Dementia with Lewy bodies

GENERAL ASPECTS

What is dementia with Lewy bodies?

Lewy’s disease is a neurodegenerative disease characterized by the brain deposition of a protein called alpha-synuclein. These deposits of alpha-synuclein can be seen under the microscope forming rounded structures called “Lewy bodies”, named after the pathologist who described them, Fritz Heinrich Lewy. Lewy bodies can also be seen in other diseases, such as Parkinson’s disease.

What is its frequency?

Dementia with Lewy bodies is the second most common cause of dementia. dementiadementia, second only to Alzheimer’s disease. It accounts for about 30% of dementia cases and affects up to 5% of the general population.

What is the starting age?

The frequency of this disease increases with age. The average age of symptom onset is around 75 years, although some cases may also begin earlier.

Is there a genetic component?

In most cases there are no other affected relatives. However, genetic factors that predispose to its appearance and modulate the risk have been identified. Some of the genes involved are SNCA, GBA or CNTN1. It also shares some genetic risk factors with Alzheimer’s disease, such as mutations in APP, PSEN1 or being a carrier of the E4 allele of the APOE gene.

What is its cause?

The factors that lead to its onset are not completely known. In addition to genetic factors, there are also environmental factors common to other neurodegenerative diseases, such as vascular risk factors (arterial hypertension, diabetes, dyslipidemia), obesity, sedentary lifestyle, social isolation or consumption of toxic substances. However, most of the risk factors are unknown.

What are the most relevant symptoms?

The disease is characterized by cognitive problems of progressive onset, in addition to other symptoms such as sleep disorders, visual hallucinations, or motor problems (parkinsonism). Sometimes not all of the symptoms appear, and it can be difficult to differentiate it from other neurodegenerative diseases, such as Alzheimer’s disease.

What are the cognitive problems like?

Problems with attention, reasoning, organization and visuospatial problems (ability to judge distances, copy drawings, identify objects, difficulty in orienting oneself, etc.) are common. Sometimes there may also be memory problems. As the disease progresses, the symptoms become more intense and may affect the patient’s ability to fend for himself. This situation is known as dementia.

It is also very common for cognitive symptoms to be fluctuating, and the patient alternates moments of apparent normality with other periods of greater cognitive dysfunction.

What are sleep disorders like?

It is often accompanied by a specific sleep disorder: REM sleep behavior disorder (RBD). REM sleep behavior disorder (REM SLEEP BEHAVIOR DISORDER (REMBD). This disorder is characterized by the development of vigorous motor behaviors during a phase of sleep in which there should be loss of muscle tone (REM phase). Thus, the patient seems to “imitate” what he/she dreams, and moves or speaks while asleep. Sometimes this disorder is present several years before the onset of cognitive or motor problems.

What are motor disorders like?

The patient usually presents with what is known as parkinsonism: symptoms similar to those that appear in Parkinson’s disease. Parkinson’s disease. There may be slowness in walking, short steps or shuffling, slower brachiation, falls, tremor, rigidity or poverty of movement. These motor problems appear more or less simultaneously with or after cognitive problems.

Can psychiatric symptoms appear?

Sometimes cognitive problems are accompanied by psychotic symptoms: visual hallucinations in the form of people or animals, delusional symptomatology (irreducible false beliefs about reality; for example, thoughts that people in the environment are trying to harm him, thoughts that his partner is trying to cheat him…) or phenomena of identity confusion (for example, confusing a child with a sibling).

The presence of depressive symptoms, anxiety, apathy or irritability is also very common.

DIAGNOSIS

How is dementia with Lewy bodies diagnosed?

The diagnosis of this disease is fundamentally clinical. It will be the symptoms that have been appearing and the order in which they have done so that give the key to make the diagnosis. A neurological examination is also important to detect the presence of parkinsonism. It is fundamental, therefore, the evaluation by a neurologist to be able to interpret the symptomatology and to be able to diagnose the disease.

What complementary tests can be performed?

Although the diagnosis is made on the basis of symptoms, tests can be performed to help interpret them, to provide complementary information and to rule out other entities. The most commonly used tests are structural neuroimaging tests, functional neuroimaging and polysomnography.

What are the structural neuroimaging tests?

Magnetic resonance imaging (MRI) and computed tomography (CT) are the most commonly used. They can identify the existence of brain atrophy in specific regions of the brain. In the case of dementia with Lewy bodies, there is usually generalized atrophy and less involvement of the hippocampal region, which, on the contrary, is usually affected early in Alzheimer’s disease.

What are the functional neuroimaging tests?

The dopaminergic system is usually affected early in this disease. DaTSCAN (SPECT with ioflupane) allows the assessment of this system, and it is common for it to be altered, even in the early stages.

Positron emission tomography (PET) is also often used to assess the metabolism of different brain areas. There is usually less metabolism in the occipital area. Occasionally other specific patterns of hypometabolism are observed that facilitate the diagnosis.

How useful is polysomnography?

In this context, polysomnography makes it possible to assess various parameters during sleep (brain electrical activity, muscle tone, movements, oxygen saturation, presence of apneas, etc.) in order to diagnose SREMT.

TREATMENT

Is there any treatment that can cure or slow down the disease?

Currently, as in other neurodegenerative diseases, there is no treatment that can stop the progression of symptoms. However, some drugs can be used to improve the symptoms and the quality of life of the patient and his or her relatives.

What drugs are used?

Acetylcholinesterase inhibitors (donepezil, rivastigmine, galantamine) can produce an overall improvement in cognitive symptomatology, reduce fluctuations and improve hallucinations and other psychiatric symptoms. They can slow disease progression, but only transiently.

Medications indicated for Parkinson’s disease may also be used to treat motor symptoms, such as levodopa. In general, the benefit of this drug is usually of lesser intensity than that seen in Parkinson’s disease.

Are there drugs that should be avoided?

Patients with dementia with Lewy bodies may be very sensitive to the effects of neuroleptic drugs (haloperidol, risperidone, quetiapine, etc.). These are often used for the treatment of behavioral disturbance in neurodegenerative diseases and sometimes their use is unavoidable. Therefore, it is very important to monitor their effects and to adjust the dose appropriately.

It is also advisable to avoid drugs with anticholinergic action (some antidepressants, drugs to prevent urine leakage, antihistamines) and to limit the use of benzodiazepines.

Any pharmacological option must be supervised and controlled by a medical professional.

What other treatments are available?

Non-pharmacological management is also important. Cognitive stimulation exercises and the establishment of specific guidelines to avoid behavioral disturbances or improve apathy are recommended. Gait support measures (cane, walker…) may be useful if motor symptoms are prominent, in addition to the development of strategies to avoid falls.