ICD-11 Criteria for Dementia due to Diseases Classified Elsewhere (6D85 )
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.
6D85.0 Dementia
due to Parkinson disease
Dementia due to Parkinson disease
develops among individuals with idiopathic Parkinson disease and is
characterized by impairment in attention, memory, executive and visuo-spatial
functions. Mental and behavioral symptoms such as changes in affect, apathy and
hallucinations may also be present. Onset is insidious and the course is one of
gradual worsening of symptoms.
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.
6D85.1 Dementia
due to Huntington disease
Dementia due to Huntington disease
occurs as part of a widespread degeneration of the brain due to a trinucleotide
repeat expansion in the HTT gene, which is transmitted through autosomal
dominance. Onset of symptoms is insidious typically in the third and fourth
decade of life with gradual and slow progression. Initial symptoms typically
include impairments in executive functions with relative sparing of memory,
prior to the onset of motor deficits (bradykinesia and chorea) characteristic
of Huntington disease.
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.
Inclusions:
- Dementia
in Huntington chorea
6D85.2 Dementia
due to exposure to heavy metals and other toxins
Dementia due to exposure to heavy
metals and other toxins caused by toxic exposure to specific heavy metals such
as aluminium from dialysis water, lead, mercury or manganese. The
characteristic cognitive impairments in Dementia due to exposure to heavy
metals and other toxins depend on the specific heavy metal or toxin that the
individual has been exposed to but can affect any cognitive domain. Onset of
symptoms is related to exposure and progression can be rapid especially with
acute exposure. In many cases, symptoms are reversible when exposure is
identified and ceases. Investigations such as brain imaging or
neurophysiological testing may be abnormal. Lead poisoning is associated with
abnormalities on brain imaging including widespread calcification and increased
signal on MRI T2-weighted images of periventricular white matter, basal ganglia
hypothalamus and pons. Dementia due to aluminium toxicity may demonstrate
characteristic paroxysmal high-voltage delta EEG changes. Examination may make
evident other features such as peripheral neuropathy in the case of lead,
arsenic, or mercury.
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.
Exclusions:
- Dementia
due to psychoactive substances including medications (6D84)
6D85.3 Dementia
due to human immunodeficiency virus
Dementia due to human
immunodeficiency virus develops during the course of confirmed HIV disease, in
the absence of a concurrent illness or condition other than HIV infection that
could explain the clinical features. Although a variety of patterns of
cognitive deficit are possible depending on where the HIV pathogenic processes
have occurred, typically deficits follow a subcortical pattern with impairments
in executive function, processing speed, attention, and learning new
information. The course of Dementia due to human immunodeficiency virus varies
including resolution of symptoms, gradual decline in functioning, improvement,
or fluctuation in symptoms. Rapid decline in cognitive functioning is rare with
the advent of antiretroviral medications.
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.
6D85.4 Dementia
due to multiple sclerosis
Dementia due to multiple sclerosis
is a neurodegenerative disease due to the cerebral effects of multiple
sclerosis, a demyelinating disease. Onset of symptoms is insidious and not
secondary to the functional impairment attributable to the primary disease
(i.e., multiple sclerosis). Cognitive impairments vary according to the
location of demyelination but typically include deficits in processing speed,
memory, attention, and aspects of executive functioning.
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.
6D85.5 Dementia
due to prion disease
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.
6D85.6 Dementia
due to normal pressure hydrocephalus
Dementia due to normal pressure
hydrocephalus results from excess accumulation of cerebrospinal fluid in the
brain as a result of idiopathic, non-obstructive causes but can also be
secondary to haemorrhage, infection or inflammation. Progression is gradual but
intervention (e.g., shunt) may result in improvement of symptoms, especially if
administered earlier in the course of the condition. Typically, cognitive
impairments include reduced processing speed and deficits in executive
functioning and attention. These symptoms are also typically accompanied by
gait abnormalities and urinary incontinence. Brain imaging to reveal
ventricular volume and characterize brain displacement is often necessary to
confirm the diagnosis.
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.
6D85.7 Dementia
due to injury to the head
Dementia due to injury to the head
is caused by damage inflicted on the tissues of the brain as the direct or
indirect result of an external force. Trauma to the brain is known to have
resulted in loss of consciousness, amnesia, disorientation and confusion, or
neurological signs. The symptoms characteristic of Dementia due to injury to
the head must arise immediately following the trauma or after the individual
gains consciousness and must persist beyond the acute post-injury period.
Cognitive deficits vary depending on the specific brain areas affected and the
severity of the injury but can include impairments in attention, memory,
executive functioning, personality, processing speed, social cognition, and
language abilities.
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.
6D85.8 Dementia
due to pellagra
Dementia due to pellagra is caused
by persistent lack of vitamin B3 (niacin) or tryptophan either in the diet or
due to poor absorption in the gastrointestinal tract due to disease (e.g.,
Crohn disease) or due to the effects of some medications (e.g., isoniazid).
Core signs of pellagra include dermatological changes (sensitivity to sunlight,
lesions, alopecia, and oedema) and diarrhoea. With prolonged nutritional
deficiency cognitive symptoms that include aggressivity, motor disturbances
(ataxia and restlessness), confusion, and weakness are observed. Treatment with
nutritional supplementation (e.g., niacin) typically results in reversal of
symptoms.
Coding
Note: Code
aslo the causing condition
6D85.9 Dementia
due to Down syndrome
Dementia due to Down syndrome is a
neurodegenerative disorder related to the impact of abnormal increased
production and accumulation of amyloid precursor protein (APP) leading to
formation of beta-amyloid plaques and tau tangles. APP gene expression is
increased due to its location on chromosome 21, which is abnormally triplicated
in Down syndrome. Cognitive deficits and neuropathological features are similar
to those observed in Alzheimer disease. Onset is typically after the fourth
decade of life with a gradual decline in functioning, and may impact 50% or
more of individuals with Down syndrome.
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.
6D85.Y Dementia
due to other specified diseases classified elsewhere
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.
REFERENCE:
International Classification of Diseases Eleventh Revision (ICD-11). Geneva: World Health Organization; 2022. License: CC BY-ND 3.0 IGO.
https://creativecommons.org/licenses/by-nc-nd/3.0/igo/