Bacterial Meningitis

Epidemiology

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Risk Factors for Meningitis

Absence of Opsonizing Antibody
- Predisposed Organisms
  - Haemophilus Influenzae (see Haemophilus Influenzae): common in very young children
  - Streptococcus Pneumoniae (Pneumococcus) (see Streptococcus Pneumoniae): common in all age groups
Asplenia (see Asplenia)
- Predisposed Organisms
  - Neisseria Meningitidis (see Neisseria Meningitidis)
  - Streptococcus Pneumoniae (Pneumococcus) (see Streptococcus Pneumoniae)
Basilar Skull Fracture
- Predisposed Organisms
  - Streptococcus Pneumoniae (Pneumococcus) (see Streptococcus Pneumoniae)
  - Other Upper Respiratory Tract Flora
Cerebrospinal Fluid Leak
Complement Deficiency
- Predisposed Organisms
  - Neisseria Meningitidis (see Neisseria Meningitidis)
Corticosteroids (see Corticosteroids)
- Predisposed Organisms
  - Cryptococcosis (see Cryptococcosis)
  - Listeriosis (see Listeriosis)
Diabetes Mellitus (DM) (see Diabetes Mellitus)
Ethanol Abuse (see Ethanol, [[Ethanol]])
Head Trauma/Traumatic Brain Injury (TBI) (see Traumatic Brain Injury)
Hypogammaglobulinemia
Human Immunodeficiency Virus (HIV) (see Human Immunodeficiency Virus)
- Predisposed Organisms
  - Cryptococcosis (see Cryptococcosis): approximately 5% of HIV patients ultimately get cryptococcosis
  - Listeriosis (see Listeriosis)
  - Streptococcus Pneumoniae (Pneumococcus) (see Streptococcus Pneumoniae)
Infective Endocarditis (see Endocarditis)
- Predisposed Organisms
  - Gram-Negative Rods
  - Staphylococcus Aureus (see Staphylococcus Aureus)
Intravenous Drug Abuse (IVDA) (see Intravenous Drug Abuse)
Travel to Regions with Endemic Meningococcal Disease (Sub-Saharan Africa, etc)

Etiology

Bacterial Meningitis

Ehrlichiosis (see Ehrlichiosis)
Gram-Negative Rods
- Predisposing Conditions
  - Advanced Medical Illness
  - Disseminated Strongyloidiasis (see Strongyloidiasis)
  - External Ventricular Drain (EVD) (see External Ventricular Drain)
  - Neurosurgery
- Predisposed Age Groups
  - Neonates
  - Older Adults
- Capnocytophaga Canimorsus (see Capnocytophaga Canimorsus): fastidious Gram-negative rod
  - Epidemiology: cases of meningitis have been reported
  - Risk Factors
    - Asplenia (see Asplenia)
    - Dog Bite (see Dog Bite)
- Citrobacter (see Citrobacter): neonatal cases have been reported
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Haemophilus Influenzae (see Haemophilus Influenzae)
- Predisposing Conditions
  - Impaired Humoral Immunity
- Predisposed Age Groups
  - Adults
  - Unvaccinated Infants/Children
- Site of Entry
  - Contiguous Spread from Focus of Infection
  - Nasopharynx
Inhalational Anthrax (see Bacillus Anthracis)
- Clinical: hemorrhagic meningitis
Leptospirosis (see Leptospirosis)
- Epidemiology: aseptic meningitis occurs in 50-85% of Leptospirosis cases if cerebrospinal fluid is examined after 7 days of illness
Listeriosis (see Listeriosis)
- Predisposing Conditions
  - Defects in Cell-Mediated Immunity (Corticosteroids, Transplant)
  - Ethanol Abuse (see Ethanol)
  - Liver Disease (see Cirrhosis)
  - Malignancy
  - Pregnancy (see Pregnancy)
- Predisposed Age Groups
  - Neonate
  - Older Adult
- Site of Entry
  - Gastrointestinal Tract
  - Placenta
Lyme Disease (see Lyme Disease)
Neisseria Meningitidis (see Neisseria Meningitidis)
- Predisposing Conditions
  - Complement Deficiency: however, not present in most cases
- Predisposed Age Groups
  - All Ages
- Site of Entry: nasopharynx
Propionibacterium Acnes (see Propionibacterium Acnes)
- Predisposing Conditions
  - Neurosurgery
Pseudomonas Aeruginosa (see Pseudomonas Aeruginosa)
- Predisposing Conditions
  - Neurosurgery
Rocky Mountain Spotted Fever (see Rocky Mountain Spotted Fever)
Staphylococcus Aureus (see Staphylococcus Aureus)
- Predisposing Conditions
  - Cellulitis (see Cellulitis)
  - Decubitus Ulcer (see Decubitus Ulcer)
  - External Ventricular Drain (EVD) (see External Ventricular Drain)
  - Foreign Body
  - Infective Endocarditis (see Endocarditis)
  - Neurosurgery
- Predisposed Age Groups
  - All Ages
- Site of Entry
  - Bacteremia
  - Foreign Body
  - Skin
Staphylococcus Epidermidis (see Staphylococcus Epidermidis)
- Predisposing Conditions
  - External Ventricular Drain (EVD) (see External Ventricular Drain)
  - Foreign Body
  - Neurosurgery
- Predisposed Age Groups
  - All Ages
- Site of Entry
  - Foreign Body
Streptococcus Pneumoniae (Pneumococcus) (see Streptococcus Pneumoniae)
- Predisposing Conditions
  - Asplenia (see Asplenia)
  - Basilar Skull Fracture
  - Cerebrospinal Fluid Leak
  - Cochlear Implant
  - Ear Ossicle Defect (Mondini Defect)
  - Fracture of Cribriform Plate
  - Pneumococcal Bacteremia
- Predisposed Age Groups
  - All Ages
- Sites of Entry
  - Bacteremia From Distant Focus of Infection
  - Direct Extension From Skull Fracture or Contiguous Focus of Infection
  - Nasopharynx
Syphilis (see Syphilis)
Tuberculosis (see Tuberculosis)
- Epidemiology
  - XXXX

Physiology

Mechanisms of Meningeal Infection

Colonization of Nasopharynx with Subsequent Bloodstream Invasion, Leading to Central Nervous System Invasion
Extension from Adjacent Structures
- Acute Bacterial Rhinosinusitis (see Acute Rhinosinusitis)
- Cerebrospinal Fluid Leak
- Cochlear Implant with Positioner
- External Ventricular Drain (EVD) (see External Ventricular Drain)
- Intracranial Epidural Abscess (see Intracranial Epidural Abscess)
- Intracranial Subdural Abscess
- Mastoiditis (see Mastoiditis)
- Neurosurgery
- Otitis (see xxxx)
- Trauma
- Ventriculoperitoneal Shunt (VP Shunt) (see Ventriculoperitoneal Shunt)
Hematogenous Seeding
- Infective Endocarditis (see Endocarditis)

Diagnosis

Head CT (see Head Computed Tomography)

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Brain MRI (see Brain Magnetic Resonance Imaging)

Lumbar Puncture (LP) (see Lumbar Puncture)

Viral Meningitis

Bacterial Meningitis

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Clinical Manifestations

Neurologic Manifestations

Altered Mental Status (see Altered Mental Status)
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Headache (see Headache)
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Hydrocephalus (see Hydrocephalus)
- Epidemiology
  - May Occur in Bacterial Meningitis

Other Manifestations

Fever (see Fever)
- Epidemiology
  - In Patients with Patients with Ischemic CVA/TBI, Fever (with Peak Temperature Below 37 Degrees C or Above 39 Degrees C) Increased In-Hospital Mortality, as Compared to Normothermia (Intensive Care Med, 2015) [MEDLINE]
    - However, for Patients with Central Nervous System Infection, Elevated Peak Temperature was Not Associated with Increased Mortality, as Compared to Normothermia (37-37.4 Degrees C) (Intensive Care Med, 2015) [MEDLINE]

Treatment

Corticosteroids (see Corticosteroids)

Corticosteroid Treatment in Pneumococcal Meningitis (see Meningitis)

Clinical Efficacy
- Systematic Review of Corticosteroids in Acute Bacterial Meningitis (Cochrane Database Syst Rev, 2015) [MEDLINE]
  - Corticosteroids Decreased the Risk of Hearing Loss and Neurological Sequelae in High-Income Countries, But Did Not Impact the Mortality Rate
  - Corticosteroids Decreased the Meningitis Mortality Rate in Patients with Pneumococcal Meningitis, But Not in Meningitis Due to Neisseria Meningitidis or Haemophilus Influenzae
Recommendations (2004 Infectious Disease Society of America, IDSA Guidelines) (Clin Infect Dis, 2004) [MEDLINE]
- Dexamethasone is Recommended in All Patients with Suspected or Proven Pneumococcal Meningitis, Regardless of the Glasgow Coma Scale Score

References

Clinical

Early temperature and mortality in critically ill patients with acute neurological diseases: trauma and stroke differ from infection. Intensive Care Med. 2015 May;41(5):823-32. doi: 10.1007/s00134-015-3676-6. Epub 2015 Feb 3 [MEDLINE]