Nervous System & Infectious Diseases: Meningitis, Tetanus, Leprosy, Rabies, and More

What structures make up the nervous system?

Brain, spinal cord, and nerves

Does the nervous system have normal microbiota?

No, it is normally sterile

What is meningitis?

Inflammation of the meninges surrounding the brain and spinal cord

What are common symptoms of meningitis?

High fever, headache, nausea, vomiting, stiff neck, confusion, and drowsiness

What are CSF findings in bacterial meningitis?

Cloudy fluid, increased WBCs, bacteria present, high protein, low glucose

Why is glucose low in bacterial meningitis CSF?

Bacteria consume glucose for energy

Which pathogen causes meningitis in unborn babies?

Listeria monocytogenes

Which meningitis pathogen is Group B and found in vaginal flora?

Streptococcus agalactiae

Which meningitis pathogen affects young children and has a vaccine?

Haemophilus influenzae

Which meningitis pathogen can cause epidemics in teens/young adults?

Neisseria meningitidis

Which meningitis pathogen commonly affects the elderly?

Streptococcus pneumoniae

What organism causes tetanus?

Clostridium tetani

How does tetanus enter the body?

Through skin puncture wounds

What type of toxin does tetanus produce?

Neurotoxin (exotoxin)

How does tetanus toxin affect muscles?

Blocks relaxation causing continuous contraction (spasms)

How is tetanus prevented?

Vaccination (toxoid)

What organism causes botulism?

Clostridium botulinum

How is botulism transmitted?

Foodborne toxin ingestion

What does botulinum toxin do?

Prevents acetylcholine release causing paralysis

Why is botulism life-threatening?

It can paralyze the diaphragm causing respiratory failure

What organism causes leprosy?

Mycobacterium leprae

What is another name for leprosy?

Hansen's disease

How is leprosy transmitted?

Aerosols or breaks in the skin

What tissues does leprosy affect?

Skin, mucous membranes, and nerve cells

Why does leprosy cause loss of sensation?

Nerve destruction by immune response

Why can leprosy remain undetected for years?

It is a slow-growing organism

How is leprosy diagnosed?

Acid-fast stain

How is rabies transmitted?

Bite or scratch of an infected animal

How does rabies reach the brain?

Travels along peripheral nerves to CNS

What is the outcome of untreated rabies?

Fatal encephalitis

What are hallmark rabies symptoms?

Hydrophobia, hallucinations, seizures, confusion

What is used for rabies treatment after exposure?

Vaccine and human rabies immunoglobulin (HRIG)

What are examples of arboviral encephalitis?

West Nile virus and Eastern equine encephalitis

What is the vector for arboviruses?

Mosquitoes

What is the natural host for arboviruses?

Birds

What does arbovirus mean?

Arthropod-borne virus

What do arboviruses cause in the CNS?

Encephalitis

What is the mortality rate of EEE?

About 30 percent or higher

What is the treatment for arboviral infections?

Supportive care

Where is Cryptococcus neoformans found?

Soil with pigeon droppings

How does Cryptococcus infect the body?

Inhalation to lungs then bloodstream to meninges

What is a key virulence factor of Cryptococcus?

Capsule

How is Cryptococcus identified?

India ink stain of CSF

Who is most at risk for Cryptococcus infection?

Immunocompromised individuals such as AIDS patients

What organism causes African sleeping sickness?

Trypanosoma brucei

What is the vector for African sleeping sickness?

Tsetse fly

Where is African sleeping sickness found?

Central and Eastern Africa

What are symptoms of African sleeping sickness?

Headache, neurological issues, extreme drowsiness leading to coma

How is African sleeping sickness diagnosed?

Protozoa found in blood or CSF

What is conjunctivitis?

Inflammation of the conjunctiva (pink eye)

What are common bacterial causes of conjunctivitis?

Haemophilus, Moraxella, Streptococcus

Is conjunctivitis contagious?

Yes

What causes neonatal gonorrheal ophthalmia?

Neisseria gonorrhoeae

How is neonatal gonorrheal ophthalmia acquired?

During passage through birth canal

What is a complication of neonatal gonorrheal ophthalmia?

Corneal damage leading to blindness

Why are newborns given eye antibiotics?

To prevent infection

What organism causes trachoma?

Chlamydia trachomatis

How is trachoma transmitted?

Birth canal or hand-to-eye contact

What causes Acanthamoeba keratitis?

Acanthamoeba protozoa

Where is Acanthamoeba found?

Freshwater, hot tubs, and soil

Who is most at risk for Acanthamoeba keratitis?

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