Lewy Body Dementia

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What is Lewy Body Dementia?

Dementia with Lewy Bodies (DLB) is a type of dementia that is closely associated with Parkinson’s and Alzheimer’s diseases. The condition is anatomically characterized by presence of clumps of ubiquitin and alpha-synuclein in neurons, tiny, spherical deposits of protein that are found in the neurons or nerve cells. These protein deposits are detectable during postmortem brain histology.

DLB is the 2nd most common form of Progressive Dementia just after Alzheimer’s disease, and is known to cause progressive decline in one’s mental abilities. It affects nearly 1.3 million people only in United States.

Lewy Body Dementia History

The Lewy bodies were first discovered by the German scientist Friedrich Heinrich Lewy. The condition was named after him.

Lewy Body Dementia Causes

The factors that lead to the development of Dementia with Lewy Bodies are not clearly understood at present. A genetic connection with PARK11 gene is suspected, although no strong evidence has been found which indicate that DLB is an inherited condition. As in Alzheimer’s, the risk of DLB is heightened with the inheritance of ε4 allele of apolipoprotein E or APOE.

In some cases, Alzheimer’s disease and dementia with Lewy bodies may coexist in certain patients. Nearly 75% of old people having Parkinson’s disease will eventually develop dementia after ten years.

Lewy Body Dementia Symptoms

Although the specific symptoms of DLB that may be seen in an individual patient can vary, the core features of the condition remain more or less the same. These include fluctuating cognitive patterns with great variability in attention span and alertness on an hour to hour or day to day basis, recurrent episodes of visual hallucinations as well as motor aspects of Parkinson’s disease. The various suggestive signs are sleep behavior disorder with REM or rapid eye movement and also the abnormalities observed in SPECT or PET scans. Under the influence of REM, patients may feel compelled to act out their dreams.

The Parkinson’s features might include:

  • Reduced arm-swing while walking
  • Shuffling gait
  • Blank expression
  • Reduced facial expressions
  • Ratchet-like cogwheeling movements
  • Stiffness of movements
  • Sialorrhea
  • Low speech volume
  • Loss of memory
  • Extreme confusion
  • Difficulty in swallowing

Episodes of tremors are less frequent in DLB cases than in Parkinson’s. DLB patients frequently experience difficulty in judging distances and have issues with:

  • Syncope
  • Orthostatic hypotension
  • Transient loss of consciousness

They also have frequent periods of:

  • Drowsiness
  • Lethargy
  • Disorganized speech
  • Staring out into space for a long time

A very distinctive and critical clinical feature the patients display is an acute hypersensitivity to antiemetic and neuroleptic medications that affect the cholinergic and dopaminergic systems. Usage of these drugs can make the patients catatonic, lose all cognitive functions and/or develop life-impending muscle rigidity. Hence drugs like haloperidol, thioridazine or chlorpromazine should only be used with much caution and discrimination.

The visual hallucinations experienced by DLB patients generally involve seeing animals and people that are not actually there. Delusional misperceptions may incorporate reduplicative paramnesia or other elaborate misinterpretations. The hallucinations might not necessarily be disturbing to the patients. In fact, in some cases these visions can be amusing or insightful. A patient may even be aware of the fact that these visions are not real. Individuals having this form of dementia may also experience vision problems, have double vision, or misinterpret what they see. An example of this would include mistaking a heap of socks for a bunch of snakes.

Lewy Body Dementia Diagnosis

It might be difficult to diagnose DLB. Proper detection of DLB is important as this condition is known to induce intolerance towards certain medications. The diagnosis is made based on the persistent symptoms of visual hallucinations as well as stiffness and trembling associated with Parkinson’s. A doctor may recommend an EEG test if the symptoms are accompanied by seizure-like episodes. Brain scans and imaging tests may show cerebral degeneration which can help in evaluating the condition. However, it is not possible to detect the Lewy bodies until after the death of a sufferer.

Lewy Body Dementia Differential Diagnosis

A number of health conditions might show symptoms that are similar to that of DLB. The differential diagnosis of Dementia with Lewy Bodies include disorders such as:

  • Hydrocephalus
  • Vascular dementia
  • Intracranial tumors
  • Parkinson’s disease
  • Lacunar Syndromes
  • Alzheimer’s disease
  • Prion-Related Diseases
  • Cerebrovascular events
  • Parkinson-Plus Syndromes
  • Progressive Supranuclear Palsy
  • Temporal and Frontal Lobe Dementia
  • Cortical Basal Ganglionic Degeneration
  • Dementia with progressive supranuclear palsy

Lewy Body Dementia Treatment

No cure for DLB exists at present. Treatment procedures are palliative, with the main goal being managing the motor, cognitive and psychiatric symptoms of the condition. Acetylcholinesterase inhibitors like galantamine, rivastigmine and donepezil are mainly used for dealing with the cognitive problems of dementia with Lewy bodies. These medications can also be partially effective in minimizing the motor and psychiatric issues of the patient. Symptoms of hallucinations may be reduced with appropriate medications; however it can be difficult to try convincing the patient that nothing is actually there in reality. Sometimes providing reassurance or alternative distractions work better than telling the person about his or her hallucinatory experiences. Doctors normally avoid giving antipsychotic drugs for the hallucinatory symptoms as the motor symptoms could be worsened by neuroleptic sensitivity.

Researchers are currently of the opinion that the cholinesterase inhibitor medications that are used to manage Alzheimer’s disease might also be used in the treatment of DLB with positive results, even though they are not licensed for such use yet. National Institute of Clinical Excellence (NICE) believes that the usage of these drugs should be considered when it comes to treating DLB patients having non-cognitive symptoms. Recent studies reveal that the drug memantine can improve the general functioning of the DLB patients, although further conclusive studies are needed to confirm this. Patients experiencing symptoms like stiffness and rigidity because of Parkinsonism might benefit from the various anti-Parkinson’s disease medications like Levodopa, although these drugs can eventually make confusion and hallucinations worse. Mobility aids and physiotherapy sessions can help to alleviate these issues.

Rapid eye movement can be managed by administering Clonazepam, and orthostatic hypotension can be controlled by antihypotensive medications or table salt. Injecting botulinum toxins in the patient’s parotid glands can help to reduce sialorrhea. Medications like modafinil and methylphenidate helps in improving daytime alertness.

As in many cases treatment with drugs can aggravate the symptoms of DLB, doctors also recommend trying various non-drug approaches. The environment in which a patient is housed should be kept free of noise and clutter. This helps them to focus as well as function effectively. Family members or caregivers should also deal patiently with the individual affected by DLB and try to make him or her feel safe. Breaking tasks into small, easier steps and focusing on success also helps to alleviate the confidence level of patients. A definite routine and structural environment helps DLB sufferers to relate to things better.

Lewy Body Dementia Complications

Dementia with Lewy bodies is a progressive disorder whose signs and symptoms do worsen over time. The swallowing problems may eventually give rise to nutritional problems in patients. Immobility and dysphagia can cause pneumonia. Prolonged bed rest can give rise to decubitus ulcers. Severe dementia can occur at the later stages of this condition, ultimately leading to death.

Lewy Body Dementia Prognosis

Like Parkinson’s disease and Alzheimer’s disease, DLB is a neurodegenerative condition that leads to progressive intellectual as well as functional deterioration. It affects a person’s overall job performance in workplace, and may force him or her to take an early retirement. An individual with this condition also eventually loses his or her ability to drive a vehicle. The person loses his or her independence over time. DLB eventually shortens the life expectancy of the patient. No remedial measure is known to slow or stop the rate of progression of DLB.  Physical and mental disabilities gradually increase with time, and death can occur after a period of about 8 years.

Lewy Body Dementia Epidemiology

DLB has been known to affect European, Asian and African population. The condition is slightly more common in men than in women. The potentiality of being affected by this form of dementia increases with age.

DLB is a progressive form of dementia that gradually makes an individual helpless both mentally and physically. The condition cannot be fully cured; however treatment can help to manage the various symptoms associated with this condition. Regular care from family members or other caregivers is needed by a DLB patient for general functioning in day-to-day life.

References:

http://emedicine.medscape.com/article/1135041-overview

http://www.mayoclinic.com/health/lewy-body-dementia/DS00795

http://www.webmd.com/mental-health/dementia-lewy-bodies

http://www.ninds.nih.gov/disorders/dementiawithlewybodies/dementiawithlewybodies.htm

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