CNS infection Flashcards
Why are CNS infections an emergency? define the following: Encephalitis Meningitis Meningoencephalitis Encephalomyelitis
-brain and spinal do not regenerate
-might cause brain herniation and death
cord compression and necrosis with paralysis
-brain inflammation
inflamed meninges
inflamed meninges and cerebral tissue
inflammation of brain and spinal cord
define the following:
- acute pyogenic meningitis
- acute aseptic meningitis
- acute focal supportive infection
- chronic bacterial infection
- Acute encephalitis
- bacterial, rapidly developing inflammation of meninges & subarachnoid space
- viral
- brain abscess, subdural and extradural empyema
- TB
- infection of the brain parenchyma
acute pyogenic meningitis
-morphology? (3)
-thick layer supportive exudate covering leptomeninges over the surface of the brain
exudate in basal and convexity
microscopically: neutrophils in subarachnoid space
Viral meningitis
- causative organisms?
- presentation? (2)
- investigations? (3)
- treatment? (1)
-enteroviruses, e.g. cocksackie
-headache
photophobia
-viral stool culture, throat swab PCR CSF (lymphocytic)
-supportive (paracetamol, fluids, rest)
viral encephalitis
- causative organism?
- related to what?
- treatable?
- presentation?
- investigations?
- findings on MRI
-herpes simplex (RAPID RECOGNITION NEEDED, tx is high dose aciclovir)
also varicella zoster, CMV, HIV and measles
- travel
- only HS and VZ- high dose aciclovir
-insidious onset meningismus stupor, coma seizures, partial paralysis Confusion psychosis speech/memory symptoms
- LP, EEG, MRI
- generally see inflammation in the temporal lobes
Abscess
- appearance in MRI?
- routes if infection?
- presentation?
- treatment?
- ring enhancing lesion in parenchyma of the brain
- blood, heart, bronchiectasis
- headahces, focal neurological deficit, seizure
- surgery and drainage
bacterial meningitis
- causative organisms in following groups?
- neonates
- children
- 10-21
- 21+
- elderly
- immunocompromised
- basilar skull fracture
- head trauma/neurosurgery
- CSF shunt
- AIDS
- listeria, group B strep, E.coli
- H.influenza
- Meningococcal
- pneumococcal > meningococcal
- Pneumococcal > listeria
- S. pneumoniae, N. meningitidis, Listeria, aerobic GNR
- S. pneumoniae, H. influenzae, beta-hemolytic strep group A.
- S. aureus, S. epidermidis, aerobic GNR
- S. epidermidis, S. aureus, aerobic GNR, Propionibacterium acnes
- Cryptococcus neoformans
Meningococcal meningitis (Neisseria Meningitis)
- population group?
- pathway of infection?
- CSF signs?
- symptoms occur due to what?
- young children
- can be carries in throats of healthy individuals, gain access via blood stream
- bacteria found in leukocytes in CSF
- enterotoxin
Hemophilus influenza Meningitis
- population group?
- vaccine?
- part of normal throat microbiota, most common cause in children under 4 is H.influenzae type b
- vaccine available, against the capsular polysaccharide
-
Streptococcus pneumoniae Meningitis
- normally found where
- population groups?
- vaccines?
- nasopharynx
- hospitalised patients, CSF skull fractures, DM, alcoholics, young children
- yes, conjugated and fro pneumococcal pneumonia
Listeria monocytogenes
- gram stain?
- pathway of infection?
- population group?
- treatment?
- gram + bacilli
- bactereamic meanly
- noenates, >55, immunosuppressed
- IV ampicillin, amoxicillin
Tuberculous meningitis
- population group?
- symptoms?
- treatment?
- elderly with reactivated TB
- non specific, weight loss, anorexia, fever, sweats
- isoniazid + rifampicin
CRYPTOCOCCAL MENINGITIS
- organism type?
- in what population?
- presentation?
- CSF appearance?
- treatment?
- fungus
- HIV, CD4< 100
- nuerological presentation
- aseptic picture, do serum and CSF cryptococcal antigen
-IV amphotericin B/lfucytosine
fluconazole
clinical signs of bacterial meningitis? (3)
-symptoms? (8)
fever
stiff neck
Altered level of consciousness
-headache vomiting pyrexia neck stiffness photophobia lethargy confusion non-blanching purpuric rash
signs might be atypical in the very young or very old
LP- principles
- when should it be performed?
- contraindicated in?
- what tests should be done on collected CSF?
- needs to be done promptly, If prolonged wait then start antibiotics
- raised ICP, coning (brain herniation) might occur
-Tube 1: haematology- cell count, differential
Tube 2: Microbiology- gram stain, cultures
Tube 3: chemistry- glucose, protein
