Alzheimer's disease: Difference between revisions

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{{subpages}}
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{{Infobox_Disease |
  Name          = Alzheimer's disease |
  Image          = Alzheimers_disease_-_MRI.jpg|thumb|
  Caption        = Post-autopsy brain scans: A brain with Alzheimer's disease (left) as compared to a normal brain (right)|
| DiseasesDB    = 490
| ICD10          = {{ICD10|G|30||g|30}}, {{ICD10|F|00||f|00}}
| ICD9          = {{ICD9|331.0}}-{{ICD9|290.1}}
| OMIM          = 104300
| MedlinePlus    = 000760
}}
'''Alzheimer's disease''' is also known as '''Alzheimer disease''', '''Alzheimer's''' and simply '''AD'''.


'''Alzheimer's disease''' is also known as '''Alzheimer disease''', '''Alzheimer's''' and simply '''AD'''. It sometimes incorrectly called "Old timer's disease".
Alzheimer's is the most common cause of [[dementia]], afflicting at least 24&nbsp;million people worldwide. Alzheimer's is a [[terminal disease]] for which there is currently no known cure. It is most commonly found in people over 65&nbsp;years old, although a less-common form called [[Familial Alzheimer's disease]], or "early-onset Alzheimer's", also occurs, affecting about 1%—5% of the total of Alzheimer's sufferers.<ref name="pmid16360788">
 
Alzheimer's the most common cause of [[dementia]], afflicting 24&nbsp;million people worldwide. Alzheimer's is a [[Terminal illness|terminal disease]] for which there is currently no known cure. It is most commonly found in people over 65&nbsp;years old, although a less-common form also occurs called [[early-onset Alzheimer's]] (or [[Familial Alzheimer's disease]]).<ref name="pmid16360788">
{{cite journal  
{{cite journal  
|author=Ferri CP, Prince M, Brayne C, Brodaty H, Fratiglioni L, Ganguli M, Hall K, Hasegawa K, Hendrie H, Huang Y, Jorm A, Mathers C, Menezes PR, Rimmer E, Scazufca M
|author=Ferri CP, Prince M, Brayne C, Brodaty H, Fratiglioni L, Ganguli M, Hall K, Hasegawa K, Hendrie H, Huang Y, Jorm A, Mathers C, Menezes PR, Rimmer E, Scazufca M
Line 17: Line 27:
}}</ref>
}}</ref>


Typically, the disease begins many years before it is diagnosed. In its early stages, [[short-term memory]] loss is the most common symptom, which is is often initially thought by the sufferer to be caused by other factors, such as aging or stress.<ref name="alzdiag">{{cite journal
Typically, the disease begins many years before it is diagnosed. In its early stages, short-term memory loss is the most common symptom, which is often initially thought by the sufferer to be caused by other factors, such as aging or stress.<ref name="alzdiag">
{{cite journal
|author=Waldemar G, Dubois B, Emre M, Georges J, McKeith IG, Rossor M, Scheltens P, Tariska P, Winblad B
|author=Waldemar G, Dubois B, Emre M, Georges J, McKeith IG, Rossor M, Scheltens P, Tariska P, Winblad B
|title=Recommendations for the diagnosis and management of Alzheimer's disease and other disorders associated with dementia: EFNS guideline
|title=Recommendations for the diagnosis and management of Alzheimer's disease and other disorders associated with dementia: EFNS guideline
Line 28: Line 39:
|doi=10.1111/j.1468-1331.2006.01605.x
|doi=10.1111/j.1468-1331.2006.01605.x
}}</ref>
}}</ref>
Later symptoms of the disease include confusion, anger, mood swings, language breakdown, [[long-term memory]] loss, and the general "withdrawal" of the sufferer as his or her senses decline.<ref name="alzdiag"/><ref name="pmid17823840">{{cite journal
Later symptoms of the disease include confusion, anger, mood swings, language breakdown, long-term memory loss, and the general "withdrawal" of the sufferer as his or her senses decline.<ref name="alzdiag"/><ref name="pmid17823840">
{{cite journal
|author=Tabert MH, Liu X, Doty RL, Serby M, Zamora D, Pelton GH, Marder K, Albers MW, Stern Y, Devanand DP
|author=Tabert MH, Liu X, Doty RL, Serby M, Zamora D, Pelton GH, Marder K, Albers MW, Stern Y, Devanand DP
|title=A 10-item smell identification scale related to risk for Alzheimer's disease
|title=A 10-item smell identification scale related to risk for Alzheimer's disease
Line 62: Line 74:
}}</ref>
}}</ref>


===Symptoms===
==Classification==
A classification has been proposed by the the ad hoc International Working Group for New Research Criteria for the Diagnosis of AD.<ref name="pmid20934914">{{cite journal| author=Dubois B, Feldman HH, Jacova C, Cummings JL, Dekosky ST, Barberger-Gateau P et al.| title=Revising the definition of Alzheimer's disease: a new lexicon. | journal=Lancet Neurol | year= 2010 | volume= 9 | issue= 11 | pages= 1118-27 | pmid=20934914 | doi=10.1016/S1474-4422(10)70223-4 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20934914  }} </ref>
 
===Asymptomatic at-risk for Alzheimer's disease===
Asymptomatic at-risk for Alzheimer's disease includes asymptomatic patients with a positive biomarker. Biomarkers include [[apolipoprotein E4]].
 
===Presymptomatic Alzheimer's disease===
Presymptomatic Alzheimer's disease includes people with autosomal dominant mutation known to have full penetrance
 
===Prodromal Alzheimer's disease===
Prodromal Alzheimer's disease includes patients with positive biomarkers who have mild cognitive dysfunction that does not cause significant functional impairment.
 
===Alzheimer's Dementia===
Alzheimer's dementia indicates functional impairment meeting criteria for [[dementia]].
 
==Symptoms==
Common symptoms of dementia include:
 
    A decline in memory
    Changes in thinking skills
    Poor judgment and reasoning
    Decreased focus and attention
    Decreased language ability
    Negative changes in behavior


Although the symptoms are common, they are typically experienced in unique ways.<ref name="alzheimers.org">
Although the symptoms are common, they are typically experienced in unique ways.<ref name="alzheimers.org">
Line 74: Line 109:
"Stages" are commonly referred to by professionals to describe the [[progressive disease|progressive]] nature of Alzheimer's (typically "early", "mid" and "late onset") but the symptoms can cross over these "boundaries" for many sufferers.
"Stages" are commonly referred to by professionals to describe the [[progressive disease|progressive]] nature of Alzheimer's (typically "early", "mid" and "late onset") but the symptoms can cross over these "boundaries" for many sufferers.


===Diagnosis===
==Diagnosis==
 
The symptoms of Alzheimer's disease are generally reported to a doctor or physician when memory-loss (or symptoms surrounding memory loss) begin to pose a serious concern. When Alzheimer's disease is suspected, diagnosis is typically confirmed by a behavioural assessment, and some form of cognitive test. Often this is followed by a [[brain scan]].<ref name="alzres">
The symptoms of Alzheimer's disease are generally reported to a doctor or physician when memory-loss (or symptoms surrounding memory loss) begin to pose a serious concern. When Alzheimer’s disease is suspected, diagnosis is typically confirmed by a behavioural assessment, and some form of [[cognitive test]]. Often this is followed by a [[brain scan]].<ref name="alzres">
{{cite web
{{cite web
| title=Alzheimer's Diagnosis of AD
| title=Alzheimer's Diagnosis of AD
Line 83: Line 117:
| accessdate=2008-02-29
| accessdate=2008-02-29
}}</ref>
}}</ref>
===Laboratory tests===
====Apolipoprotein E4====
Although [[apolipoprotein E4]] is an important susceptibility gene for Alzheimer's disease]<ref name="pmid10944568">{{cite journal |author=Skoog I |title=Detection of preclinical Alzheimer's disease |journal=N. Engl. J. Med. |volume=343 |issue=7 |pages=502–3 |year=2000 |month=August |pmid=10944568 |doi= |url=http://content.nejm.org/cgi/pmidlookup?view=short&pmid=10944568&promo=ONFLNS19 |issn= |quote=The APOE 4 allele is a susceptibility gene for Alzheimer's disease and seems to affect the age of onset of the disease. However, the presence of this allele alone is not sufficient to predict which asymptomatic subjects will ultimately have Alzheimer's disease, and the disease never develops in many subjects with this genotype}}</ref>, its [[sensitivity and specificity]] are insufficient (65 and 68 percent, respectively) to be used as a diagnostic test.<ref name="pmid12160362">{{cite journal |author=Kivipelto M, Helkala EL, Laakso MP, ''et al'' |title=Apolipoprotein E epsilon4 allele, elevated midlife total cholesterol level, and high midlife systolic blood pressure are independent risk factors for late-life Alzheimer disease |journal=Ann. Intern. Med. |volume=137 |issue=3 |pages=149–55 |year=2002 |month=August |pmid=12160362 |doi= |url=http://www.annals.org/cgi/pmidlookup?view=reprint&pmid=12160362 |issn=}}</ref>


===Causes===
However, the  level of [[apolipoprotein E4]] in [[cerebrospinal fluid]] may be predictive.<ref name="pmid20697045">{{cite journal| author=De Meyer G, Shapiro F, Vanderstichele H, Vanmechelen E, Engelborghs S, De Deyn PP et al.| title=Diagnosis-independent Alzheimer disease biomarker signature in cognitively normal elderly people. | journal=Arch Neurol | year= 2010 | volume= 67 | issue= 8 | pages= 949-56 | pmid=20697045 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20697045 | doi=10.1001/archneurol.2010.179 }} </ref>


The actual cause, or causes of Alzheimer's disease is unknown, but it is known to be associated with "[[Senile plaques]]" and "[[neurofibrillary tangles]]" in the [[brain]].<ref name="pmid15184601"/> There are many ideas about possible causes and cures of the disease.  
====Amyloid-beta protein====
Amyloid-beta protein may be elevated in the cerebrospinal fluid of some patients.<ref name="pmid20697045">{{cite journal|  author=De Meyer G, Shapiro F, Vanderstichele H, Vanmechelen E,  Engelborghs S, De Deyn PP et al.| title=Diagnosis-independent Alzheimer  disease biomarker signature in cognitively normal elderly people. |  journal=Arch Neurol | year= 2010 | volume= 67 | issue= 8 | pages= 949-56  | pmid=20697045 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20697045 | doi=10.1001/archneurol.2010.179 }} </ref>


==== Research ====
==Cause/etiology==
The etiology of Alzheimer's disease is incompletely understood. Alzheimer's disease is associated with senile plaques and neurofibrillary tangles in the [[brain]].<ref name="pmid15184601">{{cite journal |author=Tiraboschi P, Hansen LA, Thal LJ, Corey-Bloom J |title=The importance of neuritic plaques and tangles to the development and evolution of AD |journal=Neurology |volume=62 |issue=11
|pages=1984–1989 |year=2004 |pmid=15184601 |doi=}}</ref>  The incorrect folding of [[protein]]s leads to the formation of amyloid plaques. The prion protein (PrP<sup>C</sup>) may be the cellular receptor for amyloid-beta oligomer.<ref name="pmid19242475">{{cite journal |author=Laurén J, Gimbel DA, Nygaard HB, Gilbert JW, Strittmatter SM |title=Cellular prion protein mediates impairment of synaptic plasticity by amyloid-beta oligomers |journal=Nature |volume=457 |issue=7233 |pages=1128–32 |year=2009 |month=February |pmid=19242475 |doi=10.1038/nature07761 |url=http://dx.doi.org/10.1038/nature07761 |issn=}}</ref> Current research aims to determine if such plaques are the result of, or the cause of, Alzheimer's disease.


Alzheimer's disease causes incresing neurodegeneration of the brain, leading to accelerated memory loss. The incorrect folding of [[protein folding|proteins]] leads to the formation of amyloid plaquesCurrent research aims to determine if such plaques are the result of, or the cause of, Alzheimer's disease.
Regarding biomarkers, one study found that "a reduction in the CSF Aβ42 level  denotes a pathophysiological process that significantly departs from  normality (ie, becomes dynamic) early, whereas the CSF total tau level and the adjusted hippocampal volume are biomarkers of downstream  pathophysiological processes". <ref  name="pmid21825215">{{cite journal| author=Jack CR, Vemuri P, Wiste HJ, Weigand SD, Aisen PS, Trojanowski JQ et al.| title=Evidence for  ordering of Alzheimer disease biomarkers. | journal=Arch Neurol | year=  2011 | volume= 68 | issue= 12 | pages= 1526-35 | pmid=21825215 |  doi=10.1001/archneurol.2011.183 | pmc= |  url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21825215  }} </ref>


===Treatment===
Although there is a genetic susceptibility in a small percentage of people, Alzheimer's is not considered a genetic illness. The greatest risk factor for developing Alzheimer's is age, as the percentage of people developing it dramatically increases after age 65 and beyond. Major environmental/lifestyle risk factors include a diet high in saturated fats that are typical of the standard western diet, smoking, and long-term exposure to environmental toxins such as aluminium. Research is ongoing.


No treatment has been found to stop or reverse the disease, and it is not known whether current preferred treatments directly slow the spread of Alzheimer's in the brain, or simply manage the symptoms - and thus slow the progression of the disease that way. Many preventative measures have been suggested for Alzheimer's disease, but their values are uncertain: mental stimulation, [[exercise]] and a [[balanced diet]] are usually recommended, both as a possible prevention and as a sensible way of managing the disease.<ref name="prevention">  
==Treatment==
No treatment has been found to stop or reverse the disease. Many preventive measures have been suggested for Alzheimer's disease, but their values are uncertain: mental stimulation, [[exercise]], and a Mediterranean style diet are usually recommended, both as possible prevention and as a sensible way of managing the disease.<ref name="prevention">  
{{cite web
{{cite web
| title=The Search for AD Prevention Strategies
| title=The Search for AD Prevention Strategies
Line 103: Line 144:
}}</ref>
}}</ref>


====Pharmaceutical====
===Medications===
 
As of 2023, available medications offer relatively small symptomatic benefit for some patients but generally do not slow disease progression. Newer monoclonal antibody treatments against beta-amyloid protein, for example, the drug Leqembi, have been approved in the United States, but they only slightly reduce the rate of disease progression and have significant side effects, including brain bleeding and in rare cases, death. These drugs cost over $20,000 a year, which could be prohibitively expensive for many patients.
Currently available medications offer relatively small symptomatic benefit for some patients but do not slow disease progression. The American Association for Geriatric Psychiatry published a consensus statement on Alzheimer's treatment in 2006.<ref name="pmid16816009">{{cite journal |author=Lyketsos CG, Colenda CC, Beck C, ''et al'' |title=Position statement of the American Association for Geriatric Psychiatry regarding principles of care for patients with dementia resulting from Alzheimer disease |journal=The American journal of geriatric psychiatry : official journal of the American Association for Geriatric Psychiatry |volume=14 |issue=7 |pages=561–72 |year=2006 |pmid=16816009 |doi=10.1097/01.JGP.0000221334.65330.55}}</ref>
 
=====Atypical antipsychotics=====
A [[systematic review]] found that the atypical antipsychotics [[risperidone]] and [[olanzapine]] showed the most benefit of all drugs; however they may increased the risk of [[stroke]].<ref name="pmid15687315">{{cite journal |author=Sink KM, Holden KF, Yaffe K |title=Pharmacological treatment of neuropsychiatric symptoms of dementia: a review of the evidence |journal=JAMA |volume=293 |issue=5 |pages=596–608 |year=2005 |pmid=15687315 |doi=10.1001/jama.293.5.596}}</ref>


=====Acetylcholinesterase inhibitors=====
[[Randomized controlled trial]]s showed either small or absent benefit from acetylcholinesterase inhibitors<ref>  
[[Randomized controlled trial]]s showed either small or absent benefit from [[acetylcholinesterase inhibitors]]<ref> {{cite journal | author = Kaduszkiewicz H, Zimmermann T, Beck-Bornholdt H, van den Bussche H | title = Cholinesterase inhibitors for patients with Alzheimer's disease: systematic review of randomised clinical trials. | journal = BMJ | volume = 331 | issue = 7512 | pages = 321-7 | year = 2005 | id = PMID 16081444}} </ref> such as [[donepezil]].<ref name="pmid17914039">{{cite journal |author=Howard RJ, Juszczak E, Ballard CG, ''et al'' |title=Donepezil for the treatment of agitation in Alzheimer's disease |journal=N. Engl. J. Med. |volume=357 |issue=14 |pages=1382–92 |year=2007 |pmid=17914039 |doi=10.1056/NEJMoa066583}}</ref><ref>{{cite journal | author = Courtney C, '''Farrell D''', Gray R, Hills R, Lynch L, Sellwood E, Edwards S, Hardyman W, Raftery J, Crome P, Lendon C, Shaw H, Bentham P | title = Long-term donepezil treatment in 565 patients with Alzheimer's disease (AD2000): randomised double-blind trial. | journal = Lancet | volume = 363 | issue = 9427 | pages = 2105-15 | year = 2004 | id = PMID 15220031}}</ref>
{{cite journal | author = Kaduszkiewicz H, Zimmermann T, Beck-Bornholdt H, van den Bussche H | title = Cholinesterase inhibitors for patients with Alzheimer's disease: systematic review of randomised clinical trials. | journal = BMJ  
| volume = 331 | issue = 7512 | pages = 321-7 | year = 2005 | id = PMID 16081444}} </ref> such as donepezil.<ref name="pmid17914039"> {{cite journal |author=Howard RJ, Juszczak E, Ballard CG, ''et al'' |title=Donepezil for the treatment of agitation in Alzheimer's disease |journal=N. Engl. J. Med. |volume=357 |issue=14 |pages=1382–92 |year=2007 |pmid=17914039  
|doi=10.1056/NEJMoa066583}}</ref><ref>{{cite journal | author = Courtney C, '''Farrell D''', Gray R, Hills R, Lynch L, Sellwood E, Edwards S, Hardyman W, Raftery J, Crome P, Lendon C, Shaw H, Bentham P | title = Long-term donepezil treatment in 565 patients with Alzheimer's disease (AD2000): randomised double-blind trial. | journal = Lancet | volume = 363  
| issue = 9427 | pages = 2105-15 | year = 2004 | id = PMID 15220031}}</ref><ref name="doi10.1056/NEJMoa1106668">Donepezil and Memantine for Moderate-to-Severe Alzheimer's Disease. NEJM 2012. http://dx.doi.org/10.1056/NEJMoa1106668</ref>


=====N-methyl d-aspartate (NMDA) antagonists=====
The [[N-methyl-d-aspartate receptor]] antagonist memantine has shown some effectiveness<ref name="Areosa">
The [[N-methyl-d-aspartate receptor]] antagonist [[memantine]] has shown effectiveness.<ref name="Areosa">{{cite journal | author = Areosa Sastre A, McShane R, Sherriff F | title =  Memantine for dementia. | journal = Cochrane Database Syst Rev | pages = CD003154 | id = PMID 15495043}}</ref>
{{cite journal | author = Areosa Sastre A, McShane R, Sherriff F | title =  Memantine for dementia.  
| journal = Cochrane Database Syst Rev | pages = CD003154 | id = PMID 15495043}}</ref> but does not add benefit to donepezil .<ref name="doi10.1056/NEJMoa1106668"/>


==== Care management ====
=== Care management ===
 
Due to the incurable and degenerative nature of the disease care-management of Alzheimer's is essential. The role of the main caregiver is often taken by the spouse or a close relative.<ref name="glam">
Due to the incurable and degenerative nature of the disease care-management of Alzheimer's is essential. The role of the main Carer is often taken by the spouse or a close relative.<ref name="glam">{{
{{cite journal
cite journal
|url=http://www.cncforum.me.uk/S.O'Donovan%20PhD%20Thesis%20Exec%20Summary%202004.pdf
|url=http://www.cncforum.me.uk/S.O'Donovan%20PhD%20Thesis%20Exec%20Summary%202004.pdf
|author=O’Donovan ST
|author=O’Donovan ST
Line 127: Line 167:
|accessdate=2008-02-29
|accessdate=2008-02-29
}}</ref>
}}</ref>
Caregivers may themselves suffer from [[stress]], over-work, [[depression]], and from being physically assailed.<ref name="burden1">{{
Caregivers may themselves suffer from [[stress]], over-work, [[depression]], and from being physically assailed.<ref name="burden1">
cite journal
{{cite journal
|author=Selwood A, Johnston K, Katona C, Lyketsos C, Livingston G
|author=Selwood A, Johnston K, Katona C, Lyketsos C, Livingston G
|title=Systematic review of the effect of psychological interventions on family caregivers of people with dementia
|title=Systematic review of the effect of psychological interventions on family caregivers of people with dementia
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}}</ref>
}}</ref>


=== Alzheimer's in society ===
== Alzheimer's in society ==
Famous people who have, or have died of Alzheimer's disease, are the [[president of the United States of America|US president]] [[Ronald Reagan]], the [[Prime Minister of the United Kingdom| UK Prime minister]] [[Harold Wilson]], the writers [[Terry Pratchett]] and Iris Murdoch, and the film stars [[Rita Hayworth]] and Charlton Heston.
 
== History ==
[[Image:593px-Auguste D aus Marktbreit.jpg|thumb|[[Auguste D]], first recorded patient with the newly recognised form of dementia.]]


Famous people who have, or have died of Alzheimer's disease, are the [[president of the United States of America|US president]] [[Ronald Reagan]], the [[Prime Minister of the United Kingdom| UK Prime minister]] [[Harold Wilson]], the writers [[Terry Pratchett]] and [[Iris Murdoch]], and the film stars [[Rita Hayworth]] and [[Charlton Heston]].
Alzheimer’s disease is named after Dr. Alois Alzheimer, the German physician who first described it. In 1901, Alzheimer observed a 51-year-old patient at the Frankfurt asylum named Auguste Deter. Her symptoms included memory loss, language problems, and unpredictable behavior. In 1906, she died and Dr. Alzheimer noticed unusual pathology in her brain tissue; he found many abnormal clumps (now called amyloid plaques) and tangled bundles of fibers (now called neurofibrillary, or tau, tangles).


==References==
==References==
<references/>
{{reflist}}

Revision as of 08:34, 6 March 2024

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Alzheimer's disease
Alzheimers disease - MRI.jpg

Post-autopsy brain scans: A brain with Alzheimer's disease (left) as compared to a normal brain (right)
ICD-10 ICD10 F84.0-F84.1, ICD10 F84.0-F84.1
ICD-9 331.0

-290.1

OMIM 104300
MedlinePlus 000760

Alzheimer's disease is also known as Alzheimer disease, Alzheimer's and simply AD.

Alzheimer's is the most common cause of dementia, afflicting at least 24 million people worldwide. Alzheimer's is a terminal disease for which there is currently no known cure. It is most commonly found in people over 65 years old, although a less-common form called Familial Alzheimer's disease, or "early-onset Alzheimer's", also occurs, affecting about 1%—5% of the total of Alzheimer's sufferers.[1]

Typically, the disease begins many years before it is diagnosed. In its early stages, short-term memory loss is the most common symptom, which is often initially thought by the sufferer to be caused by other factors, such as aging or stress.[2] Later symptoms of the disease include confusion, anger, mood swings, language breakdown, long-term memory loss, and the general "withdrawal" of the sufferer as his or her senses decline.[2][3] Gradually the sufferer will lose minor, and then major bodily functions, until death finally occurs.[4] Survival after diagnosis has been estimated to be between 5 and 20 years.[5][6]

Classification

A classification has been proposed by the the ad hoc International Working Group for New Research Criteria for the Diagnosis of AD.[7]

Asymptomatic at-risk for Alzheimer's disease

Asymptomatic at-risk for Alzheimer's disease includes asymptomatic patients with a positive biomarker. Biomarkers include apolipoprotein E4.

Presymptomatic Alzheimer's disease

Presymptomatic Alzheimer's disease includes people with autosomal dominant mutation known to have full penetrance

Prodromal Alzheimer's disease

Prodromal Alzheimer's disease includes patients with positive biomarkers who have mild cognitive dysfunction that does not cause significant functional impairment.

Alzheimer's Dementia

Alzheimer's dementia indicates functional impairment meeting criteria for dementia.

Symptoms

Common symptoms of dementia include:

   A decline in memory
   Changes in thinking skills
   Poor judgment and reasoning
   Decreased focus and attention
   Decreased language ability
   Negative changes in behavior

Although the symptoms are common, they are typically experienced in unique ways.[8] "Stages" are commonly referred to by professionals to describe the progressive nature of Alzheimer's (typically "early", "mid" and "late onset") but the symptoms can cross over these "boundaries" for many sufferers.

Diagnosis

The symptoms of Alzheimer's disease are generally reported to a doctor or physician when memory-loss (or symptoms surrounding memory loss) begin to pose a serious concern. When Alzheimer's disease is suspected, diagnosis is typically confirmed by a behavioural assessment, and some form of cognitive test. Often this is followed by a brain scan.[9]

Laboratory tests

Apolipoprotein E4

Although apolipoprotein E4 is an important susceptibility gene for Alzheimer's disease][10], its sensitivity and specificity are insufficient (65 and 68 percent, respectively) to be used as a diagnostic test.[11]

However, the level of apolipoprotein E4 in cerebrospinal fluid may be predictive.[12]

Amyloid-beta protein

Amyloid-beta protein may be elevated in the cerebrospinal fluid of some patients.[12]

Cause/etiology

The etiology of Alzheimer's disease is incompletely understood. Alzheimer's disease is associated with senile plaques and neurofibrillary tangles in the brain.[13] The incorrect folding of proteins leads to the formation of amyloid plaques. The prion protein (PrPC) may be the cellular receptor for amyloid-beta oligomer.[14] Current research aims to determine if such plaques are the result of, or the cause of, Alzheimer's disease.

Regarding biomarkers, one study found that "a reduction in the CSF Aβ42 level denotes a pathophysiological process that significantly departs from normality (ie, becomes dynamic) early, whereas the CSF total tau level and the adjusted hippocampal volume are biomarkers of downstream pathophysiological processes". [15]

Although there is a genetic susceptibility in a small percentage of people, Alzheimer's is not considered a genetic illness. The greatest risk factor for developing Alzheimer's is age, as the percentage of people developing it dramatically increases after age 65 and beyond. Major environmental/lifestyle risk factors include a diet high in saturated fats that are typical of the standard western diet, smoking, and long-term exposure to environmental toxins such as aluminium. Research is ongoing.

Treatment

No treatment has been found to stop or reverse the disease. Many preventive measures have been suggested for Alzheimer's disease, but their values are uncertain: mental stimulation, exercise, and a Mediterranean style diet are usually recommended, both as possible prevention and as a sensible way of managing the disease.[16]

Medications

As of 2023, available medications offer relatively small symptomatic benefit for some patients but generally do not slow disease progression. Newer monoclonal antibody treatments against beta-amyloid protein, for example, the drug Leqembi, have been approved in the United States, but they only slightly reduce the rate of disease progression and have significant side effects, including brain bleeding and in rare cases, death. These drugs cost over $20,000 a year, which could be prohibitively expensive for many patients.

Randomized controlled trials showed either small or absent benefit from acetylcholinesterase inhibitors[17] such as donepezil.[18][19][20]

The N-methyl-d-aspartate receptor antagonist memantine has shown some effectiveness[21] but does not add benefit to donepezil .[20]

Care management

Due to the incurable and degenerative nature of the disease care-management of Alzheimer's is essential. The role of the main caregiver is often taken by the spouse or a close relative.[22] Caregivers may themselves suffer from stress, over-work, depression, and from being physically assailed.[23]

Alzheimer's in society

Famous people who have, or have died of Alzheimer's disease, are the US president Ronald Reagan, the UK Prime minister Harold Wilson, the writers Terry Pratchett and Iris Murdoch, and the film stars Rita Hayworth and Charlton Heston.

History

Auguste D, first recorded patient with the newly recognised form of dementia.

Alzheimer’s disease is named after Dr. Alois Alzheimer, the German physician who first described it. In 1901, Alzheimer observed a 51-year-old patient at the Frankfurt asylum named Auguste Deter. Her symptoms included memory loss, language problems, and unpredictable behavior. In 1906, she died and Dr. Alzheimer noticed unusual pathology in her brain tissue; he found many abnormal clumps (now called amyloid plaques) and tangled bundles of fibers (now called neurofibrillary, or tau, tangles).

References

  1. Ferri CP, Prince M, Brayne C, Brodaty H, Fratiglioni L, Ganguli M, Hall K, Hasegawa K, Hendrie H, Huang Y, Jorm A, Mathers C, Menezes PR, Rimmer E, Scazufca M (2005). "Global prevalence of dementia: a Delphi consensus study". Lancet 366 (9503): 2112–2117. DOI:10.1016/S0140-6736(05)67889-0. PMID 16360788. Research Blogging.
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