The term 'Alzheimer's' has been politicised. Making a diagnosis requires a brain biopsy, usually done as part of an autopsy. I don't believe a PET scan is capable of making the diagnosis, despite what the article says.
To understand what is going on, we have to see the problem that hit clinicians and families around 10-20 years ago. It seemed like an epidemic of confused elderly patients landing on wards without a specific diagnosis, very little ability to describe what is wrong with them, and causing disruption to other patients, either directly, or because they required a nurse to attend them continually.
Explaining to the family why their mother/father had gone from being someone who was independent at home to someone confused and unable to tend for themselves was difficult. Usually the blame would be attributed to infections (especially urinary tract infections, which are very difficult to diagnose in a confused patient), but doctors were reluctant to start using the term 'dementia' initially, particularly since there wasn't a good test for it.
In retrospect, what was happening was that we were seeing the success of treatment for cardiovascular disease. Many patients who would normally have died in their 50s and 60s of heart disease we now making it to their 70s, 80s and 90s, albeit with arteries that were still far from ideal.
Every organ in the body degrades with age. We tolerate and compensate for it up to a point. At the age of 20 our hearts can increase output from 5l/min to 20l/min, sometimes this is necessary to survive a particular bad infection. If your heart is unable to do this, we say it has decompensated. At the age of 60, even without a diagnosis of heart failure, this is not possible, but thankfully we are rarely in a position where 20L/min is necessary. The brain is no exception. An old brain with loss of volume can handle a daily routine in a familiar environment, but throw in a cold, or another infection, then make it worse by starting drugs and abruptly changing their environment, and we end up with an acute confusional state which can take weeks to resolve, if it ever does completely.
My suspicion is that most cases of dementia (and mild cognitive impairment) is due to a general decrease in function as we get elderly, exacerbated by vascular insufficiencies. Alzheimer's is a specific histological diagnosis - it doesn't give us a cause, it's more of a histological finding. Since we don't really have any good treatments for dementia caused by Alzheimer's or vascular causes, and we don't have a way of telling them apart, you could argue whether this histological finding matters..
Except that Alzheimer's is a term the public are familiar with, and will donate to.
NB I am not a neurologist nor a dementia expert. I've worked a lot in elderly care and have had to deal with patients and their families on many occasions. I have some amusing memories including overhearing a conversation between a confused patient on a ward who had picked up the ward phone at around 1AM - it was the bed manager calling to see if their were any beds, but the patient she was still at home so was quite confused at the question.
It's seen as fairly basic/text-book knowledge, and finding a paper on it is pretty difficult. It was probably shown in the 19th century and isn't easily found on google scholar! I did find one reference [1] from more recently. Part of our sepsis warning scores depend on the heart rate to rate the severity of the illness. I suspect even in mild colds your cardiac output goes up, but it might be difficult to notice just from measuring the pulse (stroke volume can change).
Heart is just one example - our kidneys get worse as we get older too (see figure 4 of this paper - it's a straight line pretty much [2]). In practice, it doesn't cause us problems in day to day life, but give it a really big insult (like sepsis) and it can decompensate. The difference with kidneys is that we can support kidney failure with dialysis or filtering (if their heart can support that), whereas with cardiac failure this is not so simple.
Brain failure is probably one of the worst forms of failure. Most causes have no cure, and they often require 24hr care.
To understand what is going on, we have to see the problem that hit clinicians and families around 10-20 years ago. It seemed like an epidemic of confused elderly patients landing on wards without a specific diagnosis, very little ability to describe what is wrong with them, and causing disruption to other patients, either directly, or because they required a nurse to attend them continually.
Explaining to the family why their mother/father had gone from being someone who was independent at home to someone confused and unable to tend for themselves was difficult. Usually the blame would be attributed to infections (especially urinary tract infections, which are very difficult to diagnose in a confused patient), but doctors were reluctant to start using the term 'dementia' initially, particularly since there wasn't a good test for it.
In retrospect, what was happening was that we were seeing the success of treatment for cardiovascular disease. Many patients who would normally have died in their 50s and 60s of heart disease we now making it to their 70s, 80s and 90s, albeit with arteries that were still far from ideal.
Every organ in the body degrades with age. We tolerate and compensate for it up to a point. At the age of 20 our hearts can increase output from 5l/min to 20l/min, sometimes this is necessary to survive a particular bad infection. If your heart is unable to do this, we say it has decompensated. At the age of 60, even without a diagnosis of heart failure, this is not possible, but thankfully we are rarely in a position where 20L/min is necessary. The brain is no exception. An old brain with loss of volume can handle a daily routine in a familiar environment, but throw in a cold, or another infection, then make it worse by starting drugs and abruptly changing their environment, and we end up with an acute confusional state which can take weeks to resolve, if it ever does completely.
My suspicion is that most cases of dementia (and mild cognitive impairment) is due to a general decrease in function as we get elderly, exacerbated by vascular insufficiencies. Alzheimer's is a specific histological diagnosis - it doesn't give us a cause, it's more of a histological finding. Since we don't really have any good treatments for dementia caused by Alzheimer's or vascular causes, and we don't have a way of telling them apart, you could argue whether this histological finding matters..
Except that Alzheimer's is a term the public are familiar with, and will donate to.
NB I am not a neurologist nor a dementia expert. I've worked a lot in elderly care and have had to deal with patients and their families on many occasions. I have some amusing memories including overhearing a conversation between a confused patient on a ward who had picked up the ward phone at around 1AM - it was the bed manager calling to see if their were any beds, but the patient she was still at home so was quite confused at the question.