Meningitis Flashcards
Meningitis
Meninges of brain and spinal cord become inflamed
PCA and arachnoid become
Congested and opaque
Inflammation can extend
down into first and second laters of cortex and spinal cord producing thrombosis of cortical veins
Meningitis belt
Sub-Saharan Africa
Incidence is 5-10x higher
Most commonly affected
Children and older adults
Individuals w/ compromised immune system
Infection carried by
Blood products or other fluids and can case changes in cerebral capillary endothelium —> BBB rails to prevent enters into brain or CSF
Brain lacks
Lymphatic system to help fight infection
Leukocytes in the brain increase
Cells recruited to fight infection - damage
Surrounding brain tissue by release of cytotoxic free radicals and excitatory AA like glutamate
Response to inflammation
Can block the CSF creating hydrocephalus, edema and increased ICP
Vasculitis can lead to infarction
Decreased in vertebral blood flow
Can cause a drop in glucose levels of CSF
Viral meningitis
Most common — enterovirusus, herpes simplex virus 2, EBV in adolescence/early adult
Other causes of viral meningitis
Systemic lupus
Sarcoid tumors
Drugs/chemicals (NSAIDS)
Tuberculous meningitis
Mycobacterium TB via inhalation
Abscess or SC disease
Cysts and lymphocytes + elevated protein levels
Bacterial meningitis
Organisms located in Mucosal surfaces of upper respiratory ‘
Bacteria in birth canal can transfer
Neonates: Strep, eschericha coli, listeria monocytogenes,
Geriatric: strep pneumoniae, neisseria meningitis
Bacterial meningitis process
Inflammation initially in subarachnoid then spreads to adj brain tissue —>
vasculitis starts in small subarachnoid vessels —>
thrombin obstruction can decrease cerebral perfusion resulting in ischemic lesions
Early symptoms
Fever
HA
Stiff and painful nick
Pain in lumbar areas and posterior aspects of thigh
Kernig sign
Pain w/ combined hip flexion and knee ext
Brudzinski test
Passive neck flexion will be painful and cause flexion of hips and knees
S/S in infants and children
Fever Vomiting Decreased feeding Bulging font Anel’s Seizure High pitched cry
Symptoms develop in
Hours for viral
Days to weeks, fungal or tuberculous
Pyogenic bacteria - S/S can develop in 4-24 hours
Only definitive means of obtaining dx
Lumbar puncture—>
Elevated mono nuclear cells
Normal glucose level
Mild increase in protein levels
Absence of bacterial organism
W/out antibiotics
Death can occur — prompt dx ciritical
Most common cause in children
Viral infection
Differentiation from bacterial and viral
Basis of S/S and changes in CSF
Dx accuracy
Gram stain exam of CSF faster, less expensive and 90% accurate
Open pressure - bacterial meningitis
200-500 mm H2)
Normal open pressure
70-180
Cell predominance
Neutrophils or lymphocytes
To when actue bacterial suspected
Anti micro bias therapy. ASAP
Medical emergency, esp in children
Dexamethasone
Can reduce subarachnoid inflammatory response, alleviate cerebral edema and vasculitis
Death usually occurs
In the first two weeks
Cranial nerve palsies
30% of the time —> hearing impairment
Neuro complications
75% w/ bacterial
Impaired consciousness, seizures, focal neuro abnormalities
Children can develop long term
Hearing loss Blindness Developmental delay Hydrocephalus Hypothalamic dysfunctions Hemiparesis Quad/tetraparesis
Mortality rate for tuberculous meningitis
20-50%
