Chapter 58 Infections of the Nervous System

  1. Anatomy, Physiology and Immunity of the Nervous System

     A. CNS - Brain and  Spinal Cord

            1. Meninges, CSF

    B. Enclosed by bone, close to blood

            1. Blood brain barrier

            2. CNS immune cells neuroglial cells

            3. Nerve cell damage through infection

    C. Diagnosis through CSF - GS, C & S, and CSF chemistry

    D. Peripheral infection  - Leprosy - Hansen's disease

     

  2. Infections of the Nervous System
Disease Etiologic Agent Pathogenesis & Transmission Symptoms Lab Tests Prevention and treatment
Bacterial Infections of the Nervous System
Meningitis
 		 Neisseria meningitidis
 GNDC		 Inhaled
attach via pili  epidemic, petechiae = septicemia
 		 Mild cold, severe headache, stiff-neck, high fever, nausea, vomiting, WBC in CSF decrease in CSF glucose, may lead to brain damage, hearing loss   Cephalosporins + Rifampin
Prophylaxis for family members

Vaccination
Streptococcus pneumoniae
GPDC		 Inhaled
capsule evades immune system, invasion via blood		 Ceftriaxone
Vaccination
leading cause in adults
Haemophilus influenzae
 GNCB		 Ceftriaxone
Vaccination HiB
Streptococcus agalactiae (Group B)
 GPC cl		 predominantly  inoculation in vagina during delivery Pen
Screening in OBGYN visits
leading cause in newborns
Listeria monocytogenes
 GPR psychrophiles		 foodborne
common epidemics from food products
GI tract to blood and brain, miscarriage		   Ampicillin + Gentamicin
Peripheral Nerves Mycobacterium leprae  AFB Very long generation time = chronic, slow infection
respiratory and close contact

preferentially attacks nerves, infection mediated by T cell immunity (possibly inhibition of immunity allows spread.)

 tingling and decreased sensation in extremities, pain, then loss of feeling as nerves become involved, wasting, damage - cartilaginous changes  

l

 Dapsone, rifampin, clofazimine

early treatment essential

vaccine?
Disease Etiologic Agent Pathogenesis & Transmission Symptoms Lab Tests Prevention and treatment
Viral Infections of the Nervous System
Viral meningitis Aseptic meningitis
(Coxsackie, Echo, & Mumps virus)		 infect throat -> lymph-> viremia

mild disease

 abrupt onset, fever, headache, stiff neck, light sensitivity, CSF shows lymphs CSF glucose normal contact, food no treatment

vaccines prevent mumps
Sporadic Viral Encephalitis Herpes, Mumps, MEasles etc invade nerves to brain nasal nerves antivirals
Acyclovir
Epidemic Viral Encephalitis Equine encephalitis
WEE, VEE, SLE
West Nile Virus		 invade from bite to blood

serious disease

 epidemics
mosquito via reservoirs		 mosquito abatement
sentinel chickens
no treatment
Polio
http://phil.cdc.gov/phil/
detail.asp?id=996
Illustration of polio virus.		 poliovirus - picornavirus

3 types

 selective destruction of motor neurons-> permenant paralysis headache, fever, stiff neck, nausea
post polio syndrome		 oral portal water vaccination

Sabin and Salk
Rabies Rabies virus

ssRNA

 Saliva and body fluids,long incubation, Amount of virus, distance form brain, Negri bodies pain at bite, fatigue, inability to swallow (hydrophobia), vomiting, CNS involvement, seizures, coma saliva via a bite, bat guano animal control, vaccine, post exposure vaccine, hyper immune globulin
Disease Etiologic Agent Pathogenesis & Transmission Symptoms Lab Tests Prevention and treatment
Fungal Infections of the Nervous System
Cryptococcal meningitis Filobasidiella neoformans (was Cryptococcus neoformans) opportunist in immunosuppressed mild disease inhaled in dust, usually eliminated in lungs Amphotericin B
Disease Etiologic Agent Pathogenesis & Transmission Symptoms Lab Tests Prevention and treatment
Protozoal Infections of the Nervous System
Amebic Meningitis Naegleria fowleri Enters through nasal passage infects brain headache Swimming pools, lakes, and other water sources Flagyl
Trypanosomiasis African Trypanosoma species Enters skin and spreads to blood - parasitemia, goes to brain headache, sleepiness, coma bite of tsetse fly suramin (early), melarsoprol (late infections)
Disease Etiologic Agent Pathogenesis & Transmission Symptoms Lab Tests Prevention and treatment
Other the Nervous System disease from infectious agents
Mad cow = BSE, C-J, Kuru,

 

 Prion Proteinaceous Infectious Particle eaten, pathogenesis unknown, no inflammatory or immune response anxiety, insomnia, fatigue, muscle jerks, dementia undercooked meat, transplant, blood FATAL

highly resistant
Botulism
Neural Intoxication		 Clostridium botulinum

GPR endospore former

 anaerobe found in improperly canned foods, other anaerobic conditions heat labile 7 different exotoxins
18-36 hour
(8hrs-4days)

GI symptoms, diplopia, difficulty swallowing and flaccid paralysis, inability to breathe

 soil contamination of food
(also infant botulism and wound botulism)

Botox

 proper food preparation & cooking

Antitoxin

canned corn, peppers, green beans, soups, beets,asparagus, mushrooms, ripe olives, spinach, tuna fish, chicken and luncheon meats, ham, sausage, lobster, smoked & salted fish

Lecture 9