CNS specific Flashcards
3 main causes pyogenic meningitis
S pneumo
N meningitidis groups A B C W and Y
H influenzae type B
Spell 3 causes of a eosinophilic CSF in meningitis
PT BAG
Paragonimus westermani
Taenia solium (cysticercosis)
Baylisascaris procyonis (racoon)
Angiostrongylus cantonesis
Gnathostoma spinigerum
[Gnathostoma has all the edges and spini round]
CSF stain for bacteria? TB? Cryptococcal?
Gram
ZN or auramine
india ink
Pneumococcal meningitis not responding to cef?
Meropenem
Who gets H. influenza meningitis
Kids
Meningococcal outbreak management
Early recognition Eg >15 cases / 100,000
Identify organism and drug sensitivities
Alert authorities
Produce diagnostic algorithms and case definitions
Mass chemoprophylaxis/vaccination
What is cryptococcus? full name? Usually found in the environment due to?
Yeast like fungus
cryptococcal neoformans
Bird droppings
Usual mechanism for infection with cryptococcus ? Presentation?
Inhalation
Subacute / chronic meningitis (similar to TB)
Dx cryptococcal meningitis…csf stain?
blood test?
Either with india ink of CSF
CSF/ blood culture
Latex agglutination tests detect Cryptococcal polysaccharide antigen (CrAg)
Cryptococcal meningitis Rx ?
Consolidation phase?
Secondary prophylaxis ?
Amphotericin B (10mg/kg single dose)
+ flucytosine (25mg/kg QID) for 2 weeks
+fluconazole 1200mg QID for 2 weeks
Consolidation phase 8 weeks fluconazole 800mg
Fluconazole 200mg daily for life works
Cryptococcal meningitis prevention
screening for CrAg and rx with fluconazole (especially if HIV positive)
When fluconazole prophylaxis in HIV
CD4 <100
Arboviruses are transmitted by?
Insects
Arbo = ARthropod BOrn
3 key types of of arbovirus causing CNS disease
Flavivirus
-Japanese encephalitis / West Nile / tick-borne
-[dengue / zika / yellow fever - less likely CNS]
Alphaviruses
Bunyaviruses
Japanese encephalitis 70k cases per year - how many have long term neurological sequale?
50%
20-30% die
vector and hosts of japanese encephalitis? Geography
culex mosquito (Eg Culex tritaeniorhynchus)
-Mostly birds [egret/heron]
-Domestic pigs major amplifying host
China, SE Asia and India
Japanese encephalitis sx
10% develop Non specific fever with systemic upset …
<1% develop meningeal/encephalitis reduced consciousness with
- focal CNS eg seizures/parkinsonism
-or flaccid paralysis (polio-like) or Ascending (guillian-barre like)
Japanese encephalitis ix? where are characteristic changes on imaging?
CSF - MAY be normal early in disease
-Viral picture (lymphocytes, normal glucose, mild rise protein)
- ELISA IgM of CSF
[PCR often already negative as viraemia transient]
CT/MRI - Midbrain changes
Japanese encephalitis control
Vaccination
Treating rice paddys with neem cake (insecticide)
Individual protective measures from mosquito bites
West nile flavivirus geography? transmission?
More or less everywhere (africa, asia, middle east, Europe, USA
Culex pipens mosquito
Tick bourne ecephalitis virus spread by? Features
ixodes ticks spread through rodents and other small mammals
high fever for 1 week, then afebrile
then meningoencephalitis
The historical key cause of acute flaccid paralysis? Sx?
Polio
Fever - then afebrile period followed by assymetrical flaccid paralysis of one or more limbs (may be painful)
Where do viruses affect to cause flaccid paralysis
Direct viral damage to the anterior horn cell
Compare cause of flaccid paralysis Gilllian barre vs direct viral damage. Onset? pattern? Time to reach max paralysis? sensory ? csf findings?
Direct viral - Eg Enterovirus 71 / Polio
Rapid onset eg 2 days often with fever
Asymmetrical
No sensory
CSF lymphocytosis
GBS
Slow onset eg 2 weeks and often weeks after illness
symmetrical
common sensory issues
Raised protein in CSF
Which countries’ polio still an issue?
Pakistan, Afghanistan and Nigeria
virus causing acute flaccid paralysis endemic in Asia that isn’t polio?
Enterovirus 71
Nipple / bellybuten sensory level
T4
T10
Name 2 Ways TB can cause paralysis
Potts disease - TB of vertebral bones -> collapse and cord compression
TB meningitis -> secondary arteritis and cord infarction
Tuberculoma compresses cord
Most common cause of spinal epidural abscess? Triad of Sx?
S aureus
Fever, Back pain, radiculopathy
-> spastic paralysis, bladder/bowel dysfunction, sensory loss
Transverse myelitis caused by many viruses and which key bacteria?
mycoplasma pneumonia
[HIV, schisto, syphylis, denge, scrub typus, lime disease, leptospirosis…]
When do you get HIV myelopathy? Other considerations if this is a differential?
Often with AIDS-dementia complex
-Due to direct viral damage
- consider lympoma, cryptococus and herpes in AIDS
Subacute degeneration of the spinal cord due to B12 deficiency. What infections may cause this? Super common signs?
Tropical spure
Fish tapeworm - diphyllobothrium lactum
Upgoing planters with a reduced knee jerk. Macrocytosis
[pernicious anaemia, coeliac, IBD, surgery]
HIV negative with progressive spastic paralysis, loss of proprioception and vibration. Bowel / bladder dysfunction? cause? transmission?
Tropical spastic paraparesis
Human T lymphotropic virus type 1 (HTLV-1)
breast milk or rarely blood born
What is rabies
Bullet shaped RNA Rhabdovirus
Rabies mostly found in salavia of infected animals - how does it get to CNS
Along peripheral nerves
-> Longer time to symptoms if bitten on hand/foot compared with face bite
Rabies is usually clinical diagnosis - how might you confirm?
Saliva for NAAT / PCR testing only reliable way
Brain biopsy if dead
Rabies Rx if high risk exposure in unvaccinated?
Rabies Ig + 4 site post exposure vaccine
When commence ART if dx with crptococcal meningitis
After 4-6 weeks
When investigating flavivirus what Ix do you need to do
CSF/Serum serology (IgM)
[PCR often negative by time of presentation ]
59 yo male returned from a vacation in Bali with fever, headache, confusion
Developed flaccid paralysis, altered mentation, respiratory failure
CSF lymphocytosis, N protein, glc
Respiratory failure, pneumonia, and death
Most likely?
Japanese encephalitis
Which travellers should get Japanese encephalitis vaccine?
> 4 wks to endemic region
during transmission season
Name 3 main types of enterovirus? Diagnosis of these is based on?
Polio
Coxsackie
Echovirus
PCR
- serotyping (monoclonal antibodies)
- microneutralization
Polio transmission
Faecal oral
Polio most commonly is asymptomatic 1000:1? What are the other presentations?
GI upset
Paralysis
- due to anterior horn infection
Hypogammaglobulinemia/Agammaglobulinemia
-Encephalitis
What is post polio syndrome
Slow continuous decline in strength over years following acute polio
Name a benefit of live attenuated oral polio and inactivated polio vaccine.
Live oral - spread to close contacts ie protects more than just the person getting vaccine
-High levels of luminal antibodies (and that’s how polio gets in)
IPV - Can give to immunocompromised
-No Vaccine-associated Paralytic Polio
Where in the world is meningitis most prevalent
Meningitis belt across Africa
Contraindications to LP before CT scan in meningitis
- Focal neurologic deficits (except CN palsies)
- New onset seizures
- Severely altered mental status (GCS <10)
- Severely immunocompromised state
What physiological issue prevents gent from working
Low pH
Listeria monocytogenes meningitis rx
Ampicillin + gent
Strep agalacticae meningitis rx
Ampicillin
Name 3 bacteria that present as an aseptic meningitis
Leptospira interrograns
Orienta tsutsugamushi
Rickettsia ssp eg prowazekii / typhi
Name 3 DDx of subacute meningitis
Tuberculosis
Cryptococcal disease
Noninfectious (Sarcoid, malignancy)
Spirochetes (Syphilis, Lyme)
[Less common
Other fungi (e.g. Histo, cocci),
Other bacteria (Brucella, Melioidosis, Scrub typhus, Whipple’s)
Parasites (T solium)
vasculitis]
