What is Lewy Body Dementia?
Facts
Lewy body dementia (LBD) is a progressive brain disease and the second leading cause of degenerative dementia in the elderly. The clinical name, “dementia with Lewy bodies” (DLB), accounts for up to 20% of all dementia cases, or 800,000 patients in the US. Over 50% of Parkinson’s disease patients develop “Parkinson’s disease dementia” (PDD), which accounts for at least 750,000 patients. (PDD is also a Lewy body dementia.)
Other names for the Lewy body dementias are:
- Lewy body disease (LBD)
- Diffuse lewy body disease (DLBD)
- Cortical Lewy body disease (CLBD)
- Lewy body Variant of Alzheimer's (LBV)(LBVA)
- Parkinson's disease with dementia (PDD)
In the early 1900’s, while researching Parkinson's disease, the scientist Friederich H. Lewy discovered abnormal protein deposits that disrupt the brain's normal functioning. These Lewy body proteins are found in an area of the brain stem where they deplete the neurotransmitter dopamine, causing Parkinsonian symptoms. In Lewy body dementia, these abnormal proteins are diffuse throughout other areas of the brain, including the cerebral cortex. The brain chemical acetylcholine is depleted, causing disruption of perception, thinking, and behavior. Lewy body dementia exists either in pure form, or in conjunction with other brain changes, including those typically seen in Alzheimer's disease and Parkinson's disease.
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LBD Symptoms
Lewy body dementia symptoms and diagnostic criteria
Every person with LBD is different and will manifest different degrees of the following symptoms. Some will show no signs of certain features, especially in the early stages of the disease. Symptoms may fluctuate as often as moment-to-moment, hour-to-hour or day-to-day. NOTE: Some patients meet the criteria for LBD yet score in the normal range of some cognitive assessment tools. The Mini-Mental State Examination (MMSE), for example, cannot be relied upon to distinguish LBD from other common syndromes.
The latest clinical diagnostic criteria for LBD groups symptoms into three types:
Central feature
Progressive dementia
Deficits in attention and executive function are typical. Prominent memory impairment may not be evident in the early stages.
Core features:
- Fluctuating cognition with pronounced variations in attention and alertness.
- Recurrent complex visual hallucinations, typically well formed and detailed.
- Spontaneous features of parkinsonism.
Suggestive features:
- REM sleep behavior disorder (RBD), which can appear years before the onset of dementia and parkinsonism.
- Severe sensitivity to neuroleptics occurs in up to 50% of LBD patients who take them.
- Low dopamine transporter uptake in the brain's basal ganglia as seen on SPECT and PET imaging scans. (These scans are not yet available outside of research settings.)
Supportive features:
- Repeated falls and syncope (fainting).
- Transient, unexplained loss of consciousness.
- Autonomic dysfunction.
- Hallucinations of other modalities.
- Visuospatial abnormalities.
- Other psychiatric disturbances.
A clinical diagnosis of LBD can be probable or possible based on different symptom combinations.
A probable LBD diagnosis requires either:
- Dementia plus two or more core features, or
- Dementia plus one core feature and one or more suggestive features.
A possible LBD diagnosis requires:
- Dementia plus one core feature, or
- Dementia plus one or more suggestive features.
Symptoms Explained
In this section we'll discuss each of the symptoms, starting with the key word: dementia. Dementia is a process whereby the person becomes progressively confused. The earliest signs are usually memory problems, changes in their way of speaking, such as forgetting words, and personality problems. Cognitive symptoms of dementia include poor problem solving, difficulty with learning new skills and impaired decision making.
Other causes of dementia should be ruled out first, such as alcoholism, overuse of medication, thyroid or metabolic problems. Strokes can also cause dementia. If these reasons are ruled out then the person is said to have a degenerative dementia. Lewy Body Dementia is second only to Alzheimer's disease as the most common form of dementia.
Fluctuations in cognition will be noticeable to those who are close to the person with LBD, such as their partner. At times the person will be alert and then suddenly have acute episodes of confusion. These may last hours or days. Because of these fluctuations, it is not uncommon for it to be thought that the person is "faking". This fluctuation is not related to the well-known "sundowning" of Alzheimer's. In other words, there is no specific time of day when confusion can be seen to occur.
Hallucinations are usually, but not always, visual and often are more pronounced when the person is most confused. They are not necessarily frightening to the person. Other modalities of hallucinations include sound, taste, smell, and touch.
Parkinsonism or Parkinson's Disease symptoms, take the form of changes in gait; the person may shuffle or walk stiffly. There may also be frequent falls. Body stiffness in the arms or legs, or tremors may also occur. Parkinson's mask (blank stare, emotionless look on face), stooped posture, drooling and runny nose may be present.
REM Sleep Behavior Disorder (RBD) is often noted in persons with Lewy Body Dementia. During periods of REM sleep, the person will move, gesture and/or speak. There may be more pronounced confusion between the dream and waking reality when the person awakens. RBD may actually be the earliest symptom of LBD in some patients, and is now considered a significant risk factor for developing LBD. (One recent study found that nearly two-thirds of patients diagnosed with RBD developed degenerative brain diseases, including Lewy body dementia, Parkinson’s disease, and multiple system atrophy, after an average of 11 years of receiving an RBD diagnosis. All three diseases are called synucleinopathies, due to the presence of a mis-folded protein in the brain called alpha-synuclein.)
Sensitivity to neuroleptic (anti-psychotic) drugs is another significant symptom that may occur. These medications can worsen the Parkinsonism and/or decrease the cognition and/or increase the hallucinations. Neuroleptic Malignancy Syndrome, a life-threatening illness, has been reported in persons with Lewy Body Dementia. For this reason, it is very important that the proper diagnosis is made and that healthcare providers are educated about the disease.
Other Symptoms
Visuospatial difficulties, including depth perception, object orientation, directional sense and illusions may occur.
Autonomic dysfunction, including blood pressure fluctuations (e.g. postural/orthostatic hypotension) heart rate variability (HRV), sexual disturbances/impotence, constipation, urinary problems, hyperhidrosis (excessive sweating), decreased sweating/heat intolerance, syncope (fainting), dry eyes/mouth, and difficulty swallowing which may lead to aspiration pneumonia.
Other psychiatric disturbances may include systematized delusions, aggression and depression. The onset of aggression in LBD may have a variety of causes, including infections (e.g., UTI), medications, misinterpretation of the environment or personal interactions, and the natural progression of the disease. |
Diagnosing LBD
Diagnosis
An experienced clinician within the medical community should perform a diagnostic evaluation. If one is not available, the neurology department of the nearest medical university should be able to recommend appropriate resources or may even provide an experienced diagnostic team skilled in Lewy body dementia.
A thorough dementia diagnostic evaluation includes physical and neurological examinations, patient and family interviews (including a detailed lifestyle and medical history), and neuro-psychological and mental status tests. The patient’s functional ability, attention, language, visuospatial skills, memory and executive functioning are assessed. In addition, brain imaging (CT or MRI scans), blood tests and other laboratory studies may be performed. The evaluation will provide a clinical diagnosis. Currently, a conclusive diagnosis of LBD can be obtained only from a postmortem autopsy for which arrangements should be made in advance. Some research studies may offer brain autopsies as part of their protocols. Participating in research studies is a good way to benefit others with Lewy body dementia.
Medications
Medications are one of the most controversial subjects in dealing with LBD. A medication that doesn't work for one person may work for another person.
Prescribing should only be done by a physician who is thoroughly knowledgeable about LBD. With new medications and even “over-the-counter,” the patient should be closely monitored. At the first sign of an adverse reaction, consult with the patient's physician. Consider joining the online caregiver support groups to see what others have observed with prescription and over-the-counter medicines.
Risk Factors
Advanced age is considered to be the greatest risk factor for Lewy body dementia, with onset typically, but not always, between the ages of 50 and 85. Some cases have been reported much earlier. It appears to affect slightly more men than women. Having a family member with Lewy body dementia may increase a person’s risk. Observational studies suggest that adopting a healthy lifestyle (exercise, mental stimulation, nutrition) might delay age-associated dementias.
Prognosis and Stages
No cure or definitive treatment for Lewy body dementia has been discovered as yet. The disease has an average duration of 5 to 7 years. It is possible, though, for the time span to be anywhere from 2 to 20 years, depending on several factors, including the person’s overall health, age and severity of symptoms.
Defining the stages of disease progression for LBD is difficult. The symptoms, medicine management and duration of LBD vary greatly from person to person. To further complicate the stages assessment, LBD has a progressive but vacillating clinical course. It is typical to observe a significance progression, followed by regression back to a higher functioning level. Downward fluctuations are often caused by medications, infections or other compromises to the immune system, but may also be due to the natural course of the disease.
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