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Physical Medicine and Rehabilitation

Delirium – causes, symptoms, diagnosis, treatment & pathology

Delirium – causes, symptoms, diagnosis, treatment & pathology


Delirium is a common and very serious neuropsychiatric
syndrome. Typically it affects older patients with multiple medical problems, in fact up
to half of all elderly patients in the hospital will have an episode of delirium at some point,
but being said it can affect anyone – even children, even though that’s much less common.
So, what is delirium exactly? Well let’s look at a quick example. Let’s say there
is an elderly man with diabetes and heart disease, who comes into the hospital with
pneumonia. He might be slowly recovering, even about to go home, and then one evening
things change all of the sudden. He might get really hyperactive, and by that I mean
that he may get agitated or aggressive with the staff, mumble or say things incoherently,
and have disorganized thoughts or even delusions, perhaps talking about things that haven’t
happened or happened years ago. He might even hear or see things like hallucinations, and
not know where he is or what he’s doing there. We would call this an episode of delirium,
and it can be really scary for him or someone who is taking care of him, especially the
first time it happens because it can come out of the blue. These are the symptoms of
what we call hyperactive delirium. But there’s also hypoactive delirium which
is like the flip side of the coin. As an example, you might have a woman with a history of chronic
constipation who has recently come out of back surgery. If she has hypoactive delirium
she might feel suddenly sluggish and drowsy, less reactive and sullen, and might look withdrawn,
perhaps because she’s scared of having hallucinations. These symptoms of both hyperactive and hypoactive
delirium can start pretty suddenly and can happen off and on over the course of a few
hours to a few days, with some patients having what they call mix state delirium where they
are sometimes having hyperactive symptoms and sometimes having hypoactive symptoms.
As you might guess, delirium symptoms can be really tiresome for a patient and can make
them sleepy during the day, and keep them up at night – all of which causes massive
disruption to a person’s life and to the lives of their friends and family.   Even though this sounds pretty hard to miss,
delirium can often go unnoticed or confused with other conditions like dementia, which
has some similarities. To help distinguish delirium from dementia, there are some key
differences to keep in mind. Unlike delirium where the symptoms can start pretty suddenly,
patients with dementia typically have a slow mental decline over months to years. Early
on, dementia patients are also generally alert, oriented, have normal behavior, and don’t
have hallucinations. The good news is that unlike dementia, delirium is usually temporary,
resolving when the underlying cause is addressed promptly. Delirium can sometimes resolve within
hours to days. But in other cases, it takes weeks or months to fully resolve. So what causes delirium? Well the exact mechanism
is not well understood, and unlike a lot of diseases there probably is no single cause.
But we do have a lot of clues and these come from understanding the risk factors for getting
delirium in the first place. Patients who have had recent surgery are often at risk
for delirium, and it might be related to the effects of certain medications such as narcotic
pain medication, benzodiazepines, hypnotics, and anticholinergics as well as the underlying
diseases and chronic fatigue from not sleeping well in the hospital. Since delirium can also
cause trouble sleeping, losing sleep can turn into a dangerous cycle that can really worsen
the symptoms. There are a number of risk factors related to the person’s general health as
well, for example elderly patients with multiple medical problems, especially ones like dementia,
constipation, pneumonia, and urinary tract infections are at high risk for having delirium.
But even though we know these risk factors, there isn’t a specific pathophysiologic
mechanism that explains delirium that we know of – currently we only have theories. One
theory is looking at whether the overall level of neurotransmitters like acetylcholine, dopamine,
norepinephrine, and glutamate might cause delirium. Another theory is about how the
neuronal membrane may not be able to depolarize properly in delirium, and therefore can’t
transmit an action potential from one neuron to another. A third theory suggests that it
might also have to do with inflammatory cytokines that are released during an infection or trauma
that might interfere with the neuron’s ability to do its job. There are other theories as
well, and ultimately one or maybe all of these may be involved in the neuropsychiatric changes
that we call delirium. The good news is that there are things that
can be done to help prevent delirium from happening in the first place, and many of
these things can also help calm a patient down when they are experiencing delirium as
well. The biggest key is identifying people at risk, and this is usually done with the
help of multiple members of the team that interact with the patient in different ways.
As a quick example from before, a nurse might notice that a patient hasn’t been sleeping
well, a pharmacist might notice that they are on multiple opiates for pain control,
and a physician might notice that they have a history of delirium in their medical record.
Taken together this is a high-risk patient – and recognizing these high risk patients
often requires perspectives from various members of the medical team. Once you identify patients
at risk for delirium, it’s really important to help them feel as oriented and comfortable
as possible, you can do that by creating an environment similar to their home environment.
Basic things like reducing extra noise and stimulation by turning off the TV so that
they can feel more calm, and making sure that they have their glasses on and that their
hearing aids are working. Maintaining a good daily routine really helps as well – so that
means allowing them to eat healthy meals, stay well hydrated, stool regularly to avoid
constipation, stay mobile and as active as possible, and maintain healthy sleep habits.
This of course applies to everyone but becomes even more important with patients who are
at risk for delirium. Since we know that many patients with multiple medical problems develop
delirium after having surgery, it’s ideal to manage their pain using non-opiate pain
medications, as well as avoiding the other medications that we know can cause problems.
Finally, it’s always ideal to let patients feel like they are in control and avoid using
restraints or putting them in unfamiliar situations. This becomes particularly tricky when it seems
like a patient might be unsafe, but there are medications like Haloperidol or second
generation antipsychotics that can be used to help with patients with really severe symptoms. There are also some serious long-term effects
to think about – one of the most important ones is related to falling down. When patients
are feeling disoriented, agitated, and confused, they can easily stumble and fall – in fact
some studies show that patients with delirium are up to 6 times more likely to fall down.
These falls can lead to all sorts of painful consequences including broken bones, head
injuries, as well as bruises and bleeds. Unfortunately, this is why patients with delirium often end
up having longer hospitalizations, more medical complications, and ultimately higher mortality
rates.

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