For an overview of meningitis, see Overview of Meningitis Overview of Meningitis Meningitis is inflammation of the meninges and subarachnoid space. It may result from infections, other disorders, or reactions to drugs. Severity and acuity vary. Findings typically include... read more . For acute bacterial meningitis in older children and adults, see Acute Bacterial Meningitis Acute Bacterial Meningitis Acute bacterial meningitis is rapidly progressive bacterial infection of the meninges and subarachnoid space. Findings typically include headache, fever, and nuchal rigidity. Diagnosis is by... read more , and in children < 3 months see Neonatal Bacterial Meningitis Neonatal Bacterial Meningitis Neonatal bacterial meningitis is inflammation of the meninges due to bacterial invasion. Signs are those of sepsis, central nervous system irritation (eg, lethargy, seizures, vomiting, irritability... read more . For viral meningitis, including in infants and children, see Viral Meningitis Viral Meningitis Viral meningitis tends to be less severe than acute bacterial meningitis. Findings include headache, fever, and nuchal rigidity. Diagnosis is by cerebrospinal fluid (CSF) analysis. Treatment... read more .
Etiology of Bacterial Meningitis in Infants
The etiology and incidence of bacterial meningitis are closely related to age and whether the infants have received routine immunization with the Haemophilus influenzae type b conjugate vaccine Haemophilus influenzae Type b (Hib) Vaccine Haemophilus influenzae type b (Hib) vaccines help prevent Haemophilus infections but not infections caused by other strains of H. influenzae bacteria. H. influenzae causes many childhood infections... read more and the Streptococcus pneumoniae conjugate vaccine Pneumococcal Vaccine Pneumococcal disease (eg, otitis media, pneumonia, sepsis, meningitis) is caused by some of the > 90 serotypes of Streptococcus pneumoniae (pneumococci). Vaccines are directed against many of... read more .
In infants who have not received routine immunizations, common causes of bacterial meningitis include
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S. pneumoniae Streptococcal Infections Streptococci are gram-positive aerobic organisms that cause many disorders, including pharyngitis, pneumonia, wound and skin infections, sepsis, and endocarditis. Symptoms vary with the organ... read more
(many serotypes; particularly in infants with no record of S. pneumoniae conjugate vaccination) -
Neisseria meningitidis Meningococcal Diseases Meningococci (Neisseria meningitidis) are gram-negative cocci that cause meningitis and meningococcemia. Symptoms, usually severe, include headache, nausea, vomiting, photophobia, lethargy,... read more
(especially serogroup B, but occasionally groups A, C, Y, or W135) -
H. influenzae type b Haemophilus Infections The gram-negative bacteria Haemophilus species cause numerous mild and serious infections, including bacteremia, meningitis, pneumonia, sinusitis, otitis media, cellulitis, and epiglottitis... read more (particularly in infants with no record of H. influenzae type b conjugate vaccination)
Other etiologies of bacterial meningitis in infants and children > 3 months of age have been reported but are very rare. Listeria monocytogenes, Streptococcus agalactiae, and Escherichia coli cause disease in infants < 3 months of age; they rarely are the etiology in extremely premature infants who have survived to become > 3 months of age. Staphylococcus aureus meningitis may occur in infants who have had trauma or neurologic surgery.
Symptoms and Signs of Bacterial Meningitis in Infants
The younger the patient, the less specific are the symptoms and signs of meningitis.
The initial manifestations of bacterial meningitis may be an acute febrile illness with respiratory or gastrointestinal symptoms followed only later by signs of serious illness. About 33 to 50% of neonates have a bulging anterior fontanelle, but only rarely do they have nuchal rigidity or other classic meningeal signs (eg, Kernig sign or Brudzinski sign) typically present in older children. In children < 12 months, the absence of nuchal rigidity must not be used to exclude meningitis.
As bacterial meningitis progresses, children develop central nervous system (CNS) manifestations, sometimes very rapidly. The degree of CNS derangement ranges from irritability to coma. As many as 15% of children who have bacterial meningitis are comatose or semicomatose at the time of hospitalization. Seizures sometimes occur with bacterial meningitis but in only about 20% of children—typically those who are already toxic, obtunded, or comatose. Infants who are alert and appear normal after a brief, non-focal seizure with fever are unlikely to have bacterial meningitis (see also Febrile Seizures Febrile Seizures Febrile seizures are diagnosed in children 6 months to 5 years of age who have fever > 38° C that is not caused by a central nervous system infection and who have had no previous afebrile seizures... read more ).
Papilledema Papilledema Papilledema is swelling of the optic disk due to increased intracranial pressure. Optic disk swelling resulting from causes that do not involve increased intracranial pressure (eg, malignant... read more 
is very uncommon in children of any age with bacterial meningitis. When papilledema is present, other causes of papilledema should be sought; bacterial meningitis progresses so quickly that there is usually insufficient time for papilledema to develop.
Diagnosis of Bacterial Meningitis in Infants
In general, lumbar puncture Lumbar Puncture (Spinal Tap) Lumbar puncture is used to do the following: Evaluate intracranial pressure and cerebrospinal fluid (CSF) composition (see table Cerebrospinal Fluid Abnormalities in Various Disorders) Therapeutically... read more should be done whenever the diagnosis of meningitis is known or suspected in an infant.
However, lumbar puncture may be delayed for the following reasons:
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Clinically important cardiorespiratory compromise (most often in young infants)
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Signs of significantly increased intracranial pressure, including retinal changes; altered pupillary responses; hypertension, bradycardia, and respiratory depression (Cushing triad); and focal neurologic signs
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Suspected intracranial injury, including presence of visible injuries, particularly to the head, or history suggestive of nonaccidental injury
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Infection at the site of lumbar puncture
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Suspicion or history of bleeding disorders (eg, hemophilia, severe thrombocytopenia)
In these circumstances, blood cultures should be done and antibiotics should be given empirically without doing the lumbar puncture. In cases of suspected increased intracranial pressure, arrangements should be made for a neuroimaging study (eg, cranial CT with and without contrast enhancement) during or immediately after antibiotics administration. If the results of the imaging study suggest it is safe, lumbar puncture may be done. However, it is not necessary to routinely do CT before lumbar puncture in young children with suspected meningitis; herniation of the brain is rare in young children with bacterial meningitis, even though all patients with meningitis have some degree of increased intracranial pressure.
CSF is sent for analysis, typically cell count, protein, glucose, Gram stain, culture, and, in selected infants, polymerase chain reaction (PCR) tests for enteroviruses (eg, in infants with meningitis during the late summer and autumn months in the US) or herpes simplex virus Neonatal Herpes Simplex Virus (HSV) Infection Neonatal herpes simplex virus infection is usually transmitted during delivery. A typical sign is vesicular eruption, which may be accompanied by or progress to disseminated disease. Diagnosis... read more 
(eg, infants < 3 months of age). Simultaneously, a blood sample should be drawn and sent to have the CSF:blood glucose ratio determined.
Typical CSF findings in bacterial meningitis include
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High white blood cell (WBC) count (> 500/mcL [0.5 × 109/L] often to as high as 10,000 WBC/mcL [10 × 109/L], with a predominance of polymorphonuclear leukocytes [> 80%])
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Elevated protein (> 100 mg/dL [1 gm/L])
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Low glucose (< 40 mg/dL [2.2 mmol/L], often < 10 mg/dL [0.56 mmol/L], and CSF:blood glucose ratio typically < 0.33)
Gram stain often shows organisms in the CSF in bacterial meningitis. Although findings may vary somewhat, infants who have bacterial meningitis very rarely have completely normal CSF at examination.
Infants also should have 2 sets of blood cultures (if possible; minimum 1 set of aerobic and anaerobic culture bottles), serum electrolytes, complete blood count and differential, and a urinalysis and urine culture.
Differential diagnosis
Symptoms and signs of bacterial meningitis may also be caused by other CNS infections, including viral meningitis Viral Meningitis Viral meningitis tends to be less severe than acute bacterial meningitis. Findings include headache, fever, and nuchal rigidity. Diagnosis is by cerebrospinal fluid (CSF) analysis. Treatment... read more (typically enteroviral), neonatal HSV infection Neonatal Herpes Simplex Virus (HSV) Infection Neonatal herpes simplex virus infection is usually transmitted during delivery. A typical sign is vesicular eruption, which may be accompanied by or progress to disseminated disease. Diagnosis... read more (almost exclusively in the infant < 1 month of age), pediatric HSV encephalitis, and brain abscess Brain Abscess A brain abscess is an intracerebral collection of pus. Symptoms may include headache, lethargy, fever, and focal neurologic deficits. Diagnosis is by contrast-enhanced MRI or CT. Treatment is... read more 
. Other causes of CNS infections that affect older children and adults (eg, Lyme neuroborreliosis; fungal meningitis; tuberculous meningitis; Bartonella infection; chemical meningitis resulting from use of nonsteroidal anti-inflammatory drugs, trimethoprim/sulfamethoxazole, or IV immune globulin; cancer) rarely occur in children < 12 months and should be distinguishable based on history, physical examination, and examination of the CSF.
In these other causes of meningitis, CSF findings most often include < 500 WBC/mcL (0.5 × 109/L) with < 50% polymorphonuclear leukocytes, protein < 100 mg/dL (1 g/L), normal glucose, and a negative Gram stain for organisms.
Prognosis for Bacterial Meningitis in Infants
Among older infants and children, the mortality rate with bacterial meningitis is about 5 to 10%, and neurologic morbidity (eg, sensorineural hearing loss, intellectual disability, spasticity and paresis, seizure disorder) occurs in 15 to 25%. Sensorineural deafness is most common after pneumococcal meningitis.
In older infants and children, mortality rates vary from 3 to 5% when the cause is H. influenzae type b, 5 to 10% when the cause is N. meningitidis, and 10 to 20% when the cause is S. pneumoniae.
Treatment of Bacterial Meningitis in Infants
As soon as bacterial meningitis is diagnosed (actually or presumptively), IV access should be secured and appropriate antimicrobial drugs (and possibly corticosteroids) should be given.
Empiric antimicrobial therapy for infants > 3 months is directed at the common pathogens: pneumococci, meningococci, and H. influenzae type b.
A typical drug regimen includes
Cefotaxime and ceftriaxone are extremely effective against the organisms that usually cause bacterial meningitis in infants > 3 months. The major difference between these drugs is that ceftriaxone has a much longer serum half-life than cefotaxime. Vancomycin is given because some pneumococcal strains in certain areas are not susceptible to 3rd-generation cephalosporins. In areas (and institutions) where most pneumococci are susceptible to penicillin, vancomycin may not be necessary, particularly if no gram-positive cocci are seen on the CSF Gram stain; decision to withhold vancomycin should typically be made in consultation with an infectious disease specialist.
Once the infecting organism is identified, more specifically targeted drugs are used; for example, vancomycin may no longer be required.
Organism-specific antimicrobial therapy
After immediate empiric antimicrobial drugs have been started, results of CSF and/or blood cultures are used to select a more specifically targeted drug while waiting for microbial identification and susceptibility test results. (See table Specific Therapy for Bacterial Meningitis in Infants Over 3 Months of Age Once Identification and Susceptibility Results Are Known Specific Therapy for Bacterial Meningitis in Infants Over 3 Months of Age Once Identification and Susceptibility Results Are Known Bacterial meningitis in infants is a serious infection of the meninges and subarachnoid space. Infants may present with nonspecific symptoms and signs (eg, lethargy, irritability, poor feeding... read more and see table Recommended Dosages of Antimicrobial Drugs for Infants and Children With Bacterial Meningitis Recommended Dosages of Antimicrobial Drugs for Infants and Children With Bacterial Meningitis Bacterial meningitis in infants is a serious infection of the meninges and subarachnoid space. Infants may present with nonspecific symptoms and signs (eg, lethargy, irritability, poor feeding... read more .)
If S. pneumoniae is suspected (eg, because gram-positive cocci in pairs are seen on a Gram stain of the CSF), the empiric vancomycin should be continued until susceptibility test results are available. Vancomycin is stopped if the isolate is susceptible to penicillin or the 3rd-generation cephalosporins; if the isolate is not susceptible, vancomycin is continued (and some clinicians add rifampin). Because dexamethasone can decrease the CSF penetrance (and thus effectiveness) of vancomycin, some experts advise that either dexamethasone should not be given or, if given, that rifampin be added concurrently.
Disease caused by N. meningitidis is treated reliably with penicillin G or ampicillin at high doses, or alternatively by a 3rd-generation cephalosporin. If penicillin or ampicillin therapy is used, it is followed by a 2-day course of twice-daily rifampin to clear the carrier state and prevent relapse (rifampin is not necessary if a 3rd-generation cephalosporin is used to complete therapy).
If H. influenzae type b is suspected or proved, disease may be treated reliably with either ceftriaxone or cefotaxime; ampicillin may be used only if the isolate is proved susceptible. If ampicillin therapy is used, it is followed by a 4-day course of once-daily rifampin to clear the carrier state and prevent relapse (rifampin is not necessary if a 3rd-generation cephalosporin is used to complete therapy).
Specific antimicrobial therapy for other rare infections (eg, S. agalactiae, E. coli, L. monocytogenes, S. aureus) should be selected in consultation with an infectious disease specialist.
Corticosteroids for bacterial meningitis
The use of corticosteroids (eg, dexamethasone) as adjunctive therapy in bacterial meningitis has been studied for decades and continues to be controversial. The beneficial effects of corticosteroids in reducing neurologic morbidity appear to vary with the age of the patient (child or adult), the specific bacterial etiology, and even whether the patient lives in an industrialized country or in the developing world.
At present, evidence suggests that dexamethasone reduces hearing impairment in infants and children living in industrialized countries who have bacterial meningitis caused by H. influenzae type b. The effectiveness of dexamethasone in meningitis caused by other organisms remains unproved, although some studies of adults in industrialized countries with meningitis caused by S. pneumoniae report improved neurologic outcomes and reduced mortality. Dexamethasone does not appear to benefit children or adults with bacterial meningitis who live in developing countries, nor does it seem to benefit neonates with meningitis.
Thus, dexamethasone 0.15 mg/kg IV should be given before, or within 1 hour after, antimicrobial therapy in children > 6 weeks of age with meningitis caused by H. influenzae type b. The drug is continued every 6 hours for 4 days in confirmed H. influenzae type b meningitis. Some experts also recommend using this same dexamethasone regimen in children with pneumococcal meningitis who are > 6 weeks of age.
For optimal efficacy, dexamethasone must be started at the time of diagnosis; this is not always possible, unless the Gram stain of the fluid or epidemiologic factors (eg, disease contact history) can yield an immediate etiologic diagnosis. In regions where children have been given routine H. influenzae type b and pneumococcal conjugate vaccines, bacterial meningitis caused by these organisms will be rare. For these reasons, along with the conflicting evidence regarding the benefits of dexamethasone therapy, many pediatric infectious disease experts no longer routinely give corticosteroids to infants with meningitis.
Prevention of Bacterial Meningitis in Infants
Prevention of bacterial meningitis involves vaccination and sometimes chemoprophylaxis.
Vaccination
A conjugate pneumococcal vaccine Pneumococcal Vaccine Pneumococcal disease (eg, otitis media, pneumonia, sepsis, meningitis) is caused by some of the > 90 serotypes of Streptococcus pneumoniae (pneumococci). Vaccines are directed against many of... read more effective against 13 serotypes, including > 90% of the pneumococcal serotypes that cause meningitis in infants, is recommended for all children beginning at 2 months of age (see Table: Recommended Immunization Schedule for Ages 0–6 Years Recommended Immunization Schedule for Ages 0–6 Years Vaccination follows a schedule recommended by the Centers for Disease Control and Prevention (CDC), the American Academy of Pediatrics, the American Academy of Family Physicians, and the American... read more ). For further information, see current Advisory Committee on Immunization Practices (ACIP) pneumococcal vaccine recommendations.
Routine vaccination with an H. influenzae type b conjugate vaccine Haemophilus influenzae Type b (Hib) Vaccine Haemophilus influenzae type b (Hib) vaccines help prevent Haemophilus infections but not infections caused by other strains of H. influenzae bacteria. H. influenzae causes many childhood infections... read more also is highly effective and begins at age 2 months. For further information, see current ACIP Haemophilus influenzae vaccine recommendations.
The ACIP recommends that infants > 6 weeks who are at high risk of meningococcal disease receive a meningococcal conjugate vaccine Meningococcal Vaccine The meningococcal serogroups that most often cause meningococcal disease in the US are serogroups B, C, and Y. Serogroups A and W cause disease outside the US. Current vaccines are directed... read more . For infants not at high risk, routine meningococcal conjugate vaccination Meningococcal Vaccine The meningococcal serogroups that most often cause meningococcal disease in the US are serogroups B, C, and Y. Serogroups A and W cause disease outside the US. Current vaccines are directed... read more is recommended at age 11 or 12 years (see Table: Recommended Immunization Schedule for Ages 7–18 Years Recommended Immunization Schedule for Ages 7–18 Years Vaccination follows a schedule recommended by the Centers for Disease Control and Prevention (CDC), the American Academy of Pediatrics, the American Academy of Family Physicians, and the American... read more ). High-risk infants include those who
Two serogroup B meningococcal vaccines have been approved by the ACIP for use in children ≥ 10 years of age who are at high risk of meningococcal group B disease (same categories as above); routine meningococcal B vaccination is not yet currently given. For further information, see current ACIP meningococcal vaccine recommendations.
Chemoprophylaxis for meningitis
Antimicrobial chemoprophylaxis is necessary for
Contacts of children who have meningitis caused by other bacteria do not require chemoprophylaxis.
For meningococcal meningitis, close contacts have a risk of infection that may be 25 to 500 times higher than that of the general population. Close contacts are defined as
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Household members, especially children < 2 years of age
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Child care center contacts exposed in the 7 days before symptom onset
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Anyone directly exposed to the patient’s oral secretions (eg, through kissing, sharing toothbrushes or utensils, mouth-to-mouth resuscitation, endotracheal intubation, endotracheal tube management) in the 7 days before symptom onset
Not every health care practitioner who has cared for an infant with meningitis is considered a close contact. Health care personnel should receive chemoprophylaxis only if they were managing the patient's airway or were directly exposed to the patient's respiratory secretions. Chemoprophylaxis should be given as soon as possible (ideally within 24 hours of identification of the index patient); chemoprophylaxis given > 2 weeks after exposure is likely of little to no value. Rifampin, ceftriaxone, and ciprofloxacin are appropriate drugs depending on the age of the contact (see Table: Recommended Chemoprophylaxis for High-Risk Contacts* of Children With Meningococcal or Haemophilus influenzae Type b Meningitis Recommended Chemoprophylaxis for High-Risk Contacts* of Children With Meningococcal or Haemophilus influenzae Type b Meningitis Bacterial meningitis in infants is a serious infection of the meninges and subarachnoid space. Infants may present with nonspecific symptoms and signs (eg, lethargy, irritability, poor feeding... read more ). For young children, oral rifampin or injectable ceftriaxone is preferred.
For H. influenzae type b meningitis, the risk of infection in contacts is lower than with meningococcal disease but can be substantial in young, unvaccinated infant or toddler contacts residing in the household of an index patient. Also, household contacts may be asymptomatic carriers of H. influenzae type b. Close contacts are defined more explicitly than for meningococcal prophylaxis because caretakers who spend time in the household but do not live there may nevertheless have become colonized with H. influenzae type b. Thus for this organism, household contacts are defined as the following:
Chemoprophylaxis is then recommended for each member of a household, as just defined, if that household also has
Complete immunization against H. influenzae type b is defined as having had at least 1 dose of Hib conjugate vaccine at age ≥ 15 months, or 2 doses between 12 months and 14 months, or the 2- or 3-dose primary series for children < 12 months with a booster dose at ≥ 12 months.
In addition, if a preschool or child care center has had ≥ 2 cases of invasive Hib disease within 60 days among its attendees, many experts recommend chemoprophylaxis for all attendees and staff to eliminate asymptomatic nasal carriage regardless of immunization status.
Close contacts most at risk of secondary infection are children < 4 years who are incompletely immunized against H. influenzae type b. Chemoprophylaxis should be given < 24 hours after identification of the index patient; chemoprophylaxis given > 2 weeks after exposure is likely of little to no value. Oral rifampin or injectable ceftriaxone is preferred, and ciprofloxacin is acceptable for older contacts (see Table: Recommended Chemoprophylaxis for High-Risk Contacts* of Children With Meningococcal or Haemophilus influenzae Type b Meningitis Recommended Chemoprophylaxis for High-Risk Contacts* of Children With Meningococcal or Haemophilus influenzae Type b Meningitis Bacterial meningitis in infants is a serious infection of the meninges and subarachnoid space. Infants may present with nonspecific symptoms and signs (eg, lethargy, irritability, poor feeding... read more ).
Key Points
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Infants with bacterial meningitis may first present with nonspecific symptoms and signs (eg, of upper respiratory or gastrointestinal illness) but then decompensate rapidly.
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The most common bacterial causes of meningitis are Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae type b.
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If meningitis is suspected, do lumbar puncture (unless contraindication exists) and give empiric antimicrobial therapy (and possibly dexamethasone) as soon as possible.
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Empiric antimicrobial therapy in infants > 3 months is with cefotaxime or ceftriaxone, plus vancomycin.
More Information
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Pneumococcal vaccine recommendations from the Advisory Committee for Immunization Practices (ACIP)
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Meningococcal vaccine recommendations from the ACIP
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Haemophilus influenzae vaccine recommendations from the ACIP
Drugs Mentioned In This Article
| Drug Name | Select Trade |
|---|---|
immune globulin |
Gammagard S/D |
ciprofloxacin |
CILOXAN, CIPRO |
dexamethasone |
OZURDEX |
trimethoprim |
No US brand name |
Ceftriaxone |
ROCEPHIN |
cefotaxime |
CLAFORAN |
Vancomycin |
VANCOCIN |
rifampin |
RIFADIN, RIMACTANE |
