Synopsis
Recognise bacterial meningitis without relying on a complete triad, obtain blood and cerebrospinal-fluid evidence safely, and give ceftriaxone, dexamethasone and Listeria cover in the correct sequence.
- The classic fever, neck stiffness and altered-consciousness triad is insensitive; severe headache or cognitive change with fever warrants urgent evaluation.
- Take blood cultures and EDTA blood for meningococcal and pneumococcal PCR before antibiotics only when this causes no delay.
- Give ceftriaxone 2 g intravenously every 12 hours in adults with suspected bacterial meningitis.
- Give dexamethasone 10 mg intravenously every 6 hours for 4 days, starting with or immediately before the first antibiotic and reviewing when the organism is known.
- Add amoxicillin 2 g intravenously every 4 hours for people with Listeria risk under NICE and local renal guidance.
- Lumbar puncture is the key diagnostic test when safe; do not perform it during shock, uncontrolled seizure or clinical evidence of mass effect.
- Use CT before lumbar puncture only for specified neurological risks, not because meningitis is suspected in every patient.
- Notify relevant disease, provide meningococcal contact prevention and arrange hearing and neurocognitive follow-up after survival.
Key red flags
Altered consciousness, shock, focal neurology, papilloedema or uncontrolled seizure changes lumbar-puncture safety and requires senior escalation.
A rapidly spreading non-blanching rash or severe limb pain raises meningococcal septicaemia and needs immediate sepsis care.
Older age, pregnancy or immune suppression increases Listeria risk and requires amoxicillin in addition to ceftriaxone.
Antibiotics already given do not remove the need for lumbar puncture once safe because PCR and CSF pattern remain valuable.
Fever, severe headache, neck stiffness, photophobia, vomiting and altered cognition creates a high-probability syndrome even when one feature is absent.
Purpura, mottling, severe limb pain and shock suggests concurrent bloodstream disease requiring critical care.
Falling consciousness, focal deficit, papilloedema, abnormal pupils or repeated seizure indicates mass effect and changes lumbar-puncture safety.
Older age, pregnancy, malignancy, transplant or major immune suppression increases L monocytogenes probability despite absence of a distinctive rash.
Investigation priorities
Identify bacteria without requiring lumbar puncture safety.
Management branches
Bacterial meningitis is clinically suspected in an adult.
- Use ABCDE, glucose and early senior review; take blood cultures and PCR and start therapy immediately when sampling would delay.
- Give dexamethasone with or immediately before ceftriaxone and add amoxicillin when Listeria risk exists.
- Treat seizure, shock, hypoglycaemia, hypoxia and raised intracranial pressure with critical-care and neurological support.
- Notify suspected meningococcal disease and use appropriate droplet precautions until the public-health and treatment criteria are met.
The patient is stable enough for lumbar puncture or testing can continue after initial treatment.
- Assess lumbar-puncture contraindications clinically and perform puncture promptly without routine CT when safe.
- Record opening pressure and send sufficient labelled CSF for microscopy, culture, bacterial PCR and exposure-directed viral or TB testing.
- If puncture was initially unsafe, reassess after stabilisation; prior ceftriaxone does not make later CSF worthless.
- Investigate ear, sinus, skull-base, endocardial or device sources when organism or course suggests contiguous or persistent seeding.