Bacterial meningitis in adults

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

INITIAL

suspected bacterial meningitis: presenting in hospital

<60 years and immunocompetent

1st line – supportive care

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1st line –

supportive care

Seek advice from a senior clinical decision-maker within the first hour after presentation to hospital.[15]

Practical tip

Think 'Could this be sepsis?' based on acute deterioration in a patient in whom there is clinical evidence or strong suspicion of infection.[35][36][37]

Use a systematic approach, alongside your clinical judgement, for assessment; urgently consult a senior clinical decision-maker (e.g., ST3 level doctor in the UK) if you suspect sepsis.[35][37][39]
Refer to local guidelines for the recommended approach at your institution for assessment and management of the patient with suspected sepsis.

See Sepsis in adults.

Secure the airway

Strongly consider intubation if Glasgow Coma Scale score is <12.[15] [ Glasgow Coma Scale Opens in new window ] Indications for intubation include:

Inability to maintain airway patency
Inability to protect the airway against aspiration
Failure to ventilate
Failure to oxygenate
Anticipation of a deteriorating course that will eventually lead to respiratory failure
Persistent seizures

Bag-valve-mask ventilation animated demonstration

How to use bag-valve-mask apparatus to deliver ventilatory support to adults. Video demonstrates the two-person technique.

Tracheal intubation animated demonstration

How to insert a tracheal tube in an adult using a laryngoscope.

Oxygen

Monitor controlled oxygen therapy. An upper SpO₂ limit of 96% is reasonable when administering supplemental oxygen to most patients with acute illness who are not at risk of hypercapnia.

Evidence suggests that liberal use of supplemental oxygen (target SpO₂ >96%) in acutely ill adults is associated with higher mortality than more conservative oxygen therapy.[85]
A lower target SpO₂ of 88% to 92% is appropriate if the patient is at risk of hypercapnic respiratory failure.[74]

Treat raised intracranial pressure

Seek critical care input if the patient has signs of raised intracranial pressure.[15] Do not routinely use invasive intracranial pressure monitoring.[15][22]

Fluid management

Give fluids to maintain normal haemodynamic parameters.[15]

Normal blood pressure for age in adults: ≥65 mmHg mean arterial pressure.
Urine output: >0.5 mL/kg/hour (a urinary catheter is required).
Lactate: <2 mmol/L.
Patients with uncomplicated meningitis tend to be relatively euvolaemic.[15]
- Give maintenance fluids orally or by enteral tube, if tolerated.[22]
- Do not routinely restrict fluid intake to below routine maintenance needs in people with bacterial meningitis.[22]
Underhydration and overhydration have been associated with adverse outcomes in people with bacterial meningitis.[15][75]

Check local protocols for specific recommendations on fluid choice. There is debate, based on conflicting evidence, on whether there is a benefit in using normal saline or balanced crystalloid in critically ill patients.

Seizures

Treat suspected or confirmed seizures and monitor status epilepticus with EEG.[15][23]

See Status epilepticus, Focal seizures, and Generalised seizures.

Plus – corticosteroid

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Plus –

corticosteroid

Treatment recommended for ALL patients in selected patient group

Give empirical intravenous dexamethasone to all adults with acute bacterial meningitis within 1 hour of presentation to hospital.[15][66] [ ]

Start dexamethasone shortly before or at the same time as antibiotic therapy if possible.[15][22][66][94]

However, do not delay antibiotics to wait for dexamethasone to be started.[22]
If antibiotics have already been started, dexamethasone may still be given for up to 12 hours after the first dose of antibiotics.[15][22][66]
If dexamethasone is delayed for more than 12 hours after the start of antibiotics, get advice from a microbiologist or infectious diseases consultant.[22]
Continue for 4 days if organism is confirmed to be Streptococcus pneumoniae or Haemophilus influenzae.[15][23][27][66]

Stop corticosteroid therapy if another organism is identified.[15][22][23][27][66]

If no causative organism is found, get advice from a microbiologist or infectious diseases consultant on whether or not to continue dexamethasone.[22] In practice, dexamethasone is often continued if clinical suspicion for bacterial meningitis remains high, and especially in the more severe spectrum of disease, which has a higher risk of long-term neurological sequelae.

Evidence: Corticosteroid therapy in bacterial meningitis – effectiveness

A 2015 Cochrane review found that adults and children with acute bacterial meningitis who were given corticosteroids (mostly dexamethasone) as part of their treatment had significantly lower rates of hearing loss compared with those not given corticosteroids. Adding corticosteroids did not reduce mortality or short‐term neurological sequelae.[95]

The review found 25 randomised controlled trials, involving a total of 4121 participants, of which 7 reported data separately for adults. Considering only the studies of adults, in the groups taking corticosteroids:
- The rate of hearing loss was lower: 68 of 433 (15.7%) versus 90 of 411 (21.9%; relative risk [RR] 0.74, 95% CI 0.56 to 0.98; P=0.035; 4 studies)
- There was a non-significant reduction in short-term neurological sequelae (RR 0.72, 95% CI 0.51 to 1.01, P=0.06; 4 studies)
- There was a non-significant reduction in mortality rate (RR 0.74, 95% CI 0.53 to 1.05, P=0.09).
A subgroup analysis by high- versus low-income countries found:
- There was no significant difference in mortality in adults between the group taking corticosteroids and those taking placebo in either income subgroup
- Hearing loss in adults was significantly lower with corticosteroids than with placebo in the high-income subgroup (3 studies), but not in the low-income subgroup (1 study).
Another subgroup analysis by causative organism (this time including children as well as adults) found:
- Corticosteroids protected against death in people with pneumococcal meningitis (RR 0.84, 95% CI 0.72 to 0.98; 17 studies of which 6 were in adults).
The review concluded that treatment with adjunctive corticosteroids was not associated with harm.

The 2016 European Society of Clinical Microbiology and Infectious Diseases guideline found no additional studies beyond those in this Cochrane review and concluded that these data support the use of corticosteroids in patients with bacterial meningitis in countries with a high level of medical care.[23] The UK joint specialist societies guideline distinguishes between organisms and recommends that corticosteroid treatment should be stopped if an organism other than S pneumoniae is identified.[15]

The UK National Institute for Health and Care Excellence (NICE) similarly recommends the use of high-dose dexamethasone for adults with bacterial meningitis on the basis of reductions in mortality and hearing impairment.[22] The evidence review undertaken to support its 2024 guideline recommendations on use of corticosteroids in bacterial meningitis identified one additional randomised controlled trial, involving 480 adult participants, that further supported the findings of the 2015 Cochrane review.[22][110]

Evidence: Corticosteroid therapy – stopping or continuing treatment

Guidelines suggest a 4-day course of corticosteroid therapy based on the causative organism, using evidence from a Cochrane systematic review.

A Cochrane review examining the effect of adjuvant corticosteroid therapy versus placebo on mortality, hearing loss, and neurological sequelae in people of all ages with acute bacterial meningitis found:[95]

Corticosteroids protected against death in pneumococcal meningitis (relative risk [RR] 0.84, 95% CI 0.72 to 0.98; 17 studies of which 6 were in adults)
In meningococcal meningitis, corticosteroids were associated with a non-significant reduction in mortality (RR 0.71, 95% CI 0.35 to 1.46; 13 studies of which 4 were in adults)
For children with meningitis caused by H influenzae, hearing loss was significantly reduced by corticosteroids (RR 0.34, 95% CI 0.20 to 0.59; 10 studies)

Primary options

dexamethasone: 10 mg intravenously every 6 hours

Plus – empirical antibiotics

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Plus –

empirical antibiotics

Treatment recommended for ALL patients in selected patient group

Give empirical intravenous antibiotics to patients with presumed bacterial meningitis within 1 hour of presentation to hospital and ideally immediately after blood cultures.[15][22][23]

Taking blood tests (including blood cultures) or performing lumbar puncture (LP) should not result in a clinically significant delay in the administration of antibiotics.[15][22]

The need for a rapid LP has to be weighed against the desire to start antimicrobial treatment urgently.[15]
- Some guidelines recommend giving antibiotics after LP (where LP is indicated and as long as LP is not delayed) to allow the best chance of definitive diagnosis.[15] The culture rate can drop off rapidly after 4 hours, making it difficult to identify the causative organism (but prompt molecular tests will still identify the causative organism even after antibiotics have been started).
- If LP cannot be performed within 1 hour, give antibiotics immediately after blood cultures have been taken.
- Delaying antibiotics is strongly associated with poor outcome and death.[23][31][96][97]
In practice, if a patient has received an antibiotic in the community (i.e., if a general practitioner suspected bacterial meningitis clinically) that is different to the first-choice empirical antibiotic recommended by your institution, you should still give a dose of this empirical antibiotic in the accident and emergency department. However, if the antibiotic given in the community is the same as your first-choice empirical antibiotic, you should not duplicate the dose.

Follow your local protocol when prescribing antibiotics and seek advice from microbiology. For suspected bacterial meningitis when the causative organism has not been identified, give intravenous ceftriaxone, or if ceftriaxone is contraindicated, cefotaxime.[15][22]

For patients with penicillin or cephalosporin allergy, seek advice from a microbiologist or infectious disease specialist and consider giving intravenous chloramphenicol if their reaction was a severe allergy.[15][22]

Continue initial antibiotic treatment until the results of blood and cerebrospinal fluid tests suggest an alternative treatment is needed or there is an alternative diagnosis. If test results are normal, but bacterial meningitis is still suspected, get advice from a microbiologist or infectious disease specialist.[22][98]

De-escalate treatment as soon as appropriate, including switching from intravenous to oral antibiotic therapy. When making this decision, consider response to treatment, change in disease severity, and contraindications to oral administration such as:

Patient is unable to swallow (e.g., impaired swallowing reflex, impaired consciousness)
Gastrointestinal malabsorption for functional or anatomical reasons.

Review route of administration initially on the ward round following admission and then daily thereafter.

Primary options

ceftriaxone: 2 g intravenously every 12 hours; or 4 g intravenously every 24 hours

cefotaxime: 2 g intravenously every 6 hours, increase to 12 g/day in 3-4 divided doses if necessary

Secondary options

chloramphenicol: 25 mg/kg intravenously every 6 hours

Dose may be reduced to 12.5 mg/kg every 6 hours if the patient is recovering, to reduce the risk of a dose-related anaemia.[111]

Consider – antibiotic cover for penicillin-resistant pneumococci

Consider – antibiotic cover for Listeria monocytogenes

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Consider –

antibiotic cover for Listeria monocytogenes

Additional treatment recommended for SOME patients in selected patient group

Follow your local protocol when prescribing antibiotics and seek advice from microbiology.

Give intravenous amoxicillin in addition to ceftriaxone or cefotaxime for people with risk factors for Listeria monocytogenes (e.g., diabetes).[15][22]

If a patient with risk factors for Listeria monocytogenes has a penicillin or cephalosporin allergy, seek advice from a microbiologist or infectious disease specialist and consider trimethoprim/sulfamethoxazole and chloramphenicol for those with a severe allergy.[22]

Primary options

amoxicillin: 2 g intravenously every 4 hours

Secondary options

trimethoprim/sulfamethoxazole: 10-20 mg/kg/day intravenously given in divided doses every 6 hours

and

chloramphenicol: 25 mg/kg intravenously every 6 hours

Dose may be reduced to 12.5 mg/kg every 6 hours if the patient is recovering, to reduce the risk of a dose-related anaemia.[111]

Consider – treatment for unusual pathogens