Level 2 of 6Must-remember

Meningitis and encephalitis

Assess, manage and stay safe — enough on its own

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The card — assess, manage, caution

Assessment— look, ask, measure

Think of it early: consider meningitis in anyone with fever and headache, in any sudden severe headache, and in anyone with fever plus altered behaviour or reduced consciousness — the classic triad of fever, stiff neck and altered mental status has a sensitivity of only 44%.
Do not rely on the special signs: Kernig's and Brudzinski's signs, though specific, may be as little as 5% sensitive, and meningitis frequently presents without meningism at all.
Seek neck stiffness properly: ask the patient to look at their own umbilicus or place chin on chest, and in a child watch whether the eyes follow a toy downwards.
The textbook syndrome is headache, fever, photophobia, neck stiffness and vomiting, of sudden onset with rigors, developing over hours, with presentation within hours to one or two days.
Alertness gives no reassurance: in uncomplicated meningitis the conscious level is preserved, so progressive drowsiness, lateralising signs or cranial nerve lesions indicate complications — cerebral oedema, hydrocephalus, venous sinus thrombosis — or an alternative diagnosis such as cerebral abscess or encephalitis.
Examine all the skin: a non-blanching petechial or purpuric rash develops in more than 80% of meningococcal disease but is often absent early and is usually blanching at first — macules, maculopapules or urticaria indistinguishable from a viral exanthem, becoming petechial or purpuric over hours.
Recognise the septicaemic presentation: a non-specific influenza-like illness of fever, headache, myalgia, vomiting and abdominal pain, then limb pain, pallor with mottling or cyanosis, and cold hands and feet, with tachycardia, tachypnoea, poor perfusion and oliguria; confusion here reflects falling cerebral perfusion, not meningeal inflammation.
Hypotension is a late sign, particularly in children, who present with compensated shock — tachycardia, prolonged capillary refill and a normal blood pressure.
Suspect encephalitis and give aciclovir when there is personality or behavioural change (often the earliest feature and usually reported by family), progressive reduction in conscious level, seizures, or focal deficits especially dysphasia; fever is present in 90% of viral encephalitis.
Red flags for dying or coning: falling GCS or GCS 8 or less; relative bradycardia with hypertension, abnormal posturing, unequal or unreactive pupils, papilloedema or absent retinal venous pulsations; rapidly extending purpura or purpura fulminans; mottling, cold peripheries, capillary refill over three seconds, oliguria or rising lactate; new focal deficit or seizure.
The counter-intuitive markers of a bad outcome: absence of meningism, hypotension, young age, coma and a relatively low temperature — the patient who does not look like meningitis is the one who dies of it.
Infants and young children: neck stiffness and photophobia are often absent, headache is rarely reported in early childhood, and infants present with fever, irritability and a bulging fontanelle; the warning features are a bulging or tense fontanelle, high-pitched or unusual cry, refusal to feed, a floppy or unrousable infant, non-blanching rash, cold mottled extremities, capillary refill over three seconds and grunting.
Elderly, immunosuppressed, alcoholic and pregnant patients present atypically: confusion, falls or simply "off legs", often without neck stiffness and sometimes normothermic or hypothermic, with muted inflammatory signs and a broader organism list.
A subacute presentation — vague headache, lassitude, anorexia and vomiting over one to eight weeks, with cranial nerve palsies, drowsiness and seizures later — is tuberculous or cryptococcal until disproved.
Do not be reassured by normal blood tests: inflammatory markers (C-reactive protein, procalcitonin, ESR) may be normal or low in rapidly progressive disease, and failure to rise does not exclude the diagnosis.
Look for the mimics that change treatment: cerebral malaria (severe headache but the neck stiffness and photophobia of meningitis do not occur — send a blood film and rapid diagnostic test), rickettsial disease (treat as bacterial sepsis because prompt differentiation may be impossible), leptospirosis, and subarachnoid haemorrhage (instantaneous worst-ever headache).

Management— do this, in order

Treat on suspicion: the first antibiotic dose is given as soon as bacterial meningitis is seriously considered, before imaging and before lumbar puncture — delay is the dominant modifiable determinant of death and disability.Doctor / Nurse
Dexamethasone before, or at the same moment as, the first antibiotic dose — adult 10 mg IV, 15–20 minutes before or simultaneously with the antibiotic, then 10 mg IV every 6 hours for 4 days; it is the only agent whose benefit is lost by being given late.Doctor / Nurse
Weight-based dexamethasone alternatives: 0.15 mg/kg IV every 6 hours for 2–4 days, or 0.6 mg/kg IV daily for 4 days; child over 2 months, 0.6 mg/kg per day IV in four divided doses, first dose with or before the antibiotic (2 days in Hib meningitis).Doctor / Nurse
Adult 18–50, community-acquired: ceftriaxone 2 g IV 12-hourly (or cefotaxime 2 g IV 6-hourly), plus vancomycin 15–20 mg/kg IV 8–12-hourly where resistant pneumococcus is a concern.Doctor / Nurse
Adult over 50, pregnant, immunocompromised, alcoholic, diabetic or with malignancy: add ampicillin 2 g IV 4-hourly (8–12 g/day in 4–6 divided doses) to ceftriaxone and vancomycin, because cephalosporins do not cover Listeria.Doctor / Nurse
Child beyond the neonatal period: ceftriaxone 75–100 mg/kg/day IV (maximum 4 g/day) in 1–2 divided doses, or cefotaxime 200 mg/kg/day IV (maximum 8 g/day) in 4 divided doses.Doctor / Nurse
Neonate under 1 month: cefotaxime plus ampicillin, with or without gentamicin — avoid ceftriaxone (bilirubin displacement, incompatible with calcium-containing infusions); benzylpenicillin for meningitis is 250 000–450 000 units/kg/day in 3 divided doses if 7 days old or less, and 450 000–500 000 units/kg/day in 4 divided doses if over 7 days.Doctor / Nurse
Any encephalitic feature at any age: add aciclovir 10 mg/kg IV 8-hourly (30 mg/kg/day), each dose infused over at least 1 hour, for 14–21 days in adults; child 30 mg/kg/day IV in three divided doses; neonate 20 mg/kg IV 8-hourly for 14 days, extended to 21 days with CNS involvement.Doctor / Nurse
Possible rickettsial illness: add doxycycline 100 mg twice daily to ceftriaxone.
Post-neurosurgical, post-traumatic or shunt infection: vancomycin 15–20 mg/kg IV 8–12-hourly plus cefepime 2 g IV 8-hourly (or meropenem); ceftazidime covers Pseudomonas.Doctor / Nurse
Correct shock first — fluid restriction for fear of cerebral oedema is inappropriate in a hypoperfused patient: balanced crystalloid or 0.9% sodium chloride 500 mL IV over 10–15 minutes in adults, or 20 mL/kg boluses in children, reassessing after each; failure to respond after roughly 40–60 mL/kg indicates a need for vasopressor support.Doctor / Nurse
Correct hypoglycaemia, which is common in severe meningococcal septicaemia: 50% dextrose 50–100 mL IV in adults (or equivalent volumes of 25% or 10% solutions) and 10% dextrose 2 mL/kg IV in children; check and replace calcium, magnesium, potassium and phosphate.Doctor / NurseNot available at your setup — Serum electrolytes.
Take blood cultures at the same time — positive in up to 75% of meningococcal disease — plus full blood count, renal and liver biochemistry, glucose, calcium, magnesium and phosphate, CRP, coagulation screen, blood gas with lactate, syphilis serology, a malaria film and rapid test where relevant, and a pregnancy test.Doctor / NurseNot available at your setup — Blood culture, Renal function (creatinine/urea), Liver function tests, Coagulation (PT/INR), Arterial blood gas.
Manage raised intracranial pressure: nurse head-up at 30 degrees with the head midline and nothing constricting the neck; correct hypoxaemia, hypercapnia, hypotension, hypoglycaemia, fever and hyponatraemia; mannitol 25–50 g IV as a bolus, controlled hyperventilation guided by blood gases and kept brief, and CSF drainage by repeated lumbar puncture or intraventricular catheter.Doctor / Nurse
Treat seizures with a benzodiazepine followed by a loading dose of levetiracetam, valproate or phenytoin; a patient who stops convulsing but does not wake is in non-convulsive status until electroencephalography proves otherwise.Doctor / Nurse
Purpura fulminans: send coagulation screen, fibrinogen and platelet count with early consideration of component support; amputation should usually be delayed to allow demarcation between viable and non-viable tissue, unless there is local infection.Doctor / NurseNot available at your setup — Coagulation (PT/INR), Blood & blood products.
Apply droplet precautions in suspected meningococcal disease for the first 24 hours of effective antibiotic therapy, notify public health at diagnosis, and arrange prophylaxis for close contacts: adult ciprofloxacin 500 mg orally once or rifampicin 600 mg twice daily for 2 days; child ciprofloxacin 30 mg/kg once (maximum 500 mg) or rifampicin 10 mg/kg (maximum 600 mg) twice daily for 2 days; neonates under 1 month rifampicin 5 mg/kg twice daily for 2 days; pregnancy a single intramuscular dose of ceftriaxone.
Tuberculous meningitis is treated presumptively once suspected: rifampicin, isoniazid and pyrazinamide for at least 9 months, with adjuvant prednisolone 60 mg daily for 3 weeks then tapered; cryptococcal meningitis is treated with amphotericin B plus flucytosine 25 mg/kg four times daily for at least 2 weeks, then oral fluconazole, with repeated therapeutic lumbar punctures for pressure.Doctor / Nurse

Caution— what harms

Never delay antibiotics for a lumbar puncture, and never delay them for a CT scan — lumbar puncture needs to be preceded by CT only if raised intracranial pressure is suspected, and requesting a scan reflexively in an alert patient with no focal signs and no papilloedema is a common cause of dangerous delay.
A normal CT does not exclude raised intracranial pressure — explicitly documented in meningococcal meningitis — so the decision to perform a lumbar puncture must be made on clinical grounds; "no mass lesion, no midline shift" does not license a tap in a patient with a GCS of 9 and a Cushing response.Not available at your setup — CT scan.
Do not tap against the contraindications: raised intracranial pressure (clinical or radiological), uncorrected shock, disordered coagulation or thrombocytopenia, respiratory insufficiency, local infection at the puncture site and ongoing convulsions.
Avoid lumbar puncture in meningococcal septicaemia — positioning may critically compromise the circulation in a hypovolaemic patient — and avoid it wherever possible in severe thrombocytopenia or coagulopathy, since a patient with purpura fulminans is coagulopathic by definition.
Where meningococcal disease is diagnosed clinically by the petechial rash, give immediate intravenous antibiotics and take blood cultures; lumbar puncture is unnecessary.
Cephalosporins do not cover Listeria — ampicillin (or co-trimoxazole in penicillin allergy) must be added for anyone over 50, pregnant, alcoholic, diabetic, immunosuppressed or with malignancy.
Avoid ceftriaxone in neonates (bilirubin displacement, incompatibility with calcium-containing infusions) and never use imipenem or ertapenem for meningitis because of seizure risk.
Do not stop antibacterial therapy when aciclovir is started — the two syndromes cannot be distinguished clinically, and Listeria may produce an identical picture, often with a polymorphonuclear pleocytosis, requiring ampicillin.
Do not stop aciclovir on a negative early PCR: in suspected herpes encephalitis CSF PCR may be falsely negative within the first 48 hours of symptom onset — repeat it; antibody titres rarely rise before day 10 and are useful only retrospectively.
Do not misread the CSF: the glucose is meaningless without a simultaneous blood glucose, some polymorphs occur early in viral meningitis and encephalitis, Listeria often produces a polymorphonuclear pleocytosis, and with a traumatic tap the safest approach is to treat for bacterial meningitis if the white cell count is above normal and disregard the red cell count.
Do not be reassured by prior antibiotics or a sterile pleocytosis: 12–24 hours of effective antibiotic reduces positive Gram stains by 20% and culture by 30–40% but has little effect on cell count, protein or glucose, and a sterile pleocytosis is not synonymous with "viral".
Do not withhold treatment from a sick child on the basis of a score: the Bacterial Meningitis Score is not validated under 2 months, in pre-treated or critically ill children.
Do not use therapeutic-dose glucocorticoid in meningococcal septicaemia (replacement doses only, in refractory shock with impaired adrenal responsiveness); activated protein C is not used — paediatric sepsis trials found no benefit and a potential bleeding risk.
Do not miss the traps in prophylaxis and follow-up: avoid sodium polyanethol sulfonate culture media, which may inhibit meningococcal growth; give prophylaxis to all contacts at the same time to avoid recolonisation; the index case also needs carriage eradication unless treated with ceftriaxone or cefotaxime; and arrange audiometry early for every survivor because cochlear ossification may make later implantation impossible.

Refer / escalate

Escalate immediately — after the first antibiotic and dexamethasone dose, never before it — for falling GCS or GCS 8 or less, signs of raised intracranial pressure, shock unresponsive to 40–60 mL/kg of fluid, rapidly extending purpura, new focal deficit or seizure, or any encephalitic feature requiring aciclovir and neuroimaging.

The card — assess, manage, caution

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