Introduction

Meningitis and meningococcal disease are difficult to diagnose and a high index of suspicion is needed, particularly given the potential damage that late diagnosis can have.

Epidemiology

  • Incidence: 8.00 cases per 100,000 person-years
  • Peak incidence: 1-5 years
  • Sex ratio: 1:1
Condition Relative
incidence
Febrile convulsions262.50
Bacterial meningitis1
Immune thrombocytopenia (ITP) in children0.13
Central venous thrombosis0.11
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Clinical features

NICE recommend the following in their guidelines:


Be aware that bacterial meningitis and meningococcal disease can present similarly to less serious infections (often viral).
  • Note that classical signs of meningitis are often absent in infants with bacterial meningitis.
  • Symptoms can progress rapidly and often become more specific and severe with time.

Symptoms

Signs

Investigations

Investigations suggested by NICE
  • full blood count
  • CRP
  • coagulation screen
  • blood culture
  • whole-blood PCR
  • blood glucose
  • blood gas

Lumbar puncture if no signs of raised intracranial pressure.

The table below summarises the characteristic cerebrospinal fluid (CSF) findings in meningitis:

BacterialViralTuberculous
AppearanceCloudyClear/cloudySlight cloudy, fibrin web
GlucoseLow (< 1/2 plasma)60-80% of plasma glucose*Low (< 1/2 plasma)
ProteinHigh (> 1 g/l)Normal/raisedHigh (> 1 g/l)
White cells10 - 5,000 polymorphs/mm³15 - 1,000 lymphocytes/mm³10 - 1,000 lymphocytes/mm³

The Ziehl-Neelsen stain is only 20% sensitive in the detection of tuberculous meningitis and therefore PCR is sometimes used (sensitivity = 75%)

*mumps is unusual in being associated with a low glucose level in a proportion of cases. A low glucose may also be seen in herpes encephalitis

Management

All patients should be transferred to hospital urgently. If patients are in a pre-hospital setting (for example a GP surgery) and meningococcal disease is suspected then intramuscular benzylpenicillin may be given, as long as this doesn't delay transit to hospital.

BNF recommendations on antibiotics

ScenarioBNF recommendation
Initial empirical therapy aged < 3 monthsIntravenous cefotaxime + amoxicillin
Initial empirical therapy aged 3 months - 50 yearsIntravenous cefotaxime*
Initial empirical therapy aged > 50 yearsIntravenous cefotaxime + amoxicillin
Meningococcal meningitisIntravenous benzylpenicillin or cefotaxime
Pneuomococcal meningitisIntravenous cefotaxime
Meningitis caused by Haemophilus influenzaeIntravenous cefotaxime
Meningitis caused by ListeriaIntravenous amoxicillin + gentamicin

Intravenous dexamethasone should also be given to reduce the risk of neurological sequelae.

If the patient has a history of immediate hypersensitivity reaction to penicillin or to cephalosporins the BNF recommends using chloramphenicol.


*in the 2015 update of the NICE Meningitis (bacterial) and meningococcal septicaemia in under 16s: recognition, diagnosis and management the recommendation for initial empirically therapy for children > than 3 months is intravenous ceftriaxone

Screening and prevention

Management of contacts
  • prophylaxis needs to be offered to household and close contacts of patients affected with meningococcal meningitis. Prophylaxis should also be offered to people who been exposed to respiratory secretion, regardless of the closeness of contact
  • people who have been exposed to a patient with confirmed bacterial meningitis should be given prophylactic antibiotics if they have close contact within the 7 days before onset
  • oral ciprofloxacin or rifampicin or may be used. The Health Protection Agency (HPA) guidelines now state that whilst either may be used ciprofloxacin is the drug of choice as it is widely available and only requires one dose
  • the risk is highest in the first 7 days but persists for at least 4 weeks
  • meningococcal vaccination should be offered to close contacts when serotype results are available, including booster doses to those who had the vaccine in infancy
  • for pneumococcal meningitis, no prophylaxis is generally needed. There are however exceptions to this. If a cluster of cases of pneumococcal meningitis occur the HPA have a protocol for offering close contacts antibiotic prophylaxis. Please see the link for more details