complex cognitive functions and emotional and personality disorders. The picture is characteristically progressive.

Due to the fact that life expectancy has increased significantly, the prevalence and incidence of these disorders has increased notably, constituting one of the greatest health problems, with a very important economic and social impact.

Some series describe that after the age of 60 between 5 and 10% of the population has mild to moderate dementia, a figure that increases to 20-30% in people over 80 years of age.

There are various classifications of dementias according to the etiology (degenerative or non-degenerative), the evolutionary prognosis (Potentially reversible or irreversible), the topography (cortical, subcortical or mixed), the semiological picture (with motor disorders or without them) and the evolutionary course (sudden onset, gradual or rapid course from weeks to months).

The main cause of the syndrome is Alzheimer's disease, followed by Lewy body dementia, frontotemporal dementia, vascular dementia, and finally secondary to various diseases (Parkinson's disease, Huntington's disease, etc.)

Above all, the foregoing is a priority for the primary care physician to be familiar with the signs and symptoms of these conditions and to corroborate the information with the patient's family and friends, since the agnosia that characterizes these cases reduces the reliability of the patient. direct questioning.

Clinical evaluation:

Five elements of the story are essential:

Memory evaluation : specify if the forgetfulness is of recent events (short-term memory impairment) or of events of the past (remote memory). It is also important to detect the presence of serious forgetfulness (for example, forgetting the lit fire) or if the patient misplaces objects of daily use.

Visuospatial Disorders : how to get lost in familiar places; not knowing where to get off if traveling by public transport.

Language disorders : difficulty in naming objects or remembering familiar names may be evident.

Complex cognitive functions : such as planning finances, planning and organizing activities.

Emotional and personality disorders : changes in mood such as depression, agitation, aggression, or sometimes inappropriate social behaviors that do not coincide at all with the patient's previous behavior

If any of these alterations are detected in the consultation, it is essential to carry out a complete physical and neurological examination, including evaluation of the patient's functional abilities, which is carried out through neurocognitive tests. Of the latter, the one that is usually performed in the consultation is the Mini Mental State (see Fig. 1)

By consensus, the study of these patients should include: complete blood count, vitamin B12 levels, thyroid function, and when there is any clinical suspicion, serological tests (VDRL, HIV) or metabolic tests (hepatogram, urea, creatinine).

There are no uniform criteria regarding the timing or the formal indication of neuroimaging, but most consensuses agree that they should not be lacking in the following cases:

• age of onset less than 60 years
• rapid decline in mental and physical functions
• course and noticeable deterioration of less than three years of evolution
• appearance of any focal sign (eg paresis of a limb)
• history of head trauma (suspected subdural hematoma)
• presence of headache
• history of cancer
• use of blood thinners or bleeding disorders
• history of sphincter incontinence or early gait disorders (high suspicion of Hydrocephalus at normal tension)

Next, we will briefly review the four most common types of dementia in the population.

Alzheimer disease

It is the most common cause of dementia, representing 60% of all dementia syndromes. Clinically it is characterized by a slow and progressive memory compromise, which in most cases is an initial symptom. The memory of anterograde fixation is mainly affected, manifesting as an impossibility to evoke recent events. There is a commitment to episodic memory (events related to our personal history) and then to semantic memory (referring to linguistic and cultural knowledge). Remote memory is affected to a lesser degree. Language is characteristically affected during the course of the disease showing cortical involvement, and paraphasia and neologisms gradually appear. There is also ideational and ideomotor apraxia.

Behavioral symptoms appear with disease progression and apathy, irritability, aggressiveness, and uninhibited behaviors are common. The appearance of delusions in the form of zealoty, ideas of theft and paranoia is also common. All this cognitive behavioral deterioration is progressive and inexorable and ends with the patient's life due to a state of prostration, with sphincter incontinence, flexor tendency and the inexorable infectious intercurrences and bedsores.

Regarding its etiology, it is known that 15% of cases are related to familial forms. In the rest, the cause is still unknown, but age, postmenopausal female sex, a family history of dementia, Down syndrome and head injuries are recognized as risk factors for the development of the disease.

The images show parietal or temporoparietal atrophy. Regarding the treatment for the cognitive aspect, drugs that inhibit the degradation of acetylcholine (anticholinesterase drugs) are used, of which the most used are: donepezil, rivastigmine, and galantamine.

Regarding behavioral symptoms, antidepressants (Fluoxetine, citalopram) can be used for depression, while for anxiety, insomnia and hallucinations, benzodiazepines can be used and, if necessary, neuroleptics (Olanzapine or clozapine are the first choice ).

Lewy body dementia

It is the second leading cause of dementia. Clinically it is characterized by fluctuating cognitive disorders, recurrent hallucinations (visual in 93% of patients and auditory in 50%), and parkinsonian signs.

It is striking how early these symptoms help differentiate this condition from Alzheimer's disease. Progression is faster than in other degenerative dementias. Anatomopathologically, intracytoplasmic neuronal inclusions appear identical to those of Parkinson's disease, but in cortical neurons (Lewy bodies).

Low doses of l-dopa are used for motor symptoms, while for emotional and behavioral disorders the use of quetiapine, olanzaoin or clozapine is preferred, all neuroleptics with little or no extrapyramidal effect.

Frontotemporal dementia

This dementia affects younger patients (before 65 years of age) and is characterized by an insidious and slow onset of behavioral disorders and the invariable presence of frontal or fronto temporal cerebral atrophy. In some cases aphasia dominates the picture and in others the typical behaviors of frontal dysfunction. The memory is quite preserved. Attention disorders, profane language, criminal acts and neglect of grooming and personal care are early. Pathology shows Dic bodies, neuronal loss, and gliosis. The images show a marked frontal or frontotemporal atrophy. The drugs of first choice in its treatment tend to correct the serotonergic deficit that characterizes this condition, which is why serotonin reuptake inhibitors (SRIs), such as floxetine, Paroxetine or sertraline can be used. Atypical neuroleptics are used to manage aggressiveness and arousal.

Vascular dementia

Ischemic vascular disease is a major cause of cognitive decline and dementia. The most common form is small vessel disease, which is generally seen in hypertensive, diabetic, smoker, alcoholic, dyslipidemic, and sedentary patients, all known vascular risk factors.

Gradually, the appearance of lacunar infarcts that involve the white matter, the ganglia of the base and the brain stem, lead the patient to a progressive deterioration in stages or staggered, with stability until the arrival of a new vascular event.

On cognitive examination, aphasia or visual-perceptual disorders as well as visuospatial alterations appear. Memory is less compromised than the other domains. On physical examination, pyramidal and extrapyramidal signs, gait disorders, dysphonia, dysphagia, and bucolingual apraxia appear.

The complementary methods in these patients, used to study the cardiovascular system, are: cranial CT or MRI, neck vessel Doppler and echocardiogram. The laboratory will be oriented to exploring risk factors (glycemia, lipid profile, etc.)

Treatment is aimed at modifying the vascular risk factors detected in the patient. For secondary prevention (avoid new events) acetylsalicylic acid is used and, if necessary, anticoagulation. As vasoactive drugs, memantine or nimodipine can be used.