EM · Meningitis and encephalitis
Meningitis and encephalitis (emergency department diagnosis and management)
Also known as Acute meningitis · Bacterial meningitis · Viral meningitis · Herpes simplex encephalitis · Meningococcaemia
ED meningitis and encephalitis — classic triad (fever, neck stiffness, altered mental status), NICE NG240 first-hour antibiotics with highest-BNF-dose ceftriaxone, dexamethasone 10 mg before or with the first dose, amoxicillin when Listeria risk is present, UKHSA 2 g stat ceftriaxone for suspected meningococcal disease, Hasbun CT-before-LP features, and HSV aciclovir 10 mg/kg 8-hourly from the Skoldenberg and Whitley trials. ACEM-primary, globally tagged.
Checked against its sources on 3 Sept 2026
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Target exams
Red flags
- Start antibiotics within 1 hour of hospital arrival — do not delay the first dose for CT or LP if either will cause a clinically significant delay
- A haemorrhagic non-blanching purpuric rash is a red flag for meningococcal disease — but absence of a rash does not exclude it
- Add intravenous amoxicillin (or ampicillin) when Listeria risk factors are present — NICE adds it to ceftriaxone or cefotaxime
- Do not routinely give aciclovir unless herpes simplex encephalitis is strongly suspected
- Give bloods, antibiotics and stabilisation before imaging; do not lumbar-puncture a patient with spreading purpura or a GCS of 9 or less
Meet the patient
A 24-year-old university student reaches resus at 04:00 after twelve hours of fever, headache and vomiting, now drowsy. A rapidly spreading non-blanching purpuric rash covers his buttocks and ankles. GCS is 13, temperature 39.6 degrees C, BP 96 over 60. NICE treats a haemorrhagic non-blanching rash with lesions larger than 2 mm as a red flag for meningococcal disease; the rash may be absent, and that does not exclude the diagnosis.[2]
Two questions govern the next hour: which antibiotic goes in now, and does anyone wait for a scan? The first dose is not delayed for CT or LP if either would cause a clinically significant delay.[2][8]
References10ShowHide
- [1]van de Beek D, de Gans J, Spanjaard L, Weisfelt M, Reitsma JB, Vermeulen M. Clinical features and prognostic factors in adults with bacterial meningitis. New England Journal of Medicine, 2004.PMID 15509818
- [2]National Institute for Health and Care Excellence. Meningitis (bacterial) and meningococcal disease: recognition, diagnosis and management NICE guideline NG240, 2024.Source
- [3]Brouwer MC, McIntyre P, Prasad K, van de Beek D. Corticosteroids for acute bacterial meningitis. Cochrane Database of Systematic Reviews, 2015.PMID 26362566
- [4]Whitley RJ, Alford CA, Hirsch MS, Schooley RT, Luby JP, Aoki FY, Hanley D, Nahmias AJ, Soong SJ. Vidarabine versus acyclovir therapy in herpes simplex encephalitis. New England Journal of Medicine, 1986.PMID 3001520
- [5]de Gans J, van de Beek D. Dexamethasone in adults with bacterial meningitis. New England Journal of Medicine, 2002.PMID 12432041
- [6]Hasbun R, Abrahams J, Jekel J, Quagliarello VJ. Computed tomography of the head before lumbar puncture in adults with suspected meningitis. New England Journal of Medicine, 2001.PMID 11742046
- [7]Sköldenberg B, Forsgren M. Acyclovir versus vidarabine in herpes simplex encephalitis. Scandinavian Journal of Infectious Diseases Supplementum, 1985.PMID 3912977
- [8]Auburtin M, Wolff M, Charpentier J, Varon E, Le Tulzo Y, Girault C, Mohammedi I, Renard B, Mourvillier B, Bruneel F, Ricard JD, Timsit JF. Detrimental role of delayed antibiotic administration and penicillin-nonsusceptible strains in adult intensive care unit patients with pneumococcal meningitis. Critical Care Medicine, 2006.PMID 16915106
- [9]Drost EHGM, Schepers EN, Chekrouni N, van Soest TM, Koelman DLH, Bijlsma MW, Brouwer MC, van de Beek D. Outcomes of adults with community-acquired bacterial meningitis in the Netherlands: a prospective nationwide cohort study. Lancet Regional Health Europe, 2026.PMID 41323877
- [10]UK Health Security Agency. Guidance for public health management of meningococcal disease in the UK UKHSA, 2025.Source