Dementia due to prion disease

Description

Dementia due to prion disease is a primary neurodegenerative disease caused by a group of spongiform encephalopathies resulting from abnormal prion protein accumulation in the brain. These can be sporadic, genetic (caused by mutations in the prion-protein gene), or transmissible (acquired from an infected individual). Onset is insidious and there is a rapid progression of symptoms and impairment characterised by cognitive deficits, ataxia, and motor symptoms (myoclonus, chorea, or dystonia). Diagnosis is typically made on the basis of brain imaging studies, presence of characteristic proteins in spinal fluid, EEG, or genetic testing.

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