CNS Infections - Exam 3 Flashcards
What is meningitis? What is encephalitis? What is Meningoencephalitis?
Meningitis - inflammatory disease of the meninges surrounding the brain and spinal cord can be Bacterial, Viral or Fungal
Encephalitis - acute inflammation of the brain itself can be bacterial, Viral, (Parasitic, Fungi, Spirochetes)
Meningoencephalitis - inflammation of both the brain and the meninges
What are the 3 classic CNS infection s/s?
Fever
Headache
Altered mental status
What are the 3 meningeal signs?
nuchal rigidity
kernig
Brudzinski
**What is Kernig sign?
**What is Brudzinski sign?
What are some s/s of increased intracranial pressure?
Papilledema, poorly reactive pupils
Abducens (6th CN) palsy: horizontal diplopia
N/V
Bulging fontanelle (soft spot) in infants
What can a pt not due if they have abducens palsy?
eye that is affected, they cannot look laterally
can look medially but NOT laterally
What are the 3 layers of tissue that surround the brain and spinal cord?
Dura Mater- outermost layer - strong fibrous membrane
Arachnoid Mater - middle layer has cobweb like filaments that attach to the innermost layer
Pia Mater- innermost layer - a very thin and delicate membrane that is tightly to bound the surface of the brain
What layers contains blood vessels?
Subarachnoid Space - the space between arachnoid and pia mater
bacterial meningitis is an acute purulent infection of the ______ and the _______
arachnoid mater and the subarachnoid space
What give rise to the majority of bacterial meningitis cases?
Most cases result from previously colonized distant infection
from the Nasopharynx, respiratory tract, skin, GI tract and GU tract
In bacterial meningitis how does the bacteria have access to the CNS, give 2 ways it spreads? Which one is MC?
hematogenous spread - MC
direct contiguous spread from previous sinusitis, otitis media, mastoiditis, trauma, neurosurgical procedures
Where do newborns most common acquire bacterial meningitis?
pathogens colonized from the maternal intestinal or genital tract
or
transmitted from nursery personnel or caregivers at home
What pathogen is most common in adults with bacterial meningitis? healthcare acquired?
Streptococcus pneumoniae (~50-60%)
MC cause in adults >20 yrs old
S. aureus and coagulase-negative staphylococci-> think after a neurosurgery
What are the 3 MC pathogen for neonates (0-4 weeks old)?
GBS
e. coli
gram -negative bacilli
What are the top 3 MC pathogen for children older than 1 month?
Streptococcus Pneumoniae
Neisseria meningitidis¹
Haemophilus Influenzae type B (Hib)
What are the 4 MC symptoms associated with bacterial meningitis in adults? What is the classic triad? ___ out of 4 symptoms are present in most cases
Headache - MC
Fever - 2nd MC
Nuchal rigidity/meningeal signs
Altered mental status
2/4 present in most cases
What is nuchal rigidity?
pain with neck flexion
When is a meningococcal rash seen? Describe it
seen in septic meningitis with N. Meningitidis
maculopapular rash that become petechial and/or purpuric involving the trunk, LE, mucosal membranes, conjunctiva that DOES NOT BLANCH!!!
What are the historical red flags for bacterial meningitis?
Why would you want to order a coag profile in bacterial meningitis?
helps to differentiate who may need platelet or FFP after LP
Need to immediate collect _______ if you suspect bacterial meningitis
Immediate collection of blood cultures x 2 for gram stain, culture and sensitivity (C&S)
When working a pt up for bacterial meningitis, need prompt ________.
lumbar puncture
DO NOT delay LP for labs!
DO NOT delay empiric Abx therapy for LP or CT
**What are the guidelines to do CT scan BEFORE LP if:
Immunocompromised state
History of CNS disease: mass lesion, stroke, or focal infection
New onset seizure (within one week of presentation)
Papilledema
Abnormal level of consciousness
Focal neurologic deficit
When doing a LP, what is important to note? How many tubes do you need to collect for CSF analysis? What goes in each tube?
the opening pressure-> measured using a manometer
4 tubes
Tube 1 - Cell count and differential
Tube 2 - Glucose and protein levels
Tube 3 - Gram stain, culture and sensitivity (C&S)
Tube 4 - Cell count and differential (if repeat is needed¹) or special additional studies (depending on initial CSF analysis)
If RBC are present throughout all 4 samples of CSF fluid, what are you thinking? Blood present in the first sample only?
thinking there is a brain bleed
RBC in first sample tube only -> thinking you hit a small capillary
Draw the cerebrospinal fluid analysis chart know the first 5 rows
**What is the flow chart for bacterial meningitis management?
What do you also need to order in a pt with suspected bacterial meningitis?
Non urgent CT/MRI to rule out differential diagnoses
MRI is preferred
What is the goal of empiric therapy for bacterial meningitis? When is empiric therapy started?
to started empiric therapy within 60 minutes of patient arrival
started immediately after LP but do NOT delay abx therapy if LP is delayed
What is included in the empiric tx for bacterial meningitis for a pt 1 month old to 50 years old?
- Dexamethasone
- ceftriaxone PLUS Vanc PLUS acyclovir
When is dexamethsone given in BM? Why is it given?
give to ALL patients 0-20 minutes before the first dose of empiric abx and continued for 4 days
Administered to combat release of inflammatory cytokines initiated by antibiotic action on bacterial cell wall
What is included in the empiric tx for bacterial meningitis for a pt who is LESS than 1 month old?
- Dexamethasone
- cefotaxime + ampicillin + acyclovir
Why is ceftriaxone CI in neonates?
due to high risk of hyperbilirubinemia
What is the empiric therapy in a pt who is older than 50 OR immunocompromised?
- Dexamethasone
- ampicillin PLUS ceftriaxone PLUS Vanc PLUS acyclovir
What does ampicillin cover for when added to the empiric therapy for 50+ or immunocompromised pts?
covers L. monocytogenes
What are 2 ADD ON abx options in BM and why would you add each one on?
doxycycline: during tick season to cover tick-borne bacterial infections
metronidazole (Flagyl): covers gram-negative anaerobes coinciding otitis, sinusitis or mastoiditis
What are 3 general management strategies that can help control a pt’s elevated ICP?
elevation of the patient’s head to 30–45°
intubation with hyperventilation
mannitol
**How long should you continue abx treatment based on the pathogen? Give the 5 pathogens and number of tx days required
When is repeat CSF analysis indicated? What is the expected result?
no improvement within 48 hours after starting appropriate therapy
pathogen resistant to standard abx, 2-3 days after the initiation of therapy
Persistent fever > 8 days (without other known cause)
Repeat CSF cultures should be sterile
Your repeat CSF culture is positive despite appropriate therapy, what should you do next?
consider intrathecal (or intraventricular) antibiotics administration
aka give abx straight into the spinal cord
Once your culture and sensitivity report comes back and confirms the source is bacterial, what do you do?
stop the acyclovir
When is mortality the highest in BM? What is the trend? ___ out of 10 cases will be fatal. What is common in cases that do survive?
Mortality is highest in the first year of life, decreases in midlife, and increases again in old age
1/10 cases will be fatal
Significant neurologic sequelae in 30% of survivors
1 in 7 survivors will be left with a severe handicap
_______ is needed in bacterial meningitis until etiology is determined. How long do you need to continue after initiation of “effective” abx therapy in N. meningitidis?
Droplet precaution
continue for 24 hours
What is the chemoprophylaxis for close exposure to meningitis involving H influenzae? What is the tx?
contact for ≥4 hours for at least 5 out of the 7 days before admission of index patient
AND
Anyone exposed under the age of 2 years
Anyone exposed who lives in a home with a child < 4 y/o
Anyone exposed who is not fully immunized against Hib
Tx: rifampin for 4 days
What is the chemoprophylaxis for close exposure to meningitis involving N. meningitidis? What is the tx?
prolonged (>8h) exposure in close proximity (<3 ft)
direct exposure to oral secretions
Exposure 7 days prior to onset of symptoms up through 24 hours after initiation of appropriate antibiotic
tx: rifampin for 2 days
How do you prevent bacterial meningitis in newborns? What if positive?
Vaginal/anal swab testing for group B strep between 35-37 wks gestation
if positive: prophylactic IV PCN to be administered during vaginal delivery
How do you prevent bacterial meningitis related to neurosurgery?
Perioperative antimicrobial prophylaxis is indicated for patients undergoing any form of neurosurgery
What is the prevention for BM?
vaccinations!!! specifically:
Streptococcus pneumoniae (PVC13, PPV23)
Neisseria meningitidis (MenB and MenACWY)
Haemophilus influenzae Type B (Hib)
What is viral meningitis? What is another name for it?
a condition that presents with evidence of meningeal inflammation (H&P & CSF profile) with a negative bacterial culture
“aseptic” meningitis
What is the MC etiology of viral meningitis? Who is the MC pt population?
enteroviruses
most cases occur in children younger than age 5
What are the risk factors for viral meningitis?
neonates
immunodeficient pts
exposure to someone with viral meningitis
What is important to note about viral meningitis?
travel and exposure history is important!!
concentrate on areas of endemic West Nile virus, Lyme disease, other tick borne disease
Sexual exposure: HSV-1/2, HIV, syphilis are strongly associated with what type of meningitis?
viral meningitis
What is important to note about the presentation of viral meningitis when compared to bacterial meningitis?
s/s are often LESS severe
mildly diminished LOC- drowsy or mild lethargy
profound alterations in consciousness, seizures and focal neuro deficits are NOT seen in viral meningitis
clinical presentation of viral meningitis: __________ enteroviral infection, primary HIV or syphilis
Diffuse maculopapular exanthem
clinical presentation of viral meningitis: __________ mumps in an unvaccinated patient
Parotitis/Orchitis
clinical presentation of viral meningitis: __________ HSV
Genital/Oral Lesions
clinical presentation of viral meningitis: __________ HIV
thrush
clinical presentation of viral meningitis: __________ West Nile virus meningitis
Asymmetric flaccid paralysis
What will the CSF fluid show in viral meningitis? ______ most important method of dx viral etiology
WBC - lymphocyte predominant
Gram stain of CSF will be negative for any growth
PCR for EACH individual virus has to be ordered
______ may be elevated in mumps
amylase
Blood, feces, and throat swabs for viral etiology but viral shedding in the ____ can persist for weeks and is NOT a reliable tool
stool
What 4 viruses are not good candidates for serum testing when trying to find the cause of viral meningitis? Why?
Do not use viral serology for HSV, VZV, CMV, and EBV as these viruses are frequently seropositive
aka lots of people have had those viruses in the past and that DOES NOT mean it is the source of the present viral meningitis
T/F: CT/MRI is necessary in uncomplicated viral meningitis
FALSE!! additional imaging is NOT indicated in uncomplicated viral meningitis
What are the indications for CT/MRI testing in viral meningitis?
altered LOC
seizures
focal neurologic s/s
atypical CSF profiles
underlying immunocompromising treatments or conditions
When are empiric abx/antivirals recommended in VM?
elderly
immunocompromised
a strong early suspicion of bacterial meningitis
What do you do in VM if the dx is INDETERMINATE after CSF evaluation? When can you stop empiric abx in viral meningitis?
administer empiric antibiotics after obtaining blood and CSF culture specimens
OR
observe (without abx tx) and repeat lumbar puncture (LP) in 6 to 24 hours
Empiric abx can be stopped if pt is improving and culture is negative
What is the management for viral meningitis?
Depends upon the clinical appearance of the patient and the underlying host factors
but most cases are self-limiting and tx is supportive: fluids, rest, symptomatic control
What is the tx for HSV that has been confirmed with CSF analysis?
IV acyclovir (dose based upon weight)
Newborn - 3 months - 21 days
3 months and older - 10-21 days
What is the tx for VZV with severe clinical presentation that has been confirmed with CSF analysis?
IV acyclovir - 10-14 days
only if severe clinical presentation
What is the treatment for all other viral meningitis that have been confirmed with CSF testing? How long does it usually take to resolve?
d/c acyclovir and continue with conservative treatment
Majority of patients with viral meningitis have a self- limited course that will resolve in 7-10 days without specific therapy
What is the prevention for VM?
vaccination!!
specifically polio, MMR and varicella (VAR/Zoster) vaccines
What is the MC etiology of encephalitis? What are 3 other less common causes?
viral MC - herpesviruses (HSV, VZV, EBV)
autoimmune encephalitis
amebic encephalitis: motile trophozoites seen in wet mount of warm, fresh CSF
parasitic- toxoplasmosis
When comparing encephalitis to meningitis, what is the major difference with regards to s/s?
encephalitis will have AMS when compared to meningitis
Psychotic symptoms: hallucination, agitation, personality/behavioral changes
Encephalitis occasionally involves _____ and may result in 1 of 3 things. Name them
HPA axis
temperature dysregulation (hypothermia or hyperthermia)
Diabetes Insipidus
SIADH
What are 3 finding in neonates that would make you think HSV? What 2 PE exams are NOT always accurate in babies?
herpetic lesions
keratoconjunctivitis
oropharyngeal lesions
Kernig and Brazinski signs are not always accurate in babies
______ is the primary diagnostic test in encephalitis
CSF PCR amplification
CSF PCR for each individual virus still needs to be ordered
After LP, what is the additional work-up for encephalitis? What increases the possibility of it being HSV etiology?
MRI/CT of the brain and EEG
focal finding on MRI and EEG abnormalities
What is the criteria for a brain biopsy in a pt with encephalitis? What area of the brain do you want to bx?
have focal abnormality on MRI
negative CSF analysis/PCR
who progressively deteriorate despite treatment with acyclovir and supportive therapy
bx area that was inflamed on imaging
What do you need to do for any suspected herpetic lesion?
Viral culture and Tzanck smear
What do you need to do if you suspect autoimmune encephalitis?
amebic infection?
assess specific autoantibodies in serum/CSF
take a good pt history and look for exposure to warm, iron-rich pools of water
CSF analysis will resemble bacterial meningitis but motile trophozoites are seen in wet mount of fresh warm CSF
What is the tx for encephalitis?
continuously monitor and tx any abnormal vital signs: O2, ventilation, fluids
control seizures with IV lorazepam
frequent neuro checks to look for deterioration or change in neuro status
elevate head of bed, control fever and pain, control of straining and coughing, prevent seizures and significant hypo/hypertension
empiric antiviral therapy: acyclovir
empiric abx therapy until bacterial men ruled out
What 9 things are part of neuro-checks?
Only _____ and_____ encephalitis have recommendations for definitive antiviral therapy.
HSV and VZV/EBV
**What is the goal for empiric antiviral therapy for a pt with suspected encephalitis? What are you giving them specifically?
**GOAL: First dose should be administered within 30 minutes of arrival to ED but lab specimens and blood cultures should be obtained BEFORE first antiviral dose
Adults/Pediatric: IV acyclovir 21 days
What needs to happen once a pt has completed the antiviral course for encephalitis?
CSF analysis for PCR should be repeated at the completion of antiviral therapy in those patients who were PCR (+).
If CSF PCR remains positive additional antiviral therapy should be given
What are some sequelae that might happen after encephalitis?
Seizure disorder
Cognitive impairment
Movement disorders: tremor, myoclonus, parkinsonism
Hemiplegia
What is the major difference in how encephalitis and meningitis presents?
Presence or absence of normal brain function is the most important distinguishing feature between the two
Meningitis: CEREBRAL FUNCTION is generally intact
Encephalitis: VERY common to see abnormalities in brain function
Brain Abscess is an uncommon focal, suppurative infection within the brain _____ and surrounded by a _____
parenchyma
capsule
What is cerebritis?
a non-encapsulated brain abscess
What are risk factors for a brain abscess?
direct spread from a head source (otitis media, mastoiditis (33%)
paranasal sinusitis (10%)
dental infections)
hematogenous spread: infections anywhere else on the body
trauma/surgery
_____ and ______ are the biggest infections that lead to a brain abscess
otitis media and mastoiditis (combined 33%)
What are the 4 different stages of a brain abscess? Give days
What is the MC presenting symptom for a brain abscess? Then what happens?
HA that is usually gradual, pts present usually after 10 days of HA
focal neurological deficits
fever
focal neurologic deficits that present as hemiparesis, what lobe is involved?
(MC in frontal lobe abscess)
focal neurologic deficits that present as aphasia/dysphasia, what lobe is involved?
(MC in temporal lobe abscess)
focal neurologic deficits that present as nystagmus/ataxia, what lobe is involved?
(MC in cerebellar abscess)
How is a brain abscess dx?
MRI with contrast!!! is preferred but CT with contrast if MRI not available
_______ is done for a brain abscess to guide abx therapy
CT/MRI-guided stereotactic needle aspiration
What is the tx for a brain abscess that is community acquired?
High dose of empiric parenteral antibiotics AND neurosurgical drainage of the abscess
ceftriaxone PLUS metronidazole
and anti-seizures meds prophylaxis
drain/remove abscess
What is the tx for a brain abscess that is due to head trauma or neurosurgical procedure?
ceftazidime PLUS vancomycin
OR
meropenem PLUS vancomycin
and anti-seizures meds prophylaxis
drain/remove abscess
When would you give steroids in a brain abscess?
Steroids ONLY if there is significant peri-abscess edema with associated mass effect and increased ICP
_____ is recommended in all brain abscess except what 3 conditions?
Abscess drainage
abscess is neurosurgically inaccessible
small (<2–3 cm) or non-encapsulated abscesses
patients with an unstable condition to allow performance of a neurosurgical procedure
When would you want to completely excise a brain abscess?
abscess is multiloculated or aspiration fails
For a brain abscess, how long do patients need to be on parenteral abx therapy? What else do you need to monitor? How long do they need to stay on anticonvulsant therapy? When can they stop taking everything?
Minimum of 6–8 weeks of parenteral antibiotic therapy
Serial MRI or CT scans performed monthly or twice-monthly to document resolution of the abscess
Prophylactic anticonvulsant therapy for minimum of 3 months
therapy can be d/c once EEG is normal both pre- and post medication withdrawal
What are poor prognostic signs for a brain abscess?
Rapid progression of the infection before hospitalization
Severe mental status changes on admission
Stupor or coma (60-100% mortality)
Rupture into the ventricle (80-100% mortality)
