Understanding Major and Mild Neurocognitive Disorder Due to Prion Disease
Rapidly Progressive Dementia • Neurology • Infection Control
Understanding Major and Mild Neurocognitive Disorder Due to Prion Disease
Prion diseases (including Creutzfeldt–Jakob disease) are rare, transmissible neurodegenerative disorders characterised by rapidly progressive cognitive decline, neurological signs and poor prognosis. This guide outlines typical presentation, investigations, infection control concerns and supportive management.
What are prion diseases?
Prion diseases are caused by misfolded prion proteins (PrP^Sc) that induce neurodegeneration. They present with rapidly progressive cognitive decline, motor signs and myoclonus. Most prion diseases are sporadic, but familial and acquired forms (variant CJD, iatrogenic) exist.
Clinical features
- Rapidly progressive dementia over weeks to months.
- Myoclonus, ataxia, extrapyramidal features and pyramidal signs.
- Visual disturbances and cortical blindness in some variants.
- Behavioural change, apathy, and early aphasia can occur.
- Neurological deterioration often leads to akinetic mutism in late stages.
Assessment & investigations
- MRI brain — diffusion-weighted imaging (DWI) often shows cortical ribboning and basal ganglia hyperintensities.
- EEG — periodic sharp wave complexes may be seen in some cases.
- CSF tests — 14-3-3 protein, tau, and RT-QuIC assay (highly specific) when available.
- Genetic testing for PRNP mutations if familial disease suspected.
- Consider extensive workup to exclude reversible causes and other rapidly progressive dementias (autoimmune, paraneoplastic, infectious).
Differential diagnosis
- Autoimmune encephalitis, viral encephalitis, paraneoplastic syndromes.
- Rapidly progressive Alzheimer’s disease, vascular causes and toxic/metabolic encephalopathies.
- Metabolic or iatrogenic causes that may be reversible — always exclude these.
Management — supportive & palliative
There is no cure for prion diseases. Management is supportive, focusing on symptom control, preventing complications and providing palliative care and family support.
- Treat myoclonus with clonazepam or levetiracetam as needed.
- Manage neuropsychiatric symptoms (agitation, psychosis) judiciously with low-dose antipsychotics while monitoring risks.
- Address swallowing difficulties and nutrition, consider enteral feeding if appropriate for patient goals.
- Palliative care involvement early to discuss goals of care and symptom-focused interventions.
Infection control & public health considerations
- Prion diseases are transmissible via certain tissues/instruments — follow strict sterilisation and single-use instrument policies for neurosurgical procedures.
- Notify public health/tertiary referral centres when suspected to ensure appropriate testing and surveillance.
- Genetic counselling for families in familial cases.
Red flags — urgent actions
- Very rapid cognitive decline over weeks with myoclonus — arrange urgent MRI DWI, EEG and CSF (RT-QuIC) testing.
- New focal neurological deficits or suspected treatable causes — expedite investigations to exclude reversible conditions.
- Consider isolation of surgical instruments and inform infection control teams if invasive procedures performed.
Case vignette
Patient: R., 64, rapid cognitive decline over 8 weeks with myoclonic jerks and gait instability. MRI DWI showed cortical ribboning; CSF RT-QuIC positive. Management: symptomatic control of myoclonus, early palliative care referral and family counselling. Infection control measures implemented peri-procedurally.
தமிழில் — சுருக்கம்
Prion நோய்கள் மிக விரைவாக முன்னேறும் நினைவாற்றல் குறைபாடுகளை ஏற்படுத்துகின்றன. மருத்துவமனையில் திறமையான பரிசோதனைகள் (MRI DWI, CSF RT-QuIC) தேவை. சிகிச்சை ஆதரவுச் சிகிச்சை மற்றும் காலக் காப்புக் கொள்கைகளாகும்.
Key takeaways
- Prion diseases cause rapidly progressive neurocognitive decline with characteristic MRI and CSF findings.
- No disease-modifying therapies exist; focus on symptomatic management, palliative care and infection control.
- Exclude reversible causes of rapidly progressive dementia and involve specialist centres for diagnosis and surveillance.