CNS infections and meningitis Flashcards
What are the 4 lobes of the brain?
Frontal
Temporal
Parietal
Occipital
How many spinal nerves are there?
31 pairs
What are the 4 routes of entry?
Haematogenous spread (e.g. pneumococcus, meningococcus) Direct implantation (e.g. trauma) Local extension (e.g. from the ear) PNS to CNS (e.g. rabies)
What are the meningeal layers
Dura - Outermost
Arachnoid
Pia (Innermost)
What is meningitis usually caused by?
Bacteria such as Neisseria meningitis, strep pneumo, TB, Haem influ
Fungus such as cryptococcus neoformans
What can encephalitis be caused by?
Viruses such as rabies, arboviruses
amoeba
Parasites
What can myelitis be caused by?
Spinal cord infections due to polio
What can neurotoxins like Clostridium tetani and clostridium botulinum cause?
Rigid paralyisis and flaccid paralysis respectively
Difference between meningitis and meningoencephalitis?
Meningoencephalitis is the inflammation of the meninges AND brain parenchyma
What can meningitis be classified into?
Acute - Bacterial (Meningococcal, Neiseria, H.influenzae, GBS, E Coli, Listeria)
Chronic - TB, spirochetes, crytpococcus
Aseptic - Viral
Where can Listeria be found?
Blue cheese, mayo
Babies being delivered via vaginal delivery are in bigger risk of developing which kind of meningitis?
GBS and E Coli
So if mum is positive for GBS, give Benzylpenicilin during delivery
What is a tell tale sign for meningococcal meningitis?
Purpural petichael rashes due to thrombocytopaenia as your platelet count drops. Rashes are non blanching.
How can meningococcal meningitis present?
Thrombocytopaenia
Septicaemia - Hypovolaemia, coagulopathy, metab acidosis, myocardial failure
What can be seen in a CT head of someone with TB meningitis?
Dilation of ventricles
Thick wall abscess
Space occupying lesions