Ch 26 - Nervous system infection

common infection terms

meningitis, encephalitis, meningoencephalitis

meningitis

inflammation in the meninges

encephalitis

inflammation of the brain tissue or blood stream

meningoencephalitis

inflammation of the meninges and brain tissue

Bacterial meningitis

Haemophilus influenzae type B meningitis

Meningococcal Meningitis

Neonatal Meningitis

Pneumococcal Meningitis

Tetanus

Botulism

Listeriosis

Hansen's Disease (Leprosy)

Haemophilus influenzae type B meningitis

patho: Haemophilus Influenzae

s&s: Nausea, vomiting, photobia, stiff neck, confusion

trans: direct contact, aerosis

Meningoccal meningitis

vaccine

patho: Neissaria meningitis: meningoccus

s&s: often fatal; petechial rash

trans: direct contact w/ respiratory; throat secretion

Neonatal meningitis

patho: streptococcus agalactiae

- group B strep

often fatal

pneumococcal meningitis

patho: streptococcal pneumoniae

often fatal

pathway: bacteria --> mucus membranes of oropharynx & nasopharynx --> bloodstream --> damage blood vessel walls --> bleed into the skin & organs (hemorraghic rash)

symptons: trunk, mucus membrane, extremities ( if meningococcal infection) -> petechiae

Diagnosis & treatment

- lumbar puncture

- immediate antibiotic treatment

- prophylactic treatment

- vaccine

newborn

Group B streptococcus

babies & young children

S. Pneumoniae

teens & young adults

N. meningitis

older adults

S. pneumoniae

Tetanus

aka: "lock jaw"

patho: clostridium tetani

noncommunicable

vaccine: DTap, Tdap

common resident of soil, dust, GI tract/feces of animals & humans, etc

tetanus neurotoxin - tetanospasmin

opisthotonos (backwards arching)

spastic paralysis: muscle become rigid & immobile

Botulism

food poisoning

patho: Clostridium botulinum

trans: ingestion of performed toxin in food, ingestion of endospores, food by infants or immunocompromised adults

commonly inhibits soil & water

3 forms: foodborne (15%), infants (68%), wound (20%)

removal of oxygen --> anaerobic

damage can --> endospore grows

Botulism toxin

Tetanus toxin

Botulism toxin

flaccid paralysis; stops muscle contraction

- botulinum toxin blocks release of acetylcholine, stopping muscle contraction

- ex: botox

Tetanus toxin

spastic paralysis; uncontrollable muscle contraction

- tetanus toxin prevents release of glycine and GABA, which prevents relaxation of muscles

- most potent biological toxin known

Listeriosis

important during pregnancy

patho: Listeria monocytogenes

s&s: initial flue-like symptoms, sepsis, potentially fetal meningitis

trans: contaminated food or water

- tOrch

primary reservoir: soil & water; animal & human intestines

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

cell-to-cell transmission: avoids immune system virulence

- pathogens interacts w/ actin from host cytoskeleton to produce an actin tail

- actin pushes the pathogen from one cell to another through a protrusion of the host membrane

Hansen's disease (leprosy)

obligate intracellular parasitic

very slow growth (GT 12-14)

patho: mycobacterium leprae (slowest) - rare, chronic disease

trans: communicable but not highly contagious

> 95% of all people have natural immunity

2 possible ways: tuberculoid, lepromatous

tuberculoid

shallow lesions; damaged nerves (peripheral) ---> local loss of pain reception

lepromatous

deep nodular infection ---> severe disfigurement of the face & extremities, wide spread dissemination

acelluar diseases

- viral meningitis

- viral encephalis --> EEE, WEE, SLE, - - WNE

- Zika virus

- Rabies

- Poliomyelitis

- transmissible spongiform

- encephalopathies (TSEs)

viral meningitis

patho: HSV-1 HSV-2

s&s: nausea, vomiting, stiff neck, confusion, symptoms;generally resolve within 7-10 days

trans: sequela of primary viral infection- after complication

non polio, enteroviruses (most common)

more common & less severe than bacterial meningitis

vitla encephalitis (arboviral encephalitis)

patho: EEV, WEEV, SLEV, WNE, JEV

EEE, WEEV, SLE, WNE --> found in U.S

s&s:

- mild cases: fever & chills, headache, restlessness

- serious cases: encephalitis leading to convulsions, coma, death

trans: bird reservoir --> humans & horses by mosquito vector of various species

EEE

Eastern Equine Encephalitis Virus

WEEV

western equine encephalitis virus

SLEV

St. Louis Encephalitis virus

WNE

West Nile Equipment

Japanese Encephalitis virus

JEV

Zika Virus

s&s fetal brain damage & microcephaly --> tOrch

trans: mosquito vector, sexually or blood transfusion

symptoms similar of dengue, yellow fever, chikungunya --> Aedes spp. common in ALL

Rabies

patho: Rabies virus (Rv)

s&s always fatal if not promptly treated

tans: from bite of infected mammal

- scratches & inhalation of droplets

- zoonotic

antimicrobial drugs: immunoglobulin

vaccine: attenuated vaccine

negri bodies in nervous tissue - antigen & antibody

preventative therapy treatment: active & passive

control: vaccine domesticated animals, eliminate strays, strict quarantine practices

clinical phases: prodromal phase, furious phase, dumb phase

foaming of mouth after drinking: produced by spasms in throat

prodromal phase

early stages

fever, nausea, vomiting, headache, fatigue

furious phase

agitation, disorientation, seizures, twitching, hydrophobia

dumb phase

paralyzed, disoriented, stuporous --> coma --> death

poliomyelitis

patho: poliovirus

- enterovirus

- resistant to acid, bile, detergent

s&s: asymptomatic or mild nausea, neurological infections

trans: highly contagious

vaccine

- attenuated vaccine (Sabin) --> weakened

- killed vaccine (Salk)

polioviruses --> throat & intestinal mucosa (adherence) --> tonsils (multiply, some leak into blood --> (CNS) --> sheds deterioration

Salk vaccine

- 1955

- It was an inactivated polio vaccine that generates serum antibodies to neutralize the virus in the bloodstream.

sabin vaccine

- 1962

- oral polio vaccine (OPV); attenuated

- hasn't been used in the US since 2000

Transmissible spongiform encephalopathies (TSEs)

dis: cretzfeldt - jacob disease & other TSEs

patho: prions

trans: exposure to infected nerve tissue

all TSEs are degenerated

all prions build up in cells, brain slowly shrinks, tissue fills w/holes until it resembles a sponge

Fungal & parasitic diseases

Cryptococcal meningitis

Amoebic meningitis

Human African trypanosoma/ african sleeping sickness

Neurotoxoplasmosis

Neurocysticercosis

Cryptococcal meningitis

dis: cryptococcosis

patho: cryptococcus neoformans

s&s: meningitis, granuloma formation in brain

only invade the nervous system after first infecting a different body system

trans: inhalation

amoebic meningitis

very dangerous; brain eating parasite

dis: primary amoebic meningoencephalitis (PAM)

patho: Naegleria fowleri

s&s: almost always fatal-headache, seizures, coma

trans: freshwater amoeba invade brain via nasal passeway

nasal irrigation by neti pots

can be confirmed by direct observation of CSF

Human African Typanosomiasis/ African Sleeping Sickness

insect bite

damage spleen, lymph node, brain

enter lymphatic tissues --> lymph node

patho: Trypanosoma brucei gambiense, T. brucei rhodesiense

s&s: chancre, winterbottoms sign

trans: tsetse fly

neurotoxoplasmosis

patho: toxoplasma gondii

s&s: brain abscess, chronic encephalitis

most common causes of brain abscesses in immunocompromised

neurocysticercosis

patho: taenia solium

- pork tapeworm

s&s: brain cyst, epilepsy

trans: tapeworm egg

2 infectious route:

- undercooked pork --> adult larvae tapeworm infection

- teaniasis - healthy benign disease --> eggs

- cysticercosis - a severe potentially fatal infection

- environment combination of produce