Term
NEISSERIA MENINGITIDIS
meningococcal meningitis |
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Definition
ETIOLOGY
-fastidious
-GN
-non motile
-oxidase positive
-diplococcus
-kidney bean shape gram stain
VIRULENCE FACTORS
capsular types
no crossreactivity
type B capsule is same as e.coli k1 |
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Term
NEISSERIA MENINGITIDIS
meningococcal meningitis |
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Definition
EPIDEMIOLOGY
carriers:
-colonization site is nasopharynx
-carrier state persists days to months
-non immune and short term; group specific immune carriers are responsible for spread of disease, via aerosols
-carriers quite common in epidemic situation but few develop disease |
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Term
NEISSERIA MENINGITIDIS
meningococcal meningitis |
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Definition
| infections require close contact, susceptibility (lack of antibodies for capsules) and predisposing condition - tobacco smoke exposure, crowding, binge drinking, low socioeconomic status |
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Term
NEISSERIA MENINGITIDIS
meningococcal meningitis |
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Definition
epidemiology:
susceptible popoulations in which disease predominates - infants (1m-24m)
young adults 14-24 yr
families due to carriers and genetic predisposition
-genetic predisposition, ie terminal complement deficiencies |
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Term
NEISSERIA MENINGITIDIS
meningococcal meningitis |
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Definition
| only agent of purulent meningitis capable of causing sporadic outbreaks and epidemics |
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Term
NEISSERIA MENINGITIDIS
meningococcal meningitis |
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Definition
clinical manifestations:
onset of mild sore thraot, slight fever and headache, then onset of classic clinical manifestations plus petchial rash on trunk and lower extremities which may progress to purpura (necrotic lesions; organism in lesion)
course infection and disease can be fulminant - death within hours
waterhouse-friderchsen syndrome: fulminant meningococcemia characterized by shock, DIC, hemorrhagic necrosis of adrenals
purpura fulminans - symmetrical peripheral gangrene |
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Term
NEISSERIA MENINGITIDIS
meningococcal meningitis |
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Definition
DIAGNOSIS
gram stain of CSF or skin lesion
rapid serological test available |
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Term
NEISSERIA MENINGITIDIS
Meningococcal meningitis |
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Definition
treatment:
cefotaxime or ceftriaxone |
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Term
NEISSERIA MENINGITIDIS
meningococcal meningitis |
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Definition
prophylaxis:
VACCINES
tetravalent/quadrivalent polysaccharide vaccine; type 2 T-ind antigent vaccine
limitations: only lasts 3-5 yr; poor immunogenicity in infants less than 2 yrs
not efficacious againts b serotype
tetravalent/quadrivalent diphtheria toxoid conjugate vaccine. t-dep vaccine, so should last more than eight years, and eliminate nasopharyngeal carriage, thus prevent transmission of infection; vaccine reduces prevalence by 75-90%
eliminate carrier state by chemoprophylaxis with rifampin, ciprofloxacin or ceftriaxone within 24 hours of identification; no more than 14 days after onset of illness
for small outbreaks, prophylaxis with antibiotics is effective
for large outbreaks (countries, cities) vaccination and antibiotics is most effective
vaccines for serotype B infecitons is in clinical trials
eliminate nasopharyngeal carriage of N. meningitidis with ciprofloxacin, ceftriaxone, rifampin, or azithromycin unless fluoroquinolone-resistant strain is detected |
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Term
CRYPTOCOCCOSIS: FUNGAL MENINGITIS
cryptococcus neoformans |
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Definition
encapsulated yeast
worldwide distribution, found in soil
cryptococcus neoformans var grubii is MAJOR CAUSATIVE AGENT worldwide
cryptococcus gattii is primary pathogen that infects immunocompetent persons; associated with eucalyptus trees
infectious form is yeast; not thermally dimorphic; grows as yeast in humans
virulence factor: capsule, multiple capsular serotypes
in aids pt, c. neoformans var grubii capsule A predominates - antiphagocytic |
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Term
CRYPTOCOCCOSIS: FUNGAL MENINGITIS
cryptococcus neoformans |
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Definition
epidemiology:
sporadic, world wide distribution
risk factor: impaired CMI; rarely causes disease in immunocompetent pt
aids: 3rd most common cause of CNS infection - HIV, toxomplasmosis
aids: 4th most common opportunisitc infection - p. carinii, CMV, m. avium
other impaired immunity:
lymphoreticular malignancies
immunosuppressive therapies |
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Term
CRYPTOCOCCOSIS: FUNGAL MENINGITIS
cryptococcus neoformans |
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Definition
clinical manifestations:
enters RT, agent in monocytes disseminates through blood
site of initial infection and disease is lungs; no symptoms in competent person but immunosuppresed have fever, cough, dyspnea, weight loss, headache. chest x ray reveals interstitial infiltrates
meningoencephalitis: chronic, progressive disease which is fatal if not treated.
insidious onset 2-4 weeks of headache, fever, lethargy, n/v, minimal nuchal rigidity
progresses onto focal signs: personlity change; impairment of higher mental functions; ends with coma and death |
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Term
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Definition
diagnosis:
test CSF, blood, urine, respiratory samples, biopsied tissue by serologic tests - latex agglutination and ELISA; detect presence of capsular antigen
microscopic exam of sedimented CSF with india ink; presence of small capsulated yeast forms and cells of monocyte lineage |
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Term
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Definition
treatment
high dose amphotericin B with 5-fluorocytosine (fluconazole), maybe itraconazolelater; drug resistance is rare
prognosis is poor - some die initially, 30-60% die within a year |
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Term
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Definition
human herpes virus HHV 6 and 7
and
non-polio enteroviruses |
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Term
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Definition
major cause of acute febrile illness in young children
hh6 infection in children 6-12m; accounts for many visits to ER many hospitalizations; many first time febrile seizures (CNS infection) among children less than 2yr |
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Term
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Definition
primary infection:
manifestions-
abrupt onset of high fever; lethargy, irritability, malaise, no rash
take kid to ER, but no obvious cause so do spinal tap on kids; but tap is aseptic |
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Term
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Definition
| meningitis or encephalitis, depending on serotype |
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Term
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Definition
etiology:
echoviruses
coxsackie virus
enterovirus 68-71
non polio enterviruses are most common infection of CNS
ECHO and coxsackie viruses are most common and important viral pathogens in humans; causes a nonspecific febrile illness with or without rash; initially replicate in small intestine |
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Term
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Definition
epidemiology
most common cause of aseptic meningitis in countries that immunize against mumps
humans are host
summer and fall months - responsible for half febrile illness in infants and small children
transmission: acid stable viruses acquired via fecal oral route; also transmitted via aerosols or passed in utero
peak incidence: less than 9 yr old; highest attack rate under one yr; incidence and severity varies with age |
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Term
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Definition
CLINICAL MANIFESTATIONS
abrupt onset of fever, constitutional signs and symptoms -s ore throat, diarrhea, malaise;
rash
meningeal signs
in neonate: fever, rash, vomiting, anorexia, nuchal rigidity; death due to destruction of liver or heart |
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Term
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Definition
diagnosis:
PCR for enteroviral agents |
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Term
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Definition
| symptomatic and supportive |
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Term
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Definition
| arthropod-borne viruses -arboviruses |
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Term
diffuse encephalitis
ARBOVIRUSES |
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Definition
etiology:
togaviridae group
+ssRNA
easter equine encephalitisEEE - worst mortality rate; survivors have severe problems; EEEV is unique in that infection often but not always leads to EEE. asymptomatic infeciton is NOT the norm
western equine encephalitis - most benign form
st. louis encephalitis - related to west nile; leading cause of epidemic arboviral encephalitis in us before west nile
west nile encephalitis - like sLE, causes more severe disease in elderly; most COMMON ARBOVIRUS INFECTION in us today |
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Term
ARBOVIRUSES
DIFFUSE ENCEPHALITIS |
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Definition
etiology
bunyaviridae group:
california encephalitis - la cross virus
-ssRNA
most importatn cause of arboviral pediatric encephalitis in USA; seizures may occur during illness |
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Term
ARBOVIRUS
DIFFUSE ENCEPHALITIS |
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Definition
epidemiology - zoonosis
survival of virus depends on alternating between vertebrate host (birds are reservoir) and arthropod host (mosquitos are vector); humans are infected tangentialy
entire geographic distribution includes US
primary cause of sporadic and epidemic meningoencephalitis in humans in summer months when reservoir (birds), vector and humans are outdoors |
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Term
ARBOVIRUS
DIFFUSE ENCEPHALITIS |
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Definition
clinical manifestations:
asymptomatic infection is most common result
abrupt onset of symptoms:mild flu like symptoms; mild, self limited aseptic meningitis; acute fulminant diffuse encephalitis, death
west nile: note that focal symptoms seen with west nile are not common manifestations in diffuse encephalitis caused by other arbovirus agents; focal symptoms of muscle weakness, asymmetrical flacid paralysis; parkinson like tremors |
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Term
ARBOVIRUS
DIFFUSE ENCEPHALITIS |
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Definition
diagnosis:
serologic diagnosis using specific ab tests performed on CSF or serum specimens
eeg, CT scan, MRI |
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Term
ARBOVIRUS
diffuse encephalitis |
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Definition
Control/prevention:
limit vector population
avoid exposure
no treatment for arbovirus - bening outcome |
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Term
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Definition
poliovirus
rabies virus
HSV |
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Term
POLIOVIRUS
FOCAL ENCEPHALITIS |
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Definition
| acute systemic disease that results in viral destruction of motor neurons in spinal cord resulting in flaccid, ascending asymmetrical paralysis |
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Term
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Definition
picornavirus +ssRNA
acid stable
3 serotypes that dont cross |
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Term
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Definition
| infection acquired by fecal oral route from infected person |
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Term
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Definition
virus replicates in small intestine; source of agent is shedding in feces
viremia may occur; rarely, virus crosses bbb or travels neural routes along PNS via retrograde axoplasmic flow like polio and rabies) to the CNS
virus infecs neurons esp anterior horn cells of spinal cord -- lYTIC VIRUS; destroys neurons |
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Term
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Definition
clinical manifestations
ASYMPtomatic infection
rarely, a flaccid ascending asymmetrical paralysis
post polio syndrome - survivors of paralytic polio now have recurrent muslce weakness |
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Term
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Definition
diagnosis
differential diagnosis acute flaccid paralysis
ECHO, coxsackie and enterovirus 68-71
arbovirus
tick paralysis
guillian barre
botulism
dumb rabies
myathenia gravis
intoxication due ot poisons |
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Term
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Definition
vaccine prophylaxis for polio
prevents any cases of vaccine associated paralytic polio |
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Term
rabies virus
FOCAL ENCEPHALITIS |
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Definition
neurotrophic virus
-ssRNA
single serotype |
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Term
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Definition
zoonosis
incidence of rabies in humans is refleciton of both distribution of disease in animals, degree of human contact wiht animals, and extent of vaccination of animals
rabies is zoonosis; transmissoin of rabies to humans by:
animal bites, scratches, inhalation of aerosols
all mammals are susceptible; domestic animals or wild animals
rabies is epidemic, and worldwide
control of human rabies primarily contingent on control of dog and cat rabies
most common rabid dogs
in us vaccination eliminates dog and cat
bats are most common source of rabies today |
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Term
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Definition
pathogenesis:
virus injected through epidermis at bite site; initially replicates in adjacent striated skeletal muscle
when virus titer is high enough enters PNS, sequestered from immune system; travels slow up to CNS nerves
virus predominates in grey matter but localizes in limbic region (focal sympotms) and infects neurons in almost all brain areas
then travels back down autonomic nerves to salivary glands, bite site, others
when it enters sensory terminals and nm junctions, pt will eventually die because virus is sequestered from rabies specific ab
post exposure prophylaxis is imp! can prevent person from developing rabies |
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Term
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Definition
acute, fulminant fatal, focal encephalitis
inc period 2-16 weeks
prodome is flu like illness 2-4 days
highly variable presentation:
neurological phase / excitation/furious form: most common; aggressive sexual behavior; foaming at mouth; coma, death
paralytic dumb rabies:
less common; same as viral encephalitis; paralysis stating at extremities; hypoventialtion; resp paralysis; hypotension; coma death |
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Term
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Definition
lab diagnosis:
provide health officials wiht animal
demonstration of intracytoplasmic viral inclusion via fluorescent antibody testin (negri bodies)
isolation of virus via mouse inoculaiton
PCR; rabies ab in blood and CSF
differential: non polio enterivrus; arbovirus, HSV1 |
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Term
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Definition
pre exposure management and prophylaxis:
prevention is key; there is vaccination for vets, spelunkers, lab workers, animal handlers
primes immune sys for response ; reduces number of doses of rabies vaccine for postexposure treatment |
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Term
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Definition
post exposure management:
decision to do prophylaxis:
know animals in which rabies is endemic (reservoir) and geographic distribution of rabies infection in each animal is imperative when considering initiation of prophylaxis in case of human exposure
immediate and thorough cleansing of wound with soap and water
vacccine and antirabies serum MUST DO BOHT
HRIG; give with vaccine but diff site; half in gluteal half in wound site
HDVC human diploid cell strain rabies vaccine; all are killed vaccines; NEVER ADMINISTER IN GLUTEAL - neuropathy; lower ab titers |
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Term
HERPES SIMPLEX VIRUS 1 AND 2
FOCAL ENCEPHALITIS |
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Definition
ds DNA
causes latent infections
lytic virus |
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Term
HERPES SIMPLES VIRUS 1 AND 2
FOCAL ENCEPHALITIS |
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Definition
transmission: direct contact with saliva, vaginal secretions, semen
causes 20% of all cases of viral encephalitis in US and most common cause of non epidemic, sporadic, usually focal encephalitis (versus arbovirus diffifuse epidemic enceph)
peak incidence in:
neonates where infection occurs during natural birth with infected mother
young adults and elderly via reactivation of latent infection
in an adult primary genital herpes can result in bening, aseptic meningitis where there is urinary retentino, paresthesias, weakness of lower extremities |
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Term
HERPES SIMPLEX VIRUS 1 AND 2
focal enceph |
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Definition
spread to CNS by hematogenous dissemination or neural routes of PNS via retrograde axoplasmic flow as per polio and rabies virus
in adult, herpes in brain is usually focal encp with distinctive features because of location - usually one lobe; mostly cerebral cortex, localized lesions - inflammation, focal hemorrhage, necrosis
with temporal lobe involvement, clinical manifestations occur which reflect areas of brain affected - memory defect, psychosis, slurred speech, personality changes
fatality rate is high
survivors have disability
relapse is common |
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Term
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Definition
in neonates:
3 possible presentations - HSV2 or 1, starts 9-14 d after birht:
localized herpes
disseminated disease
CNS diagnosis
in adult, primary genital herpes are benign, aspetic meningitis |
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Term
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Definition
diagnosis:
lab tests - EEG, CT scan
PCR of sedimented CSF
differential diagnosis: any viral or bacerial agent capable of causing enceph, brain absceess, tumor, intracerebral hemorrhae, temporal lobe, epilepsy |
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Term
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Definition
treatment:
antiviral agents, nucleoside analogs- prodrugs NOT A CURE
-inhibits HSV polymerase, acts as chain terminator
acyclovir has selective toxicity
vidarabine/adenosine arabinoside AraA, idoxuridine, trifluridine, famciclovir, valacyclovir
cNS or disseminated disease in neonates: high dose acyclovir
MUST Initiate treatment immediately after obtaining sample; if test results are negative, stop treatment. only treatment can decrease both fatality rate and neurological sequelae
for management of pregnant mother with genital herpes, ACO recommendations for prophylaxis and C section - treat with suppressive therapy; acyclovir; use c section bc can pass on in utero |
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