Meningitis: Difference between revisions

(Major update: CSF interpretation table, empiric antibiotics by age, dexamethasone timing (before/with abx), CT before LP indications, jolt accentuation, meningococcal prophylaxis, references with PMIDs)
(Strip excess bold)
 
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*Inflammation of the meninges (membranes surrounding the brain and spinal cord)
*Inflammation of the meninges (membranes surrounding the brain and spinal cord)
*'''Bacterial meningitis is a medical emergency''' — mortality 15-25% even with treatment; up to 50% untreated<ref>van de Beek D, et al. Community-acquired bacterial meningitis. ''Nat Rev Dis Primers''. 2016;2:16074. PMID 27808261</ref>
*'''Bacterial meningitis is a medical emergency''' — mortality 15-25% even with treatment; up to 50% untreated<ref>van de Beek D, et al. Community-acquired bacterial meningitis. ''Nat Rev Dis Primers''. 2016;2:16074. PMID 27808261</ref>
*'''Time to antibiotics is the most critical intervention''' — every hour of delay increases mortality
*Time to antibiotics is the most critical intervention — every hour of delay increases mortality


===Common Organisms by Age===
===Common Organisms by Age===
*'''Neonates (<1 month)''': Group B Streptococcus (GBS), ''E. coli'', ''Listeria monocytogenes''
*Neonates (<1 month): Group B Streptococcus (GBS), ''E. coli'', ''Listeria monocytogenes''
*'''Infants/Children (1 month - 18 years)''': ''Neisseria meningitidis'', ''Streptococcus pneumoniae'', ''Haemophilus influenzae'' type b (less common post-vaccination)
*Infants/Children (1 month - 18 years): ''Neisseria meningitidis'', ''Streptococcus pneumoniae'', ''Haemophilus influenzae'' type b (less common post-vaccination)
*'''Adults (18-50)''': '''S. pneumoniae''' (most common), '''N. meningitidis'''
*Adults (18-50): S. pneumoniae (most common), N. meningitidis
*'''Adults >50, immunocompromised, alcoholics''': S. pneumoniae, '''Listeria''', gram-negative bacilli
*Adults >50, immunocompromised, alcoholics: S. pneumoniae, Listeria, gram-negative bacilli
*'''Post-neurosurgical/VP shunt''': ''Staphylococcus'' species, gram-negative bacilli
*Post-neurosurgical/VP shunt: ''Staphylococcus'' species, gram-negative bacilli


===Viral Meningitis===
===Viral Meningitis===
*Most common cause overall; '''enterovirus''' in majority
*Most common cause overall; enterovirus in majority
*Generally self-limited; much better prognosis than bacterial
*Generally self-limited; much better prognosis than bacterial


==Clinical Features==
==Clinical Features==
*'''Classic triad''' (headache, fever, neck stiffness): present in '''only ~44% of bacterial meningitis'''
*Classic triad (headache, fever, neck stiffness): present in only ~44% of bacterial meningitis
*At least '''2 of 4''' (headache, fever, neck stiffness, AMS) present in '''95%'''<ref>van de Beek D, et al. Clinical features and prognostic factors in adults with bacterial meningitis. ''N Engl J Med''. 2004;351(18):1849-1859. PMID 15509818</ref>
*At least 2 of 4 (headache, fever, neck stiffness, AMS) present in 95%<ref>van de Beek D, et al. Clinical features and prognostic factors in adults with bacterial meningitis. ''N Engl J Med''. 2004;351(18):1849-1859. PMID 15509818</ref>
*'''Headache''' (87%), '''fever''' (77%), '''neck stiffness''' (83%)
*Headache (87%), fever (77%), neck stiffness (83%)
*'''Altered mental status''' (ranging from confusion to coma)
*'''Altered mental status''' (ranging from confusion to coma)
*'''Photophobia'''
*Photophobia
*'''Kernig sign''': pain with knee extension when hip is flexed (sensitivity ~5%)
*Kernig sign: pain with knee extension when hip is flexed (sensitivity ~5%)
*'''Brudzinski sign''': involuntary hip flexion with passive neck flexion (sensitivity ~5%)
*Brudzinski sign: involuntary hip flexion with passive neck flexion (sensitivity ~5%)
*'''Jolt accentuation''': worsening headache with horizontal head rotation (better sensitivity than Kernig/Brudzinski)
*Jolt accentuation: worsening headache with horizontal head rotation (better sensitivity than Kernig/Brudzinski)
*'''Petechial/purpuric rash''': highly suggestive of '''N. meningitidis''' (meningococcemia)
*Petechial/purpuric rash: highly suggestive of N. meningitidis (meningococcemia)
*Neonates: irritability, poor feeding, bulging fontanelle, hypothermia or fever
*Neonates: irritability, poor feeding, bulging fontanelle, hypothermia or fever
*Elderly: may present with '''only confusion''' without classic features
*Elderly: may present with only confusion without classic features


==Differential Diagnosis==
==Differential Diagnosis==
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==Evaluation==
==Evaluation==
===DO NOT DELAY ANTIBIOTICS FOR LP===
===DO NOT DELAY ANTIBIOTICS FOR LP===
*If '''LP will be delayed''' (CT needed, patient unstable): '''give antibiotics FIRST, then CT, then LP'''
*If LP will be delayed (CT needed, patient unstable): give antibiotics FIRST, then CT, then LP
*Blood cultures should be drawn before antibiotics when possible (do not delay abx for cultures)
*Blood cultures should be drawn before antibiotics when possible (do not delay abx for cultures)


===Lumbar Puncture===
===Lumbar Puncture===
*'''CT BEFORE LP''' only if:
*CT BEFORE LP only if:
**Immunocompromised, history of CNS disease
**Immunocompromised, history of CNS disease
**New-onset [[seizures]]
**New-onset [[seizures]]
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**Focal neurologic deficits
**Focal neurologic deficits
**Altered level of consciousness (GCS <10-12)
**Altered level of consciousness (GCS <10-12)
*'''CSF findings''':
*CSF findings:


{| class="wikitable"
{| class="wikitable"
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*Blood cultures (before antibiotics if possible)
*Blood cultures (before antibiotics if possible)
*CBC, BMP, lactate, coagulation studies
*CBC, BMP, lactate, coagulation studies
*'''Procalcitonin''' (may help distinguish bacterial from viral; level >0.5 ng/mL supports bacterial)
*Procalcitonin (may help distinguish bacterial from viral; level >0.5 ng/mL supports bacterial)
*'''CSF studies''': cell count with differential, protein, glucose, Gram stain, culture
*CSF studies: cell count with differential, protein, glucose, Gram stain, culture
*Consider: CSF lactate, HSV PCR, cryptococcal antigen, meningitis/encephalitis PCR panel
*Consider: CSF lactate, HSV PCR, cryptococcal antigen, meningitis/encephalitis PCR panel


==Management==
==Management==
===Empiric Antibiotics (Give IMMEDIATELY if Suspected)===
===Empiric Antibiotics (Give IMMEDIATELY if Suspected)===
*'''Adults <50 years''':
*Adults <50 years:
**'''Ceftriaxone 2g IV q12h + vancomycin 15-20 mg/kg IV q8-12h'''
**Ceftriaxone 2g IV q12h + vancomycin 15-20 mg/kg IV q8-12h
*'''Adults >50 years, immunocompromised, or alcoholics''':
*Adults >50 years, immunocompromised, or alcoholics:
**'''Ceftriaxone 2g IV q12h + vancomycin 15-20 mg/kg IV q8-12h + ampicillin 2g IV q4h''' (Listeria coverage)
**Ceftriaxone 2g IV q12h + vancomycin 15-20 mg/kg IV q8-12h + ampicillin 2g IV q4h (Listeria coverage)
*'''Neonates''':
*Neonates:
**'''Ampicillin + gentamicin''' (or ampicillin + cefotaxime)
**Ampicillin + gentamicin (or ampicillin + cefotaxime)
*'''Post-neurosurgical/VP shunt''':
*Post-neurosurgical/VP shunt:
**'''Vancomycin + cefepime (or meropenem)'''
**Vancomycin + cefepime (or meropenem)


===Dexamethasone===
===Dexamethasone===
*'''Dexamethasone 0.15 mg/kg IV q6h x 4 days'''
*Dexamethasone 0.15 mg/kg IV q6h x 4 days
*'''Give with or just before FIRST dose of antibiotics'''<ref>de Gans J, van de Beek D. Dexamethasone in adults with bacterial meningitis. ''N Engl J Med''. 2002;347(20):1549-1556. PMID 12432041</ref>
*Give with or just before FIRST dose of antibiotics<ref>de Gans J, van de Beek D. Dexamethasone in adults with bacterial meningitis. ''N Engl J Med''. 2002;347(20):1549-1556. PMID 12432041</ref>
*'''Greatest benefit in pneumococcal meningitis''' (reduced mortality and hearing loss)
*Greatest benefit in pneumococcal meningitis (reduced mortality and hearing loss)
*If given >1 hour after antibiotics, benefit is reduced — '''do not withhold antibiotics for dexamethasone'''
*If given >1 hour after antibiotics, benefit is reduced — '''do not withhold antibiotics for dexamethasone'''


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===Meningococcal Prophylaxis===
===Meningococcal Prophylaxis===
*Close contacts of confirmed N. meningitidis require prophylaxis:
*Close contacts of confirmed N. meningitidis require prophylaxis:
**'''Rifampin 600 mg PO q12h x 2 days''' OR
**Rifampin 600 mg PO q12h x 2 days OR
**'''Ciprofloxacin 500 mg PO x 1 dose''' (preferred for adults) OR
**Ciprofloxacin 500 mg PO x 1 dose (preferred for adults) OR
**'''Ceftriaxone 250 mg IM x 1 dose''' (preferred for pregnant women)
**Ceftriaxone 250 mg IM x 1 dose (preferred for pregnant women)
*Notify public health
*Notify public health


==Disposition==
==Disposition==
*'''Admit all patients with suspected bacterial meningitis''' to ICU or monitored bed
*Admit all patients with suspected bacterial meningitis to ICU or monitored bed
*Viral meningitis: may discharge if well-appearing, tolerating PO, reliable follow-up
*Viral meningitis: may discharge if well-appearing, tolerating PO, reliable follow-up
*'''Repeat LP''' not routinely needed if clinically improving
*Repeat LP not routinely needed if clinically improving


==See Also==
==See Also==

Latest revision as of 09:26, 22 March 2026

Background

  • Inflammation of the meninges (membranes surrounding the brain and spinal cord)
  • Bacterial meningitis is a medical emergency — mortality 15-25% even with treatment; up to 50% untreated[1]
  • Time to antibiotics is the most critical intervention — every hour of delay increases mortality

Common Organisms by Age

  • Neonates (<1 month): Group B Streptococcus (GBS), E. coli, Listeria monocytogenes
  • Infants/Children (1 month - 18 years): Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae type b (less common post-vaccination)
  • Adults (18-50): S. pneumoniae (most common), N. meningitidis
  • Adults >50, immunocompromised, alcoholics: S. pneumoniae, Listeria, gram-negative bacilli
  • Post-neurosurgical/VP shunt: Staphylococcus species, gram-negative bacilli

Viral Meningitis

  • Most common cause overall; enterovirus in majority
  • Generally self-limited; much better prognosis than bacterial

Clinical Features

  • Classic triad (headache, fever, neck stiffness): present in only ~44% of bacterial meningitis
  • At least 2 of 4 (headache, fever, neck stiffness, AMS) present in 95%[2]
  • Headache (87%), fever (77%), neck stiffness (83%)
  • Altered mental status (ranging from confusion to coma)
  • Photophobia
  • Kernig sign: pain with knee extension when hip is flexed (sensitivity ~5%)
  • Brudzinski sign: involuntary hip flexion with passive neck flexion (sensitivity ~5%)
  • Jolt accentuation: worsening headache with horizontal head rotation (better sensitivity than Kernig/Brudzinski)
  • Petechial/purpuric rash: highly suggestive of N. meningitidis (meningococcemia)
  • Neonates: irritability, poor feeding, bulging fontanelle, hypothermia or fever
  • Elderly: may present with only confusion without classic features

Differential Diagnosis

Template:Altered mental status and fever DDX

Evaluation

DO NOT DELAY ANTIBIOTICS FOR LP

  • If LP will be delayed (CT needed, patient unstable): give antibiotics FIRST, then CT, then LP
  • Blood cultures should be drawn before antibiotics when possible (do not delay abx for cultures)

Lumbar Puncture

  • CT BEFORE LP only if:
    • Immunocompromised, history of CNS disease
    • New-onset seizures
    • Papilledema
    • Focal neurologic deficits
    • Altered level of consciousness (GCS <10-12)
  • CSF findings:
Parameter Bacterial Viral TB/Fungal
Opening pressure Elevated (>20 cm H2O) Normal/mild ↑ Elevated
WBC 1000-5000+ (PMN predominant) 10-500 (lymphocytes) 50-500 (lymphocytes)
Glucose <40 mg/dL (or CSF:serum <0.4) Normal Low
Protein Elevated (>250 mg/dL) Mild elevation Elevated
Gram stain Positive in 60-90% Negative Negative (AFB rarely +)

Labs

  • Blood cultures (before antibiotics if possible)
  • CBC, BMP, lactate, coagulation studies
  • Procalcitonin (may help distinguish bacterial from viral; level >0.5 ng/mL supports bacterial)
  • CSF studies: cell count with differential, protein, glucose, Gram stain, culture
  • Consider: CSF lactate, HSV PCR, cryptococcal antigen, meningitis/encephalitis PCR panel

Management

Empiric Antibiotics (Give IMMEDIATELY if Suspected)

  • Adults <50 years:
    • Ceftriaxone 2g IV q12h + vancomycin 15-20 mg/kg IV q8-12h
  • Adults >50 years, immunocompromised, or alcoholics:
    • Ceftriaxone 2g IV q12h + vancomycin 15-20 mg/kg IV q8-12h + ampicillin 2g IV q4h (Listeria coverage)
  • Neonates:
    • Ampicillin + gentamicin (or ampicillin + cefotaxime)
  • Post-neurosurgical/VP shunt:
    • Vancomycin + cefepime (or meropenem)

Dexamethasone

  • Dexamethasone 0.15 mg/kg IV q6h x 4 days
  • Give with or just before FIRST dose of antibiotics[3]
  • Greatest benefit in pneumococcal meningitis (reduced mortality and hearing loss)
  • If given >1 hour after antibiotics, benefit is reduced — do not withhold antibiotics for dexamethasone

Viral Meningitis

  • Supportive care (analgesia, antiemetics, IV fluids)
  • If HSV encephalitis suspected: acyclovir 10 mg/kg IV q8h (do NOT wait for confirmation)

Meningococcal Prophylaxis

  • Close contacts of confirmed N. meningitidis require prophylaxis:
    • Rifampin 600 mg PO q12h x 2 days OR
    • Ciprofloxacin 500 mg PO x 1 dose (preferred for adults) OR
    • Ceftriaxone 250 mg IM x 1 dose (preferred for pregnant women)
  • Notify public health

Disposition

  • Admit all patients with suspected bacterial meningitis to ICU or monitored bed
  • Viral meningitis: may discharge if well-appearing, tolerating PO, reliable follow-up
  • Repeat LP not routinely needed if clinically improving

See Also

References

  1. ↑ van de Beek D, et al. Community-acquired bacterial meningitis. Nat Rev Dis Primers. 2016;2:16074. PMID 27808261
  2. ↑ van de Beek D, et al. Clinical features and prognostic factors in adults with bacterial meningitis. N Engl J Med. 2004;351(18):1849-1859. PMID 15509818
  3. ↑ de Gans J, van de Beek D. Dexamethasone in adults with bacterial meningitis. N Engl J Med. 2002;347(20):1549-1556. PMID 12432041
  • Tunkel AR, et al. Practice guidelines for the management of bacterial meningitis. Clin Infect Dis. 2004;39(9):1267-1284. PMID 15494903
  • Brouwer MC, et al. Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis. Clin Microbiol Rev. 2010;23(3):467-492. PMID 20610819
  • McGill F, et al. Acute bacterial meningitis in adults. Lancet. 2016;388(10063):3036-3047. PMID 27265346
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