Meningitis: Difference between revisions

(Add MedicationDose entry (dexamethasone) with SMW annotations)
(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)
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''This page is for <u>adult</u> meningitis. See [[Meningitis (peds)]] for the pediatric page.''
==Background==
==Background==
[[File:Meningitis-Epidemics-World-Map.png|thumb|Epidemic meningitis geographic distribution showing "meningitis belt."]]
*Inflammation of the meninges (membranes surrounding the brain and spinal cord)
===Microbiology===
*'''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:
*'''Time to antibiotics is the most critical intervention''' — every hour of delay increases mortality
**[[Pneumococcus]] (60%), [[meningococcus]] (15%), [[group B streptococcus]] (15%), [[H flu]] (7%), [[listeria]] (2%)
*Viral meningitis
**Echovirus, [[Coxsackie_virus|coxsackies]], enterovirus (85%)
**[[HSV]], [[CMV]], [[Herpes B virus]]


===Pathophysiology===
===Common Organisms by Age===
*Hematogenous spread via respiratory tract
*'''Neonates (<1 month)''': Group B Streptococcus (GBS), ''E. coli'', ''Listeria monocytogenes''
*Contiguous spread ([[otitis media]], [[sinusitis]], [[brain abscess]])
*'''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


===Risk Factors===
===Viral Meningitis===
{{Meningitis risk factors}}
*Most common cause overall; '''enterovirus''' in majority
 
*Generally self-limited; much better prognosis than bacterial
===Classification===
*Acute (<24hr)
**Usually bacterial in origin (25%)
*Subacute (1-7d)
**Viral or bacterial  
*Chronic (>7d)
**Viral, [[TB]], [[syphilis]], [[fungi]], carcinomatous


==Clinical Features==
==Clinical Features==
Almost all adults present with at least 2 of the following:<ref>van de Beek D. et al. Clinical features and prognostic factors in adults with bacterial meningitis. N Engl J Med. 2004 Oct 28. 351(18):1849-59.</ref>
*'''Classic triad''' (headache, fever, neck stiffness): present in '''only ~44% of bacterial meningitis'''
*[[Headache]]
*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>
*[[Fever]]
*'''Headache''' (87%), '''fever''' (77%), '''neck stiffness''' (83%)
*Neck stiffness
*'''Altered mental status''' (ranging from confusion to coma)
*[[Altered Mental Status]]
*'''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


Other nonspecific symptoms include:
==Differential Diagnosis==
*Photophobia
*[[Subarachnoid hemorrhage]]
*[[Vomiting]]  
*[[Encephalitis]]
*Prodromal [[URI]]  
*Brain abscess
*[[Focal neuro|Focal neuro symptoms]] (e.g. [[cranial nerve palsies|CN deficit]])
*[[Subdural hemorrhage]] / epidural abscess
*[[Seizures]]
*[[Stroke]]
*Rash
*Viral meningitis
**Approximately 2/3 of patients with [[meningococcemia]] develop rash.<ref>Sara Bode; Contagious Exanthematous Diseases. ''Quick References 2022''; 10.1542/aap.ppcqr.396150</ref>
*Carcinomatous meningitis
**Can include erythematous, morbilliform, or urticarial macules and papules<ref>Sara Bode; Contagious Exanthematous Diseases. ''Quick References 2022''; 10.1542/aap.ppcqr.396150</ref>
*Drug-induced meningitis (NSAIDs, IVIG, TMP-SMX)
**Most common hallmark is purpuric lesions with jagged edges. <ref>Sara Bode; Contagious Exanthematous Diseases. ''Quick References 2022''; 10.1542/aap.ppcqr.396150</ref>


==Differential Diagnosis==
{{Altered mental status and fever DDX}}
{{Headache DDX}}
{{AMS and fever DDX}}


==Evaluation==
==Evaluation==
===Physical Exam===
===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''':
 
{| class="wikitable"
{| class="wikitable"
|+Clinical Tests for Meningitis
| align="center" style="background:#f0f0f0;"|'''Finding'''
| align="center" style="background:#f0f0f0;"|'''Description'''
| align="center" style="background:#f0f0f0;"|'''Sensitivity'''
| align="center" style="background:#f0f0f0;"|'''Specificity'''
|-
|-
| Nuchal rigidity||
! Parameter !! '''Bacterial''' !! '''Viral''' !! '''TB/Fungal'''
*Rigidity of neck muscles with flexion
|-
||13%<ref name="Nakao">Nakao JH, et al. Jolt accentuation of headache and other clinical signs: poor predictors of meningitis in adults. Am J Emerg Med. 2014;32(1):24-28.</ref>||80% <ref name="Nakao" />
| Opening pressure || '''Elevated (>20 cm H2O)''' || Normal/mild ↑ || Elevated
|-
|-
| Kernig's sign||
| WBC || '''1000-5000+ (PMN predominant)''' || 10-500 (lymphocytes) || 50-500 (lymphocytes)
*With flexed hip at 90°, extension of knee produces pain
||2%<ref name="Nakao" />||97%<ref name="Nakao" />
|-
|-
| Brudzinski's sign||
| Glucose || '''<40 mg/dL (or CSF:serum <0.4)''' || Normal || Low
*Involuntary lifting of legs with passive flexion of the neck
||2%<ref name="Nakao" />||98%<ref name="Nakao" />
|-
|-
| [[EBQ:Jolt Test|Jolt Test]]||
| Protein || '''Elevated (>250 mg/dL)''' || Mild elevation || Elevated
*Horizontal rotation of the head at frequency of 2 rotations/second
|-
*Exacerbation of pre-existing headache is positive test.
| Gram stain || Positive in 60-90% || Negative || Negative (AFB rarely +)
||100%?^||
|}
|}
^Although a 1991 study<ref>Jolt accentuation of headache: the most sensitive sign of CSF pleocytosis. Headache. 1991 Mar;31(3):167-71.</ref> showed high sensitivity with this test, multiple newer studies have cast doubt on its sensitivity.<ref>Absence of jolt accentuation of headache cannot accurately rule out meningitis in adults. Am J Emerg Med. 2013 Nov;31(11):1601-4</ref><ref>Jolt accentuation of headache and other clinical signs: poor predictors of meningitis in adults. Am J Emerg Med. 2014 Jan;32(1):24-8</ref> Although it may be clinically useful in the right subset of patients, it should not be considered to be 100% sensitive.


===Work-Up===
===Labs===
#CBC
*Blood cultures (before antibiotics if possible)
#Chem
*CBC, BMP, lactate, coagulation studies
#Blood culture  
*'''Procalcitonin''' (may help distinguish bacterial from viral; level >0.5 ng/mL supports bacterial)
#?CT head: See [[CT Before Lumbar Puncture]]
*'''CSF studies''': cell count with differential, protein, glucose, Gram stain, culture
#[[CXR]] (50% of patients with pneumoccocal meningitis have evidence of pneumonia on CXR)
*Consider: CSF lactate, HSV PCR, cryptococcal antigen, meningitis/encephalitis PCR panel
#[[Lumbar Puncture]]


===[[Lumbar Puncture]] Diagnosis===
==Management==
{{Lumbar Puncture Diagnosis}}
===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)'''


====Delay in LP====
===Dexamethasone===
*CSF cultures become sterile in '''2 hrs''' after parenteral antibiotics in meningococcal meningitis and '''6 hrs''' in pneumococcal meningitis<ref>Kanegaye JT, Soliemanzadeh P, Bradley JS. Lumbar puncture in pediatric bacterial meningitis: defining the time interval for recovery of cerebrospinal fluid pathogens after parenteral antibotic pretreatment. Pediatrics2001;108:1169–74</ref><ref>Michael B1, Menezes BF, Cunniffe J, Miller A, Kneen R, Francis G, Beeching NJ, Solomon T. Effect of delayed lumbar punctures on the diagnosis of acute bacterial meningitis in adults. Emerg Med J 2010;27:6 433-438. PMID 20360497</ref>
*'''Dexamethasone 0.15 mg/kg IV q6h x 4 days'''
*12 hrs after antibiotics: CSF glucose levels increase and protein levels decrease. CSF WBC and neutrophils are not affected<ref>Lise E. Nigrovic, Richard Malley, Charles G. Macias, John T. Kanegaye, Donna M. Moro-Sutherland, Robert D. Schremmer, Sandra H. Schwab, Dewesh Agrawal, Karim M. Mansour, Jonathan E. Bennett, Yiannis L. Katsogridakis, Michael M. Mohseni, Blake Bulloch, Dale W. Steele, Ron L. Kaplan, Martin I. Herman, Subhankar Bandyopadhyay, Peter Dayan, Uyen T. Truong, Vince J. Wang, Bema K. Bonsu, Jennifer L. Chapman, Nathan Kuppermann. Effect of Antibiotic Pretreatment on Cerebrospinal Fluid Profiles of Children With Bacterial Meningitis. Pediatrics Oct 2008, 122 (4) 726-730. PMID 18829794</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)
*If given >1 hour after antibiotics, benefit is reduced — '''do not withhold antibiotics for dexamethasone'''


==[[Antibiotics]]==
===Viral Meningitis===
*''Give as soon as possible (if [[LP]] performed within 2hr of antibiotics, [[CSF]] culture will not be affected)''
*Supportive care (analgesia, antiemetics, IV fluids)
{{Meningitis Antibiotics}}
*If '''HSV encephalitis''' suspected: '''acyclovir 10 mg/kg IV q8h''' (do NOT wait for confirmation)


 
===Meningococcal Prophylaxis===
If patient has a cephalosporin allergy, you can replace the third generation cephalosporin with Meropenem or chloramphenicol.
*Close contacts of confirmed N. meningitidis require prophylaxis:
 
**'''Rifampin 600 mg PO q12h x 2 days''' OR
==[[EBQ:De_Gans_-_Steroids_for_Bacterial_Meningitis|Steroids]]==
**'''Ciprofloxacin 500 mg PO x 1 dose''' (preferred for adults) OR
*[[Dexamethasone]] in adults
**'''Ceftriaxone 250 mg IM x 1 dose''' (preferred for pregnant women)
**Only give 15 min prior to or with first dose of [[antibiotics]]
*Notify public health
**10mg IV q6hr x4d
*Overall, steroids only decreased mortality in patients with meningitis caused by [[Streptococcus pneumoniae]]<ref>Brouwer MC, McIntyre P, de Gans J, Prasad K, van de Beek D. Corticosteroids for Acute Bacterial Meningitis. Cochrane Database of Systematic Reviews 2010, Issue 9.</ref>
*Steroids did decrease rates of any hearing loss, severe hearing loss, and any neurological sequelae in meningitis caused by all species
**This benefit was present in high-income countries but not in low-income countries
*[[Dexamethasone]] in children and infants
**There has been no mortality benefit found with steroid use in children<ref>Mongelluzzo J, Mohamad Z, Ten Have TR, et al. Corticosteroids and mortality in children with bacterial meningitis. JAMA. 2008. 299(17):2048-2055.</ref>
**Steroids decreased the rate of hearing loss in children with meningitis caused by [[Haemophilus influenzae]]<ref>Brouwer MC, McIntyre P, de Gans J, Prasad K, van de Beek D. Corticosteroids for Acute Bacterial Meningitis. Cochrane Database of Systematic Reviews 2010, Issue 9.</ref>
*[[Hydrocortisone]] for [[adrenal insufficiency|adrenal failure]] (Waterhouse–Friderichsen syndrome, bilateral adrenal hemorrhage causing adrenal failure, seen in meningococcemia)
 
==Antivirals==
*[[Acyclovir]]
**Consider for patients with suspected viral meningitis who present with neurologic deficits
**10mg/kg IV q8hr (Obese patients should be dosed using [[ideal body weight estimation|ideal body weight]])
 
==Other Considerations==
*Inpatient team may consider MRI with MRV for further diagnostic considerations
*If there is concern for tick-borne illness, it may be prudent to add [[doxycycline]] before ID consult can occur
 
==Prophylaxis==
{{Neisseria meningitis post exposure prophylaxis}}
 
 
==Medication Dosing==
{{MedicationDose
| drug = Dexamethasone
| dose = 10mg q6hr x 4 days
| route = IV
| context = Give 15 min prior to or with first dose of antibiotics
| indication = Meningitis
| population = Adult
| notes = Mortality benefit limited to S. pneumoniae meningitis; decreases hearing loss in all species
}}


==Disposition==
==Disposition==
===Bacterial meningitis===
*'''Admit all patients with suspected bacterial meningitis''' to ICU or monitored bed
*Admit with [[droplet precautions]]
*Viral meningitis: may discharge if well-appearing, tolerating PO, reliable follow-up
 
*'''Repeat LP''' not routinely needed if clinically improving
===Viral meningitis===
*Admit for empiric [[antibiotics]] until culture results return '''OR'''
*Discharge with 24hr follow up


==See Also==
==See Also==
*[[Encephalitis]]
*[[Subarachnoid hemorrhage]]
*[[Lumbar puncture]]
*[[Meningitis (peds)]]
*[[Meningitis (peds)]]
*[[Neoplastic meningitis]]
*[[Brain abscess]]
*[[Sepsis]]


==References==
==References==
<references/>
<references/>
*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


[[Category:ID]]
[[Category:Infectious Disease]]
[[Category:Neurology]]
[[Category:Neurology]]
[[Category:Critical Care]]

Revision as of 19:52, 21 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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