CNS Infections Flashcards
Meningitis is an inflammatory disease of the arachnoid and pia and defined by ____________________ in the CSF. It is a leading cause of acute ________________. Early diagnosis is crucial!
Major cause of bacterial meningitis:
1.
2.
These people are often sick.
abnormal white blood cells
confusional states
1. strep pneumo
2. neisseria meningitidis
What is the pathophysiology of bacterial meningitis?
colonization of mucus membranes of nasopharynx > tissue invasion > bacteremia > inflammatory response associated with release of inflammatory cytokines that promote BBB permeability, vasogenic cerebral edema, changes in blood flow and possible neuronal toxicity.
Half of patients with bacterial meningitis presents with these symptoms within 24 hours of onset…..
What are physical exam findings?
What is the classic tetrad (in reality theres 4 tho)
95% of patients will have two of these while 99-100% of pts will have at least one.
fever
confusion, lethargy
vomiting
headache
neck stiffness
PE:
1. meningismus - can be absent in very young and very old
2. brudzinski sign
3. kernig sign
4. seizures
Tetrad:
fever
neck stiffness
AMS
headache
What is the gold standard workup for bacterial meningitis?
What are the contraindications?
lumbar puncture
-opening pressure is elevated in 90% of cases
-protein 200-500 mg/dL
-glucose- lower than 40 mg/dL in 80% of cases
contraindications:
mass lesion- papiledema or focal deficits
-increased ICP > herniation
What is the treatment for bacterial meningitis ?
You also want to treat sepsis symptoms, what are they?
if the CSF is not clear and colorless, antibiotics should be started WITHOUT DELAY
Dexamethasone should be given before or during initial antibiotics in immunocompetent patients.
What is the empiric treatment?
vanco + ceftriaxone/cefotaxime and add ampicillin if > 50 y/o, neonate or immunocomopromised.
sepsis=fever and hypotension
What are the complications associated with bacterial meningitis?
HA
seizures
SIADH
cognitive disruptions and CN palsies
fatality is possible
What is the prevention for bacterial meningitis?
vaccines for h flu type B, N meningitidis and S pneumo
Rifampin for prophylaxis in household contacts and other close contacts x2 days
In viral meningitis, the cause can be determined by time of year, travel, immunosuppression. Brain function should be _______________.
Etiology:
1.
2.
What are the symptoms?
normal.
Etiology: enterovirus, herpesvirus
S/S:
1. HA
2. Fever
3. N/V
4. Rash?
5. stiff neck/ nuchal rigidity
6. photophobia
What are the three primary mechanisms of viral meningitis?
- spread of virus through the body via bloodstream
- neuronal spread of virus by axonal transport (herpes simplex,rabies)
- autoimmune post infectious demyelination (varicella)
What is the workup and treatment for viral meningitis?
CSF IS MOST IMPORTANT
-pressure will be normal to increased
- WBC count wont be as high as bacterial
-protein normal to slightly raised 80-200
-glucose usually normal
What is the treatment for viral meningitis? What is the prognosis?
acyclovir if HSV is suspected.
MUCH better than bacterial meningitis, not typically associated with long term complications.
What is encephalitis?
it is an infection of the brain parenchyma and It is manifested by neurologic dysfunction. In this infection, brain function is NOT normal. 1/2 of the patients are over 50.
What is the etiology of encephalitis?
HSV Type I is the most common fatal cause in the US along with west nile virus
What are the risk factors for neonatal encephalitis?
In adults, HSV II usually causes _________________
mother with HSV type II at birth, travel history
meningitis
What are the s/s of encephalitis?
Sequela: __________ and ___________ changes shows the predilection of HSV for limbic structures
behavioral changes
hallucinations
HA
stiff neck
vomiting
memory loss
aphasia
hemiparesis or flaccid paralysis
focal or generalized seizures
CN palsies
lethargy, coma
ataxia, tremors
weakness
memory changes, behavior changes
What is the workup for encephalitis?
- CT head to rule out masses
- CSF- THE WAY TO GO
- increased pressure
-mild protein elevation
-normal glucose - EEG- periodic slow wave complexes arising from one or both temporal lobes
- MRI edema and mass effect in one or both temporal lobes but may be normal
- BRAIN BIOPSY FOR DEFINITIVE DIAGNOSIS
What is the treatment for encephalitis?
What are the complications associated with it?
acyclovir 10-15mg/kg q8hrs x 14-21 days START AS SOON AS YOU SUSPECT. this treatment is most beneficial in HSV and varicella zoster
complications: concentration, behavioral and speech changes, memory loss
What is chronic encephalitis and in which population is this condition typically seen in?
What is the imaging and treatment?
severe or repetitive head trauma may cause a progressive syndrome manifested by impaired memory and concentration, personality changes, headache, tremor, rigidity, bradykinesia, dysarthria, cerebellar ataxia, seizures. This condition is classically seen in boxers and now it is recognized in athletes subject to subtle forms of head trauma including concussion.
Imaging:
1. MRI- cortical atrophy and cavum septi pellucidum
2. Histology- neurofibrillary tangles consistent with progressive tauopathy (dementia)
The treatment is supportive care and prevention.
What are the risk factors/pathogenesis of a brain abscess/subdural empyema?
Aerobic, Anaerobic and microaerophilic strep and gram negative anaerobes. MULTIPLE ORGANISMS are present in most cases.
- blood borne mets from distant systemic infection
- direction extension for parameningeal sites
- recent or remote head trauma
- cyanotic congenital heart disease
- recent neurosurgical procedure
What are the symptoms and workup for someone with a brain abscess/subdural empyema?
these patients will have stroke like symptoms with a fever.
Workup:
1. Head CT
-mass lesion with contrast enhancing rim
2. MRI brain with and without contrast
-RIM ENHANCING LESION IS CHARACTERISTIC OF ABSCESS
3. CSF DO NOT PERFORM IF SUSPECTED
What is the treatment of someone with a brain abscess/subdural empyema?
surgery when there is significant mass effect or near ventricular surface, accessible.
give antibiotics when surgically inaccessible, multiple or early abscesses
broad spectrum antibiotics
ceftriaxone
metronidazole
if staph suspected = vanco
What is prion disease and how many categories does this disease consist of?
It is a neurodegenerative disease with long incubation period that progresses to death once symptoms appear.
The three categories are
1. sporadic- MOST COMMON
2. genetic
3. acquired
In sporadic prion disease, most cases are ______________________
creutzfeldt-jakob disease (CJD)
A type of prion disease called bovine spongiform encephalopathy (mad cow disease) is seen in teens or young adults from eating
infected meat
What are s/s of prion disease?
psychiatric- symptoms- anxiety, depression, delusions, hallucinations and change in personality
rapid neuropsychiatric decline
diffuse CNS dysfunction to localized dysfunction
myoclonus
DEMENTIA PRESENT IN ALL CASES
NO FEVER
What is the workup and diagnosis for prion disease?
MRI head
EEG
LP
biopsy or detection of PRPsc in DNA
NO TX DEATH OCCURS WITHIN A YEAR some mutations may last 1-5 years.
Progressive Multifocal Leukoencephalopathy (PML) is a severe __________________ disease of the CNS caused by ________________________ - polyomavirus. It is almost exclusively in ________________ patients. The infection occurs in _________________ and can be found in 86% of adults. It remains latent in the ______________ and ______________ organs but can reactivate and spread to the brain in immunosuppresion causing lytic infection of _____________________.
The symptoms are progressive, multifocal CNS symptoms involving the _____________ but may involve ____________.
To diagnose, the gold standard is a ________________. the treatment is none.
demyelinatiing
john cunningham virus (JCV)
immunocompromised
early childhood
kidneys
lymphoid
oligodendrocytes
white matter, gray matter
brain biopsy
