Pathophysiology of Delirium Transcript PDF

Pathophysiology of Delirium Transcript https://alt-5c5afaf83f339.blackboard.com/bbcswebdav/pid-2533795-dt-... Pathophysiology of Delirium In this section, we're going to talk about delirium, otherwise known as an acute confusional st...

Pathophysiology of Delirium Transcript https://alt-5c5afaf83f339.blackboard.com/bbcswebdav/pid-2533795-dt-... Pathophysiology of Delirium In this section, we're going to talk about delirium, otherwise known as an acute confusional state. Now, I think acute confusional state really de!nes it much better than the term delirium because we have the term acute meaning that it happens quickly, and obviously, it's sort of de!ned by confusion. And other de!ning characteristics tends to be transient, so it lasts for hours or days. So this is not a chronic condition. This is an acute condition that is hours to days. Now, so what is the pathophysiology of delirium? Well, the pathophysiology of delirium occurs in what is called the reticular activation system, or is sometimes called the RAS. So the reticular activation system is actually a collection of neuronal centers or neuronal clusters in the thalamus, the pons, and the medulla, and a few other places. There's some in the brain stem as well. Now, these areas of the reticular activation system is actually involved in several di"erent pathologies, including ADHD, and it can be involved in chronic dementias as well. But in this particular case, we're going to be talking about just how it is involved in the acute confusional state. So the acute confusional state is de!ned by a disruption of consciousness, so an altered state of consciousness, a loss of cognition or decreased cognition, and this is because of a decreased ability to focus. And it can be de!ned by underactivity or overactivity, so the person may be lethargic or agitated. And also, in some occasions it can be associated with hallucinations or intrusive thoughts. Now, so what is causing this? Well, the reticular activating system is responsible for helping us change states of consciousness. So the reticular activating system is the system that helps us wake up in the morning and stay awake and alert all day and fall asleep at night. It is changes to this reticular activating system that helps us change our level of consciousness or the sleep wake cycle. And it is also the reticular activating system that allows us to direct our attention. Okay? So if you have changes in the reticular activating system, you're going to directly impact this consciousness and directly impact our ability to focus and problem-solve. Okay? So interestingly enough, the elderly people actually have some atrophy and decreased activity in the reticular activating system. So it decreases with age. So this makes elderly people more prone to developing delirium. Now, however, again, this is an acute 1 of 3 12/8/24, 4:29 PM Pathophysiology of Delirium Transcript https://alt-5c5afaf83f339.blackboard.com/bbcswebdav/pid-2533795-dt-... condition, so elderly people may be prone to it, but they need another precipitating event. So what happens? Well, the reticular activating system is dependent on acetylcholine. Acetylcholine is one of the most... Actually, there's two sets of neurotransmitters that are very active in the reticular activating system. One is acetylcholine and the other is norepinephrine. So if we have things that change the level of acetylcholine that decrease the level or interfere with acetylcholine receptors, then we can cause delirium, and things that change the levels of norepinephrine in this area of the brain can also a"ect it. So what kinds of things can cause delirium? Anything that causes increased anticholinergic activity, anticholinergics, or increased norepinephrine levels. Now, there are all host of things that can do that. One is medications, bladder infections, because irritation of the bladder actually stimulates the vagus nerve. The bladder is integrated with the vagus nerve, and that kind of causes a vagal re#ex response that causes anticholinergic activity. So elderly people with UTIs and irritation to the bladder can develop delirium. Other types of infection or in#ammation or stress response, disruption of the sleep- wake cycle, so sleep apnea, hospitalization, because we tend to wake patients up every couple of hours, and the list goes on. Working up a patient with acute delirium, actually vitamin de!ciencies. And I'm not sure of the exact mechanism of this, but it probably has some e"ect on the acetylcholine or the acetylcholine receptors. So B6 and B12, and the list goes on. If you look at the table in the reading that I assigned on delirium, it will give you a very lengthy list of di"erent things that can cause delirium. So the workup can be sometimes very tricky. The way that I work up delirium is I begin with the history of the patient, and I talk to the patient and the family and try to !gure out, okay, so when did the delirium start? Okay, it started 24 hours ago. What changed in the last few days? Did the patient stop or start medications? Are they using any drugs of abuse? Narcotics, cocaine, anything like that can have direct impacts in their reticular activating system? How has their nutrition been? Is there any possibility that they have vitamin de!ciencies? Are there recent changes in health status? Could they have an infection? Have they been complaining of signs or symptoms of UTI? Have they been having di$culty sleeping, or do they snore very loudly? And then the other possibility can be electrolyte disturbances, because as we talked 2 of 3 12/8/24, 4:29 PM Pathophysiology of Delirium Transcript https://alt-5c5afaf83f339.blackboard.com/bbcswebdav/pid-2533795-dt-... about when we talked about action potentials and the importance of the sodium potassium pump, anything that changes the concentration levels of sodium, potassium, calcium, magnesium inside or outside of the cell can interfere with the action of neurons. So electrolytes disturbances can also be a culprit. Okay. So I hope that helps you to understand sort of the basis or the theory behind what may be the cause of delirium in most patients. Print this page 3 of 3 12/8/24, 4:29 PM