Nervous System Infections

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Meningitis and Encephalitis

• Meningitis

  • inflammation of the meninges

  • membranes surrounding the brain and spinal cord

  • caused by bacteria or virus

• Encephalitis

  • inflammation of the brain

  • usually caused by viruses

Bacterial Meningitis

• signs and symptoms

• s/s

  • fever, severe headache, stiff neck

  • nausea, vomiting, confusion, coma

Bacterial Meningitis

Pneumococcal Meningitis

• bacteria

  • cause

• treatment/prevention

Bacterial Meningitis

Pneumococcal Meningitis

• Streptococcus pneumoniae

  • normal microbiota of upper respiratory tract

  • capsule helps it escape phagocytosis

  • exoenzymes (released from bacteria)

    • degrade tissues, allow movement into blood then into meninges

• treatment/prevention

  • antibiotics

  • subunit vaccine > 50yo

  • conjugate vaccine < 5yo

Bacterial Meningitis

Meningococcal Meningitis

• bacteria

• transmission

• s/s

  • Petechiae

• t/p

Bacterial Meningitis

Meningococcal Meningitis

• Neisseria meningitidis

  • gram negative : endotoxin causes shock and can become fatal

• transmission : respiratory droplet contact

  • epidemics in crowded conditions (prisons, dorms)

  • begins as throat infection and spreads to the meninges

• s/s

  • pneumococcal pneumonia

    • fever, severe headache, nausea, vomiting, confusion, coma

  • Petechiae

    • purple spots on the skin

• t/p

  • antibiotic

  • vaccination

• Bacterial Meningitis

  Hib Meningitis

  • bacteria

  • s/s effects

  • t/p

Bacterial Meningitis

Hib Meningitis

• Haemophilus influenzae

  • gram negative bacteria

  • produces endotoxin → meningitis → shock & death

• s/s effects

  • causes ear, eye, and throat infections

  • pneumonia : spread to lungs from blood → meninges

• t/p

  • antibiotics

  • vaccine at 2 months old

Bacterial Diseases

Listeriosis

• bacteria

• transmission

• Listeria monocytogenes

• transmission

  • found in soil and water → contaminated produce

  • animals spread through products

  • traces back to deli meats

    • psychrotroph can grow in refrigerated food

Bacterial Diseases

Listeriosis

• s/s

• epidemiology

• t/p

• s/s

  • mild flu-like symptoms

  • in very young old or immunecomp → meningitis

  • treat to fetus of pregnant women

• epidemiology

  • cheese in LA

• t/p

  • antibiotics

  • monitor food supply and cooking deli meats

  • bacteriophage sprays to destroy bacteria on produce

Bacterial Diseases

Hansen’s Disease (Leprosy)

• bacteria

  • growth

  • immune response

• transmission

• progresses to what 2 types of leprosy

• Mycobacterium leprae

  • intracellular parasite

  • grows is peripheral nerves cells in fingers, toes, and face

  • cell-mediated immune response which attacks nerve cells

• transmission

  • direct contact

• progresses into

  • Tuberculoid Leprosy or Lepromatous Leprosy

Bacterial Diseases

Hansen’s Disease (Leprosy)

• s/s

• tuberculoid

• lepromatous

• treatment

• s/s

  • nerve damage and loss of feeling in infected tissue

  • shortening of fingers and toes, nose disfigured, blindness

• Tuberculoid Leprosy

  • immune response can limit the spread

  • nerve damage is permanent (stops getting worse tho)

  • treatment

    • 2 antibiotics for 6 months

• Lepromatous Leprosy

  • cell-mediated immunity may fail

  • continuous nerve damage

  • necrosis of tissues and deformed extremities

  • treatment

    • 3 or 4 antibiotics for 1-2 years

Bacterial Diseases

Tetanus and Botulism

• both caused by what

• Clostridium bacteria

  • caused by neurotoxins produced by these bacteria

Bacterial Diseases

Tetanus

• bacteria

  • toxin

  • effects

• t/p

• Clostridium tetani

  • produces tetanospasmin toxin

    • localized infection + toxemia

  • rigid paralysis : muscles cannot relax ; spasms cause death

• t/p

  • DTaP vaccine

  • given after potential infection

Bacterial Diseases

Botulism

• bacteria

  • toxin

  • effects

• transmission

• t/p

• Clostridium botulinum

  • produces botulinum toxin

  • flaccid paralysis : muscles cannot contract

    • → respiratory and cardiac failure

• transmission

  • food borne illness : often result from improper home canning

• t/p

  • no vaccine - passive immunization with pre-made antibodies

Viral Diseases

Arboviral encephalitis

• transmission

• s/s

• effects

• arthropod-borne-virus

• transmission

  • insect bites : mosquitos are the vector

  • virus enters blood and peripheral nerves

• s/s

  • most cases are asymptomatic

  • immune system quickly overcomes infection

• effects

  • in weakened patients, virus travels to brain → encephalitis

  • can cause neurological damage, paralysis, coma, or death

Viral Diseases

• West Nile Virus

  • transmission

  • outcomes

• transmitted by mosquitos from infected birds

• rarely causes disease in humans

  • 80% asymptomatic

  • 20% headache and fever

  • <1% → encephalitis, meningitis, acute flaccid paralysis

Viral Diseases

• Poliomyelitis - Polio Virus

  • transmission

  • infection route

• transmission

  • fecal contaminated food and water

  • multiplies in throat and intestine : usually defeated by immune system

• in rare cases, virus can attack the nerve cells

  • travel from intestines → peripheral nerves → CNS

• s/s

  • back pain, muscle spasms, permanent paralysis

  • paralytic poliomyelitis

Viral Diseases

• Poliomyelitis

  • treatment

  • prevention (2 vaccines)

• treatment

  • none treat the symptoms

• prevention

  • oral polio vaccine : live attenuated

    • mimics natural route of infection

    • stimulates complete antibody and cell mediated immunity = long lasting

  • inactivated polio vaccine

    • safer option

    • confers less effective immunity : requires a series of injections

Viral Diseases

• Rabies - Rabies virus

  • transmission

  • effects

• transmission

  • zoonotic disease : through saliva of infected animals

• effects

  • virus infects peripheral nerves and travels to the brain → encephalitis

  • long incubation period of 5-8 wks

Viral Diseases

• Polio

  • symptoms in animals

  • animal diagnosis

  • animal t/p

• symptoms

  • agitation or unusual tameness, behavioral changes, biting is fatal within a few days

  • spasms in mouth and throat

    • hydrophobia : accumulation of saliva (foaming at the mouth)

• animal Dx

  • isolated and observed for 10 days

  • brain tissue testing

• animal t/p

  • euthanize animals and supportive care for humans

  • 100% fatality rate

  • vaccination and boosters

Viral Diseases

• Rabies

• human prevention

  • wound care

  • immediate treatment

  • immunization

• human prevention

• wound care

  • clean wound with soap and water along with virucidal solution

• administer human rabies immune globulin (HRIG)

  • passive immunization

  • contains antibodies against the rabies virus

  • administer around the wound or in the muscle

• administer inactivated rabies virus

  • active immunization

  • one injection days 0 3 7 14 post exposure

  • stimulates adaptive immune system

  • long incubation period allows time to develop complete immunity before the virus can enter the brain

Viral Diseases

• Rabies

• human prevention

  • pre-exposure prophylaxis (PrEP)

• for people who work with animals infected w rabies

• two doses : one week apart

• check antibody levels every 1-3 years

Protozoan Diseases

• African Sleeping Sickness - Trypanosoma

  • transmission

  • acute vs. chronic

• transmission

  • vector : Tsetse fly

  • multiplies at infection site

  • enters blood and lymphatic system → carried to the brain

• acute

  • East African Sleeping Disease

• chronic

  • Gambian Sleeping Sickness

Protozoan Diseases

• African Sleeping Sickness - Trypanosoma

  • s/s

  • t/p

• s/s

  • lethargy, loss of interest, drowsiness, coma, eventual death

• prevention

  • control vector

• treatment

  • difficult due to protozoan biology

  • “The Resurrection Drug”

    • demographic suffering cannot afford treatment