Now we will talk about important cognitive disorders -
formerly and colloquially referred to as dementia.
Which is defined as an impairment of memory and other cognitive functions,
very importantly though, this is without an alteration in ones level of consciousness.
Most forms of dementia are progressive and irreversible; however, some forms are treatable.
The incidence of dementia increases with age and 20% of people over 80
will actually have some form of dementia. Some of the symptoms of dementia
that you may see are actually psychiatric symptoms. Things like delusions and hallucinations
which will occur in up to 30% of people with dementia.
Also, affective symptoms like mood disorder, depression, or mania
will be seen in up to 50% of people with dementia.
Personality changes can also occur and the most common causes of dementia
are the following three: Alzheimer's disease leading the group, followed by vascular dementia,
vascular disease important to note is a stepwise decline in the progression to dementia
whereas non-vascular disease is a very steep decline in ones cognitive functioning.
There is also major depression which can be a very common cause of dementia.
Major depression causing dementia is actually called pseudo-dementia,
so it's very important to rule this out before attributing cognition and memory loss to dementia.
It's very important to make sure that you are not just dealing
with somebody who has depression because that is very treatable
and their cognition can significantly improve when appropriately managed.
Here's a question for you, what is the differential diagnosis for dementia?
Well, let's start with organic causes and again it is very important to rule out
general medical conditions when considering any disorder.
So there can be structural problems, things like a normal pressure hydrocephalus,
normal forgetfulness with aging, a subdural hematoma, Huntington's disease,
multiple sclerosis, Down's syndrome, head trauma, a brain tumor, and also Parkinson's disease.
There can be metabolic problems like B12 or folate deficiency, thiamine deficiency,
Wilson's disease, hypoxia, lead toxicity, and also hypothyroidism.
There can be infectious causes that look like dementia, things like encephalitis and meningitis,
CJD, neurosyphilis, HIV, and also Lyme disease. Certain drugs are also gonna be included
in your differential diagnosis for dementia. So consider alcohol, phenothiazines, anticholinergics,
and sedatives. Also, you wanna make sure to rule out psychiatric disorders,
things such as pseudo-dementia, delirium, schizophrenia,
and also malingering where a patient is basically looking for secondary gain.