Alzheimer disease

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Teoria 
Diagnóstico 
Tratamento 
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Última revisão das evidências: 3 Sep 2026

Última atualização do tópico: 25 Aug 2026

Alzheimer disease (AD) is a chronic, progressive neurodegenerative disorder characterized by a global, nonreversible impairment in cerebral functioning.

AD is characterized by memory loss, loss of social and occupational functioning, diminished executive function, speech and motor deficits, personality change, and behavioral and psychological disturbance.

It has a deteriorating course over up to 8-10 years.

Brain lesions are marked by neurofibrillary tangles, senile plaques, neuronal loss, and brain atrophy, with defects in acetylcholine synthesis at the cellular level.

Treatment requires a multidisciplinary approach with increasing emphasis on treating behavioral and psychological symptoms. Cholinesterase inhibitors and memantine have some evidence of efficacy in treating the symptoms of the disease. Emerging treatments include monoclonal antibodies that target amyloid-beta, with the aim of slowing decline in cognition and function.

Psychosocial interventions and caregiver support are key. Caregiver support groups are beneficial to caregivers and should be considered, where available.

Definição

Alzheimer disease (AD) is a chronic neurodegenerative disease with an insidious onset and progressive but slow decline. AD is the most common type of dementia.[1][2] It often coexists with other forms of dementia, particularly vascular dementia (mixed-type dementia). The histopathology of AD is characterized by senile plaques, neurofibrillary tangles, and neuronal loss. The hallmark symptoms are memory loss, impairment of daily activities, and neurobehavioral abnormalities. Definition of severity varies according to country, but a commonly accepted categorization is mild, moderate, and severe. The Mini-Mental State Examination can be used as a guide to cognitive impairment, but education, language, and any other relevant factors must be taken into consideration when interpreting scores.

História e exame físico

Principais fatores diagnósticos

memory loss
disorientation
nominal dysphasia
misplacing items/getting lost
apathy
decline in activities of daily living and instrumental activities of daily living (IADLs)
personality change
unremarkable initial physical exam

Detalhes completos

Outros fatores diagnósticos

mood and behavior changes
poor abstract thinking
constructional dyspraxia
prosopagnosia
autoprosopagnosia

Detalhes completos

Fatores de risco

advanced age
family history
genetics
Down syndrome
cerebrovascular disease
lifestyle factors and environment
use of certain drugs
less than high school education
traumatic brain injury
depression
hearing loss
periodontal disease
visual impairment
herpes simplex virus type 1 (HSV-1) infection
hyperlipidemia
female sex
elevated plasma homocysteine level
surgery under general anesthesia

Detalhes completos

Investigações diagnósticas

Primeiras investigações a serem solicitadas

cognitive testing
CBC
metabolic panel
serum thyroid-stimulating hormone (TSH)
serum vitamin B12
urine drug screen
CT brain (without contrast)
MRI brain (without contrast)

Detalhes completos

Investigações a serem consideradas

cerebrospinal fluid (CSF) analysis
serum rapid plasma reagin/Venereal Disease Research Laboratory (VDRL)
serum HIV testing
formal neuropsychological testing
genetic testing
fluorodeoxyglucose-PET (FDG-PET)
CSF biomarker testing

Detalhes completos

Novos exames

amyloid-PET
tau-PET
blood biomarkers

Algoritmo de tratamento

CONTÍNUA

all patients

Colaboradores

Autores

Judith Neugroschl, MD

Associate Professor of Psychiatry

Alzheimer's Disease Research Center

Icahn School of Medicine at Mount Sinai

New York, NY

Declarações

JN is supported by a National Institutes for Health (NIH) grant. She is director of the clinical core of the Alzheimer’s Disease Research Center.

Agradecimentos

Dr Judith Neugroschl would like to gratefully acknowledge Dr Brandy R. Matthews, Dr Asif S. Bhutto, and Dr Julie K. Gammack, the previous contributors to this topic.

Declarações

BRM, ASB, and JKG declare that they have no competing interests.

Peer reviewers

Roy J. Goldberg, MD, FACP, AGSF, CMD

Medical Director

Kings Harbor Multicare Center

New York, NY

Disclosures

RJG declares that he has no competing interests.

Philip Scheltens, MD, PhD

Professor of Neurology

Department of Neurology/Alzheimer Center

VU University Medical Center

Amsterdam

The Netherlands

Disclosures

PS declares that he has no competing interests.

Peer reviewer acknowledgements

BMJ Best Practice topics are updated on a rolling basis in line with developments in evidence and guidance. The peer reviewers listed here have reviewed the content at least once during the history of the topic.

Disclosures

Peer reviewer affiliations and disclosures pertain to the time of the review.

References

Our in-house evidence and editorial teams collaborate with international expert contributors and peer reviewers to ensure that we provide access to the most clinically relevant information possible.

Key articles

Livingston G, Huntley J, Liu KY, et al. Dementia prevention, intervention, and care: 2024 report of the Lancet standing commission. Lancet. 2024 Aug 10;404(10452):572-628. Abstract

American College of Radiology. ACR appropriateness criteria: dementia. 2024 [internet publication].Full text

McShane R, Westby MJ, Roberts E, et al. Memantine for dementia. Cochrane Database Syst Rev. 2019 Mar 20;(3):CD003154.Full text Abstract

Birks JS, Chong LY, Grimley Evans J. Rivastigmine for Alzheimer's disease. Cochrane Database Syst Rev. 2015 Sep 22;(9):CD001191.Full text Abstract

Birks JS, Harvey RJ. Donepezil for dementia due to Alzheimer's disease. Cochrane Database Syst Rev. 2018 Jun 18;(6):CD001190.Full text Abstract

Reus VI, Fochtmann LJ, Eyler AE, et al. The American Psychiatric Association practice guideline on the use of antipsychotics to treat agitation or psychosis in patients with dementia. Am J Psychiatry. 2016 May 1;173(5):543-6.Full text Abstract

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

Differentials
- Delirium
- Depression
- Vascular dementia
More Differentials
Guidelines
- ACR-ACNM-ASNR-SNMMI practice parameter for the performance of brain PET-CT imaging in dementia
- European intersocietal recommendations for the biomarker-based diagnosis of neurocognitive disorders
More Guidelines
Patient information
Alzheimer disease and other kinds of dementia
Caring for someone with dementia
More Patient information
Calculators
Geriatric Depression Scale
More Calculators
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Alzheimer disease

Resumo

Definição

História e exame físico

Principais fatores diagnósticos

Outros fatores diagnósticos

Fatores de risco

Investigações diagnósticas

Primeiras investigações a serem solicitadas

Investigações a serem consideradas

Novos exames

Algoritmo de tratamento

all patients

Colaboradores

Autores

Judith Neugroschl, MD

Declarações

Agradecimentos

Declarações

Peer reviewers

Roy J. Goldberg, MD, FACP, AGSF, CMD

Disclosures

Philip Scheltens, MD, PhD

Disclosures

Peer reviewer acknowledgements

Disclosures

References

Key articles

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

Differentials

Guidelines

Patient information

Calculators

Log in or subscribe to access all of BMJ Best Practice

Log in or subscribe to access all of BMJ Best Practice

Log in to access all of BMJ Best Practice