Meningitis:
- Inflammation of the meninges surrounding the brain & spinal cord
- Peak age: 6-12 mo, 90% <5yr
- Common Organisms
- 0-4wk: GBS, E Coli, Listeria monocytogenes, Klebsiella
- 1-23mo: GBS, E Coli, S. Pneumo, N. Meningitidis, H. Influenzae
- >2yr: S. Pneumo, N. Meningitidis, Listeria Monocytogenes (>50yo + comorbidities)
- Viral: HSV1/2, VZV, enteroviruses, West Nile
- Fungal: Cryptococcus, coccidiides
- Other: Lyme dz, Neurosyphilis, TB
1 In the patient with a non-specific febrile illness, look for meningitis, especially in patients at higher risk (e.g., immuno-compromised individuals, alcoholism, recent neurosurgery, head injury, recent abdominal surgery, neonates, aboriginal groups, students living in residence).
Risk Factors:
- Lack of immunization against S. penumoniae & H. Influenzae type B
- hematogenous spread after invasion from a mucosal surface (nasopharynx)
- Parameningeal focus: Otitis media, infection, sinusitis
- Penetrating head trauma
- Anatomical meningeal defects – CSF leaks
- Prev Neurosurgical procedures, shunts
- Immunocompromise: corticosteroids, DM, prematurity, asplenia, HIV, hypogammaglobulinemia, complement deficiency
- Contact with colonized or infected persons – exposures at day care centres, recent travel, household contact
Clinical Features:
- Classic Triad: fever, neck stiffness, altered mental status (absence doesn’t r/o meningitis)
- No fever, no neck stiffness, normal mental staus = 99% sensitivity
- Neonates / children:
- Hx: Fever or hypothermia, vomiting, lethargy, irritability, poor feeding, diarrhea, respiratory distress, Sz
- PE: Toxic, bulging anterior fontanelle, respiratory distress / apnea, petechial/purpuric rash, jaundice, omphalitis
- Older children / adults:
- Hx: fever, H/A, neck/back pain/stiffness, confusion, n/v, lethargy, photophobia, altered LOC, confusion, Sz,irritability
- PE: Toxic, ↓LOC, nuchal rigidity, Kernig’s / Bruzinski’s, focal neurological signs, papilledema, petechial/purpuric rash
- Meningococcal meningitis: petechial rash on lower extremities
- Signs of Meningismus – BONK
- Brudzinski’s – flexion of neck = involuntary flexion of the knee + hip
- Opisthotonos – rigid spasm of the body w/ the back fully arched & heels / head bent back
- Nuchal rigidity
- Kernig’s = pain with passive extension of a flexed knee
- Jolt accentuation (sen 97% spec 60%) = turn head horizontally at 2-3/sec; + = ↑ h/a
- Neuroexam: papilledema, sz, focal deficit
2 When meningitis is suspected ensure a timely lumbar puncture.
Ix:
- B/W: CBCD, electrolytes (SIADH), blood C & S
- LP: LP w/o CT in pt
- w/o altered LOC,
- no recent Sz, no Hx of CNS dz,
- not immunocompromised,
- <60yr
- CSF: cloudy in bacterial meningitis
- opening pressure
- cell (WBC & RBC) count + differential
- glucose, protei concentration
- gram stain, bacterial C&S
- AFB, fungal C&S, cryptococcal antigen in
- immunocompromised pt,
- subacute illness,
- suggestive travel hx or TB exposure
- PCR for HSV, VZV, EBV, enteroviruses if viral cause suspected
- U/A & U C&S in infants, Gram stain + Cx of petechial / purpuric lesions
- CT, MRI, EEG if focal neurological signs present
3 In the differentiation between viral and bacterial meningitis, adjust the interpretation of the data in light of recent antibiotic use.
CSF profiles
- Bacterial meningitis
- ↓ glucose (<30), ↑↑ protein (>100), WBC 500-10,000/ul – predominant Neutrophils >50%
- Viral Meningitis
- Normal glucose, ↑ protein (50-100), WBC 10-500/ul – predominant Lymphocytes (herpes WBC 10-1000)
4 For suspected bacterial meningitis, initiate urgent empiric IV antibiotic therapy (i.e., even before investigations are complete).
Bacterial meningitis is a medical emergency – don’t delay Abx before CT or LP
- Isolation with appropriate infection control until 24 hr after Cx-sensitive abx therapy
- Fluid restrict if any concern for SIADH
- hearing test after
- Report to public health
Empiric Tx:
- <1mo: ampicillin + cefotaxime ± gentamicin IV
- >1mo: Vancomycin + ceftriaxone IV
- Add ampicillin IV (or TMP-SMX) if risk factors for Listeria monocytogenes present
- >50yo,
- alcoholism,
- immunocompromised
- Add ampicillin IV (or TMP-SMX) if risk factors for Listeria monocytogenes present
- Acyclovir for HSV meningitis
- Dexamethasone IV within 20minpriortoorwithfirst dose of Abx if >6 weeks
- ? benefit on prevention of hearing loss
Prognosis
C/I:
- H/A, Sz, cerebral edema,
- hydrocephalus, SIADH,
- residual neurological deficit (especially CN VIII),
- deafness, death
Mortality:
- S. Pneumoniae 25%, N. Meningitidis 5-10%, H. influenzae 5%
- Worse prognosis if
- extremes of age,
- delays in dx and tx
- stupor or coma, Sz, focal neurological signs, septic shock at presentation
5 Contact public health to ensure appropriate prophylaxis for family, friends and other contacts of each person with meningitis.
Prophylaxis: close or household contacts
- H. Influenzae – Tx with Rifampin if they live with an inadequately immunized or immunocompromised child <4yr
- N. Meningitidis – Ciprofloxacin, rifampin, or ceftriaxone
Prevention – Immunization
- Children: Immunization against H. influenze (Pentacel), S penumoniae (Synflorix, Prevnar-13), N. Meningitidis (Menjugate / Menactra)
- Adult: Immunization against N. Meningitidis in selected circumstances: Outbreaks, travel, epidemics & S. Pneumoniae (pneumovax) for high-risk groups
Public healthy Agency of Canada Indications:
- Pneumococcal polysaccharide vaccine (Pneumovax)
- >65
- <2 with chronic cardio/respiratory/hepatic/renal disorders, asplenia, sickle cell or immunosuppression
- Meningococcal C-conjugate vaccine (Menjugate)
- young adults (not immunized in childhood)
- Asplenia – Quadraveltn vaccine (Menactra / Menomune) preferred
- Travellers to high-risk areas – Quadraveltn vaccine (Menactra / Menomune) preferred
- Military recruits – Quadraveltn vaccine (Menactra / Menomune) preferred
- Complement, factor D, or properdin deficiency- Quadraveltn vaccine (Menactra / Menomune) preferred
Leave a Reply