Diseases of the nervous system

CNS

brain and spinal cord

PNS

nerves that stem from CNS to sense organs and other parts of the body

three meninges

dura matter (outermost)

arachnoid matter

pia matter

cerebrospinal fluid

provide nutrition and cushion to CNS

blood brain barrier

cells of vessels delivering blood to brain allow very few molecules to pass through

normal biota in CNS or PNS

none

CNS immune response

limited to preserve important function

meningitis

inflammation of the meninges

can be caused by many different microorganisms

meningitis diagnosis and treatment

lumbar puncture and culture

start broad spectrum antibiotics immediately

meningitis signs and sx

painful and stiff neck

fever

increased lymphocytes in CSF

neisseria meningitidis gram and morphology

gram negative diplococci

coffe bean shape

most serious accute meningitis

neisseria meningitidis

strains responsible for most cases of infection of neisseria meningitidis

B, C, and Y

vaccines target these capsules

neisseria meningitidis pathogenesis

enter through respiratory tract and then into blood and CSF

trojan horses in macrophages

releases endotoxin (LPS)

neisseria meningitidis virulence factors

capsule

intracellular survival

neisseria meningitidis transmission

reservoir is humans

transmitted through people living in close proximity

modified thayer martin

selects for niserria genus

neisseria meningitidis prevention and treament

vaccine for A,C,Y strains

IV penicillin

prophalax treatment for people in contact with those infected with rifampin or tetracycline

Streptococcus pneumoniae gram and morphology

gram positive cocci in pairs

most frequent cause of community acquired meningitis

Streptococcus pneumoniae

pneumococcus

Streptococcus pneumoniae

Streptococcus pneumoniae virulence

capsule, alpha hemolysin + hydrogen peroxide that damage CNS

Streptococcus pneumoniae pathogenesis

can penetrate respiratory mucosa, then to bloodstream, then CNS

Streptococcus pneumoniae treatment

NOT penicillin

Use vancomycin + ceftriaxone

Streptococcus pneumoniae prevention

vaccine

Haemophilus influenzae

causes meningitis

not the flu lol

Haemophilus influenzae gram and morphology

gram negative rods

Haemophilus influenzae requirements

requires hemin (X) and NAD (V)

Haemophilus influenzae virulence

capsule

Haemophilus influenzae prvention

Hib vaccine (targets B capsule)

Haemophilus influenzae treatment

ceftriaxone

Listeria monocytogenes gram and morphology

Gram positive with ranging morphology

Listeria monocytogenes virulence

resistant to cold, heat, salt, pH, and bile

Listeria monocytogenes pathogenesis

grows inside cells and can move from infected cell to adjacent healthy cell (twitching motility)

Listeria monocytogenes signs and sx

fever, diarrhea, sore throat

Listeria monocytogenes at risk population

elderly, immunocompromised, fetuses, and neonates

pregnant women (microbe can cross placenta)

Listeria monocytogenes reservoir

contaminated food

why pregnant women cant eat deli meats

Listeria monocytogenes diagnosis

ELISA

Listeria monocytogenes treatment

ampicillin, SXT, and erythomycin

Listeria monocytogenes prevention

pasteurization and food washing

Cryptococcus neoformans

fungus that causes meningitis

Cryptococcus neoformans morphology

mega large capsule

spherical

Cryptococcus neoformans transmission

through bird droppings

humans have a pretty good resistance to it though

Cryptococcus neoformans treatment

steroids

Coccidioideds species

fungi that causes valley fever/meningitis

Coccidioideds morphology

hyphae with thick walls and block-like arthroconidia

Coccidioideds pathogenesis

starts as pulmonary infection and then spreads throughout body

arthrospores develop into spherules in lungs

Coccidioideds spherules

spherical cell with many spore

aseptic meningitis

no bacteria or fungi found in CSF

4 out of 5 cases of meningitis are viral

demographic for viral meningitis

mostly childern

common cause of viral meningitis

initial infection of HSV-2 (herpes simplex virus) concurrent with a genital infection

viral meningitis severity

generally milder than bacterial or fungal

viral meningitis diagnosis

begins with failure to find growth in CSF

confirmed with viral culture or antigen test

viral meningitis treatment

most don’t need treatment, just treating sx

neonatal meningitis

almost always caused by transmission from mother in utero or during passage in birth canal

neonatal meningitis: E.coli

occurs most often in premature babies

usually transmitted through birth canal

Cronobacter sakazakii

causes neonatal meningitis

Cronobacter sakazakii transmission

contaminated infant formula

Zika virus

causes microcephaly (babies born with abnormally small heads)

Zika signs and sx

adults: skin rash, conjunctivitis, muscle pain. triggers guillain barre in some adults

Babies in gestation: small head and brain stem dysfunction

Zika transmission

bite of Aedes mosquito and intercourse

Zika prevention

no vaccine available

poliomyelitis

viral infection of spinal cord that can cause neuromuscular paralysis

poliomyelitis signs and sx

mild viremia, fever, HA, nausea, myalgia

if viremia persists can reach CNS and infiltrate motor neurons which can cause paralysis

neurotropic

infiltrates motor neurons of spinal cord

Bulbar poliomyelitis

brain stem, medulla, or cranial nerves are affected

poliomyelitis causative agent

poliovirus

poliomyelitis pathogenesis

adsorbs to receptors of mucosal cells in oropharynx and intestine

poliomyelitis transmission

food, water, hands, mechanical vectors

poliomyelitis treatment

alleviation of pain and suffering

poliomyelitis prevention

vaccination at 2 months

meningoencephalitis causative agent

naegleria fowleri

acanthamoeba

naegleria fowleri transmission

bodies of freshwater

naegleria fowleri

normally harmless but can cause meningoencephalitis if it reaches the brain

naegleria fowleri pathogenesis

get in nasal passage and then to brain

Primary amoebic meningoencephalitis

causes destruction of brain

death occurs within a week

naegleria fowleri treatment

advances so rapidly that treatment is usually futile

sometimes early therapy with amphotericin B, sulfadiazine, or tetracycline can be of some benifit

acanthamoeba

causes miningoencephalitits

granulomatous amoebic meningoencephalitis

infection of acanthamoeba

acanthamoeba transmisison

invades broken skin, conjunctiva, and occasionally lungs

encephalitis

inflammation of the brain

acute encephalitis

typically caused by viruses borne by insects

bacterial encephalitis

less common than viral

typically bacterial symptoms are more pronounces in the meninges than in the brain

acute encephalitis signs and sx

behavior changes, seizures, sx of meningitis

acute encephalitis treatment

empiric treatment for herpesvirus with acyclovir

will do no harm if infection is actually another agent

herpes simplex virus type 1 and 2

can cause encephalitis

subacute encephalitis

sx take longer to show up

cause of subacute encephalitis

toxoplasma gondii, persistent measles virus, prions, variety of infections elsewehere in the body

toxoplasma gondii

fetal infection is often fatal but otherwise healthy people its typically harmless

toxoplasma gondii signs and sx

most cases are asymptomatic or mild sx

can cause encephalitis in patients with immune suppression

toxoplasma gondii in pregnant women

30% chance of passing to fetus

can cause stillbirth or complications if in 1st or 2nd trimester

toxoplasma gondii virulence

intracellular pathogen

toxoplasma gondii transmission

released in cat feces

raw or undercooked meats

prions

proteinaceous infectious particles w no genetic material

transmissible spongiform encephalopathies

neurodegenerative diseases caused by prions

creutzfeldt jakob disease

human transmissible spongiform encephalopathies (prions)

mad cow disease

animal transmissible spongiform encephalopathies

creutzfeldt jakob disease signs and sx

altered behavior, memory loss, delirium, uncontrollable muscle contractions

prions in CJD

transform normal host proteins that then convert other normal proteins into the abnormal form

cause brain to shrink and develop holes

transmissible agents

PrP proteins can be acquired through transmission and genetic mutations of PrP genes can be passed on as heritable traits