Viral & Bacterial CNS Infections Flashcards
What part of the brain has resistanec to ifnection?
Cerebral tissue
What part of the nervou system is never infected by blood-borne pathogens?
Cranial epidural and subdural spaces
What are the 2 pathways of pathogen infection?
Diploic vein flow = from diploic sinuses to meningeal veins then brain
Erosion of osteomyelitis focus = ostoeomyelitic focus erros the inner table of bone & invade the dura, subdural space, pia-arachnoid and even the brain
What are the most common neonates causing bacterial CNS infection?
E coli
Group B Strep
What is the most common pathogen causing CNS infection in infants & unvax child?
H influenzae
What are common pathogens causing bacterial CNS infeciton in adults?
Pneuococcus (Streptococcus pneumoniae)
Meningococcus (Neisseria meningitidis)
Group B Strep
Listeria monocytogenes
Staphylococcus
What condition is caused by inflammatory reaction in the pia and arachnoid in the CSF
How can an infection reach the ventricles?
- Directly from CHOOROID PLEXUSES
- Reflux through FORMAINA OF MAGENDIA AND LUSCHKA
What type of acute meningeal inflammation can acuse Kernig and Brudzinski signs?
Pure pia-arachnoiditis
What are the signs & symtoms of Hydrocephalus?
- at first = purulent exudate around the baes of the brain
- later = meningeal fibrosis w/c impairs CSF reabsorption
- rarely = aqueductal stensosis as complication of meningitis
What are signs & symptoms seen in those suspected of acute bacterial meningitis?
Fever
Headache (usually severe)
Stiffness of the neck
(+) Brudzinski sign & Kernig signs
Memorize or familiarize empiric therapy of bacterial meningitis!!!!!
Cefoxatime + Ampicillin = 0-4 weeks
Headtrauma; neurosurgery = Vancomycine + Ceftazidime
What is the Osler Triad?
Pneumococcal meningitis + pneumonia + endocarditis
In wha tcases do u see Osler triad?
Leptomeningitis (acute bacterial meningitis)
What is the tx of childhood meningitis?
Corticosteroids + high dose of Dexamethasone
What is the tx of meningitis in adults?
Dexamethasone just before the 1st dose of antibiotics
What are the common location of brain abscess?
1/3 = anterolateral part of the cerebellar hemisphere
2/3 = middle and inferior parts of the temporal lobe
What is the most common location of brain abscess?
Abscess originaitng in the ear
What location is indicated if sinuses are implicated in brain abscess?
Frontal = abscess in the frontal lobe
Sphenoid = abscess in the temporal lobe
What is the most common anomaly of brain abscess?
Tetralogy of fallot
What is the most comon organism causing brain abscess?
Streptoccci
What are the focal neurologic deficits of brain abscess?
Motor
Sensory
Speech disorders
Other:
Fever, leukocytosis
Elevated ESR
What is the appearance of brain abscess in CT scan and MRI?
CT = ring enhancing lesion with HYPODENSE center
MRI = ring enhancing lesion with HYPOINTENSE center
What is the most comon cause of Acute Aseptic Meningitis?
Enterovirus
- Echovirus
- Coxsackie virus