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
- Kernig's & Brudzinski's signs - reported to be highly specific but low sensitivity. Absence of these signs should NOT exclude entertaining meningitis as Dx
- Head jolt test variously considered more sensitive
- seizures occur significantly more often in patients with pneumococcal meningitis than in meningococcal infection and are associated with increased mortality
Mollaret meningitis
- 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
References include:
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/
NICE meningitis
https://rarediseases.info.nih.gov/diseases/10868/mollaret-meningitis
CLin Inf Dis. Recurrent benign lymphocytic meningitis