We’ve covered Alzheimer’s and said that that’s about 60% of all dementias but what about
the other 20 to 40%? Can you think of any other dementias? Let’s take a quick look
at a number of different kinds. You don’t need to know them in as much detail
as you need to understand Alzheimer’s but there are a number of different kinds of dementias.
Vascular dementia, this one pretty much makes sense because we have some kind of blockage
whether it’s an acute stroke or a progressive blockage of a vessel. Decreased oxygen levels
lend themselves to cells dying off and thus decrease synoptic connections
and perhaps dementia developing. Another type is Lewy body dementia. This one you definitely
need to be familiar with. We’ll talk about Lewy body specifically in a later lecture.
I will say though we don’t really understand how the Lewy bodies work. But again, it’s an aggregation
of proteins, so broken protein structures causing this aggregation interrupting signaling.
We see Parkinson’s disease dementia. Now, Parkinson’s disease as we’ll learn in another lecture
is predominantly a movement disorder. However, in the later stages, Parkinson’s will develop
its own form of dementia which, you know, it’s going to look fairly like Alzheimer’s.
Then there’s a fourth kind of dementia that stands out there which is frontotemporal dementia
that actually doesn’t really go any further than that. So we see symptoms associated with degradation
of the frontal and temporal lobes. Again, you don’t need to know specific details of each of these.
Just be familiar that these are four other kinds of dementia that we see in addition to Alzheimer’s disease.
I want to bring this up because often in practice, you will see or maybe not often, but you’ll see patients
come in that are acting as if they may have Alzheimer’s. You may be tempted to predict
that they are affected by Alzheimer’s. But as it turns out, about 50% of older adult patients
that make their way into the emergency room are experiencing some sort of episode of dementia.
But it’s episodic and we call that episodic dementia a delirium because it’s temporary, so it’s transient.
It turns out that we can incite, so to say, an Alzheimer’s-like condition with stressful situations.
Stressful situations, of course, anytime anyone ends up in a hospital especially the emergency room,
it’s going to be a stressful situation. Individuals may display these kinds of symptoms.
In fact, recently one of my friend’s mothers went into hospital and she was telling me it’s crazy.
My mom was working in the pharmacy one day. Two days later, she’s in the hospital insulting people
and yelling at people and acting like she has no idea what’s happened. So immediately, it came to mind
that she was having episodes of delirium because it turns out she had a very acute infection
in her shoulder. So, things like acute infections, dehydration resulting in electrolyte imbalance
can manifest themselves in an episode of delirium. The thing that characterizes them as separate from
regular dementias is that they go away and everything returns to normal. Now, some individuals
will experience this as a result of withdrawal from their drugs. Many older patients are on opioids
or any number of different antibiotics as was the case with my friend’s mom. Lots of these things
with withdrawal creates stress and thus can throw someone into an episode of delirium.
This is where the sort of word of delirium tremens comes from because they start displaying
some tremors perhaps also. So, something to certainly keep in mind when you are assessing patients.
Is this an episodic condition or has it been like this for a while and maintained itself
and become progressively worse? Hopefully, this lecture has given you some insight
into the variety of dementias that there are and a good understanding of how or what we know
about how Alzheimer’s disease works. So, I look forward to seeing you again shortly.