Generality
Dementia with Lewy bodies is the third most common form of dementia in humans, after Alzheimer's disease and vascular dementia.
Its particular name derives from the fact that, within some brain neurons, insoluble protein aggregates are formed called Lewy bodies .
Diagnosing dementia with Lewy bodies is not easy; the doctor is based on an accurate evaluation of the symptomatology (which is very varied), on some diagnostic tests for images (CT and MRI) and on tests that exclude pathologies of similar disorders.
Unfortunately, dementia with Lewy bodies is an incurable disease with deadly consequences.
What is dementia with Lewy bodies?
Dementia with Lewy bodies (or dementia from Lewy bodies ) is a neurodegenerative disorder of the brain, which causes a progressive decline of a person's cognitive faculties.
Its name derives from the unusual presence, in the cells of the cerebral cortex and of the substantia nigra of patients, of insoluble protein aggregates called Lewy bodies .
Consisting of a protein known as alpha-synuclein, Lewy bodies are the same anomalous agglomerates that occur within the neurons of people with Parkinson's disease and multi systemic atrophy .
The substantia nigra
The substantia nigra - also called Sommering black substance - is a particular area of the brain located between the midbrain and the diencephalon, near the cerebral peduncles.
In the substantia nigra two regions can be recognized: the so-called pars compacta (or compact part ) and the so-called pars reticulata (or reticulated part ).
With different specific functions, these two regions provide for the execution and control of various motor functions .
EPIDEMIOGIA
Dementia with Lewy bodies makes up 10-15% of all known forms of dementia and, by diffusion, comes immediately after Alzheimer's disease (by far the most common dementia, with 50-70 cases every 100 of dementia) and vascular dementia (with about 25 cases per 100).
Lewy body dementia affects both sexes with the same incidence and, like most dementias, occurs more frequently in people aged 65 and older (so it is more prevalent in old age).
Causes
Like many forms of dementia, dementia with Lewy bodies also arises because brain neurons die or do not work as they should.
Although the studies in this regard still present some question marks, the researchers believe that the already mentioned Lewy bodies formed in the latter's cytoplasm cause the death (or malfunction) of the brain cells.
ASPECTS TO CLARIFY
On the role played by Lewy bodies, doctors and researchers have yet to clarify at least two aspects:
- What causes its formation at some point in a person's life;
- How they damage the neurons that contain them.
Regarding this second point, there is a hypothesis - still not scientifically proven - based on which Lewy bodies would interfere with the chemical signaling between the neurons of the cerebral cortex and those of the substantia nigra ; chemical signaling that has among its main actors molecules called, in general, neurotransmitters.
RISK FACTORS
After several studies, doctors and researchers have concluded that the conditions that favor the appearance of dementia with Lewy bodies - or risk factors - are:
- Advanced age
- A certain predisposition to the disease .
Specific genetic mutations have been identified, which - if transmitted from a parent to a child - increase the possibility of developing dementia. However, scientists are keen to point out that these genetic abnormalities are very rare.
Symptoms and Complications
Like other forms of dementia, even that with Lewy bodies is responsible for mild symptoms only in the initial phase. In fact, as the involvement of brain neurons becomes ever wider, the disorders and alterations of cognitive abilities tend to worsen inexorably. Moreover, in the final stages of the disease it is impossible to carry out even the simplest daily tasks.
Although every patient represents a case in itself, the manifestations of dementia with Lewy bodies are usually a mixture of Alzheimer's symptoms and symptoms of Parkinson's disease.
Entering into details, the symptom picture includes:
- Attention and vigilance problems.
They are very common and quite inconstant. In fact, they tend to vary from hour to hour, alternating sudden improvements with equally sudden deteriorations.
- Problems with three-dimensional perception and in quantifying object distances.
- Difficulty judging, planning and thinking.
- Memory loss.
It is a more common disorder in the final stages of the disease.
- Visual hallucinations, or to see things that do not exist.
They are very frequent.
- Auditory hallucinations, ie feeling things that do not exist.
They are less common than the previous ones.
- Motor problems, which follow the typical symptoms of Parkinson's disease.
Among the most common manifestations are the stiffness and the slowing of movements, the empty expression of the face, the drowsiness, the curved gait in the walk, the shuffling step, the precarious balance and the tremors of the limbs.
The typical symptomatology of Parkinson's disease concerns about 2/3 of people with Lewy body dementia and is responsible for temporary loss of consciousness.
The more dementia is at an advanced stage, the more serious these disorders are.
- Particular sleep disorders, which lead the patient to fall asleep during the day and feel restless at night, with difficulty sleeping.
- Confusion
- Depression
- Language problems
- Chewing and swallowing problems.
These disorders are particularly marked in the final stages of the disease and are possible causes of inhalation pneumonias or choking episodes.
HOW DO THE PARKINSON SYMPTOMS EXPLAIN?
HOW LONG DOES A PATIENT LIVE AFTER THE FIRST SYMPTOM?
Although each patient represents a case in its own right, usually individuals with dementia from Lewy bodies live about 7-8 years since the first symptom appeared.
WHEN TO REFER TO THE DOCTOR?
Doctors advise contacting them as soon as the first signs of dementia appear.
This is to reduce the impact that the disease can have on the patient, as it gets more and more serious.
Diagnosis
Diagnosing dementia with Lewy bodies is complex for at least a couple of reasons:
- The similarity of symptoms with those of other forms of dementia (Alzheimer's disease in particular).
- The lack of an examination or instrumental test that specifically recognizes this dementia. This often leads doctors to proceed by exclusion (differential diagnosis).
In general, the diagnostic procedure for a suspected case of Lewy dementia involves a fair number of different assessments, including:
- An analysis of clinical history, followed by a thorough physical examination.
- A neurological exam
- An analysis of mental abilities
- Laboratory tests
- A magnetic resonance imaging (MRI) and / or a CT scan (computerized axial tomography), both referred to the brain.
CLINICAL HISTORY AND OBJECTIVE OBJECTIVE
The analysis of clinical history is a medical investigation aimed at clarifying how and when the first disorders appeared, if the patient suffers or has suffered in the past from particular pathologies, if he takes certain drugs, etc.
The most important symptoms:
- Lack of attention and vigilance
- Visual hallucinations
- Typical symptoms of Parkinson's disease
The objective examination, instead, is the observation and the collection of the symptoms manifested (or complained) by the patient.
In both cases, it is particularly important to interrogate even a close relative of the patient (or a person who spends a lot of time with him), in such a way as to obtain a more detailed symptomatology.
NEUROLOGICAL AND CAPACITY EXAMINATION? MENTAL
The neurological examination consists of an analysis of tendon reflexes, motor skills (balance, etc.) and sensory functions.
The assessment of mental abilities, on the other hand, involves the study of cognitive abilities (ie reasoning, faculty of judgment, language, etc.) and their degree of impairment.
For a physician experienced in Lewy body dementia, two such investigations can provide fundamental information.
LABORATORY EXAMINATIONS
Among the laboratory exams we highlight in particular:
- Blood tests
- Urine analysis
- Toxicological tests
- Blood glucose measurement
Their execution serves, more than anything else, in the perspective of differential diagnosis, and therefore excludes morbid conditions with similar symptoms. For example, blood tests allow you to rule out the hypothesis that the disorders are related to a vitamin B12 deficiency.
MRI and TAC
Nuclear magnetic resonance and CT scans are two diagnostic imaging exams, which allow to:
- Evaluate the presence of tumors, strokes and cerebral haemorrhages. To ascertain that these conditions are not present, it is very important information in view of the final diagnosis.
- Observe the appearance of the brain area identified with the term substantia nigra . In the case of dementia with Lewy bodies, this particular encephalic portion is altered in a singular way.
Treatment
Like most dementias, even that with Lewy bodies is a neurodegenerative disease from which, based on current medical knowledge, it is impossible to heal. However, there are treatments able to reduce the symptomatology and improve, albeit limitedly, the health conditions of sick individuals ( symptomatic therapy ).
DRUGS FOR SYMPTOMATIC THERAPY
With different efficacy from patient to patient, the drugs used for dementia with Lewy bodies are:
- Acetylcholinesterase inhibitors .
Medicines belonging to this category, which can be effective against hallucinations, confusion and drowsiness, are donepezil, galantamine and rivastigmine.
Side effects: feeling sick, diarrhea, headache, sense of recurrent fatigue and muscle cramps.
- Levodopa .
It aims to reduce parkinsonian symptoms, hence the problems of movement.
Side effects: worse hallucinations.
- Antidepressants .
They serve in those cases of dementia with Lewy bodies marked by depression.
- Clonazepam .
In some individuals, it alleviates sleep disorders
- Antipsychotics, particularly haloperidol .
They are rarely administered and in low doses (because they are responsible for serious side effects), when the patient reports serious difficulties in judgment.
Side effects: they can cause stiffness and immobility
OTHER TREATMENTS THAT PART OF THE SYMPTOMATIC THERAPY
- Physiotherapy . It is used to improve motor disorders and balance problems.
- Occupational therapy . Its aim is to make the patient as independent as possible from others and to re-insert him in a social context.
- Language therapy . It is used to alleviate speech disorders (which have an impact on communication skills) and to improve the ability to swallow.
- Cognitive stimulation . It includes exercises aimed at improving memory, language and thinking skills.
- The correction of sight problems . It can be a partial remedy for the visual hallucinations of which patients are usually victims.
- A light physical activity (a simple walk is enough) and the renunciation of any type of alcoholic beverages, cigarette smoking and coffee . These suggestions (NB: for the first one, a person must follow the patient step by step) are given to improve sleep at night.
Precautions at home
Although this is not a real treatment, doctors advise relatives of individuals with dementia with Lewy bodies to change the decor of the home in which they live and to create a home environment with minimal fall risk.
Therefore, it is good practice to remove the old loose carpets and add bars or handrails where the sick can lean.
Prognosis
Since the process of neurodegeneration is unstoppable and sooner or later death occurs, the prognosis for dementia with Lewy bodies can only be negative.
