Lewy body dementia

Also called Dementia with Lewy bodies, DLB

Dementia with hallucinations, fluctuation and Parkinson's-like movement. The one where the wrong drug can kill.

What it is

Lewy body dementia accounts for perhaps 10 to 15% of dementia cases, and it is the type where getting the diagnosis right has the most immediate consequences.

Abnormal protein deposits called Lewy bodies build up in the brain. The result looks like a mixture of Alzheimer's disease and Parkinson's disease, with two distinctive extras: vivid visual hallucinations, and marked fluctuation in alertness from hour to hour.

Here is the part that must not be missed. Up to half of people with Lewy body dementia have a severe, sometimes fatal, reaction to antipsychotic medication. Haloperidol and similar drugs can cause rapid, irreversible deterioration.

Signs you might notice

Visual hallucinations, usually detailed and often of people or animals, occurring early rather than late.

Fluctuating attention: bright and conversational in the morning, vacant in the afternoon, with no obvious cause.

Movement changes: stiffness, slow shuffling walk, reduced facial expression, falls.

Acting out dreams during sleep, sometimes years before anything else. This is a strong early pointer.

Fainting, dizziness on standing, and severe sensitivity to antipsychotics.

How it can affect day-to-day life

The fluctuation causes accusations. Family and staff see somebody sharp at ten and absent at three, and conclude they are choosing when to engage. They are not.

Hallucinations are often not frightening to the person, and arguing about them is worse than accepting them.

Because it moves like Parkinson's and thinks like Alzheimer's, it commonly gets one label or the other, and the antipsychotic warning gets lost with the misdiagnosis.

Supporting someone well

Flag the antipsychotic sensitivity on every record, every admission, every handover. In capitals if necessary. This is the highest-stakes line in this entry.

Do not argue with hallucinations. Acknowledge, reassure, redirect, and check the lighting: shadows and reflections make them worse.

Work with the good hours. Put anything demanding into them and do not schedule around the calendar.

Manage falls actively, including checking lying and standing blood pressure.

Ask about cholinesterase inhibitors, which often help hallucinations and cognition more in this type than in other dementias.

Fiducia Guardian carries the alert, the medicines and what normal looks like into every setting, which is exactly the information an out-of-hours doctor does not otherwise have.

Where to get help

Ask a GP for a memory service referral and mention hallucinations and dream enactment specifically, because those are the features that point to this diagnosis.

Lewy Body Society produce a medication alert card. Get one and use it.

Alzheimer's Society support line: 0333 150 3456.