Penn Researchers Find No Link Between Anesthesia Dementia
Varshini Chellapilla
A common question asked of physicians and surgeons is whether anesthesia, generally given during surgeries, is associated with a risk of developing Alzheimers disease or other related dementias in the future.
Its not an unreasonable notion that anesthesia would affect brain health, Dr. Wolk said. Anesthesia has many effects on the brain, and surgery itself is associated with all sorts of systemic changes in the body and brain.
Dr. David Wolk
A new study conducted by Penn Memory Center Co-Director and Alzheimers Disease Research Center Director David Wolk, MD, in collaboration with colleagues in the Perelman School of Medicine and The Wharton School, observed elderly patients who were exposed to anesthesia during an appendectomy, a surgical procedure performed to remove the appendix, and then followed post-operation to determine if there was an association between anesthesia and development of clinical Alzheimers disease. The study, titled Alzheimers Dementia After Exposure to Anesthesia and Surgery in the Elderly, was published in the Annals of Surgery in the November 2020 issue.
The team of Penn researchers found that there was no indication suggesting that anesthesia in elderly patients undergoing appendectomies increased the risk for Alzheimers disease or other related dementias.
A Caregivers Asks: Does Anesthesia Make Dementia Worse
by Bobbi Carducciin Alzheimer’s, care giving, Caregiving, Dementia, Lewy Body Dementia, sandwich generationTags: Alzheimer’s disease, Bobbi Carducci, caregiver advice, Caregiver Support, elder care
It can. It doesnt always. This ambiguous response is true of many questions regarding what happens when someone has Alzheimers disease or one of the many other forms of dementia. What is true for one person is not true for many others.
Some factors that can have an effect on whether or not someone experiences cognitive decline after general anesthetic are:
Age The older we are, the more vulnerable we are to side effects of anesthesia. Our brain, like the rest of us does not respond in the same way it once did.
Medical Conditions and Medications The more health issues one has and the more medication one requires the greater the chances of cognitive decline with the added stress of surgery.
Loss of Blood Blood loss during surgery can reduce oxygen flow to the brain resulting in cognitive impairment.
Type of Anesthesia Needed and What Procedure has to be Done Depending on the circumstances, the surgeon may need to use heavy sedation over a relatively long period of time increasing the chance of a negative reaction. For less extensive procedures, he or she may opt for a spinal block and twilight sleep. Doing this could lessen the risk of cognitive decline.
How Does Alzheimers Disease Affect The Brain
The brain typically shrinks to some degree in healthy aging but, surprisingly, does not lose neurons in large numbers. In Alzheimers disease, however, damage is widespread, as many neurons stop functioning, lose connections with other neurons, and die. Alzheimers disrupts processes vital to neurons and their networks, including communication, metabolism, and repair.
At first, Alzheimers disease typically destroys neurons and their connections in parts of the brain involved in memory, including the entorhinal cortex and hippocampus. It later affects areas in the cerebral cortex responsible for language, reasoning, and social behavior. Eventually, many other areas of the brain are damaged. Over time, a person with Alzheimers gradually loses his or her ability to live and function independently. Ultimately, the disease is fatal.
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Preoperative Use Of Levodopa
Patients with advanced Parkinson’s disease are at risk for exacerbations in the perioperative period. The timing of doses of Parkinson’s medication is very important, as abrupt withdrawal of drugs can often cause a very sudden return or even worsening of symptoms and in some cases can lead to the development of a condition known as neuroleptic malignant syndrome, which can be very dangerous. The half-life of levodopa is 13 h and so interruption should be as brief as possible, and therapeutic administration should be continued through the morning of surgery with sips of water. As it is absorbed from the proximal small bowel and thus has to first traverse the stomach making administration of tablets through gastric tube suboptimal or ineffective, because patients with Parkinson’s often have delayed gastric emptying. As such a duodenal feeding tube may be necessary when a prolonged period of normal feeding is expected. Patients may self-administer additional levodopa, so it is important to find out exactly how much they are taking.
Enteral levodopa has a clear advantage over intravenous levodopa and should be preferred. Treatment with and drug titration of levodopa for intravenous administration alone may be dangerous during general anesthesia because of interactions with anesthetic agents. It may increase the risk of a variety of arrhythmias or hypertension. These side effects of levodopa are mediated through its metabolite, dopamine.
How Can You Tell Dementia From Delirium
The differences between dementia and delirium Dementia develops over time, with a slow progression of cognitive decline. Delirium occurs abruptly, and symptoms can fluctuate during the day. The hallmark separating delirium from underlying dementia is inattention. The individual simply cannot focus on one idea or task.
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Management Of Pocd Or Other Mental Changes After Surgery
People reporting changed mental function after undergoing an operation should be taken seriously. The discussion above reveals this to be a real and serious problem, and one which potentially has an enormous impact upon the personal functioning of the individuals concerned, as well as a significant impact upon their surroundings and the societies in which they live. Management should be serious and efficient. Why efficient? That sounds cold and unpleasant. Actually, efficiency is of utmost importance. Delay and incorrect management reduces the chance of successful management, as well as increasing the distress of the individuals concerned and their families. Rapid placement of people into correct treatment regimes improves the chances of successful management, and means the incurable are placed in appropriate support programs.
Here are some personal thoughts regarding general management of POCD and postoperative altered mental function according to when they occur, and how long they last.
A Comprehensive Preoperative Evaluation Is Crucial
Scientists are still investigating possible causes and risks for POCD, but one key to preventing unnecessary complications during and after surgery is to undergo a thorough preoperative evaluation with a primary care physician. The surgeons and anesthesiologists who will be involved in the procedure must be aware of a patients important health information, including:
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The Real World And Selective Blindness
Nearly all physicians, together with nearly all non-medical people, as well as the popular press, attribute these changes in mental function to the effects of anesthesia. Many of these people even believe that anesthetic drugs remain in the body for many months exerting a deleterious effect upon mental function. This is the real world of people who themselves have experienced POCD, or who have relatives who manifested POCD.
Most people believe anesthesia is the cause of POCD, yet seem to forget that administration of anesthesia is never done without a purpose. This is a curious form of socio-culturally induced selective blindness. No one undergoes anesthesia without undergoing an operation. Anesthesia is always administered to make surgical procedures, or an operation, possible. So POCD is always a consequence of the combined effect of anesthesia plus surgery upon mental function. In fact the effects of surgery upon the functioning of the body can be quite profound. For example, major surgery has an effect upon body function comparable that due to being hit by a truck, only the wounds are tidier. Recovery from such major injury also has a long-lasting effect upon mental and body function. There are also several other factors determining whether a person develops POCD. In fact, studies reveal reasonably consistent information about who is most likely to develop changed mental function after anesthesia and operation. These are listed below.
What Happens To The Brain In Alzheimer’s Disease
The healthy human brain contains tens of billions of neuronsspecialized cells that process and transmit information via electrical and chemical signals. They send messages between different parts of the brain, and from the brain to the muscles and organs of the body. Alzheimers disease disrupts this communication among neurons, resulting in loss of function and cell death.
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Anesthesia And A Oligomerization
Amyloid-beta is a peptide of 3943 amino acids generated in vivo by specific proteolytic cleavage of amyloid precursor protein , a transmembrane glycoprotein. Aggregated A is the main constituent of amyloid plaques found in the brain of AD patients. It appears that soluble oligomeric A forms, rather than amyloid plaques, contribute to the cellular pathology of the disease and correlate with the severity of cognitive impairment in humans . Different studies have shown that anesthetics can promote the oligomerization of A peptide, supporting a potential link between anesthesia and the acceleration of A-related toxicity .
Theoretical pathways by which anesthesia could affect AD pathogenesis. Volatile anesthetics could promote A pathology and NFT formation, both leading to a decrease in synaptic plasticity and neurodegeneration. Interestingly, anesthesia could enhance tau phosphorylation, either directly, through kinases activation, or indirectly, through hypothermia-induced phosphatases inhibition.
Is It Possible To Wake Up During Surgery
Very rarely, people may be aware of whats going on during surgery. Some experts estimate that about 1 out of every 1,000 people regain consciousness but remain unable to move, talk, or otherwise alert their doctor. Other sources report it being even more rare, as infrequent as 1 out of 15,000 or 1 out of 23,000.
When this happens, the person usually doesnt feel any pain. However, operative awareness can be very distressing and may cause long-term psychological problems, similar to post-traumatic stress disorder.
If you experience operative awareness under general anesthesia, you may find it beneficial to talk to a therapist or a counselor about your experience.
If you need surgery, you probably dont want to feel whats going on. Depending on the type of surgery, this can be accomplished in a variety of ways.
Your doctor will likely recommend general anesthesia if your procedure is going to:
- take a long time
- result in blood loss
- affect your breathing
General anesthesia is essentially a medically induced coma. Your doctor administers medication to make you unconsciousness so that you wont move or feel any pain during the operation.
Other procedures can be done with:
- local anesthetic, like when you get stitches in your hand
- sedation, like when you get a colonoscopy
- a regional anesthetic, like when you get an epidural to deliver a baby
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Does Surgery Cause Or Worsen Dementia
Question: My father needs surgery. Will this worsen his dementia?
Answer: This is one of the more common questions I get asked as a dementia specialist. Similarly, there are numerous families that come to me on the first visit, convinced that their relatives dementia started immediately after some type of surgery. So, does surgery cause or worsen dementia?
There have been numerous studies over the years that have attempted to answer this question. Unfortunately, the results are often conflicting, with some studies showing an increased risk of dementia and/or cognitive impairment following surgery, and others suggesting no increase risk. As you might imagine, the reasons for these discrepancies are that the results likely depend on a multitude of factors including the characteristics of the patients , the type of condition requiring surgery , the type of surgery, the anaesthetic and the operative complications .
The story of surgery and dementia is not all negative. In a future blog, I will highlight some surgical procedures that might actually improve cognition and examine new ways that might specifically help protect the brain during operations.
Anesthetic Management For Steriotactic Pallidotomy/thalamotomy
Classically local anesthesia with minimal or no sedation has been used for patients undergoing stereotactic procedures. This allows for patient participation in target localization and immediate observation of effects of test and lesion. Antiparkinsonian mediations are withheld for 1224 h prior to surgery. Therapy for concurrent diseases must be continued till the day of surgery.
Under LA, in magnetic resonance imaging suite stereotactic frame applied. Extra padding and rolls can make the patient more comfortable. Also these patients are very motivated to co-operate, unless there is dementia present. LA again is used to do burr hole and if the patient becomes agitated, midazolam can be titrated to desired effect. It is important that level of sedation does not impair co-operation or interfere with communication between surgeon and patient. Age, varying levels of dementia, fatigue, and cumulative effects of medication make it necessary to titrate the drugs slowly. Since propofol may elicit abnormal movements and may at times improve parkinsonian tremor, it might not be ideally suited for patients with movement disorders undergoing functional stereotactic neurosurgery.
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Surgery And General Anesthesia
A cocktail of drugs called General Anesthesia is administered to the patients that render them unconscious, prevents them from moving and blocks any memories of the surgery. The state of anesthesia is more of a carefully controlled coma. Elderly patients achieve this state with as little as half the dose of anesthesia that is required for a younger adult, owing to their age-related declines in cardiovascular, respiratory, liver and kidney function, but primarily in the brain and central nervous system. After GA, short term impairment of cognitive and psychomotor performance is common and expected.
Although anesthetic drugs have been around since 1846, doubts about their mechanism of action remain. Evidences from research suggest that the drugs are only partly effective because they bind to and incapacitate the proteins on the neuron surface that are essential for regulating sleep, attention, learning, and memory. It also seems that interrupting the usual activity of neurons may disrupt communication between far-flung regions of the brain, triggering unconsciousness.
In older people, there are three particular anesthesia-related surgery risks:
References:
Is There A Connection Between Anesthetics And Dementia
It concluded that anesthesia could cause long-term changes in older brains that arent too resistive to its effects. This research found general anesthetics to be a contributing factor in dementia. This research found general anesthetics to be a contributing factor in dementia.
While its extremely common to feel groggy and confused upon waking from anesthesia, post-op delirium is something far different from the typical post-anesthesia fogand it typically peaks anywhere from 1-3 days after the patients operation. There are three main types of post-op delirium:
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Anesthesia In Individuals With Cognitive Impairment
Alzheimers disease accounts for the majority of cases of dementia . AD is a fatal progressive neurodegenerative disorder, characterized by neuronal degeneration in the basal forebrain, entorhinal cortex, hippocampus, and cortex . Pathological hallmarks include the presence of senile plaques which contain Amyloid- , and neurofibrillary tangles which form in the presence of pathological modifications to the microtubule-associated protein, tau. The pathways underlying neurodegeneration are complex and involve many players including soluble and insoluble A, hyperphosphorylated tau, neuroinflammation and microglia dysfunction, cholinergic deficits, and oxidative stress .
AD and other forms of dementia can impact the ability of anesthesiologists to collect a detailed history and elicit appropriate cooperation for physical examination. The potential for confusion and limited cooperation may make approaches such as neuraxial anesthesia, peripheral nerve blocks, or sedation more challenging. In terms of pharmacologic management, it is commonly accepted that short-acting medications should be used, and medications which may increase risk of postoperative confusion should be avoided . Available evidence does not support the hypothesis that these patients are more sensitive to anesthetic agents however, the sample size employed in these studies and use of the BIS monitor as a surrogate of anesthetic depth make it challenging to draw any definitive conclusion .
Advantages Of Regional Anesthesia Over General Anesthesia
Regional anesthesia allows for communication of the subjective feelings accompanying Parkinson’s disease attacks, thereby prompting earlier treatment
The muscle-relaxing effects of general anesthesia and neuromuscular blockers are avoided. These mask the myopotentials, which are usually the first sign of intraoperative exacerbation
Residual GA or neuromuscular blocker, which may delay diagnosis and treatment of an exacerbation is avoided
Inhalational anesthesia in combination with adjunctive drugs can precipitate overt symptoms of primary parkinsonism in a patient
The high incidence of nausea and vomiting associated with GA prevents effective administration of oral medications and exacerbation can occur in the postoperative period
Better pain relief and attenuation of surgical stress response with regional anesthesia
Patients with PD are more prone to chest infection before and after surgery under GA as these patients may have difficulty in clearing secretions because of ineffective cough effort and impaired swallowing
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Anesthesia And Dementia Wheres The Connection
Post-surgery memory loss is acommon phenomenon. It is not unusual for the patients to appear disoriented andlost as they recover from the effects of anesthesia. This general observationhas led to many studies that try to figure out the connection between anesthesia and dementia.
So far, the results are mixed.While some studies prove there is a risk of dementia after anesthesia, otherspin it on the surgery itself.
The elderlies are most likely tosuffer from the impact of general anesthesia on memory. Today, we will exploreif there really is a connection between anesthesia and dementia in that demographic.
Reducing Cognitive Impairment After Surgery
Older patients with neurodegenerative disease quite often need surgery for reasons unrelated to their cognitive problems. Both the hospital and surgical environments can be challenging for patients, but with some planning, these difficulties can be minimized. The suggestions that follow are not all inclusive, and we suggest discussing suggestions your physician/s may have prior to any surgical procedure.
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