Micro

• Microbial Diseases of the Nervous System

  • How Microbes Enter the Nervous System
  • The Nervous System Divisions
  • Microbial Diseases of the Nervous System Overview
  • Bacterial Meningitis
  • Specific Bacterial Infections
  • Botulism and Tetanus
  • Leprosy (Hansen's Disease)
  • Viral Diseases of the Nervous System
• How Microbes Enter the Nervous System

  1. Skull or backbone fractures can provide entry points for microbes into the nervous system

  2. Medical procedures can introduce microbes into the nervous system

  3. Microbes can enter along peripheral nerves or through blood or lymph
• The Nervous System Divisions

  • Central Nervous System (CNS) includes the brain and spinal cord
  • Peripheral Nervous System (PNS) consists of cranial nerves and spinal nerves
  • Meninges of the brain & spinal cord include Dura mater, Arachnoid, and Pia mater
• Microbial Diseases of the Nervous System Overview

  • Bacteria can grow in the cerebrospinal fluid in the subarachnoid space of the CNS
  • The blood-brain barrier prevents the passage of some materials into the CNS
  • Common diseases include Meningitis (inflammation of meninges) and Encephalitis (inflammation of the brain)
• Bacterial Meningitis


  A suppurative infection of the meninges & subarachnoid spaces
• Bacterial Meningitis Diagnosis


  Gram stain or latex agglutination of cerebrospinal fluid
• Bacterial Meningitis Treatment


  Typically involves Cephalosporins
• Bacterial Meningitis Positive Signs


  • Brudzinski's sign
  • Kernig's sign
• Tetanus


  Caused by Clostridium tetani, prevented by vaccination with tetanus toxoid
• Botulism


  Caused by Clostridium botulinum, results in paralysis and can be fatal
• Leprosy (Hansen's Disease)


  Caused by Mycobacterium leprae, primarily affects peripheral nerves
• Forms of Leprosy


  • Tuberculoid leprosy
  • Lepromatous leprosy
  • Borderline leprosy
• Viral Meningitis


  More common than bacterial meningitis, with milder symptoms and recovery in 7 to 10 days
• Transmission of Viruses


  Fecal-oral route, respiratory secretions, or saliva
• Most cases of viral meningitis are caused by members of the picornavirus family