Central Nervous System Infections

• What are the key components of the central nervous system discussed in the study material?

  • Meningitis
  • Clinical symptoms
  • Transmission of infection
  • Analysis of CSF
  • Microbial agents causing meningitis
• What is the function of the meninges in the central nervous system?


  They form a structural and functional barrier between the brain and the circulation.
• What are the three layers of the meninges?

  Pia Mater, Arachnoid membrane, Dura Mater
• What happens to CSF protein levels during meningitis?


  They increase.
• What is the effect of severe inflammation in meningitis on CSF?


  It increases the risk of CSF obstruction.
• What are the common symptoms of meningitis?


  • Fever
  • Headache
  • Stiff neck
  • Nausea
  • Sensitivity to light
• What is a common route of transmission for infections leading to meningitis?

  Nosocomial transmission
• What is the purpose of a lumbar puncture in the analysis of CSF?


  To collect cerebrospinal fluid for examination.
• What is the appearance of CSF that may indicate infection?


  Cloudy appearance
• What is xanthochromia in the context of CSF analysis?


  It refers to a yellowish discoloration of the CSF, indicating the presence of bilirubin.
• What type of agar is used for culturing CSF in bacterial meningitis analysis?

  CHOC agar
• What are the different microbial origins of meningitis?


  • Viral: Enteroviruses (Coxsackie, Echovirus)
  • Bacterial: Various genera of bacteria
  • Fungal: Cryptococcus neoformans, Candida species
  • Amoebic: Naegleria fowleri
• What are the most common bacterial causes of meningitis?

  Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae
• What is the mortality rate for untreated bacterial meningitis?


  100%
• What are the potential long-term effects of bacterial meningitis?


  Loss of limb(s), deafness, vision loss, nervous system problems, brain damage
• What are the characteristics of Neisseria meningitidis?


  • Aerobic gram-negative diplococci
  • Fastidious growth requirements
  • Cultured on blood and chocolate agar
  • Differentiated by ability to ferment maltose
• What are the common routes of transmission for Neisseria meningitidis?


  Saliva secretions, respiratory secretions, close contact
• What are the serogroups of Neisseria meningitidis and their significance?


  • 13 serotypes recognized worldwide
  • Determined by polysaccharide capsule
  • Target of meningococcal vaccines
• Which serogroups of Neisseria meningitidis dominate in Europe?


  B, C, Y, W
• What is the impact of vaccination on meningococcal disease?


  • Drastic decrease in cases of MenC with MenACWY vaccine
  • Continued presence of group B
  • Rise in group W since 2009
• What vaccines are routinely offered in Scotland for meningococcal disease?

  MenB and MenACWY
• What is the treatment for meningococcal meningitis?


  Penicillin and third-generation cephalosporins like cefotaxime or ceftriaxone
• What are the complications associated with meningococcal disease?


  • Rapid onset of symptoms
  • Purpuric/petechial rash
  • Septicaemia
  • Risk of coma and death
• What is the leading cause of neonatal invasive disease related to meningitis?

  Group B streptococci (Streptococcus agalactiae)
• How is Group B streptococci transmitted to neonates?


  During or preceding birth from the mother.
• What are the growth requirements for Haemophilus influenzae?


  • Requires factor X (haemin)
  • Requires factor V (NAD)
  • Cannot grow on unsupplemented blood agar
• What is the treatment for Hib meningitis?


  Broad spectrum cephalosporin like ceftriaxone or cefotaxime
• What are the characteristics of Streptococcus pneumoniae?


  • Gram-positive diplococcus
  • Alpha-haemolysis on blood agar
  • Polysaccharide capsule
  • Associated with respiratory tract infections
• What is the efficacy of the Pneumococcal Conjugate Vaccine?


  50-70% efficacy
• What is the carriage rate of Streptococcus pneumoniae in the first two years of life?


  Highest in the first two years, then declines
• What is the role of the polysaccharide capsule in Streptococcus pneumoniae?


  It prevents mechanical removal from phagocytes and masks PAMPs.
• What is the significance of the 23 serotypes in the Pneumococcal Polysaccharide Vaccine?


  It provides protection against all 23 serotypes.
• Why is the Pneumococcal Polysaccharide Vaccine not very effective in children younger than 2?


  Because their immune systems are not fully developed.
• What is the treatment for beta-lactam allergy in meningitis?


  Chloramphenicol
• What are the common sequelae of bacterial meningitis?


  Neurological defects and hearing loss