Chapter 22: Disease fo the Nervous System

What is the CNS?

The brain and spinal cord; processes and integrates information

What are the meninges?

Protective membranes covering the brain and spinal cord.

What are the three layers of the meninges?

Dura mater, arachnoid mater, Pia mater

What is CSF

Cerebrospinal fluid; a clear fluid that circulates around the brain and spinal cord

What is the purpose of the Blood Brain Barrier

It tightly controls what enters the brain from the blood

Why is the BBB considered an immunological feature?

It tightly restricts the movement of microbes, immune cells, and molecules from the blood into the brain

What are the hallmark signs of meningitis?

Fever, headache, stiff neck, nausea, vomiting

Why is bacterial meningitis a medial emergency?

Bacteria can cross the BBB, cause brain swelling and lead to death within hours

How is bacterial meningitis treated?

Immediate IV antibiotics

Why is viral meningitis usually less severe?

It is more common, usually mild, and treated with supportive care

Haemophilus influenza—key features?

• capsule antigen type b; once caused around 45% of bacterial meningitis cases

Neisseria meningitidis — key features?

Many healthy carriers; ~80% mortality without antibiotics.

Streptococcus pneumoniae — key features?

Many healthy carriers; high mortality in the elderly

Listeria monocytogenes — key features?

Foodborne; dangerous in pregnancy; can cross the placenta

What causes Tetanus?

Clostridium tetani

Hallmark symptoms of tetanus?

blocks muscle relaxation, causing severe spasms

Vaccine for tetanus?

DTap (tetanus toxoid vaccine)

What causes botulism

Clostridium botulinum

Hallmark symptom for botulism

Flaccid paralysis

What food is associated with botulism?

Honey (infants) and improperly canned foods

Is there a vaccine for botulism?

No; treated with botulinum antitoxin

What causes leprosy?

Mycobacterium leprae

Why is leprosy relevant to Hawaiʻi?

Historically high rates; forced isolation at Kalaupapa.

Is leprosy still common today?

Rare and treatable; occasional cases still occur.

What causes polio?

Poliovirus

How is polio transmitted?

Fecal–oral route (contaminated water)

What happens in severe polio cases?

Virus enters CNS, destroys motor neurons, causes paralysis.

Why is the Sabin vaccine controversial?

It is live-attenuated and can mutate back to a virulent form.

How is rabies transmitted?

Animal saliva, usually through bites.

What is the fatality rate of rabies after symptoms appear?

Nearly 100% fatal.

Is rabies preventable?

Yes, with vaccination after exposure before symptoms start

How is Zika transmitted

Mosquito bites, sexual contact, blood transfusion, mother to child

What is the major risk of Zika during pregnancy?

Microcephaly and other serious birth defects.