02 Meningitis

• Blood-Brain Barrier - Filtering mechanism of the capillaries that carry blood to the brain and spinal cord tissue, blocking the passage of certain substances.
• Membrane - It is a layer of tissue or cells that provides a barrier and lining.
• Meningitis - Inflammation of the meninges of the brain and spinal cord.
• Meninges - Three layers of membranes that cover and protect your brain and spinal cord
• Otitis media - Infection of the middle ear, causing inflammation (redness and swelling) and a build-up of fluid behind the eardrum.
• Purpuric rash - Occurs when small blood vessels burst, causing blood to pool under the skin.
• Sequelae - It is a serious long-term complication of Meningitis.
• Meningitis is a CNS infection that affects the meninges which are protective membranes that surround the brain and spinal cord.
• The word meningitis comes

  from two Greek words meninx which means

  “membrane” and -itis meaning “inflammation”.
• Viral meningitis [type of meningitis] is the most common type and usually mild and resolves on its own.
• However, bacterial meningitis is less

  common but more serious compared to viral infection.
• Meningitis can also affect the three layers of the

  meninges which is the dura mater, arachnoid mater,

  and pia mater.
• Dura mater is the outermost layer and it

  is tough.
• Arachnoid layer is the middle layer while pia mater is the innermost layer which is closest to the brain and spinal cord.
• Viral meningitis is the most common type of meningitis
• There are 4 main sources of Meningitis Neisseria meningitidis (meningococcus) ○ Streptococcus pneumoniae (pneumococcus) ○ Haemophilus influenzae ○ Streptococcus agalactiae (group B streptococcus)
• There are 4 main sources of Meningitis

  • Neisseria meningitidis (meningococcus) ○ Streptococcus pneumoniae (pneumococcus) ○ Haemophilus influenzae ○ Streptococcus agalactiae (group B streptococcus)
• There are 4 main sources of Meningitis

  • Neisseria meningitidis (meningococcus)
  • Streptococcus pneumoniae (pneumococcus)
  • Haemophilus influenzae
  • Streptococcus agalactiae (group B streptococcus)
• Kernig’s sign - it is assessed by having the patient lie flat on their back, then a leg is raised with the knee flexed to a 90-degree angle.
• Brudzinski’s sign - performed with the individual lying flat on their back, it is checked by flexing the patient’s neck.
• Classic triad of symptoms of meningitis:

  1. Fever
  2. Nuchal rigidity (neck stiffness)
  3. Altered mental status
• 3 major pathways in which the infectious agent:

  1. Invasion of the bloodstream (ie, bacteremia, viremia, fungemia, or parasitemia) and subsequent hematogenous seeding of the CNS – known as the most common mode of spread for most agents
  2. A retrograde neuronal (eg, olfactory and peripheral nerves) pathway (eg, Naegleria fowleri or Gnathostoma spinigerum)
  3. Direct contiguous spread (eg, sinusitis, otitis media, congenital malformations, trauma, or direct inoculation during intracranial manipulation)
• Lumbar puncture - also known as spinal tap.
• Lumbar puncture - process used to collect cerebrospinal fluid
• CSF culture - The gold standard for diagnosis of bacterial meningitis
• Polymerase chain reaction - Particularly used for patients who have received antimicrobial therapy before lumbar puncture or have negative cultures.
• Blood culture - Should be collected before the first dose of antibiotics.
• Penicillin - drug of choice for Neisseria meningitidis
• NICE meaning - National Institute for Health and Care Excellence
• Dexamethasone - used if the CSF fluid appears purulent or cloudy
• What antimicrobials are available for empiric treatment of menigitis?

  Ceftriaxone & Vancomycin
• Cranial imaging via MRI - test that clearly identifies areas of

  cerebral edema.
• Bacterial meningitis - This is a more serious type of meningitis that can be life-threatening.
• Fungal meningitis - This is a rare type of meningitis that is usually caused by inhaling fungal spores
• Children under the age of five have the highest risk of developing meningitis, especially bacterial meningitis, according to the Centers for Disease Control and Prevention (2022).
• Streptococcus pneumoniae - remains the most common pathogen responsible for bacterial meningitis.
• CSF lactate measurement - may be useful in differentiating between bacterial and other types of meningitis
• C-reactive protein - reactant used in the diagnosis and in monitoring the course increases in most microbial infections, making it a reliable and sensitive marker for infection.
• Dexamethasone - attenuates the inflammatory response and the products of neutrophil activation (deterimental effects of host defenses), improving the outcome of treatment
• Acyclovir - should be the choice for suspected or proven HSV or VZV infections.