Neurological Infections Flashcards
What are the 3 major concerns of neurological infections?
- the development of drug resistant infectious agents
- increasing number of immunocompromised human populations (people taking medications that are putting their immune systems at risk)
- the rising number of diseases previously considered rate (i.e. the ZIKA virus)
what four things are considered essential to prevent and treat resorting and emerging neurological infectious disease?
- education
- surveillance
- development of new drugs
- vaccines
What are 6 types of neurological infectious agents (with examples)?
- Bacterium (i.e. tuberculosis)
- Virus (i.e. HIV)
- Fungus (i.e. cryptococcus)
- Protozoa (i.e. malaria)
- Prion (i.e. BSE) –> from beef
- Helminth (i.e. cysticercosis)
What are the big 3 global neurological infectious agents?
- tuberculosis
- HIV/AIDS
- malaria
what are 2 unique aspects of CNS infections?
- localization of the infection dictates how it is clinically represented (i.e. if it presents in the CNS or PNS)
- Brain is an immune privileged organ (it has a lot of protection against foreign substances) things that help with this are blood-brain barrier protection and some innate (macrophases/neurophils) vs. adaptive (T cells/B-cells) immunity
there SHOULD be only innate immunity in the brain and no adaptive immunity however, if theres a severe infection the adaptive immune cells might come into the brain
What are 5 determinants of emerging infections?
- susceptible populations: poverty, war, famine, immunosuppression
- altered human and animal contact
- medical practices (more immunosuppressive medication)
- rapid and frequent global movement of animals and humans
- disrupted environments: climate change, and economic development
What is the summary of the evolution of West Nile virus?
mosquitos replicated in the water and infected birds, the birds then infected zoo animals and humans caught it from them and transformed the virus into a human version
this caused encephalitis (inflammation of the brain)
What has the highest annual global incidence of viral encephalitis?
japanese encephalitis
what are some of the symptoms of meningitis?
- headache/stiff neck/fever
- nuchal rigidity (inability to flex the neck forward due to rigidity of neck muscles)
- cranial neuropathies
what are two tests that can be done to test for meningitis signs?
- Kerning’s sign: neck pain associated with leg stretch
2. Brudzinski’s neck sign: stretch of the legs when neck is pulled upwards
what are some signs of encephalitis?
infection agents that affect the astrocytes in the brain
- headache
- fever
- confusion/altered behaviour (coma, seizure, focal signs)
What are some signs of myelitis?
- limb weakness
- back pain
- B & B dysfunction
- sensory loss (spinal cord infection)
What are signs of Absceess?
- focal signs
- fever
- seizure (focal infection in brain)
What is radiculopathy/neuropathy signs?
infection of the peripheral nerves (PNS)
- localized radicular pain
- fever
- weakness
How does the invasion of CNS via the meninges happen?
fibroblast and macrophages that infiltrate meninges and activate during infections
What is the neurological infection algorithm (how we come to a conclusion of prognosis)?
- presentation (syndrome/ acute vs. chronic)
- Infection risks (where it could’ve came from) including exposure, prophylaxis, season, co-morbities
- physical exam –> focal signs, extra ons features
- localization –> meninges, brain, spinal cord ?
- two things –> one is neuroimaging (CT and MRI) and other is blood test (CBC, electrolytes etc…)
- CSF tests (lumbar puncture)
- management (diagnosis of blood and neuroimaging leads to the possible treatment) –> is it supportive, is it specific?
- pronosticate –> morbidity and mortality
if at management stage you realize that its not the right diagnosis then you have to go back to a re-evaluation possibly at a brain imaging or blood test stage (usually takes multiple trials)
What are different types of CNS neural cells?
neurons, astrocytes, oligodendrocytes, endothelial cells and microglia/macrophages and BBB
what are different types of PNS cells?
neurons, schwann cells, macrophages protected by the BBB
how do the T and B cells (acquired immune cells) enter the BBB?
when theres an infection in the brain, it activates astrocytes and calls t and b cells and other non-CNS immune cells into the CNS.. this causes brain problems such as delirium and confusion etc…
t cells and neutrophils don’t reside in the BBB but can traffic in the nervous system and cause inflammation
What happens the microglia during infection and what do they do?
microglia is the brains phagocytes. Their bodies expand at time of activation
when the brain is in ‘normal’ state the microglia are immune ‘sensors’
but when the brain is under attack and micgrolia are activated they:
- phagocytosis
- chemotaxis
- antigen presentation
- cytotoxicity
- morphological changes
- proliferation
- respiratory burst
- they can release cytokines and clean up the environment and produce trophic growth factors to help myelin development