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Dementia with Lewy bodies

 
Neurological Disorder:

Lewy body dementia

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Definition

Lewy body dementia (LBD) is a neurodegenerative disorder that can occur in persons older than 65 years of age, which typically causes symptoms of cognitive (thinking) impairment and abnormal behavioral changes.

Description

The condition was first described by Frederick Lewy in 1941 when he described Lewy bodies, which are abnormal inclusions in the cytoplasm (components of a cell outside the nucleus) of cells found in patients who had Parkinson's disease (PD). There is some controversy concerning the relationship between Lewy body dementia and Parkinson's disease. When cognitive impairment and behavioral disturbance are early and prominent symptoms, then LBD is the likely diagnosis. When motor symptoms are the predominant and early symptoms, then Parkinson's disease is likely to be the diagnosis. Typically, on autopsy examination of the brain, both PD and LBD would probably demonstrate Lewy bodies. Autopsy examination is the only method to available for a definitive diagnosis.

The signs and symptoms of LBD stem from a multi-factorial cause of disrupted bidirectional (two-way) information flow in neurons, especially those located in the frontal lobe; that is, there are abnormalities in the chemicals that regulate and pass on message signals between neurons in the brain. Alterations in neurotransmitter chemicals can also impair nerve cell circuitry, causing abnormalities in bidirectional information flow.

Most patients with LBD also have brain evidence of Alzheimer's disease pathology. Additionally, most patients with LBD possess amyloid plaques in their cerebral cortex. Lewy bodies can also occur in a genetically transmitted form of Alzheimer's disease, Pick's disease, and Down syndrome.

Demographics

Dementia (used as a general term) has been an increasingly common disorder that is especially more frequent in the elderly. Dementia affects 7% of the general population older than 65 years and that incidence increases with age to 30% of those age 80 years and older. Autopsy results in the United States estimate that LBD accounts for 10–20% of dementia cases. Approximately 40% of patients with Alzheimer's disease also have LBD. Data from autopsy results in Europe and Japan reveal similar frequencies as reported in studies from the United States. No data is available concerning age, gender, or potential risk factors.

Causes and symptoms

The formation of Lewy bodies is thought to occur because of an abnormal increase in the production of a normally occurring protein in nerve cells called alpha-synuclein. Called upregulation, this overproduction can cause substances to accumulate or multiply in increased numbers. Other theories propose that alpha-synuclein may become insoluble (unable to mix in a watery environment), which could make the molecule more prone to accumulate abnormally in the brain.

Symptoms can include cognitive impairment, neurological signs, sleep disorder, and autonomic failure. Cognitive impairment is the presenting feature of LBD in most cases. Patients have recurrent episodes of confusion that progressively worsen. The fluctuation in cognitive ability is often associated with shifting degrees of attention and alertness. Cognitive impairment and fluctuations of thinking may vary over minutes, hours, or days.

Psychological manifestations

Psychological manifestations of LBD predominantly include:

Neurological symptoms in patients affected with LBD include extrapyramidal features early in the disease. The extrapyramidal symptoms in LBD can be differentiated from other dementias such as Parkinson's disease. Patients affected with LBD tend to show axial involvement with greater postural instability and facial impassivity, and less tremor. Disorders of sleep in patients with LBD typically can include impairment of rapid-eye-movement (REM) sleep; REM sleep behavior disorder causes vivid and frightening dreams. Patients may also exhibit loss of muscle tone or cataplexy, hypersomnolence (an increased inclination to sleep), hallucinations, and narcolepsy. Patients with LBD also have deficits in the autonomic nervous system, part of which regulates specific body functions such as blood pressure and bladder control. Autonomic abnormalities can cause orthostatic hypotension and urinary incontinence.

Diagnosis

Clinically, patients have features of fluctuating cognitive impairment such as from alert to confused state, recurrent visual hallucination, depression, and REM sleep disorder. Patients may have impairment of memory retrieval and they often do poorly on tests that measure visuospatial skills such as copying figures or drawing a clock. Patients may have mild gait (walking) impairment. An accurate diagnosis can include identification of target symptoms, including cognitive impairment, psychological disorders (hallucinations, depression, sleep disorder, and behavioral disturbances), extrapyramidal motor features or autonomic dysfunction (orthostatic hypotension), or urinary incontinence. Standard blood tests are ordered and additional tests are typically required, including thyroid studies, vitamin B-12 levels, and, if appropriate, tests for Lyme disease, syphilis, or HIV since these infections can affect the brain. Currently, there are no specific tests used to diagnose LBD. A magnetic resonance imaging (MRI) scan is indicated to distinguish LBD from another disorder called vascular dementia, which can present with similar clinical signs and symptoms. It is important to exclude diseases or drugs that can cause delirium.

Treatment team

The treatment team can be broad, including general practitioners, geriatric psychotherapists, emergency services, or movement disorder specialists. Additionally, the team can include family members, primary care practitioners, caregivers, and neurologists. Special consultations from a neurologist with special expertise in dementias may be appropriate for caregiver education.

Treatment

The management of LBD can be approached in four stages: accurate diagnosis, identification of target symptoms, nonpharmacological treatment, and pharmacological treatment. Nonpharmacological interventions include management of environment and other necessities associated with LBD patient care. Caregiving skills should be specifically tailored to the patient. Pharmacological treatment can include several different medications, most notably a class of drugs called cholinesterase inhibitors. These medications tend to increase a brain neurochemical called acetylcholine, which is an excitatory brain chemical that is decreased in persons with LBD. With a typical dose of a cholinesterase inhibitor (Donepezil or Aricept), the symptoms of visual hallucinations, apathy, anxiety, sleep disorder, and cognitive impairments can be improved. Generally, medications can be utilized to slow the rate of cognitive decline, treat agitation and hallucinations, treat depression, and improve cognition and/or alertness.

Recovery and rehabilitation

Generally, there are no dietary restrictions for persons affected with LBD, except for those who have swallowing impairment. Physical therapy and an exercise program can be useful to maintain mobility. There are potential problems for patients who drive a motor vehicle, and family members and caregivers should be advised.

Clinical trials

Currently, the National Institute of Neurological Disorders and Stroke (NINDS) supports research concerning diagnosis, prevention, and treatment. Research efforts studying the biological consequences of Lewy body formation and mechanisms of disease progression are funded by NINDS.

Prognosis

LBD is a slowly progressive chronic disorder. However, the rate of progression may be faster than in Alzheimer's disease. The disease is fatal from complications of poor nutrition, swallowing difficulties, and immobility.

Special concerns

Primary caregivers and family members require information concerning management of symptoms such as hallucinations, agitation, and cognitive changes. Children of patients with LBD may require genetic counseling. Family members should be aware that LBD affects job performance and medical leave of absence or early retirement may be advisable. Driving may become problematic and should be addressed with the medical treatment team, patient, and family.

Resources

BOOKS

Goetz, Christopher G., et al, eds. Textbook of Clinical Neurology, 1st ed. Philadelphia: W. B. Saunders Company, 1999.

Goldman, Lee, et al. Cecil's Textbook of Medicine, 21st ed. Philadelphia: W. B. Saunders Company, 2000.

PERIODICALS

McKeith, Ian. "Dementia with Lewy bodies." The Lancet Neurology 3, no. 1 (January 2004).

WEBSITES

Crystal, Howard A. eMedicine—Dementia with Lewy Bodies. November 11, 2003 (May 23, 2004). http://www.emedicine.com/neuro/topic91.htm.

Lewy Body Dementia.http://www.alzheimer.ca (May 23, 2004).

National Organization for Rare Disorders (NORD).http://www.rarediseases.org (May 23, 2004).

ORGANIZATIONS

National Institute on Aging, National Institutes of Health. Building 31, Room 5C27, Bethesda, MD 20892-2292. (301) 496-1752. http://nih.gov/nia.


Laith Farid Gulli, MD


Robert Ramirez, DO


Nicole Mallory, MS, PA-C


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Wikipedia: Dementia with Lewy bodies
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Home > Library > Miscellaneous > Wikipedia
Dementia with Lewy bodies
Classification and external resources

Lewy bodies are the pathophysiological characteristic of the disease
ICD-10 G31.8
ICD-9 331.82
DiseasesDB 3800
eMedicine neuro/91
MeSH D020961

Dementia with Lewy bodies (DLB), also known under a variety of other names including Lewy body dementia, diffuse Lewy body disease, cortical Lewy body disease, and senile dementia of Lewy type, is a type of dementia closely allied to Parkinson's Disease. It is characterized anatomically by the presence of Lewy bodies-- clumps of alpha-synuclein and ubiquitin protein in neurons, detectable in post-mortem brain biopsies.[1]

DLB is thought to be second only to Alzheimer's disease as a cause of dementia.[2][3]

Contents

Classification

Dementia with Lewy bodies overlaps clinically with Alzheimer's disease and Parkinson's disease, but is more associated with the latter [1]. Within DLB, the loss of cholinergic (acetylcholine-producing) neurons is thought to account for the degradation of cognitive functioning, as in Alzheimer's disease, while the loss of dopaminergic (dopamine-producing) neurons is thought to account for the degradation of motor control, as in Parkinson's disease. Thus, DLB is similar in some ways to both the dementia resulting from Alzheimer's disease and the movement problems of Parkinson's disease. The overlap of neuropathologies and presenting symptoms (cognitive, emotional, and motor) can make an accurate differential diagnosis difficult. In fact, it is often confused in its early stages with Alzheimer's disease and/or vascular dementia (multi-infarct dementia) although, where Alzheimer’s disease usually begins quite gradually, DLB often has a rapid or acute onset, with especially rapid decline in the first few months. DLB tends to progress more quickly than Alzheimer’s disease. [4] Despite the difficulty, prompt diagnosis of DLB is important because of the risks from sensitivity to neuroleptic drugs and because appropriate treatment of symptoms can improve life for both the person with DLB and caregivers.[4]

DLB is distinguished from the dementia that sometimes occurs in Parkinson's Disease by when dementia symptoms appears relative to Parkinsonian symptoms.[5] Parkinson's disease with dementia (PDD) would be the diagnosis when dementia onset is more than 1 year after the onset of parkinsonism. DLB is diagnosed when cognitive symptoms begin at the same time or within a year of Parkinsonian symptoms.

Signs and symptoms

While the specific symptoms in a person with DLB will vary, core features of DLB are: 1) fluctuating cognition with great variations in attention and alertness from day to day and hour to hour 2) recurrent visual hallucinations (observed in 75% of people with DLB), and 3) motor features of parkinsonism. Suggestive symptoms are rapid eye movement behavior disorder and abnormalities detected in PET or SPECT scans.[6]

Parkinsonism features could include shuffling gait, reduced arm-swing during walking, blank expression (reduced range of facial expression), stiffness of movements, ratchet-like cogwheeling movements; low speech volume, sialorrhea and difficulty swallowing. Tremors are less common in DLB than in Parkinson's disease.[7] DLB patients also often experience problems from orthostasis, including repeated falls, syncope (fainting), and transient loss of consciousness.

One of the most critical and distinctive clinical features is hypersensitivity to neuroleptic and antiemetic medications that affect dopaminergic and cholinergic systems.[8] In the worst cases, a patient treated with these drugs could become catatonic, lose cognitive function and/or develop life-threatening muscle rigidity. Some commonly used drugs which should be used with great caution, if at all, for people with DLB are chlorpromazine, haloperidol, or thioridazine.[4]

Visual hallucinations in people with DLB most commonly involve perception of people or animals that aren't there. Delusions may include reduplicative paramnesia and other elaborate misperceptions or misinterpretations.[9] These hallucinations are not necessarily disturbing. In some cases, the person with DLB may have insight into the hallucinations and even be amused by them or conscious that they are not really there, for example. People with DLB may also have problems with vision, including double vision[4] and misinterpretation of what they see, for example, mistaking a pile of socks for snakes or a clothes closet for the bathroom.[9]

Causes

The causes are not yet well understood, but a locus at PARK11 has been described.[10] As with Alzheimer's and Parkinson's diseases, most cases of DLB appear sporadically and DLB is not thought to be a strongly hereditary disease[8]. As with Alzheimer's Disease, DLB risk is heightened with inheritance of the ε4 allele of the apolipoprotein E (APOE).[11]

Pathophysiology

Pathologically, DLB is characterized by the development of abnormal proteinaceous (alpha-synuclein) cytoplasmic inclusions, called Lewy bodies, throughout the brain. These inclusions have similar structural features to "classical" Lewy bodies seen subcortically in Parkinson's disease. Additionally, there is a loss of dopamine-producing neurons (in the substantia nigra) similar to that seen in Parkinson's disease, and a loss of acetylcholine-producing neurons (in the basal nucleus of Meynert and elsewhere) similar to that seen in Alzheimer's disease. Cerebral atrophy (or shrinkage) also occurs as the cerebral cortex degenerates. Autopsy series have revealed that the pathology of DLB is often concomitant with the pathology of Alzheimer's disease. That is, when Lewy body inclusions are found in the cortex, they often co-occur with Alzheimer's disease pathology found primarily in the hippocampus, including: senile plaques (deposited beta-amyloid protein), and granulovacuolar degeneration (grainy deposits within, and a clear zone around hippocampal neurons). Neurofibrillary tangles (abnormally phosphorylated tau protein) are less common in DLB, and it is not clear whether DLB is an Alzheimer's variant or a separate disease entity. [1] [12], [13], [14]

Management

There is no cure for DLB; available treatments offer relatively small symptomatic benefit but remain palliative in nature. Current treatments can be divided into pharmaceutical, and caregiving.

Pharmaceutical

Pharmaceutical management, as with Parkinson's disease, involves striking a balance between treating the motor and emotive/cognitive symptoms.

Treatment of the movement portion of the disease can worsen hallucinations and psychosis, while treatment of hallucinations and psychosis can worsen parkinsonian symptoms. Doctors may find that the use of cholinesterase inhibitors represents the treatment of choice for cognitive problems and donepezil (Aricept), rivastigmine (Exelon) and galantamine (Reminyl) may be recommended as a means to help with these problems and to slow or prevent the decline of cognitive function.[4] Reports indicate that Lewy body dementia may be more responsive to donepezil than Alzheimer's disease.[15] Sinemet may help with movement problems, but in some cases may, like dopamine agonists, tend to aggravate psychosis in people with DLB. Clonazepam may help with Rapid eye movement behavior disorder; table salt or antihypotensive medications may help with fainting and other problems associated with orthostasis. Botulinum toxin injections in the parotid glands may help with sialorrhea. Other medications, such as methylphenidate and modafinil, may improve daytime alertness.[1] Experts advise extreme caution in the use of anti-psychotic medication in people with DLB because of their sensitivity to these agents. When these medications must be used, atypical antipsychotics are preferred to typical antipsychotics; a very low dose should be tried initially and escalated only slowly; and patients should be carefully monitored for bad reactions to the drugs.

Due to hypersensitivity to neuroleptics prevention of DLB patients taking this drugs is of great importance. People with DLB are at risk for Neuroleptic Malignant Syndrome, a life-threatening illness, because of their sensitivity to these medications, especially the older Typical antipsychotics such as haloperidol. Other medications, including drugs for urinary incontinence and the cold medication Benadryl can also exacerbate dementia.

Caregiving

Because DLB has no cure, it gradually renders people incapable of tending to their own needs. Caregiving is thus very important and must be carefully managed over the course of the disease. Caring for people with DLB involves adapting the home environment, schedule, activities, and communications to accommodate declining cognitive skills and parkinsonian symptoms.[9]

People with DLB may swing dramatically between good days -- high alertness and few cognitive or movement problems -- and bad days, and the level of care they need may thus vary widely and unpredictably. Sharp changes in behavior may be due to the day-to-day variability of DLB, but they may also be triggered by changes in the schedule or home environment, or by physical problems, such as constipation, dehydration, bladder infection, injuries from falls and other problems that the person with DLB may not be able to convey to caregivers. Potential physical problems should always be checked out when a person with DLB becomes agitated.

Especially when hallucinations and delusions are not dangerous or troubling to the person with DLB, it may be best for caregivers not to disabuse patients of them. Often the best approach may be benign neglect -- acknowledging, but not encouraging or agreeing. Trying to talk the DLB patient out of his delusion may be frustrating to caregivers and discouraging to patients, sometimes provoking anger or dejection. When misperceptions, hallucinations, and the behaviors stemming from these become troublesome, caregivers should try to identify and eliminate environmental triggers, and perhaps offer cues or "therapeutic white lies" to steer patients out of trouble. Doctors may prescribe low doses of atypical antipsychotics, such as quetiapine for psychosis and agitation in DLB. A small clinical trial found that about half of DLB patients treated with low doses of quetiapine experienced significant reduction in these symptoms. Unfortunately, several participants in the study had to discontinue treatment because of side-effects -- excessive daytime sleepiness or orthostatic hypotension.[5]

Changes in the schedule or environment, delusions, hallucinations, misperceptions, and sleep problems may also trigger behavior changes. It can help people with DLB to encourage exercise; simplify the visual environment; stick to a routine; and avoid asking too much (or too little) of them. Speaking slowly and sticking to essential information improves communication. The potential for visual misperception and hallucinations, in addition to the risk of abrupt and dramatic swings in cognition and motor impairment should put families on alert to the dangers of driving with DLB.[11]

Epidemiology

DLB is thought to be second only to Alzheimer's disease as a cause of dementia.[2][3] Current estimates are that about 60 to 75% of diagnosed dementias are of the Alzheimer's and mixed (Alzheimer's and vascular dementia) type, 10 to 15% are Lewy body type, with the remaining types being of an entire spectrum of dementias including frontotemporal lobar degeneration, alcoholic dementia, pure vascular dementia, etc. It is slightly more prevalent in men than women.[11]

History

Frederic Lewy (1885-1950) was first to discover the abnormal protein deposits ("Lewy body inclusions") in the early 1900s.[16] Dementia with Lewy bodies only started to be diagnosed in the mid-1990s after the discovery of alpha-synuclein staining first highlighted Lewy bodies in the cortex of post-mortem brains of a subset of dementia patients.[8] Because it was only recently discovered, DLB is not a recognized diagnosis in DSM-IV, which was published in 1994. It is, however, briefly mentioned in the DSM-IV-TR (published in 2000) under Dementia Due to Other General Medical Conditions. In 1996, a consortium of scientists initially proposed and later revised diagnostic guidelines.

References

  1. ^ a b c d Van Gerpen, Jay A.; Assn, Lewy Body Dementia (2007), New Trends in Lewy Body Dementia, from "The Many Faces of Lewy Body Dementia" series at Coral Springs Medical Center, FL, http://www.youtube.com/watch?v=ql87Lmw4wJo 
  2. ^ a b Heidebrink JL (2002). "Is dementia with Lewy bodies the second most common cause of dementia?". J Geriatr Psychiatry Neurol 15 (4): 182–7. PMID 12489913. 
  3. ^ a b Zaccai J, McCracken C, Brayne C (November 2005). "A systematic review of prevalence and incidence studies of dementia with Lewy bodies". Age Ageing 34 (6): 561–6. doi:10.1093/ageing/afi190. PMID 16267179. http://ageing.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=16267179. 
  4. ^ a b c d e Scotland, Alzheimer; Dementia, Action on, Dementia with Lewy Bodies, http://www.alzscot.org/pages/info/lewybody.htm 
  5. ^ a b Weintraub, Daniel; Hurtig, Howard I. (2007), "Presentation and Management of Psychosis in Parkinson's Disease and Dementia with Lewy Bodies", American Journal of Psychiatry 164 (10): 1491–1498, doi:10.1176/appi.ajp.2007.07040715, PMID 17898337, http://ajp.psychiatryonline.org/cgi/content/full/164/10/1491?ijkey=09b84ab4e4b96ff64717b438a92784dbf5daae61&keytype2=tf_ipsecsha 
  6. ^ Association Inc., Lewy Body Dementia (2007), "What is Lewy Body Dementia", Slideshare, http://www.slideshare.net/guest89f54/what-is-lewy-body-dementia-presentation 
  7. ^ Lennox, Graham; Lewy-net, Nottingham Medical School, Dementia with Lewy Bodies, http://www.nottingham.ac.uk/pathology/lewy/lewyinfo.html 
  8. ^ a b c Stewart, Jonathan T.; Assn, Lewy Body Dementia (2007), Difficulties in Diagnosing Lewy Body Dementia, from "The Many Faces of Lewy Body Dementia" series at Coral Springs Medical Center, FL, http://www.youtube.com/watch?v=mbMXYB-Kf3g 
  9. ^ a b c Ferman, Tanis J.; Assn, Lewy Body Dementia (2007), Behavioral Challenges in Dementia with Lewy Bodies, from "The Many Faces of Lewy Body Dementia" series at Coral Springs Medical Center, FL, http://www.youtube.com/watch?v=3nJQncMlneI 
  10. ^ Bogaerts V, Engelborghs S, Kumar-Singh S, et al. (September 2007). "A novel locus for dementia with Lewy bodies: a clinically and genetically heterogeneous disorder". Brain 130 (Pt 9): 2277–91. doi:10.1093/brain/awm167. PMID 17681982. http://brain.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=17681982. 
  11. ^ a b c Crystal, Howard A. (2008), "Dementia with Lewy Bodies", E-Medicine from WebMD, http://emedicine.medscape.com/article/1135041-overview 
  12. ^ Uchikado H, Lin WL, DeLucia MW, Dickson DW . PMID 16825955. Alzheimer disease with amygdala Lewy bodies: a distinct form of alpha-synucleinopathy]
  13. ^ Kotzbauer PT, Trojanowsk JQ, Lee VM . PMID 11816795.  Lewy body pathology in Alzheimer's disease
  14. ^ http://www.oumedicine.com/body.cfm?id=844&action=detail&aeproductid=Adam2004_1&aearticleid=000739
  15. ^ Neef, Doug Walling, "Dementia with Lewy Bodies: an Emerging Disease", Am Fam Physician 73 (7): 1223–1229, PMID 16623209 
  16. ^ Lewy body dementia at Who Named It?

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