ClinMed Final Exam: CNS Infections (Meningitis, Encephalitis, etc)

- strep pneumo (g+)
- neisseria meningitidis (g-)
- listeria monocytogenes (g+) - neonates, >50, immunodeficient
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- strep pneumo (g+)
- neisseria meningitidis (g-)
- listeria monocytogenes (g+) - neonates, >50, immunodeficient
Meningitis is an inflammatory disease of the meninges (dura, arachnoid, and pia mater) and CSF. When it is bacterial, it is most often caused by what 3 organisms?
symptoms:
- fever
- AMS
- neck stiffness (nuchal rigidity, kernig/brudzinksi sign)
- HA (generalized, severe) +/- photophobia

only 44% will have classic triad (fever, stiff neck, AMS)

dx: LP
- may do CT first if immunocompromised, hx of CNS dz, new onset seizure, papilledema, decreased consciousness, focal neuro deficits (CT not needed for most pts)
What are the symptoms of meningitis and how is it diagnosed?
A - nuchal rigidity (neck does not want to flex forward)

B - kernig sign

C - brudzinksi sign
What are these?
Image: A - nuchal rigidity (neck does not want to flex forward) B - kernig sign C - brudzinksi sign
rule out strep pneumo meningitis (no rash)

ask if the rash blanches (if not = more concerning)

non-blanching rash is more likely meningitis
If a patient has a fever and rash, what pathogen can you rule out? What do you want to ask this pt?
pneumococcal meningitis
- concurrent URI, no rash, fever, HA/neck stiff
If a pt has a fever, decreased consciousness, HA, neck stiffness, cough and increased mucus production due to URI, and no rash, what type of meningitis do you suspect?
ceftriaxone

(recall: pneumococcal is ceftriaxone + vanco)
Neisseria meningitidis is more likely to cause sepsis with non-blanching rash, AMS, and HA.
listeria meningitis:
- less common but may occur in infants <2 mo or immunocompromised
- seizures are more common than with other pathogens

listeria coverage - amp + gentamicin
Listeria is a less common pathogen of meningitis. If it does cause meningitis due to ingesting contaminated foods, it is usually in ___ or ____ pts.
administer dexamethasone with 1st dose of atb
- if isolate strep pneumo as cause continue dexamethasone (otherwise can d/c)

* in patients with strep pneumo meningitis, dextamethasone reduced hearing loss, neuro complications and mortality
When you start a patient on antibiotics for suspected meningitis, what should you also administer?
more common in 1st month than any other age

more likely to be listeria too since that occurs in neonates, immunocompromised, and >50
bacterial meningitis is more common in _____ than any other age.
neonatal meningitis risk factors:
- LBW, premature (<37 weeks), PROM, traumatic delivery, maternal peripartum infection

clinical features:
- fever, hypothermia
- poor feeding, vomiting and diarrhea
- respiratory distress/apnea
- neuro changes (irritable, lethargic, tremors/seizures)

**GET LP if s/s of sepsis
neonatal meningitis is usually bacterial. What are the risk factors for neonatal meningitis and what symptoms do they have?
CT usually not needed but will do before LP if: - hx of CNS disease - immunocompromised - new onset seizure - papilledema - abnormal LOC - focal neurologic deficit relative CI to LP (no absolutes): increased ICP, bleeding issue, epidural abscessWhen should you do a CT before a LP in suspected meningitis?-gram stain will come back in hrs, culture takes several days -cultures dont always grow so stain is importantwhy should you always order a gram stain with a culture for CSF analysis in suspected meningitis?normal: - cell count: 0-5 lymphocytes - glucose: 45-85 mg/dL - protein: 15-45 mg/dL - opening pressure: 70-180 mmhg bacterial: - cell count: 200-20,000 PMN - glucose: low (<45) - protein: high (>50) - opening pressure: markedly elevated (such as 205+) viral: - cell count: 25-2000, mostly lymphocytes - glucose: normal or low (<45) - protein: high (>50) - opening pressure: slightly elevated (such as right above 180)Name the following for normal, bacterial, and aseptic (viral) meningitis. - cells/mcl - glucose (mg/dL) - protein (mg/dL) - opening pressuretrueT/F: if a patient with meningitis has positive blood cultures, they must be negative before they are discharged regardless of symptoms18-50 years old: vanco + ceftriaxone - covers strep pneumo and neisseria - how most are usually tx >50 years old: vanco + ceftriaxone + ampicillin - broader coverage of gram-neg and some listeria coverage (if really suspect listeria add gentamicin since listeria tx w/ amp + gent) immunocompromised: vanco + ampicillin + cefepime - more coverage of gram neg (enterococcus) than ceftriaxone post traumatic or post surgerical meningitis: vanco + cefepime - covers GI flora in addition to othershow is meningitis treated? recall: tx is different for ages and disease statesenterovirusaseptic meningitis is usually viral, what is the most common virus?test all culture - meningitis for HSV HSV meningitis is more complicated and can be fatal - test for HSV with PCR on CSFWhat should all culture negative meningitis cases be tested for and why? recall culture negative = aseptic/viral causetest for HSV with PCR on CSF tx: acyclovir - often acyclovir will be added to all empiric meningitis tx while pending CSF analysis due to the severe complications25% of patients with genital herpes simplex virus have meningeal signs. You should test all culture negative meningitis for HSV with _____ on CSF. What is the treatment for HSV meningitis?meningitis = cerebral function normal - HA, fever, neck stiffness, AMS encephalitis = cerebral function impaired (not just meninges/layers around brain, but inside brain is inflammed too) - often see AMS, seizures, neuro deficits (+ may have meningeal s/s too) - often viralWhat is the difference between meningitis and encephalitis?encephalitis - usually viral some (not all) causes: - HSV - varicella - west nile - rabies - enterovirus - mumps - prion disease - post-infectious from influenzaencephalitis often causes AMS, seizures, and neuro deficits since the cerebrum is inflammed. It is often _____ but can be paraneoplastic or autoimmune too.west nile virus - caused by mosquitos (tick exposure is something different) tx: self-limited - recall west nile can cause encephalitisflaccid paralysis (lose/floppy/weak muscles), maculopapular rash and tremor may make you think _____ which is caused by ____brain abscess - 90% hematogenous spread (infx elsewhere) - once capsule forms (after first 1-2 weeks) ATB wont be able to reach inflammation/wont work for tx90% of these arise from infection elsewhere in the body (hematogenous spread). it starts at a inflammatory lesion with swelling for first 1-2 weeks and then fibrous capsule forms around inflammation, what does this cause?- HA - increased ICP (Nausea, papilledema, AMS, seizures, CN 3-4 deficits such as eye movement) tx: - ATB wont work after 1-2 weeks due to fibrous capsule forming - tx with dexamethasone initially (~6 weeks)What are the signs/symptoms of a brain abscess? What is this usually caused by and what does treatment include?Pott puffy tumor (osteomyelitis of frontal bone) - complication of brain abscess *cavernous sinus thrombosis also a complicaton of brain abscesswhat is this and what is it a complication of?discitis - usually hematogenous spread (if post-surgical likely staph aureus) s/s: - fever - back pain (usually doesnt radiate unless causes vertebral compres) - neuro symptoms may or may not be seen (vary based on part of cord being impinged) - will have spinal tenderness (and elevated esr, crp, wbc) dx: MRI - will show disk collapse or irregular vertebral bodies tx: surgical I&D and IV ATB for 6-8 weeksdiscitis (vertebral osteomyelitis) is usually caused by hematogenous spread but if post-surgical it is likely _____. what are the symptoms and how is this diagnosed/treated?discitis tx: surgical I&D and IV ATB for 6-8 weeks epidural abscess can occur if discitis is untreated - will have increased neuro signs due to cord compression (weakness, numbness, radicular pain)A patient with back pain and 101F has an mri of the following. what do they have and how is this treated? what complication can arise if this is not treated?