Encefalopatias Espongiformes Transmissíveis

As encefalopatias espongiformes transmissíveis são doenças causadas por priões. Os priões diferem dos vírus por serem pequenos agentes patogénicos infeciosos que não contêm ácido nucleico. As encefalopatias espongiformes incluem a doença de Creutzfeldt-Jakob (DCJ), a variante da doença de Creutzfeldt-Jakob (vDCJ), a Kuru Kuru A prion disease found exclusively among the fore linguistic group natives of the highlands of new guinea. The illness is primarily restricted to adult females and children of both sexes. It is marked by the subacute onset of tremor and ataxia followed by motor weakness and incontinence. Death occurs within 3-6 months of disease onset. The condition is associated with ritual cannibalism, and has become rare since this practice has been discontinued. Pathologic features include a noninflammatory loss of neurons that is most prominent in the cerebellum, glial proliferation, and amyloid plaques. Transmissible Spongiform Encephalopathies, a insónia familiar fatal (IFF) e a síndrome de Gerstmann-Straussler (SGS). Este grupo de doenças apresenta como características comuns a demência, ataxia Ataxia Impairment of the ability to perform smoothly coordinated voluntary movements. This condition may affect the limbs, trunk, eyes, pharynx, larynx, and other structures. Ataxia may result from impaired sensory or motor function. Sensory ataxia may result from posterior column injury or peripheral nerve diseases. Motor ataxia may be associated with cerebellar diseases; cerebral cortex diseases; thalamic diseases; basal ganglia diseases; injury to the red nucleus; and other conditions. Ataxia-telangiectasia e mioclonia. Infelizmente, estas doenças estão associadas a longos períodos de incubação ( mais MAIS Androgen Insensitivity Syndrome de 20 anos) e, assim que os sintomas ocorrem, progridem rapidamente para a morte.

Last updated: Dec 15, 2025

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Epidemiologia e Etiologia

Epidemiologia

As encefalopatias espongiformes são extremamente raras.

Pertencem a um grupo de doenças no qual estão incluídas:

  • Doença de Creutzfeldt-Jakob (DCJ)
  • Kuru Kuru A prion disease found exclusively among the fore linguistic group natives of the highlands of new guinea. The illness is primarily restricted to adult females and children of both sexes. It is marked by the subacute onset of tremor and ataxia followed by motor weakness and incontinence. Death occurs within 3-6 months of disease onset. The condition is associated with ritual cannibalism, and has become rare since this practice has been discontinued. Pathologic features include a noninflammatory loss of neurons that is most prominent in the cerebellum, glial proliferation, and amyloid plaques. Transmissible Spongiform Encephalopathies
  • Insónia Familiar Fatal (IFF)
  • Síndrome de Gerstmann-Straussler (SGS) (incidência: 1 em cada 100 milhões de novos casos por ano)

A encefalopatia espongiforme mais MAIS Androgen Insensitivity Syndrome comum é a doença de Creutzfeldt-Jakob. Os seus subtipos são:

  1. Doença esporádica de Creutzfeldt-Jakob (sDCJ):
    • Incidência: 1 em cada 1.000.000 casos por ano (90% dos casos)
    • A idade média de início é de 62 anos
  2. Variante da doença de Creutzfeldt-Jakob (vDCJ) e doença de Creutzfeldt-Jakob iatrogénica (iDCJ): idade de início mais MAIS Androgen Insensitivity Syndrome jovem (não está claramente definida)
  3. Doença genética de Creutzfeldt-Jakob (gDCJ): maior predominância no norte de África, Israel e Itália

Etiologia

Os fatores de alto risco são:

  • Canibalismo ( Kuru Kuru A prion disease found exclusively among the fore linguistic group natives of the highlands of new guinea. The illness is primarily restricted to adult females and children of both sexes. It is marked by the subacute onset of tremor and ataxia followed by motor weakness and incontinence. Death occurs within 3-6 months of disease onset. The condition is associated with ritual cannibalism, and has become rare since this practice has been discontinued. Pathologic features include a noninflammatory loss of neurons that is most prominent in the cerebellum, glial proliferation, and amyloid plaques. Transmissible Spongiform Encephalopathies)
  • História familiar de gDCJ, SGS ou IFF

Fisiopatologia

As doenças priónicas ocorrem quando uma proteína ⍺ helicoidal normal, conhecida como PrP PRP Raynaud Phenomenonc, é convertida numa proteína β-pregueada anormal, conhecida como PrP PRP Raynaud Phenomenonsc.

  • Baseia-se num desdobramento anormal das proteínas
  • A PrP PRP Raynaud Phenomenonsc anormal é resistente à degradação da protease Protease Enzyme of the human immunodeficiency virus that is required for post-translational cleavage of gag and gag-pol precursor polyproteins into functional products needed for viral assembly. HIV protease is an aspartic protease encoded by the amino terminus of the pol gene. HIV Infection and AIDS, o que facilita a conversão de PrP PRP Raynaud Phenomenonc em PrP PRP Raynaud Phenomenonsc anormal. Esta conversão constante substitui lentamente as proteínas normais.
  • A PrP PRP Raynaud Phenomenonsc acumula-se nos órgãos linforreticulares e secretores
    • Dissemina-se para o sistema nervoso central (SNC) → astrocitose → perda de neurónios → vacuolização do cérebro
    • Este processo leva ao aparecimento dos sintomas clássicos da encefalopatia espongiforme:
      • Ataxia Ataxia Impairment of the ability to perform smoothly coordinated voluntary movements. This condition may affect the limbs, trunk, eyes, pharynx, larynx, and other structures. Ataxia may result from impaired sensory or motor function. Sensory ataxia may result from posterior column injury or peripheral nerve diseases. Motor ataxia may be associated with cerebellar diseases; cerebral cortex diseases; thalamic diseases; basal ganglia diseases; injury to the red nucleus; and other conditions. Ataxia-telangiectasia cerebelar
      • Demência
      • Morte

Transmissão

Existem 3 formas principais de desenvolver encefalopatia espongiforme:

  1. Adquirida ou infeciosa:
    • Exposição direta a tecidos infetados pelo SNC, como um transplante de córnea (iDCJ)
    • Administração de hormonas hipofisárias humanas cadavéricas (iDCJ)
    • Ingestão de alimentos contaminados através de produtos animais infetados por encefalopatia espongiforme bovina (BSE) (“doença das vacas loucas”) (vDCJ)
    • Canibalismo de tecidos infectados pelo SNC ( Kuru Kuru A prion disease found exclusively among the fore linguistic group natives of the highlands of new guinea. The illness is primarily restricted to adult females and children of both sexes. It is marked by the subacute onset of tremor and ataxia followed by motor weakness and incontinence. Death occurs within 3-6 months of disease onset. The condition is associated with ritual cannibalism, and has become rare since this practice has been discontinued. Pathologic features include a noninflammatory loss of neurons that is most prominent in the cerebellum, glial proliferation, and amyloid plaques. Transmissible Spongiform Encephalopathies)
  2. Genética:
  3. Espontânea:
Transmissão da doença da vaca louca

Origem das doenças priónicas

Imagem por Lecturio.

Apresentação Clínica e Diagnóstico

As encefalopatias espongiformes transmissíveis estão associadas a tempos de incubação extremamente longos (20 a 50 anos) e, uma vez que os sintomas aparecem, a doença progride rapidamente até à morte.

Não existem medidas curativas e a doença é universalmente fatal.

Apresentação clínica e diagnóstico de encefalopatias espongiformes transmissíveis
Sintomas Diagnóstico
Doença de Creutzfeldt-Jakob
  • Demência rapidamente progressiva (durante semanas a meses)
  • Mioclonia de sobressalto (fenómeno “startle”)
  • Ataxia Ataxia Impairment of the ability to perform smoothly coordinated voluntary movements. This condition may affect the limbs, trunk, eyes, pharynx, larynx, and other structures. Ataxia may result from impaired sensory or motor function. Sensory ataxia may result from posterior column injury or peripheral nerve diseases. Motor ataxia may be associated with cerebellar diseases; cerebral cortex diseases; thalamic diseases; basal ganglia diseases; injury to the red nucleus; and other conditions. Ataxia-telangiectasia
  • Morte dentro de 1 ano desde início dos sintomas
  • TC/RM da cabeça: aparentemente normal
  • Líquido cefalorraquidiano (LCR): ↑ na proteína 14-3-3
  • Eletroencefalograma ( EEG EEG Seizures): complexos periódicos de ondas agudas
  • Biópsia cerebral post-mortem:
    • Vacúolos intracitoplasmáticos no córtex espongiforme
    • Acumulação de PrP PRP Raynaud Phenomenon sc na histopatologia
    • Perda neuronal
Kuru Kuru A prion disease found exclusively among the fore linguistic group natives of the highlands of new guinea. The illness is primarily restricted to adult females and children of both sexes. It is marked by the subacute onset of tremor and ataxia followed by motor weakness and incontinence. Death occurs within 3-6 months of disease onset. The condition is associated with ritual cannibalism, and has become rare since this practice has been discontinued. Pathologic features include a noninflammatory loss of neurons that is most prominent in the cerebellum, glial proliferation, and amyloid plaques. Transmissible Spongiform Encephalopathies
  • Primeiro estadio: tremores (“shivering”), ataxia Ataxia Impairment of the ability to perform smoothly coordinated voluntary movements. This condition may affect the limbs, trunk, eyes, pharynx, larynx, and other structures. Ataxia may result from impaired sensory or motor function. Sensory ataxia may result from posterior column injury or peripheral nerve diseases. Motor ataxia may be associated with cerebellar diseases; cerebral cortex diseases; thalamic diseases; basal ganglia diseases; injury to the red nucleus; and other conditions. Ataxia-telangiectasia, instabilidade postural
  • Segundo estadio: perda de deambulação, mioclonias
  • Fase tardia: demência
  • Morte dentro de 1 ano desde início dos sintomas
Desconhecido; poucos estudos realizados devido a casos limitados (principalmente isolados na Papua Nova Guiné na década de 1950)
Insónia familiar fatal Pacientes entre os 23 e 73 anos:
  • Insónia progressiva
  • Perda do padrão circadiano normal de atividade do sono
  • Mioclonias
  • Ataxia Ataxia Impairment of the ability to perform smoothly coordinated voluntary movements. This condition may affect the limbs, trunk, eyes, pharynx, larynx, and other structures. Ataxia may result from impaired sensory or motor function. Sensory ataxia may result from posterior column injury or peripheral nerve diseases. Motor ataxia may be associated with cerebellar diseases; cerebral cortex diseases; thalamic diseases; basal ganglia diseases; injury to the red nucleus; and other conditions. Ataxia-telangiectasia
  • Disautonomia
  • Morte dentro de 1 ano desde início dos sintomas
Pouco claro; biópsia cerebral post-mortem
Síndrome de Gerstmann-Straussler-Scheinker Pacientes com média de 40 anos:
  • Degeneração cerebelar progressiva (desajeitamento, incoordenação, ataxia Ataxia Impairment of the ability to perform smoothly coordinated voluntary movements. This condition may affect the limbs, trunk, eyes, pharynx, larynx, and other structures. Ataxia may result from impaired sensory or motor function. Sensory ataxia may result from posterior column injury or peripheral nerve diseases. Motor ataxia may be associated with cerebellar diseases; cerebral cortex diseases; thalamic diseases; basal ganglia diseases; injury to the red nucleus; and other conditions. Ataxia-telangiectasia)
  • Demência
  • Morte dentro de 5 anos desde início dos sintomas
Biópsia cerebral post-mortem

Diagnóstico Diferencial

O diagnóstico diferencial engloba doenças associadas à demência de progressão rápida, incluindo as seguintes:

  • Demência de corpos de Lewy:
    • Pode progredir rapidamente
    • Associada a demência, alucinações visuais e síncope
    • Achados histológicos: corpos de Lewy intracelulares (⍺-sinucleína)
  • Demência frontotemporal (doença de Pick):
    • Associada a mudanças precoces na personalidade e no comportamento que progridem para movimentos semelhantes ao parkinsonismo
    • RM: degeneração do lobo frontotemporal
  • Demência vascular:
    • Geralmente declínio gradual da função neurológica com comprometimento da memória de início tardio
    • RM: múltiplos enfartes corticais
  • Doença de Alzheimer:

Referências

  1. Baiardi, S., Capellari, S., Bartoletti-Stella, A., & Parchi, P. (2023). Human Prion Disease: Molecular Pathogenesis, and Possible Therapeutic Targets and Strategies. Expert Opinion on Therapeutic Targets, 27(12), 1271–1284. https://doi.org/10.1080/14728222.2023.2199923
  2. Geschwind M. D. (2015). Prion Diseases. Continuum (Minneapolis, Minn.)21(6 Neuroinfectious Disease), 1612–1638. https://doi.org/10.1212/CON.0000000000000251
  3. Ironside, J. W., Ritchie, D. L., & Head, M. W. (2017). Prion diseases. Handbook of clinical neurology145, 393–403. https://doi.org/10.1016/B978-0-12-802395-2.00028-6
  4. Liu, F., Lü, W., & Liu, L. (2024). New implications for prion diseases therapy and prophylaxis. Frontiers in molecular neuroscience17, 1324702. https://doi.org/10.3389/fnmol.2024.1324702
  5. Prusiner S. B. (2013). Biology and genetics of prions causing neurodegeneration. Annual review of genetics47, 601–623. https://doi.org/10.1146/annurev-genet-110711-155524
  6. Appleby, B. S., & Cohen, M. L. (2024). Creutzfeldt-Jakob disease. UpToDate, Inc. Retrieved January 19, 2025, from https://www.uptodate.com/contents/creutzfeldt-jakob-disease
  7. National Institute of Neurological Disorders and Stroke. (n.d.). Kuru. U.S. Department of Health and Human Services. Retrieved January 19, 2025, from https://www.ninds.nih.gov/health-information/disorders/kuru
  8. World Health Organization. (2003). WHO guidelines on transmissible spongiform encephalopathies in relation to biological and pharmaceutical products. World Health Organization. Retrieved January 19, 2025, from https://www.who.int/publications/m/item/who-guidelines-on-transmissible-spongiform-encephalopathies 

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