CNS infections Flashcards
What are the common causes of bacterial meningitis in each of the following age groups
- newborn
- 1-23mo
- 2-18yrs
- 19-50yrs
- 50+
Common cause of Nosocomial Bacterial meningitis?
newborn: Group B strep
1-23mo: Strep Pneumo
2-18: Niesseria meningitidis
19-50: Strep Pneumo
50+: Strep pneumo
Nosocomial: E coli, Klebsiella pneum, Pseudomonas aeruginosa
Meningitis is shifting from a peds to adult dz, T/F?
True, most commonly Strep pneumo.
Risk factors for development of meningitis?
- asplenia
- corticosteroid use
- immune compromised/HIV
- exposure to someone with meningitis
Meningitis/Encephalitis pathogenesis
-bacteria cause vasogenic brain edema, increased intracranial pressure resulting in brain ischemia, cytotoxic injury and neuronal apoptosis.
Meningitis
- presentation
- PE special tests
- Work uP
Presentation”
- Fever*
- Nuchal rigidity*
- change in mental status(lethargy)*
- HA
- Photophobia
- characteristic rash (neisseria); nonblanching
- N/V
- seizures
- papilledema
PE Test:
- kernig Sign: inability to alllow full extension of the knee when hip is flexed at 90 degrees
- brudzinski sign: spontaneous flexion of hips during attempted passive flexion of the neck
Work Up:
- Labs: CBC w/ diff, CMP, UA, blood cultures
- gram stain
- LP: this is diagnostic**
- possible CT to R/O mass lesion or other cause of IICP. Not always required.
- -if LP is deferred or delayed get blood cultures and start emperic abx
- remember always get CT before LP if..
- immunocompromised
- Hx of seizure within 1 week
- papilledema
- altered level of conciousness
What are the common bugs for each of the following:
- gram + diplococci
- gram - diplococci
- gram - coccobacilli
- gram + rods and coccobacilli
Gram + diplococci = strep pneumo
gram - diplococci = niesseria meningitidis
gram - coccobacilli = h flu
gram + rods and coccobacilli = listeria
Meningitis:
empiric tx
Strep pnemo and meningococcal:
-Cefotaxime or ceftriaxone + vancomycin
Listeria:
-ampicillin + gentamycin or bactrim
Nosocomial:
-ceftazidime + vancomycin
Tx is generally7-21 days
*usually doubled if immunocompromised
Neurological complications of bacterial menintigis
- neurological:
- -cerebral edema
- -seizures
- -cranial nerve palsies
- -hemiparesis
Cerebrovascular:
sensorineural hearing loss (strep pneumo)
What is the role of dexamethasone in tx of meningitis?
-adding dexamethasone before of with the start of abx has been evaluated as adjuvent therapy in attempt to diminish rate of hearing loss, cerebral edema, and neurologic complications..
reduces mortality and neurologic disability in pts w/ GCS 8-11 and strep pneumo*
Prevention of Meningitis
- dont share saliva
- good hand washing
- Vaccine:
- -HIB
- -PCV13 (child)
- -PPSV23 (adults greater than 65, young adults)
- -Menactra (11-18 for those who havent yet been vaccinated)
Aspetic meningitis
- what is this?
- presentation
- Dx
what: clinical and lab evidence for meningeal inflammation w/ negative bacterial cultures, MC enterovirus
“non-bacterial”
Presentation:
-Fever, HA, stiff neck, photophobia, rash
Dx:
- hx
- LP
Tx:
- resolves w/o therapy
- if uncertain treat with empiric abx
- supportive
Encephalitis
- causes
- clinical presentation
- dx
- complications
Cause:
- viral** (herpes simplex 1), post infectious, autoimmune, paraneoplastic, medication induced
- West Nile
- Lymes
- Rocky Mtn Spotted Fever
- TB
Clinical presentation:
- altered mental status***
- seizures*
- exaggerated DTR
- hemiparesis
Dx:
- LP
- CT r/o space occupying lesion
- MRI*** detects demyelination
- EEG abnormal
Complication:
- status epilepticus
- SIADH
- cardiorespiratory failure
- DIC
- death
What are the big differences between meningitis and encephalitis?
meningitis = photophobia, nuchal rigidity, lethargy not change in mental status
Encephalitis: altered mental status (confusion), NO meningeal irritation (photophobia, nuchal rigidity)
Viral Encephalitis:
- CSF characteristics
- dx
CSF: increased WBC with differential showing mostly lymphocytes, elevated protein, normal glucose
dx:
- knowledge of pt immune status
- brain bx as last resort
West Nile Cause of Encephalitis:
- sx & neurologic signs
- tx
Sx:
-fever, stiff neck, sore throat, N/V, stupor..convulsions..coma
neurologic signs:
-UMNL = exaggerated DTR, spastic paralysis, primitive reflexes
Tx:
-Ribavirin
