Microbial Diseases of the Nervous System

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Questions and Answers

What is the primary treatment for endotoxin-induced shock from Gram-negative bacteria?

Corticosteroids

Heavy administration of IV antibiotics (correct)

Oral antibiotics only

Supportive care with pain relief

Which bacterium accounts for the highest percentage of bacterial meningitis cases?

Neisseria meningitidis

Listeria monocytogenes

Haemophilus influenzae (type B) (correct)

Streptococcus pneumoniae

What is a characteristic of Neisseria meningitidis related to its transmission?

Spread through insect bites

Commonly spread via respiratory droplets (correct)

Transmitted only through sexual contact

Transmitted primarily through contaminated water

Which of the following groups is at the highest risk for Streptococcus pneumoniae infections?

Children and the elderly Signup and view all the answers

What is a unique risk factor associated with Listeria monocytogenes transmission?

Commonly linked to deli meats and unpasteurized dairy products Signup and view all the answers

Which population is most at risk for serious infections due to certain bacteria crossing the placenta?

Pregnant women Signup and view all the answers

What is the primary route for diagnosing bacterial meningitis?

Spinal tap Signup and view all the answers

What is the likely outcome of untreated tetanus due to Clostridium tetani infection?

Uncontrolled spasms Signup and view all the answers

Which antibiotic is commonly used in combination to treat bacterial meningitis?

Vancomycin Signup and view all the answers

What is the mechanism by which botulinum toxin affects the nervous system?

Inhibiting acetylcholine release Signup and view all the answers

How is tetanus primarily prevented in individuals?

Vaccination with a tetanus toxoid vaccine Signup and view all the answers

What potential complication can arise from infant botulism associated with honey consumption?

Acute respiratory distress Signup and view all the answers

Which of the following statements about Clostridium tetani is true?

It is an endospore-forming obligate anaerobe. Signup and view all the answers

What is the primary role of the central nervous system (CNS)?

Processes sensory information and coordinates movement Signup and view all the answers

Which of the following statements accurately describes the blood-brain barrier?

It is a semi-permeable membrane regulating entry of substances. Signup and view all the answers

What is a common method of transmission for bacterial meningitis?

Airborne respiratory droplets Signup and view all the answers

Which bacteria is NOT commonly associated with bacterial meningitis?

Escherichia coli Signup and view all the answers

What are the hallmark symptoms of bacterial meningitis?

Fever, headache, and stiff neck Signup and view all the answers

What is the significance of the 'immune privilege' of the CNS?

It minimizes immune responses to protect neural tissues. Signup and view all the answers

Why is treatment for CNS infections often challenging?

Limited diffusion of drugs due to the blood-brain barrier. Signup and view all the answers

Which organism causes both botulism and tetanus?

Clostridium botulinum Signup and view all the answers

What is the primary feature that distinguishes meningitis from encephalitis?

Encephalitis refers to inflammation of the brain. Signup and view all the answers

What is a distinctive characteristic of Mycobacterium leprae infections?

It requires a prolonged treatment course. Signup and view all the answers

Study Notes

What to Know

Central nervous system (CNS) components, central vs. peripheral function
Blood-brain barrier purpose, and potential drawbacks of tight regulation
Bacterial meningitis: classic signs, bacterial components, diagnosis, and treatment
- Bacteria to consider: H. influenzae, N. meningitidis, S. pneumoniae, L. monocytogenes
Distinguishing characteristics between botulism and tetanus, causing organisms
Distinguishing characteristics of M. leprae infections, duration of treatment
Information about viruses (discussed), transmission, population affected, prevalence, mortality, pathogenicity, viruses of concern (specifically poliovirus, rabies virus, Zika virus)

Microbial Diseases of the Nervous System

Structure and function of the nervous system
- Central nervous system (CNS): brain and spinal cord. Brain's role in thoughts, learning, movements, and feelings. Spinal cord's function in conveying messages (from/to brain to peripheral nerves).
- Peripheral nervous system (PNS): nerves branching from the CNS, protective membranes (meninges) that anchor the CNS to surrounding bone and provide stability.
- Cerebrospinal fluid (CSF).
- Blood-brain barrier purpose: guarding the brain by preventing harmful substances from entering, allows passage of nutrients/essential molecules into the brain. Crucial immunological feature protecting the central nervous system.
CNS is highly guarded
- Skull protects the brain; vertebrae protect the spinal cord
Blood-brain barrier
- Semipermeable membrane protecting the brain from harmful substances
- Allows passage of nutrients and essential molecules
- Crucial immunological feature of the human central nervous system

Diseases of the CNS

Blood-brain barrier limitations; parasites, bacteria and viruses that developed strategies for CNS invasion, and limited quantities of immune cells in a healthy CNS.
Meningitis: inflammation of the meninges
Encephalitis: inflammation of the brain
Meningoencephalitis: inflammation of both meninges and brain
Typical Features of meningitis/encephalities

Bacterial Nervous System Diseases

Bacterial Meningitis: initial symptoms (fever, headache, stiff neck), progression to coma/death, endotoxins causing shock/inflammation, treatment with IV antibiotics, viral meningitis being more common and milder.
Bacterial meningitis causative agents:
- Haemophilus influenzae type B (HiB),
  - Gram-negative, aerobic coccobacilli, high mortality rate (6%)
  - Transmitted via respiratory droplets, person-to-person contact, most common in children 6 months to 4 years
- Neisseria meningitidis (meningococcal meningitis)
  - Aerobic, gram-negative diplococcus, capsule formation, 40% are healthy nasopharyngeal carriers
  - Transmission via respiratory droplets, person to person contact.
Streptococcus pneumoniae (pneumococcal meningitis)
- Gram-positive diplococcus, capsule formation, 70% are healthy nasopharyngeal carriers
- Mortality rates relatively higher among children and elderly
Listeria monocytogenes (listeriosis)
- Gram-positive rod, foodborne transmission, commonly linked to deli meats and unpasteurized dairy products.
Diagnosis and Treatment of Bacterial Meningitis, specifically spinal tap (lumbar puncture) for CSF extraction. CSF analysis, and antibiotic therapy initiated before diagnosis confirmation.

Viral Diseases

Rabies virus: causes rabies, transmission through animal bites/saliva, symptoms (muscle spasms, hydrophobia), prevention by vaccination, and high fatality rate.
Poliomyelitis (polio): virus transmission via water contaminated with feces, impact on the spinal cord, symptoms, and treatment/prevention with vaccination.
Zika virus: mosquito-transmitted virus, vertical transmission possible, potential CNS birth defects like microcephaly. Symptoms that are usually mild.

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Description

This quiz covers the essential components of the central nervous system (CNS) and peripheral functions. It also examines major microbial diseases affecting the nervous system, including causes, symptoms, diagnosis, and treatment strategies for bacterial meningitis and distinguishing factors for botulism and tetanus. Explore the impact of viruses like poliovirus and Zika virus on nervous system health.