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Can Anesthesia Cause or Worsen Dementia?

Can Anesthesia Cause Dementia

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Are you considering getting hip joint surgery to fix the pain you’ve been having? But you’re worried about how the anesthesia will affect you?

It is understandable that you might worry about the likelihood of memory loss following general anesthesia. Or if being under anesthesia could make you more susceptible to developing dementia.

When someone older needs surgery, there are many factors to consider. One of which is how the anesthesia will affect them. There’s often a concern that an anesthetic may cause dementia.

Even though the answer to this question is “no,” an anesthetic cannot induce dementia. Yet, it can have other consequences that mirror the symptoms of dementia. When planning a surgery, you should consider this.

It is quite natural to experience anxiety over the administration of an anesthetic. The consequences that it will have on your body. These questions have been the subject of investigation in many studies.

However, the essential thing for anyone who plans to undergo surgery is to discuss with their doctor about the advantages and disadvantages of the procedure.

Different Kinds of Anesthesia

Surgical operations typically involve anesthesia. Anesthesia is referred to as a medical  treatment that keeps one from feeling pain during surgery and procedures. Depending on the surgery type, there are different types of anesthesia. These different types include the following: general anesthesia, local anesthesia, regional anesthesia, sedation. General anesthesia is typically used for more invasive surgeries.

Is There a Link Between Exposure to General Anesthetics And Dementia?

After surgery, some older patients encounter cognitive difficulties or changes in behavior. But for the most part, these issues are only temporary concerns.

More than half a century ago, it was hypothesized that as many as 7% of older adults who underwent surgery might develop a kind of dementia. But, the data supporting this was purely anecdotal. However, more subtle shifts in cognition were more typical.

Recent research explored postoperative reasoning or cognitive alterations, their causes, and long-term effects. Cognitive function can decreas after surgery (when compared to their cognitive function before surgery).

Changes in thinking can manifest themselves after surgery. It could be confusion, delirium, or a decline in certain aspects of cognitive function. Cognitive impairments after surgery and anesthesia are similar to general cognitive decline.

Therefore, new research has been done, keeping in mind the current needs. It will match cognitive alterations after surgery with cognitive changes that occur in the community. These are referred to as mild cognitive impairment (MCI) and dementia.

Aligning terminology will help researchers and medical professionals. They can better understand postoperative cognitive dysfunction (POCD) and cognitive decline in the general population. Delirium is also something that can occur post surgery. In the next few paragraphs, we will discuss the differences between delirium and POCD that can arise following surgery.

Delirium following surgery is a temporary and variable disruption of cognition. It is common for patients to have delirium after surgery. It often takes place in the days directly following surgery when patients are still in the hospital. Hence, there are differences in the courses of delirium and postoperative cognitive decline.

Postoperative cognitive dysfunction can arise anywhere from weeks to months after surgery. There is evidence that postoperative cognitive dysfunction may be persistent. In certain cases, it lasts for more than five years following surgery. See below for more in depth information on each topic.

Postoperative Cognitive Dysfunction (POCD)

Postoperative Cognitive Dysfunction (POCD)

Postoperative cognitive dysfunction is a deterioration in a patient’s cognitive functioning after surgery. Changes in the individual’s ability to perform short cognitive function tests indicate a decline.

The performance changes that generally give rise to a categorization of POCD are subtle. These changes in performance may go unnoticed by others. They may even appear to be only slight modifications in a person’s capacity to operate in normal life. In any case, a person may be diagnosed with POCD.

Alzheimer’s disease can cause a deterioration in thinking that disrupts some people’s daily lives.

People under the age of 40 have only very seldom been reported to have POCD. The condition is most common in people aged 65 and older. There is some indication of cognitive alterations similar to POCD in middle-aged people. But these changes are less obvious.

The following show indications of POCD one to two weeks after surgery:

  • 50% of cardiac surgery patients
  • 20% of other major surgery patients
  • 7% of minor surgery patients

Older, sicker, more surgically complex, or postoperatively problematic patients are more prone to develop POCD. Patients who have issues after surgery also have a higher risk of having POCD.

Approximately 10% of patients, no matter what kind of surgery they had, will get POCD three months following the procedure. Therefore, there is a decrease in the frequency of POCD over the weeks following major surgery. This indicates that most patients recover and get back to normal after the procedure.

Delirium

Delirium

In most cases, the cognitive and attentional deficits brought on by delirium may be treated successfully and quickly. Signs and symptoms appear suddenly and shift throughout the day. Some of these symptoms are:

  • Haziness
  • Agitation
  • Anxiety
  • Irritability
  • Detachment from others
  • Inability to focus
  • Sleep problems

The most prevalent reasons are age-related and include medication, illness, and metabolic disruption.

However, delirium is a common side effect of surgery. Multiple medications and longer and more complicated surgery could be the culprits. Other reasons that could increase the risk of delirium:

  • Fluid loss
  • Malnutrition
  • Physical or mental illness
  • Disorientation to time and place
  • Impaired senses (poor vision or hearing without aids)
  • Pain
  • Advanced age
  • Preexisting cognitive deficits or dementia

Older patients often experience delirium following surgery. Studies show that it affects 10%-15% of outpatient surgery patients, 30%-50% of major surgery patients, and 60% of heart surgery patients.

Delirium causes prolonged hospital stays and slower recoveries. Therefore it’s crucial to identify and treat the causes of this condition. Postoperative delirium in elderly individuals is likely to be underdiagnosed.

Delirium after surgery typically occurs on the first or second post-op day. Its symptoms tend to be more severe after the sun goes down. While most patients will feel better within some days, some may experience delirium for weeks or months. It’s important to note that persistent delirium differs from dementia.

Can Anesthesia Trigger Dementia in Healthy Older People?

Alzheimer’s disease is characterized by protein ‘plaques’ in the brain. In animal studies, certain anesthetics speed up brain cell plaque formation. Lab results may not match what happens in a living person undergoing surgery and anesthesia.

Several inhaled anesthetics employed in this animal research are no longer used in hospitals. This further weakens the Alzheimer’s-like mechanism theory. Surgery and anesthesia have not been linked to Alzheimer’s disease or other kinds of dementia in these trials.

The use of general anesthesia in the past has not been linked to an increased risk of dementia.

Patients with early-stage dementia, which may go unnoticed and unreported, may be more likely to have POCD due to brain changes. The possibility exists that they will get dementia later in life. The stress of surgery might amplify whatever cognitive decline that was already there.

Research has indicated that individuals with postoperative delirium are at a higher risk of acquiring dementia. Postoperative delirium increases the risk of dementia; however, most patients don’t develop it.

Can The Effects of Anesthesia Worsen Dementia?

People with dementia have a higher chance of having delirium for any cause, not only after surgical procedures. But, it is important to keep in mind that delirium is a different condition that passes quickly. Thus, it is not a sign of a growing dementia condition.

People who have dementia are more likely to experience it for a longer period. Because of this, it might be more challenging to determine what causes it and then cure it.

It’s also important the anesthesia team is made aware if the person has dementia before surgery so the anesthetic can be tailored for that individual. Also, postoperative pain management for people living with dementia is an essential component.

Those living with dementia  may have a harder time communicating the degree of discomfort they are in.

Because it is recognized that pain might raise the likelihood of delirium, pain must be managed appropriately.

Research

Multiple studies have investigated the impact of anesthetics on individuals. Some 130,000 adults aged 65 and up were analyzed in research on the effects of general anesthesia in the previous seven years. Researchers discovered that using general anesthesia increased one’s risk of developing dementia.

There was a correlation between the patient’s age at the time of operation and their chance of developing dementia. According to the study’s authors, aging brains may be more vulnerable to anesthetic-induced harm.

Another research looked at the cognitive abilities of almost 8,500 sets of twins. They concluded that neither surgery nor general anesthetics increased the risk of dementia. The condition that the surgery treated was more likely to have caused cognitive decline than the procedure itself.

Dementia risk is known to rise in people with certain heart and circulatory system problems. Those experiencing these issues are also more likely to need surgery.

Postoperative delirium disrupts cognition and memory after surgery. It would indicate that older people are at a greater risk of developing this condition. Studies provide inconsistent conclusions on the link between temporary shifts and dementia in old age.

General anesthetics may cause transitory cognitive changes, according to certain research. One study suggests seniors may benefit more from particular types of anesthetic. It can help them to regain cognitive function after brain changes.

This suggests that general anesthesia may affect cognition and short-term memory after surgery.

Summary

Some research suggests a relationship between anesthesia and dementia. But, not enough investigations exist to determine if there is a genuine connection.

Instead of fretting about anesthetics and cognitive impairment, take precautions. They include watching your diet, getting regular exercise, and keeping your blood pressure in check. These have been shown to reduce the risk of dementia time and time again in scientific studies.

References

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