Diseases of Brain & Meninges Flashcards
(Septic) Bacterial Meningitis
Commonly caused by: Haemophilus influenzae Type B, Streptococcus pneumoniae, Neisseria meningitidis
HiB vaccine has reduced occurrences caused by Hib
All treated w/antibiotics
Meningococcal Meningitis
Neisseria meningitidis
G(-) diplococci
Causes 2,000-3,000 cases in US per year
- Mortality is 85% if untreated, 1% if treated
- Organisms colonize nasopharynx, spread to blood & meninges
- Cause endotoxin shock & death w/in hours: called Waterhouse-Frederichsen syndrome
- Vaccines: Menomune/Menactra
Haemophilus Meningitis
Haemophilus influenzae type B (HiB)
G(-) bacillus
- once the leading cause of meningitis & mental retardation in kids
- humans are exposed to bacteria early in life & rapidly acquire immunity; disease is rare in adults
- HiB vaccine has drastically reduced incidence
Pneumococcal Meningitis
Streptococcus pneumoniae
G(+) diplococci or chains; alpha hemolytic, optochin sens.
- spread via blood from lungs, sinuses, & ear infections
- Vaccines: Pneumovax (adults) & Prevnar (kids)
(Aseptic) Viral Meningitis
Aseptic meningitis (entertovirus, mumps virus)
- usually self-limiting & nonfatal
- enterovirus more common cause in US since most people have been vaccinated against mumps.
- cannot be treated w/antibiotics
- cannot get viral meningitis from someone
Tetanus (= Lockjaw)
Clostridium tetani
G(+) bacilli, strict anaerobe, endospore former
- found in intestines of many animals
- causes opposing muscles to contract at same time
- flush wound w/hydrogen peroxide
-treat w/antitoxin
Botulism
Clostridium botulinum
G(+) bacillus, endospore former, strict anaerobe
- toxin production depends on a viral prophage
- food-borne intoxication
- IP 12-72 hours, duration days to a month; flaccid paralysis
- cause of death is respiratory paralysis
- produces a neurotoxin that blocks release of acetylcholine at neuromuscular junction, so muscle contraction is inhibited.
- transmitted by improper home-canning, herb-infused oils
- treat with antitoxin
Infant Botulism
Clostridium botulinum
G(+) bacillus, endospore former, strict anaerobe
- causes “floppy baby syndrome”; may be cause of some SIDS
- associated with feeding honey to infants
- no honey to kids under 12 months
- treat w/antitoxin
Equine Encephalitis
Viral; infection/inflammation of CNS
Transmission: from a mosquito to a bird, back to a mosquito, & to a horse, human or other mammal
4 types (all caused by diff virus):
1. Eastern Equine Enceph (EEE) - most serious
2. Western Equine Enceph (WEE)
3. Venezuelen Equine Enceph (VEE) - resembles flu in humans
4. St. Louis Enceph (SLE) - occurs in late summer
- affects horses more than humans; vaccine only for horses; afraid might cause disease in humans
West Nile virus
Spread by bite of mosquito
- most people have no symptoms or mild ones
- rarely can cause West Nile encephalitis; risk is higher for 50 yrs >
- fever, headache, stiff neck, stupor, disorientation
IP usually 3-15 days
Rabies
Reservoirs are animals - #1 raccoons, #2 skunks #3 bats #4 foxes
- transmitted from animal bite
- diagnose w/ immunoflourescent antibody test (IFAT)
- virus slowly migrates to nerves until reaches CNS.
- 2 forms: Furious - mad dog form
Paralytic - dumb form - inability to swallow, profuse salivation, can’t swallow
- Treat w/vaccine (b/c of slow replication rate of virus)
- Milwaukee Protocol - some success in inducing coma
- Vaccines: Rabavert; Rabies Bait Drop
Prion Diseases
Infectious agent made only of protein (no DNA or RNA)
1. Kuru (“Laughing Disease”) - mainly New Guinea women. Cannibalistic rites spread disease.
2. Creutzfeldt Jakob (CJD) - seems to be a genetic predisposition in families; # of cases is on decline
3. Mad Cow Disease - caused by feeding infected animal remains to cattle
4. Chronic Wasting Disease - diagnosed in US elk & mild deer
Prion have been transmitted from one species to another in lab trials.
Could play a role in Alzheimers & Parkinsons….
