What is the main difference between meningitis and encephalitis?
- Meningitis is when the meningeal layers of the brain become infected due to a virus, bacteria or (rarely) fungus
- Encephalitis is inflammation of the brain itself, can be due to bacteria but more commonly a virus
What has better outcomes, viral meningitis or bacteria meningitis?
Viral meningitis - it is not generally life threatening and has a less pronounced sequelae compared to bacterial meningitis
What primary sites of the brain are affected in bacterial meningitis?
Pia mater and arachnoid
What are the key long term neuropsychological effects of bacterial meningitis?
- Neurodevelopmental delays (in up to 40% of cases at 12 months post infection, hence needs monitoring)
- Post 12 years, bacterial meningitis pts has lower IQs, academic functioning, and high level language deficits
- Lower order skills like attn and processing tend to improve
- Chronic difficulties with higher order skills (memory and executive functioning)
- Significant behaviour concerns
- Cognitive slowing
- Depression
- Poorer QoL
What are the predictors of poor outcome in bacterial meningitis?
- Age <12 months at illness
- > 24 hrs symptoms before dx
- Prolonged or complicated seizures
- Focal neurological signs, ataxia (impaired coordination)
- Pneumococcal infection
- Reduced QoL assocaited with academic and/or behavioural problems
What conditions does encephalitis commonly cause?
- Herpes simplex virus (HSV)
- Human Immunodeficiency Virus (HIV)
Imaging is important, esp in HIV, as CT/MRI changes can be evidence before cog deficits emerge
What is the difference between Acute Disseminated Encephalomyelitis (ADEM) and Multiple Sclerosis?
- They both demyelinating diseases on a spectrum together
- ADEM is often preceded by an infectious disease
- ADEM often only occurs once. If a multiple episodes occur, it is usually associated with juvenille MS. 6-25% of children with ADEM will go on to be dx with MS.
Why is follow up neuropsych important in ADEM?
Because even after neurologic symptoms had resolved, subtle long term problems exist such as poorer overall cognitive functioning (IQ and academic) and severe behavioural and emotional problems especially in younger onset ADEM
What is Adrenoleukodystophy (ALD)?
- A bilaterally symmetric demyelinating disorder where the body is uanble to break down very long chain fatty acids, resulting in irreversible cerebral destruction.
- Almost always affects males with the gene passed down from female carriers.
- NP symptoms include attention problems, hyperactivity, language difficulties, behaviour disturbance and reduced school performance, hence can be misdiagnosed as ADHD
- Death is within 2-3 years of onset of neurological symptoms
Why is neuropsych input important in cerebral infections and demyelinating diseases?
Regular monitoring of cognitive functioning is
essential to identify:
- Slowed developmental trajectory
- Plateau (arrested development)
- Cognitive decline
- Disease progression
- Late effects (of disease and/or treatment)
