Dementia due to Lewy body disease

Description

Dementia preceding or occurring within one year after the onset of motor parkinsonian signs in the setting of Lewy body disease. Characterized by presence of Lewy bodies, which are intraneuronal inclusions containing α-synuclein and ubiquitin in the brain stem, limbic area, forebrain, and neocortex. Onset is insidious with attentional and executive functioning deficits often present. These cognitive deficits are often accompanied by visual hallucinations and symptoms of REM sleep behaviour disorder. Hallucinations in other sensory modalities, depressive symptoms, and delusions may also be present. The symptom presentation usually varies significantly over the course of days necessitating longitudinal assessment and differentiation from delirium. Spontaneous onset of Parkinsonism within approximately 1 year of the onset of cognitive symptoms is common.

Coding note

This category should never be used in primary tabulation. The codes are provided for use as supplementary or additional codes when it is desired to identify the presence of dementia in diseases classified elsewhere. When dementia is due to multiple aetiologies, code all that apply.

Coding note from above levels

This category should only be used for primary tabulation, if the aetiology of the dementia is unknown. If the aetiology of the dementia is known code to the aetiology of the dementia for primary tabulation. When dementia is due to multiple aetiologies, code all that apply.

Exclusions from above levels

• 6A00 – Disorders of intellectual development
• 6D70 – Delirium
• http://id.who.int/icd/entity/1516623224 – Neurodevelopmental disorders