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What is delirium?

Visit us (http://www.khanacademy.org/science/healthcare-and-medicine) for health and medicine content or (http://www.khanacademy.org/test-prep/mcat) for MCAT related content. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video. Created by Tanner Marshall.

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Video transcript

- Delirium is defined as this acute, or like, sudden change in mental state. Which is different from dementia because remember that dementia usually is this, like, gradual change in the brain. Delirium, just like dementia though, affects things like your attention, your memory, your cognition and your consciousness level. But this change will usually happen over the course of hours or days, as opposed to years with dementia. Patients with delirium often have this decreased awareness of their environment and become very confused. So, if you're having a conversation with them they might not be able to stay focused on one particular topic and they might wander, or be easily distracted by something else. Or, they may simply not respond to the environment at all. They may also have this poor ability to remember things, especially with respect to recent events. And finally, in some cases they might have hallucinations, or extreme emotions, like fear, anxiety, anger and depression. Many of these symptoms are similar to symptoms of dementia. However, with delirium these symptoms can fluctuate throughout the day. So there might be periods where no symptoms are present and everything's normal. And then there might be sudden periods where some or all of the symptoms appear. And with that said, delirium and dementia are different disorders entirely. But because of the similarities in their symptoms, it can sometimes be really hard for doctors to distinguish between delirium and dementia. Especially because delirium can even happen alongside dementia. So, in order to tell the difference, there are a couple of important things that physicians will look for. They'll first try to figure out when the onset was. That is, when the change in mental state happened. Delirium is a relatively sudden change in cognition that seemingly can go from no symptoms at all, to major symptoms very quickly. Where dementia starts with these minor symptoms that usually get worse gradually, over the long periods of time. And they might also test the patient's attention. Staying focused and maintaining attention is often seriously limited with delirium. Where patients in their early stages of dementia are generally pretty alert. And finally, and probably most importantly, they'll try to figure out if the symptoms fluctuate. Symptoms of delirium can fluctuate significantly, coming and going throughout the day. If you plotted them on a graph, it might look something like this, where symptoms come and go relatively frequently. And patients with dementia, though, will have this pretty constant level of memory and thinking skills over time. It might get worse gradually, but you don't see this huge fluctuation like with delirium. Cases of delirium are usually caused by this disruption in the normal sending and receiving of brain signals. Which, more often than not, is from the lack of oxygen, or some other substance that the brain's used to receiving. And because of this, and unlike dementia, delirium is typically temporary and reversible. Which is a major distinction. It's not necessarily permanent like dementia is. And drugs are a very common cause of delirium, especially the ones that tend to cause a change in the way the brain functions, right? Drugs like anticholinergics, psychoactive drugs and opioides are all culprits. But also it can be caused by the withdrawal from certain drugs, and from alcohol. Alcoholics may develop delirium if they suddenly quit drinking alcohol after drinking for a long time. And this is sometimes called delirium tremens. Another major cause are stressful situations. Stressful situations alone might be enough to trigger delirium, especially when they're paired with drugs. For example, delirium is common after a surgery. Which is one, usually a very stressful ordeal, and two, usually accompanied by drugs or sedatives during the surgery, and likely pain medications after the surgery. Also, other physiologic conditions that may cause delirium are things like dehydration and electrolyte imbalances. And infections like urinary tract infections, pneumonia, skin infections and abdominal infections. Delirium is significantly more common in the older population. Although, it's unknown as to why, though there are a couple theories. One is that the neurotransmitter acetylcholine is reduced when the body is stressed, like with drugs or just stressful situations. Since the amount of the acetylcholine the brain makes tends to decrease as we age, older people are more susceptible to further drops in acetylcholine levels during stressful situations. Secondly, as we age, the body becomes less able to filter toxins in the blood and prevent them from entering the brain. So, as you age, it may be that more toxins are allowed to accumulate in the brain, therefore, making delirium more likely. Since delirium is, in fact, reversible, it's super, super important to have it properly treated. But the treatment given will depend on the underlying cause, right? For example, if dehydration is suspected, administering fluids and electrolytes will help correct the problem. Or, alternatively, if drugs are involved, removal of the drugs may help resolve the delirium. Often times it's important to provide supportive care for the patient if they're susceptible to cases of delirium, or during their recover from delirium. Keeping patients calm and oriented with their surroundings is very, very important. The less stressful, the better. Things that are helpful are things like regular verbal reminders of their location and what's going on, involvement of family members, use of relaxation techniques, and making sure that they're given proper nutrients and fluids.