Chapter 20 Infections of the Nervous System

Signs versus Symptoms

Differential Diagnosis

Definitive DX

RX

HX

1. Anatomy, Physiology and Immunity of the Nervous System

    A. CNS - Brain and  Spinal Cord

           1. Meninges

           2. CSF

           3. CNS immune cells neuroglial cells

           4. Portals of Infection

   B. Enclosed by bone, close to blood - sterile

           1. Blood brain barrier

           2. Nerve cell damage through infection

   C. Diagnosis through CSF - Gram Stain, Culture & Sensitivity (C&S), and CSF chemistry

    

2. Infections of the Nervous System

Disease	Etiologic Agent	Pathogenesis	Symptoms	Transmission	Prevention and treatment
Bacterial Infections of the Nervous System
Meningitis	Neisseria meningitidis GNDC	attach via fimbrae capsules petechiae = septicemia epidemic 13 strains A,B,C & W135	Mild cold, severe headache, stiff-neck, high fever, nausea, vomiting, WBC in CSF decrease in CSF glucose, may lead to brain damage, hearing loss	Inhaling microorganism through respiratory tract or associated ear or sinus infections	Chloramphenicol Cephalosporins + Rifampin for Prophylaxis for family members Vaccination
	Streptococcus pneumoniae GPDC pneumococci	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			Ampicillin +Cefotaxime Screening in OBGYN visits leading cause in newborns
	Listeria monocytogenes GPR psychrophiles	GI tract to blood and brain, miscarriage		foodborne common epidemics from food products	Ampicillin + Gentamicin
Peripheral Nerves	Mycobacterium leprae  AFB	Very long generation time = chronic, slow infection 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	respiratory and close contact l	Dapsone, rifampin, clofazimine early treatment essential vaccine?
Botulism Neural Intoxication	Clostridium botulinum	Intoxication anaerobe found in improperly canned foods, other anaerobic conditions Foodborne -ingestion of toxin Infant botulism Wound botulism	toxin binds to Ach site preventing muscle contraction = flaccid paralysis Botox	heat labile 7 different exotoxins 18-36 hour (8hrs-4days) GI symptoms, diplopia, difficulty swallowing and flaccid paralysis, inability to breathe	Botulinum Ig antibiotics and antitoxin for wound and infant botulism 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
Tetanus	Clostridium tetani GPR endospore former	Wound infection and toxin production	neurotoxin binds preventing release of AChe and muscle relaxation	anaerobic wounds contaminated with endospores	Prevention with vaccination toxoid
Disease	Etiologic Agent	Pathogenesis	Symptoms	Transmission	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	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
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	Symptoms	Transmission	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

Chapter 20 Infections of the Nervous System

1. Describe the protective and immune barriers found in the Nervous System.

2. Compare and contrast Meningicoccal meningitis, Haemophilus meningitis, Listeriosis, Botulism, and Leprosy (Hansen's Disease) with regards to transmission, treatment and control.

3. Describe the transmission routes, pathogenesis, diagnosis, treatment and prevention of the various types of viral encephalitis agents including WNV,WEV, EEV.

4. Describe the transmission routes, pathogenesis, diagnosis, treatment and prevention rabies.

5. Describe the transmission routes, pathogenesis, diagnosis, treatment and prevention of opportunistic infections with Cryptosporidiosis.

6. Describe the transmission routes, pathogenesis, diagnosis, treatment and prevention Trypanosomiasis.

7. Describe the transmission routes, pathogenesis, diagnosis, treatment and prevention Prion diseases such as Kuru, Crutzfeld-Jakob, and Mad Cow disease.

8. Compare and contrast the clinical picture involved in viral, fungal, and bacterial nervous system infections.

9. When given a patient with Nervous symptoms indicating a potential infection, evaluate and analyze the evidence to determine a differential diagnosis, additional testing needed, and a probable diagnosis and treatment for the patient with the information provided.

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Date last updated 11/02/2010
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