Type of dementia code NN

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Collection and usage attributes

There are many forms of dementia as defined by their putative pathologies. The cognitive symptoms of different causes of dementia often overlap, and multiple different causes of dementia can be present in a single person, especially after the age of 80. The codes 01-16 may only be assigned after a diagnosis has been recorded by a clinician.

A diagnosis of dementia should be made only after a clinical assessment, which should include:

• history taking from the person
• history taking from a person who knows the person well, if possible
• cognitive and mental state examination with a validated instrument
• physical examination
• a review of medication in order to identify and minimise use of medications, including over-the-counter products, that may adversely affect cognitive functioning and to simplify medication dosing
• consideration of other causes (including delirium or depression).

A basic dementia screen should be performed at the time of presentation, usually within primary care. It should include the following blood tests:

• routine haematology
• biochemistry tests (including electrolytes, calcium, glucose, and renal and liver function)
• thyroid function tests
• serum vitamin B12.

Structural imaging (with computed tomography (CT) or magnetic resonance imaging (MRI)) should usually be used in the assessment of people with suspected dementia to exclude other cerebral pathologies and to help establish the subtype diagnosis, unless clinical judgement indicates this inappropriate. Structural imaging may rarely be needed in those presenting with moderate-to-severe dementia, if the diagnosis is already clear.

CODE 01     Alzheimer’s disease

Alzheimer's disease is a primary degenerative cerebral disease of unknown aetiology with characteristic neuropathological and neuro-chemical features. The disorder is usually insidious in onset and develops slowly but steadily over a period of several years.

This code corresponds to ICD-10-AM code combinations assigning F00.00-F00.01, F00.10-F00.11, F00.20-F00.21, F00.90-F00.91, G30.0, G30.1, G30.8, or G30.9.

Two codes must be recorded i.e. F00.00-F00.01 with G30.0, F00.10-F00.11 with G30.1, F00.20-F00.21 with G30.8, or F00.90-F00.91 with G30.9.

CODE 02     Vascular dementia

Vascular dementia is the result of infarction of the brain due to vascular disease, including hypertensive cerebrovascular disease. The infarcts are usually small but cumulative in their effect. Onset is usually in later life.

This code corresponds to ICD-10-AM codes F01.00-F01.01, F01.10-F01.11, F01.20-F01.21, F01.30-F01.31, F01.80-F01.81, F01.90-F01.91.

CODE 03     Dementia with Lewy bodies

Dementia caused by the degeneration and death of nerve cells in the brain, and characterised by Lewy bodies. Also known as Lewy body dementia.

This code corresponds to ICD-10-AM code combinations assigning F02.80-F02.81 and G31.3. Two codes must be recorded.

CODE 04     Mixed dementia

The person has dementia with atypical or mixed presentation, not distinct to a single dementia type.

This code corresponds to ICD-10-AM code combinations assigning F00.20-F00.21 and G30.8. Two codes must be recorded.

CODE 05     Fronto-temporal dementia - Behavioural variant

A progressive dementia caused by nerve cell damage to the frontal lobes of the brain, often leading to changes in personality, emotion and behaviour, as well as reduced judgement, empathy and motivation. Also known as Pick’s disease.

This code corresponds to ICD-10-AM code combinations assigning F02.00-F02.01, and G31.0. Two codes must be recorded.

CODE 06     Fronto-temporal dementia - Primary progressive aphasia

A progressive dementia caused by nerve cell damage to the temporal lobes of the brain, leading to reduced abilities in language, speaking, writing and comprehension. Includes semantic variant and progressive non-fluent aphasia. Also known as Pick’s disease.

This code corresponds to ICD-10-AM code combinations assigning F02.00-F02.01, and G31.0. Two codes must be recorded.

CODE 07     Fronto-temporal dementia - Other/unspecified

The person has a confirmed diagnosis of fronto-temporal dementia where the type is not the behavioural variant (code 05) or primary progressive aphasia (code 06), or where the type is unknown or unspecified.

This code corresponds to ICD-10-AM code combinations assigning F02.00-F02.01, and G31.0. Two codes must be recorded.

CODE 08     Dementia in Creutzfeldt-Jakob disease

A progressive dementia with extensive neurological signs, due to specific neuropathological changes that are presumed to be caused by a transmissible agent. Onset is usually in middle or later life, but may be at any adult age. The course is subacute, leading to death within one to two years.

This code corresponds to ICD-10-AM code combinations assigning A81.0 and F02.10-F02.11. Two codes must be recorded.

CODE 09     Dementia in Huntington's disease

A dementia occurring as part of a widespread degeneration of the brain. The disorder is transmitted by a single autosomal dominant gene. Symptoms typically emerge in the third and fourth decade. Progression is slow, leading to death usually within 10 to 15 years.

This code corresponds to ICD-10-AM code combinations assigning F02.20-F02.21 and G10. Two codes must be recorded.

CODE 10     Dementia in Parkinson's disease

A dementia developing in the course of established Parkinson's disease. No particular distinguishing clinical features have yet been demonstrated.

This code corresponds to ICD-10-AM code combinations assigning F02.30-F02.31 and G20. Two codes must be recorded.

CODE 11     Dementia in human immunodeficiency virus disease

Dementia developing in the course of HIV disease, in the absence of a concurrent illness or condition other than HIV infection that could explain the clinical features.

This code corresponds to ICD-10-AM codes B22 and F02.40-F02.41. Two codes must be recorded.

CODE 12     Delirium superimposed on dementia

Delirium superimposed on dementia occurs when a delirium occurs concurrently with a pre-existing dementia.

This code corresponds to ICD-10-AM code F05.1.

CODE 13     Dementia due to use of alcohol

Dementia caused by a disorder in which alcohol-induced changes of cognition, affect, personality, or behaviour persist beyond the period during which alcohol might reasonably be assumed to be operating.

This code corresponds to ICD-10-AM code F10.7.

CODE 14     Dementia in other substance abuse

Dementia caused by a disorder in which substance-induced changes of cognition, affect, personality, or behaviour persist beyond the period during which a direct psychoactive substance-related effect might reasonably be assumed to be operating.

This code corresponds to ICD-10-AM codes F13.70-F13.79, F18.7.

CODE 15     Dementia in other conditions

The person has dementia due to specific disease. Where specific dementia types and another condition are recorded, the specific type assigned to CODE 01–CODE 14 should be used in preference to CODE 15.

This code is equivalent to ICD-10-AM codes F02.80-F02.81 used in conjunction with any of the following codes: E75.0-E75.6, G40.00-G40.91, E83.0, E83.5, E01.0-E01.8, E03.0-E03.9, T36-T65, G35, A52.1, E52, M30.0, M32.0-M32.9, B56.0-B56.9, B57.0-B57.5, N18.5, or E53.8. 

Two codes should be recorded, except where G31.3 is also recorded.

CODE 16     Unspecified dementia

The person has a confirmed diagnosis of dementia, and the type is unknown or unspecified.

This code is equivalent to ICD-10-AM codes F03.00-F03.01.

CODE 17     Suspected dementia/diagnosis not confirmed.

The person has undergone or is in the process of assessment for dementia and a diagnosis has not yet been clinically confirmed.

CODE 18     Not diagnosed with dementia after clinical assessment

The person has not received a diagnosis of Alzheimer’s disease, vascular dementia, mixed dementia, fronto-temporal dementia, dementia with Lewy bodies, dementia in other conditions or dementia of type unspecified, as recorded in CODE 01–CODE 16 after a clinical assessment.

CODE 98     Unknown

Record if person has not been assessed for dementia in a clinical setting.

CODE 99     Not stated/inadequately described

This code is for use where information is insufficient to assign CODE 01–CODE 18 or information is unclear or unavailable.

The diagnosis must be recorded in a clinical setting by a qualified clinician, i.e. Geriatrician, GP, Neurologist etc.

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