Central Nervous System Flashcards
3 components of the meninges?
dura mater, arachnoid mater, pia mater
CNS?
brain and spinal cord
What does inflammation fo the Brian cause?
- pressure increase in the brain
- brain is enclosed in a hard bone skull, brain can only swell so big
Blood-Brain Barrier?
- capillaries that limit access to CSF and brain tissue
- limits toxin and chemical access tot the brain
- pharmacologically it can be difficult if treating a brain infection/ injury
CNS Host Factors?
- sterile site
- no normal flora
- few immune cells present (b/c it is sterile)
- pathogen has advantage when infection occurs due to lack of normal flora and immune cells
- inflammation increases permeability of BBB (pathogen entry increases, more permeable to toxins as well as immune cells and medications
CNS Infections: Portals of Infection?
- trauma to skull and meninges
- peripheral neurons (migrates to the CNS such as rabes)
- respiratory system
- GI
Inflammation of the meninges?
-can occur due to infection or not because of infection
Acute Meningitis?
- fast onset
- less than 2 weeks
- medical emergency
- seriously ill
- bacterial cause mainly
- always caused by an infection
- increases ICP
Chronic and Aseptic Meningitis?
- more than 2 weeks
- viral cause
- usually caused from a weak pathogen that can cause damage in immunosuppressed patients
Systemic infection: clinical findings?
- fever
- myalgia
- rash
Meningeal Inflammation: clinical findings?
- neck stiffness
- brudzinki’s sign
- kernig’s sign
- jolt accentuation of headache
Cerebral Vasculitis: clinical findings?
- inflammation of cerebral vasculature
- seizures
Elevated ICP: clinical findings?
- headache
- nausea and vomiting
- seizures
- neurologic symptoms
Signs and Symptoms of Meningitis?
- no single S and S is sufficient for diagnosis
- fever, headache, neck stiffness, altered metal state
Meningitis clinical triad?
fever, nuchal rigidity (neck stiffness), headache
-present in 44% of patients
Absence of all 3 meningitis triad symptoms?
- rule out meningitis
When is nuchal rigidity (neck stiffness) considered absent?
- flexion of neck is painful but full ROM is present
- chin to neck movement
Brudzinki’s sign?
- unconscious movement
- patient lyes on their back, neck is flexed forward. and knees will pop up to release pressure in spinal cord
Kernig’s sign?
- patient on their back
- hip flexed at 90 degrees
- try to extend and straighten the knee, pain in lower back or posterior thigh and/ orresistance is a positive test result
Jolt accentuation of headache?
-worsening of headache with active horizontal head Turing at 2-3 turns per second
Can you rule out meningitis with absent jolt accentuation, Brudzinski’s and Kerning sign, but positive fever, headache and altered mental state?
-No
What procedure should you preform with any client suspected with meningitis?
-lumbar puncture
CSF glucose, WBC and protein levels in bacterial meningitis?
- low CSF glucose
- high CSF proteins
- elevated WBC, mainly neutrophils
why are CSF glucose levels low in bacterial meningitis?
-inflammation causes impairment of glucose transport form the blood
why are CSF protein levels high in bacterial meningitis?
- increased permeability of the BBB
WBC, glucose and protein levels in CSF of viral meningitis?
- normal glucose
- normal-moderately high protein level
- elevated WBC (from monocytes and lymphocytes
2 pathogens associated with 80% of bacterial meningitis?
- streptococcus pneumoniae
- neisseria meningitides
Pathogen associated with GI caused meningitis?
What bacterial meningitis causing pathogen do we have good vaccines for?
- listeria monocytogenes
- haemophilus influenza
Rare causing bacterial pathogen? (meningitis)
-group B streptococcus
gram - or +: S. pneumoniae and neisseria menigitidis?
S. pneumoniae= gram positive
N. M= gram negative
2 viruses that can cause meningitis?
- enteroviruses (Coxsackie B)
- herpes simplex virus
Pneumococcal Meningitis?
-caused by S. pneumoniae
-505 of bacteria meningitis
75% of use are colonized with it in nasopharynx
transmitted by respiratory. droplets
-infectious 1-3 days prior to onset of symptoms and remains infectious until bacterium is absent in nasal and oral discharge
Pneumococcal meningitis public health implications and immunizations?
- reported to public health
- no droplet precaution unless patients cough and sputum has increased
- no cemoprophylaxis
- infant pneumococcal conjugated vaccine
- adult/elderly (65+) pneumococcal polysaccharide vaccine
Neisseria Meningitides: movement, fimbriae and capsule?
- move in and out of cells
- attach with fimbriae
- capsule protects against human immune system
- steals iron from us
Meningococcal meningitis?
- caused from neisseria meningitides
- affects children, adolescents and young adults
- 25% of all bacterial meningitis
- rates decline as you age
- produces an endotoxin; fever, weakness, generalized aches, petechial rash
- transmitted via droplets
- infectious period 7 days prior to symptom onset and until pathogen is not present in nasal or oral discharge
Why is meningococcal meningitis associated with younger populations?
-associate with a lot of people when young
What causes the petechial rash?
- endotoxic shock and disseminated intravascular coagulation
- scattered all over the body
% of fatalities and % of permanent neurological or physical deficit with neisseria meningitides?
10% fatality
20% of survivors show permanent neurological or physical deficits
Public health implicated of NEISSERIA MENINGITIDIS?
- vaccinations to control the outbreaks
- MEN-C-C (ages 2months -11yrs
- Men-C-ACYW (grade 7)
- Bexsero (2 months-17 years old
- ciprofloxacin and rifampin
Why is ciprofloxacin only given to patients aged 18 years+?
-change the development of cartilage in younger patients
leading cause of meningitis prior to 1986?
- H. influenza
- was once highly pathogenic
H. influenza caused meningitis implications?
resp. droplet trasmission
- isolation post targeted antibiotic therapy
Listeriosis?
-caused by listeria monocytgenes
-transmission by ingestion of unpasteurized foods, deli meats, poor hand hygiene
-young patients and elderly (extreme ages) and pregnant women
10% of meningitis cases
% of people colonized with S. pneumoniae?
75% of people colonized
Group B streptococcus
30% of women colonized
40-70% will transmit during delivery
1-3% will develop infection
-swab rectum and vagina at 35-37 weeks gestation to test
-comes through the mouth, moves into the blood stream and then into the brain
Risk factors for Group B streptococcus?
- GBS positive
- premature labour (didn’t swab swab yet)
- UTI caused by GBS
- treat with antibiotics
What age group is susceptible to GBS?
newborns-1 month olds
Basic bacterial meningitis treatment?
- bacterial antibiotic therapy
- administered after blood cultures
- directed at pathogens
- antibiotic drugs that can cross BBB
General Treatment Regimen for bacterial meningitis?
corticosteroid co-administered with antibiotic
-antipyretics, fluid and electrolyte supplements, nutritional support
Viral meningitis?
- less acute in severity than bacterial
- supportive treatments
Enteroviruses: meningitis?
-85% of viral meningitis
-direct contact, fecal-oral route
most common in summer and fall
-usually in immunocompromised patients
-lasts 7-10days
% of meningitis survivor that have neurological or physical deficits?
40%
Encephalitis?
- inflammation of the brain
- viral is the most common
- seasonal, geography, travel history, occupational exposure, immune status of patient influence the risk of you acquiring it
Most common cause of encephalitis?
-viral
Clinical triad of signs and symptoms of encephalitis?
- fever
- headache
- altered LOC
Clinical findings of encephalitis? (CSF lab values, neurologic symptoms)
- disorientation
- seizures
- increased protein and lymphocyte and normal glucose in CSF
- serology= look for antibodies for various viruses
Serology?
-looks for antibodies for various viruses
Viral encephalitis: initial sites of infection?
- Resp. tract
- GI
- GU
- SC tissues
- viruses most commonly access the brain via the blood stream
Viral encephalitis: HSV
- herpes simplex virus
- most common cause of non-epidemic encephalitis in Canada
- no cure
- constantly reoccurs
- some antivirals slow down the replication of the pathogen
- start HSV therapy when we see viral encephalitis
- control immune system with corticosteroids
- older or younger you are, the worse the potential outcomes
Symptoms with Viral Encephalitis (HSV)?
-focal temporal lobe symptoms (hemiparesis, aphasia, visual field cut)
West nile virus?
-triggers swollen lymph noses and can cause both meningitis as well as encephalitis
Brain abscess?
-puss containing cavity surrounded by inflamed tissue
-up to 25% mortality rates
(infection within the brain)
Major symptoms of brain abscess?
- headache
- mental status change
- fever
- focal neurologic deficits
- symptoms depends on the location of the abscess
3 major predisposing conditions for brain abscesses?
- Neutropenia
- Transplantation
- HIV
Diagnosing a Brian abscess?
CT SCAN with injection of contrast material
- can be treated without surgery
Empiric therapy for brain abscesses?
antimicrobial therapy
- aspiration or surgery to remove abscess
- corticosteroids when there is high ICP
How do you diagnose bacterial meningitis?
-hx, physical examination, lab tests
