=====Meningitis=====
  *adults - Bacterial meningitis in the Western world is most often caused by S pneumoniae
  *children - infection with Neisseria meningitidis is more common
  ***classic triad** of fever, nuchal rigidity, and altered mental status in adults
  *The sensitivity of the classic triad in adults presenting with community-acquired acute bacterial meningitis is low, and absence of specific clinical signs is not unusual. Neonates often not febrile
  *<anno:10>Kernig's</anno><@anno:[10;;anno_deep]>flexing the hip and extending the knee to elicit pain in the back and the legs</@anno> & <anno:11>Brudzinski's</anno><@anno:[11;;anno_deep]>passive flexion of the neck elicits flexion of the hips</@anno> signs - reported to be highly specific but low sensitivity. Absence of these signs should NOT exclude entertaining meningitis as Dx
  *<anno:12>Head jolt test</anno><@anno:[12;;anno_deep]>considered positive if headache accentuated by horizontal rotation of head at frequency of 2-3x per sec</@anno> variously considered more sensitive
  *seizures occur significantly more often in patients with pneumococcal meningitis than in meningococcal infection and are associated with increased mortality

<wrap em>Mollaret meningitis</wrap>
  *due to a viral infection (aseptic meningitis) that occurs multiple times. Most often herpes simplex, HSV-2 but occasionally HSV-1
  *known by many other names including Recurrent benign lymphocytic meningitis (RBLM), aseptic meningitis etc
  *characterized by repeated episodes of meningitis, typically lasting 2-5/7, occurring weeks to years apart.
  *spontaneous full recovery usually after 5/7
  *neurological signs - not unlike migraine presentation
  *Almost 1/2 develop long-term CNS impairment eg. memory, balance, coordination, and/or hearing.


===CT scan before LP if:===
  *Altered mental status
  *New onset seizures
  *Immunocompromised
  *Focal neurology
  *Papilloedema
  *Hx of CNS disease - mass, infection, stroke)
  *//**CT is unreliable for identifying raised intracranial pressure**//

===CSF findings===

^CSF findings ^Bacterial ^Viral ^Fungal |
^opening Press ^↑ |N |↑ |
^WCC |1k-10k |<300 |<500 |
^Neutrophils |>80% |1-50% |1-50% |
^Glu ^↓ |N |↓ |
^Protein ^↑ |N |↑ |
^g stain |bacteria |- |- |

===Treatment===
  *IV ceftriaxone.
  *children <3/12 IV cefotaxime + amoxycillin or ampicillin
  *consider herpes simplex encephalitis, consider other unusual pathogens eg Listeria, TB
  *IV dexamethasone
  *PCR should be taken for bacterial and viral studies
{{ :wiki:neurology:cuh_meningitis.png?400|}}
==References include:==
[[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5562335/|Pitfalls in Dx and Mx of pneumococcal meningoencephalitis -  case review]]\\ 
https://www.saem.org/cdem/education/online-education/m4-curriculum/group-m4-neurology/meningitis-encephalitis\\
https://litfl.com/bacterial-meningitis/\\ 
http://www.emdocs.net/meningitis-clinical-pearls-pitfalls/\\ 
[[https://www.nice.org.uk/guidance/CG102/chapter/1-Guidance#bacterial-meningitis-and-meningococcal-septicaemia-in-children-and-young-people-symptoms-signs|NICE meningitis]]\\ 
https://rarediseases.info.nih.gov/diseases/10868/mollaret-meningitis\\ 
[[https://academic.oup.com/cid/article/43/9/1194/425988|CLin Inf Dis. Recurrent benign lymphocytic meningitis]]\\