Chapter 22 - Microbial Diseases of the Nervous System Flashcards
What are meninges?
-3 continuous membranes: dura mater, arachnoid mater, pia mater
Subarachnoid Space
-between pia mater and arachnoid mater
-houses CSF
Blood Brain Barrier
-capillary system that prevents the passage of some substances but not others
Drugs cannot cross the BBB unless they are ____ soluable
lipid
What is a common lipid-soluable antibiotic?
chloramphenicol and sometimes penicillin in large amounds
Meningitis
inflammation of the meninges
Encephalitis
inflammation of the brain
Meningoencephalitis
when both the brain and meninges are inflamed
Initial Meningitis Symptoms
-fever
-headache
-stiff neck
Secondary Meningitis Symptoms
-nausea
-vomiting
Possible Progressions of Meningitis
-convulsions
-coma
-death
The progression of meningitis may only take ___ hours.
24
Kernig’s Sign
-a diagnostic tool in older or younger patients
-non-invasive
-stiffness when they bend their hamstrings
How is meningitis diagnosed?
spinal tap
What is a spinal tap?
-collection of a CSF sample from the spinal cord
-needle inserted between L3 and L4
Serology of Meningitis
-use a gram stain to diagnose
-keep the sample culture at storage temp and move quickly
What is used to treat bacterial meningitis?
3rd generation cephalosporins
*What is not reccomended to treat bacterial meningitis?
chloramphenicol due to adverse effects?
Haemophilus Influenzae
-aerobic
-gram-negative
-has a capsule
-member of normal throat microbiota
-can cause meningitis when it enters the bloodstream
How many strains of H. influenzae are there? Which most commonly causes disease? Why?
-6 strains classified by capsular antigens
-strain B causes 95% of cases
Hib Meningits occurs mostly in _______
children under age 4
Is there a vaccine for H. influenzae meningitis
Yes: HiB vaccine
-it can be effective by 6 months of age
-is given at 6 weeks of age
Meningococcal Meningitis is cause by which bacteria?
Neisseria meningitidis
N. Meningitidis
-aerobic
-gram-negative
-diplococcus
-has a capsule
-present in the nose and throat of carriers
How is N. meningitidis spread?
-droplet or contact
What are the strains of N. meningitidis? Which is the most common?
-strains A, B, C, W135, X, Y
-C is the most common
Who are commonly affected by N. meningitidis?
-children under 2
-college students
How long is the progression of N. meningitidis?
-it is fast
-may only be 24 hours
What are the primary symptoms of N. meningitidis?
throat infection that spreads to the blood stream
What are the secondary symptoms of N. meningitidis?
throbbing headache
Is there a vaccine for N. meningitidis?
yes
What are possible effects of N. meningitidis?
-necrosis that may lead to amputation
-deafness
-paralysis
-death
Petichiae
-rash associated with necrosis
Where does Streptococcus pneumoniae commonly reside?
-nasopharyngeal region
What % of the population are carriers of S. pneumoniae?
70%
Streptococcus pneumoniae
-gram-positive
-capsule
-diplococci
What is the leading cause of bacterial meningitis?
S. pneumoniae
Who is commonly affected by S. pneumoniae meningitis?
children between 1 month and 4 years