CNS infections Flashcards
what is the 3 layers of meninges
- pia (closest to brain)
- arachnoid
- dura (closest to scalp)
where does the CSF flow in the meninges
between pia & arachnoid (subarachnoid space)
where does the meninges surround
cerebral cortex & spinal cord
what forms the BBB
capillaries of brain & spinal cord have tight junctions linking the endothelial cells in blood vessels, forming a physiological barrier
Why is antibiotics dosage higher in patients with meningitis
To allow the antibiotics to cross the BBB to reach the site of CNS infection
Meningitis?
Infection of the meninges
Encephalitis?
Infection/Inflammation of the cebrebral cortex
Brain abscess?
Abscess of cerebral coetex
Subdural abscess?
Abscess between dura and arachnoid mater
Epidural abscess?
Abscess immediately outside, adjacent to dura mater
Signs of bacterial meningitis
- Generalised headache
- Neck stiffness
- Photophobia
- Non-blanching rash
- Abnormal mental state/reduced conscious level
what sample should be taken for bacterial meningitis (2)
- perform lumbar puncture ASAP to obtain CSF specimen
- blood culture
- if pt is febrile
❗pathogens that cause bacterial meningitis
- neisseria meningitidis
- streptococcus pneumoniae
- haemophilus influenza
❗prevention of bacterial meningitis (2)
- vaccination
- neiserria meningitidis
- strep pnuemoniae
- haemophilus influenzae
- chemoprophylaxis (IV atbx) for household & close contacts
- neiserria meningitidis
- haemophilus influenzae
What is cryptococcus neoforms meningitis + who it tends to infect?
- Fungal infection of the brain and spinal cord
- Tends to infect immunocompromised hosts, especially HIV
what is the diagnosis of viral meningitis
PCR
what is the management of viral meningitis
supportive, self limiting
Definition of encephalitis
Infection/inflammation of cerebral cortex (Whole brain)
What are the bugs that can cause viral encephalitis (8)
- HSV-1
- HSV-2
- Mumps
- Measles
- HHV6 (Herpes virus type 6)
- CMV
- EBV
- Enterovirus
Symptoms of viral encephalitis
- Hallucinations
- Repetitive higher motor activity (E.g. dressing and undressing)
- Seizures
- Severe headache
- Unsteady gait
list 1 diagnosis of viral encephalitis
CSF PCR
❗what is the treatment of viral encephalitis
aciclovir (antiviral drug)
what is the bug that cause neonatal sepsis/meningitis
group B strep
