CNS Infections Flashcards
Name of two leptomeninges:
Arachnoid and Pia mater
What has lead to the decrease of meningitis rates?
Conjugate vaccines
Where does meningitis infection take place?
Subarachnoid space - No immune protection here
Organism that causes highest mortality of meningitis:
S. pneumoniae - 20%
*Droplet spread
Organism with <10% mortality:
N. meningitidis
*Intimate contact
Organism with 5% mortality:
H. flu
Contagious spread from rarer adjacent spreads: (3)
OM or sinusitis (rare)
Trauma or Post-op infection
Indwelling devices (CSF shunts)
What causes leaking of albumin and vasogenic brain edema?
LPS on gram negative and cell wall on gram positive –> inflammation –> leaky BBB
If a patient is immunosuppressed or is on low dose steroids (vasculitis, RA, transplant) they have what organism:
Cryptococcus neoformans
TB infection can cause:
Chronic meningitis
Anatomic or functional asplenia exposes you to (3):
The three encapsulated organisms that cause meningitis: S. pneumonia, N. meningitidis and H. flu
Pregnant women may have what bug:
L. monocytogenes (listeria)
Facial or skull trauma may cause for you to get this bug:
Staphylococcus species
Children are at risk for meningitis from what bug:
S. pneumonia that is penicillin-resistant
Acute meningitis develops within:
Hours to days
Subacute meningitis develops over:
More than one week
What is subacute meningitis usually caused by? (3)
Mycobacterium, fungi or B. burgdorgeri (Lymes)
Chronic meningitis usually lasts: months to years and is causes by:
TB or Syphilis (T. pallidum)
Meningioencephalitis involves both the leptomeninges and the brain parenchyma. Causes by (2):
HSV or arbovirus (mosquito > tick)
Seizing is a big problem in what category of meningitis?
Meningoencephalitis
What is parameningeal infection?
Abscess, tumor that mimics symptoms of meningitis
Pre-term - 1 month: Causative bacterial agent is (3):
S. agalactiae (GBS)*
E. coli
Listeria
Over 1 month - 50 years: Causative bacterial agent is (3):
**Vaccination offers protection
S. pneumonia and N. meningitidis
*H. flu is rare
What two viruses causes 95% of pediatric meningitis:
Arboviruses
Enteroviruses
*ASEPTIC
The 4 medications that can cause aseptic meningitis:
- TMP-SMX
- Ibuprofen
- Metronidazole
- Lamotrigine - Bipolar
If you think you have a drug induced meningitis syndrome what do you do?
Stop medication, re-test the CSF
___ meningitis is most common
Viral
The signs and symptoms of meningitis are most often caused by:
The immune system not the bug itself
CN palsies possible with meningitis
4, 6, 7
Symptoms of meningitis (6):
- HA
- Fever
- N/V
- Photophobia
- Increased ICP - Brady, HTN, papilledema
- Seizures/CN palsies
The Kernig and Brudzinski test are:
Not sensitive but are highly specific
Range or the Glascow coma scale:
3 - Lowest (bad news)
15 - Highest
What is purpura fulminans
Mengococcemia - Starts as URI symptoms and progresses to the rash (can be in a day)
Tests you order for Meningitis (5) 3C’s, B, L:
- CBC with diff
- CMP
- Coagulation and platelets if alcoholic
- Blood cultures
- Lumbar puncture (4 tubes)
What are the four tubes for the lumbar puncture:
- Glucose and protein
- Cell count with differential
- GS and bacterial
- Repeat and future studies
What is the VDRL test?
Neurosyphilis
What would you order to test for TB?
AFB stain
What would you order if you suspected crypto coccus neoformans?
Cryotococcal antigen
When do you not do a LP?
If someone comes in with back pain AND meningitis symptoms - could be an epidural abscess
Medication for viral meningitis:
Acyclovir
What is the ME panel?
Tests meningitis and encephalitis (yeast - crypto neoformans), viruses and bacteria)
What will be high on labs if bacterial meningitis?
- High opening PSI
- High cell count - PMNs
- High protein
What will be high on labs if viral meningitis?
- High Lymphs
**All else is LOW
Strep pneumoniae morphology:
Gram positive lanceolate diplococci
Neisseria meningitidis morphology:
Gram negative coffee bean diplococci
H. Flu morphology:
Brat-like gram negative rods/coccobacilli
Listeria Monocytogenes morphology:
Gram positive SMALL rod
If you do an LP and get pus:
Epidural abscess - BAD
Most common SE of a LP (10 - 30% of patients):
Headache - Frontal/occipital (will improve in 12-24 hours)
HA post LP improvement with what position:
HA improves in the supine position
Treatment of post LP HA: (2 steps):
- Bed rest + oral analgesics (opioids if necessary)
2. Epidural blood patch - autologous blood injected at site of LP (volume replacement)
CT SCANS ARE ___for meningitis treatment
Not needed for meningitis right away and delay treatment
It takes ___ hours before the ABX for meningitis would affect a LP result
6 hours
If you get a head CT before a LP, also get __
Two sets of blood cultures and start treatment immediately (2 IVs)
Who should get a CT before a LP? (6) HANNIP
HANNIP:
- History of stroke/lesion
- Abnormal level of consciousness
- New onset seizure (within 1 week)
- Neuro déficit - dilated pupil, gaze palsy etc.
- Immunocompromised
- Papilledema
What is started ASAP for a patient with meningitis in the ED?
- 1 shot dexamethasone
- Vanco. + 3rd gen cephalosporin (ceftriaxone)
Isolation for meningitis:
Droplet
ABX for meningitis must have these characteristics (3):
- Bacteriocidal
- ABX that penetrates the CSF
- Go after MRSA
If you think the patient has meningitis from listeria, add what medication?
Ampicillin
If steroids or given, how should they be given?
WITH or slightly before the ABX
- 0.15 mg/kg IV q6 hours x 4 days
How long do you treat for? Meningitis –> Pneumococcal –> Listeria
- Meningococcal: 5 - 7 d
- Pneumococcal: 10 - 14 d
- Listeria: Minimum of 21 d
Three vaccines available to prevent meningitis:
- Pneumococcal
- HIB
- Meningococcal
MENGIOCOCCAL ONLY: Treatment for those exposed to oral secretions or respiratory droplets >8 hours duration before symptom onset (3 options):
- Ceftriaxone (250 mg IM x1)
- Ciprofloxacin (500 mg PO x1)
- Rifampin ( 600 mg PO q12 X2d)
If exposed to pneumococcal meningitis, what can you give?
Nothing is recommended
What is most common of meningitis and encephalitis?
Meningitis > Encephalitis
Aseptic > Bacterial
Most common cause of sporadic fatal encephalitis in the US all year long:
HSV
If a patient has HSV-2 they also may have:
Herpetic lesions on there genitals
What lobe of the brain does HSV like to hit?
Temporal
What are three later signs of an HSV encephalitis?
- Word salad
- Impaired memory
- Loss of emotional control - Naked woman around the house
What are the three findings in CSF for HSV encephalitis?
- Increased RBC - May be hemorrhagic
- Increased protein
- Lymphocytic pleocytosis
Test for HSV by sending it for (when is it positive):
PCR - positive within 1st 24 hours of symptoms
MRI findings for HSV +:
Unilateral temporal mass effect or changes
Treatment of HSV encephalitis:
All ABX for bacterial meningitis + IV acyclovir (can stop the ABX when you are SURE it is not bacterial)
Arbovirus encephalitis - Know ___
Flaviviridae - West NIle
What tick is the Arbovirus encephalitis transmitter?
Deer dick
1 cause of epidemic encephalitis in the US
West Nile virus - Flaviviridae
Indicator of WNV in the US:
Dead birds (ravens and jays)
Symptoms of WNV:
3-6 days (flu-like)
What are the two serious things you can develop with WNV?
- Polio-like paralysis (ascends - legs don’t work first)
- Mengioencephalitis or aseptic meningitis
Testing for WNV:
Serum WNV for CSF (IgM) OR PCR - use the fourth tube
Most common prion disease:
CJD
Average age of CJD:
60 YO
Most common cause of CJD (80%):
Sporadic
What is Kuru?
Endocanabilism (W > M) can cause CJD
Two categories of clinical findings in CJD:
- 100% cognitive (fast onset dementia)
2. 60% psychiatric (anxiety, euphoria etc.)
Someone with CJD may have this when you scare them(80%):
Startle sensitive myoclonus
Special test for CJD:
LP for CSF - RT-QulC assay/14-3-3-3 **CALL THE LAB - this can ruin equipment
What two imaging studies will reveal abnormalities for CJD?
EEG and MRI
Prognosis of CJD
Death within 1 year - no Tx.
