Lewy body dementia (LBD)

• What is Lewy Body Dementia (LBD)
• Statistics on Lewy Body Dementia (LBD)
• Risk Factors for Lewy Body Dementia (LBD)
• Progression of Lewy Body Dementia (LBD)
• Symptoms of Lewy Body Dementia (LBD)
• Clinical Examination of Lewy Body Dementia (LBD)
• How is Lewy Body Dementia (LBD) Diagnosed?
• Prognosis of Lewy Body Dementia (LBD)
• How is Lewy Body Dementia (LBD) Treated?
• Lewy Body Dementia (LBD) References

What is Lewy Body Dementia (LBD)

Dementia with Lewy bodies (DLB) is a neurodegenerative disorder associated with abnormal structures (Lewy bodies) found in certain areas of the brain. In addition to dementia, patients with dementia with Lewy bodies experience hallucinations, motor impairment, and fluctuating alertness.

Statistics on Lewy Body Dementia (LBD)

Dementia with Lewy bodies is the third most frequent cause of dementia in older adults, and accounts for 15–35% of all dementias. Dementia with Lewy bodies is also the most common dementia syndrome associated with Parkinsonism. It is primarily a disease affecting the elderly population. Men may be at higher risk of developing Lewy body dementia than women.

Risk Factors for Lewy Body Dementia (LBD)

The cause of dementia with Lewy bodies is still unknown. A very few cases of familial (inherited) dementia with Lewy bodies have been reported, but this is rare.

Progression of Lewy Body Dementia (LBD)

As with other forms of dementia, the patient will experience a steady decline in their cognitive ability. This may include loss of recent memory, poor awareness of location and the development of inappropriate behaviours. This occurs in a similar fashion to Alzheimer’s disease.

In some cases of Lewy Body dementia, patients may also develop increased muscle activity resulting in muscle stiffness and the development of a tremor. The severity of the physical and psychological symptoms may fluctuate greatly, making some days more difficult than others. Patients with this disease may also be unusually sensitive to certain medications such as anti-psychotics and sedatives, which must be used carefully to avoid an increase in the severity of symptoms.

Symptoms of Lewy Body Dementia (LBD)

People with dementia with Lewy bodies may present with classical symptoms of any dementia: the subtle development of defects in thinking, reasoning, remembering, imagining, or learning words.

In particular, people with dementia with Lewy bodies will have the following:

1. Motor symptoms such as rigidity and tremor (similar to the symptoms of Parkinson’s disease).
2. Fluctuations in alertness and consciousness.
3. Frequent visual hallucinations.
4. Increased sensitivity to some drugs which act on the brain.

How is Lewy Body Dementia (LBD) Diagnosed?

As with other forms of dementia, the aim of investigation is to exclude other causes of the altered mental state. A large number of blood tests and imaging procedures will be carried out to exclude infection, electrolyte imbalance, anaemia, thyroid and liver disease. A CT and MRI scan of the patient’s head may be required to improve the accuracy of diagnosis and exclude certain brain conditions that may result in an altered mental state.

Prognosis of Lewy Body Dementia (LBD)

The prognosis of dementia with Lewy bodies is generally poor, as there is no specific treatment to reverse the progression of disease. Many patients with this form of dementia respond well to medications that may improve psychological and physical symptoms over a limited period of time. This condition, however, will inevitably progress over time.

How is Lewy Body Dementia (LBD) Treated?

Any secondary causes of DLB should be treated if found – these are infrequent (10%), but must be excluded as some causes are potentially reversible. There is currently no treatment to cure Lewy body dementia, or to slow its progression. As such, medical treatment aims to control the symptoms of the dementia, such as the muscle stiffness, tremor and psychiatric disturbances.

Medications can be divided into the following groups:

• Acetylchlinesterase inhibitors (e.g. galantamine or donepezil): these may be used to treat agitation and hallucinations, or to reduce confusion and symptom fluctuation. They do not worsen motor symptoms of disease.
• Anti-Parkinson’s medications (e.g. levodopa/carbidopa, dopamine agonists): these are used to treat the motor symptoms (muscle stiffness and tremor) of Parkinson’s disease, which are similar to the motor symptoms of Lewy body dementia. However, patients with DLB are often very sensitive to these medications, with little change to motor symptoms but worsening hallucinations and confusion. Because of this, anti-Parkinson’s medications are used very carefully in DLB, and only in patients with severe motor symptoms.
• Antidepressants: these may be used to treat symptoms of depression, common in patients with DLB.

More information

For more information on dementia, including Alzheimer’s disease and other types of dementia, information for carers of dementia patients and supportive care, as well as some useful tools and videos, see Dementia.

Lewy Body Dementia (LBD) References

1. Collerton D, Burn D, McKeith I, O’Brien J. Systematic review and meta-analysis show that dementia with Lewy bodies is a visual-perceptual and attentional-executive dementia. Dement Geriatr Cogn Disord. 2003; 16(4): 229-37. Abstract
2. Fernandez HH, Wu CK, Ott BR. Pharmacotherapy of dementia with Lewy bodies. Expert Opin Pharmacother. 2003; 4(11): 2027-37. Abstract
3. Galvin JE. Dementia with Lewy bodies. Arch Neurol. 2003; 60(9): 1332-5. Abstract
4. Braunwald E, Fauci AS, Kasper DL, et al. Harrison’s Principles of Internal Medicine (16th edition). New York: McGraw-Hill Publishing; 2005. Book
5. NINDS Dementia With Lewy Bodies Information Page [online]. National Institute of Neurological Disorders and Stroke; 2005 [cited 12 January 2006]. URL link
6. McKeith IG, Galasko D, Kosaka K, et al. Consensus guidelines for the clinical and pathologic diagnosis of dementia with Lewy bodies (DLB): Report of the consortium on DLB international workshop. Neurology. 1996; 47(5): 1113-24. Abstract
7. Small GW. Neuroimaging as a diagnostic tool in dementia with Lewy bodies. Dement Geriatr Cogn Disord. 2004; 17(Suppl 1): 25-31. Abstract
8. Kaufer DI. Pharmacologic treatment expectations in the management of dementia with Lewy bodies. Dement Geriatr Cogn Disord. 2004; 17(Suppl 1): 32-9. Abstract
9. Duda JE. Pathology and neurotransmitter abnormalities of dementia with Lewy bodies. Dement Geriatr Cogn Disord. 2004; 17(Suppl 1): 3-14. Abstract
10. Kumar P, Clark M (eds). Clinical Medicine (5th edition). Edinburgh: WB Saunders Company; 2002. Book