CNS infection Flashcards
what is meningitis? aseptic meningitis? encephalitis? meningoencephalitis?
Meningitis = Infection of the meninges
•Aseptic meningitis = meningitic symptoms plus white cells in CSF, but no growth on routine cultures
•Encephalitis = Inflammatory process of the brain (usually acute and diffuse, often viral, altered mental status early, focal signs)
•Meningoencephalitis = combination of meningeal and parenchymal disease)
encephalitis symptoms?
seizures, focal signs, altered mentation reduced GCS
history and examination?
Fever, headache, photophobia, neck stiffness
•Rash, sore throat, swollen glands, vomiting, genitourinary symptoms
•Illness in contacts
•Sexual history
•Travel abroad
•HIV risk factors
•Immunisation history
•Exposure to rodents / ticks
three signs of meningism?
nuchal rigidity - Nuchal rigidity is the inability to flex the neck forward due to rigidity of the neck muscles; if flexion of the neck is painful but full range of motion is present, nuchal rigidity is absent.[citation needed]
Kernig’s sign - Kernig’s sign (after Waldemar Kernig (1840–1917), a Baltic German neurologist) is positive when the thigh is bent at the hip and knee at 90 degree angles, and subsequent extension in the knee is painful (leading to resistance).[3] This may indicate subarachnoid hemorrhage or meningitis.[4] Patients may also show opisthotonus—spasm of the whole body that leads to legs and head being bent back and body bowed backwards.[citation needed]
Brudzinski’s sign - Jozef Brudzinski (1874–1917), a Polish pediatrician, is credited with several signs in meningitis. The most commonly used sign (Brudzinski’s neck sign) is the appearance of involuntary lifting of the legs when lifting a patient’s head off the examining couch, with the patient lying supine.[2][5]
Other signs attributed to Brudzinski:[6]
The symphyseal sign, in which pressure on the pubic symphysis leads to abduction of the leg and reflexive hip and knee flexion.[7]
The cheek sign, in which pressure on the cheek below the zygoma leads to rising and flexion in the forearm.[7]
Brudzinski’s reflex, in which passive flexion of one knee into the abdomen leads to involuntary flexion in the opposite leg, and stretching of a limb that was flexed leads to contralateral extension.[8]
CSF?
Clear / colourless
•Sterile
•Glucose 60-70% of blood glucose
•Protein 0.15-0.5g/l
•White cells <5 / mm3
•Red cells <1 / mm3
papilloedema?
veinsengorged run downhjill to retinal surface
blurry indistint margin
Feathery kane shaped hemorrhage in nerve fiber layer
viral meningitis?
Enteroviruses (46%) now most common because of MMR
•HSV type 2 (31%)
•Varicella zoster virus
•HSV type 1
•Often no cause identified
Enteroviruses>
Coxsackie A & B, echoviruses, polioviruses, enterovirus 71
•Systemic infection; neuroinvasion
•Check viral PCR
HSV type 2?
Second most common cause
•Esp. young adults
•In genital HSV-2 meningeal symptoms in:
36% women
13% men
But frequently unrelated to genital herpes
infections and cells involved
?
Bacterial meningitis?
- Pneumococcal (streptococcus pneumoniae): esp. elderly, immunocompromised, alcoholics, smokers, diabetics
- Meningococcal (neisseria meningitides): children & young adults; epidemics
- Listeria monocytogenes: neonates; defective cell-mediated immunity
Treatment of pneumococcal/meningococca meningitis?
Benzylpenicillin IV / IM (if no access)
•Adults and children >10 y: 1.2g
•1-9 y: 600mg
•Under 1 year: 300mg
empirical antimicrobial therapy?
N meningitides
•S pneumoniae
•L monocytogenes
•Vancomycin 15mg/kg every 8h +/- ceftriaxone 2g bd or cefotaxime 2g qds
•ampicillin
sensitivity of s.pneumonia, menigitidis, ad l. monocytogenes?
S. pneumoniae, H influenzae, gp B strep – 10 days of antibiotics
•N. meningitidis – 7 days of antibiotics (plus: Rifampicin 600mg orally every 12 h for 2 days to eradicate nasal carriage)
•L monoctogenes / enterobacteriacaea – 3-4 weeks
dexamethasone?
Helpful in pneumococcal
•NOT all types and NOT for postsurgical meningitis or severe immunocompromise
brina piospy for toxoplasmosis?
