Adult meningitis

Important points

• Neck stiffness is absent in 18% of patients
• Skin rashes are more common in meningococcal than in pneumococcal meningitis
• The initial rash in meningococcal infection may be non-specific (50% of patients with meningococcal meningitis do not have a rash on first presentation)
• Fundoscopic abnormalities are unusual
• Papilloedema, although an uncommon manifestation of rapid onset ↑ICP is a definite contra-indication to lumbar puncture without prior CT
• Cranial nerve palsies (notably nerves III, IV, VI and VII) and focal neurological signs occur in 10-30% of cases. They may be an early sign in Listeria meningitis
• Abnormal mental states found in 85% of patients (may be only sign in the elderly)
• Seizures occur in about 30%. Pneumococcal > meningococcal
• Tuberculous meningitis may present with an abrupt onset of meningeal signs but more commonly presents as a slow onset of vague illness with fever, developing headache and mental state changes. In some patients fever is minimal. 16 - 50% have evidence of TB outside the CNS (pulmonary or miliary). Discuss cases with the duty microbiology consultant. A viral prodrome with headache, confusion and less meningitic features is suggestive of viral encephalitis. Discuss with duty consultant virologist

Table III Clinical symptoms and signs in 132 adults with community acquired bacterial meningitis in Iceland.

• Fever (>30ºC) on admission 97%
• Fever > one day 12%
• Neck stiffness 82%
• Abnormal mental states 66%
• Confused or lethargic 45%
• Only responsive to pain 8%
• Unresponsive to pain 11%
• Triad of fever, neck stiffness and Impaired consciousness 51%
• Seizures 10%
• Rash 52% (petechial, purpuric or maculopapular

Approach algorithm

Resusc. Management

Airway Management

• Consider RSI in patients with airway compromise
• Contact ICU at an early stage

Breathing Management

Early assisted ventilation is required if there is:

• Hypoxaemia persisting despite administration of high flow oxygen and/ or
• Hypercapnia and/or
• A vulnerable airway and/or
• Prolonged or uncontrolled seizures and/or
• Heart failure arising from myocardial depression
• Clinical signs of raised intracranial pressure
• A declining conscious level

Circulatory Management

Treatment aims are adequate cardiac output/oxygen delivery and therefore organ perfusion.

• Patients should be kept euvolaemic (not fluid restricted)
• Fluid resuscitation with CVP response to fluid
• Consider inotropes early, if no response to fluid
• Beware coagulopathy; (DIC & thrombocytopenia). Treatment is given if coagulopathy is severe or symptomatic, or prophylactically prior to invasive procedures

Disability (Neurological) Management

• Patients with significant ↑ICP should be intubated and given appropriate therapy to reduce ICP
• Routine use of intracranial pressure monitoring is not recommended. It should be considered if evidence of ⇑ICP (papilloedema/pupillary signs)
• Mannitol should be considered in patients with impaired conscious levels, lateralising neurological signs, markedly raised opening pressure at LP or CT evidence of cerebral oedema
• Patients with seizures requiring mechanical ventilation and neuromuscular paralysis should have continuous electroencephalogram monitoring to exclude ongoing seizure activity
• Nurse patients head up at 30°
• Avoid neck lines

Renal Management

Renal replacement therapy should be considered if:

• Persisting oliguria despite restoration of adequate cardiac output, or
• Hyperkalaemia, or
• Severe metabolic acidosis, or
• Severe metabolic acidosis secondary to renal failure, or
• Fluid overload, or
• Need for intravascular compartment space for administration of drugs or nutrition

ICU should be involved early

The following patients require intensive care unit facilities and expertise:

• Those with CNS depression
• Those with airway or respiratory instability
• Those with cardiovascular instability with ⇓BP not responding promptly to fluid challenges, oliguria persisting for more than 2-3 h or rising acidosis
• Those with neurological impairment and/or seizures;

There are five life support interventions which are best carried out in an intensive care unit.

1. Respiratory support techniques including tracheal intubation, mechanical ventilation, continuous positive airways pressure (CPAP) or biphasic positive airways pressure, or possibly extracorporeal oxygenation techniques
2. Specialised cardiovascular monitoring possibly including monitoring of cardiac output, blood gases, art. line or other haemodynamic monitoring techniques, e.g. oesophageal Doppler US or ECHO
3. Inotropic/vasopressor support
4. Specialised neurological monitoring including ICP monitoring, jugular venous bulb catheterisation for monitoring of jugular venous bulb saturation, cerebral venous lactate measurement, middle cerebral artery Doppler blood flow measurement, and continuous EEG monitoring.;
5. Renal replacement therapy.

Antimicrobial Therapy CUH

• Give Dexamethasone 0.15mg/kg q6h iv just before first dose of antibiotics. Avoid in septic shock. Steroids are not indicated in meningococcal septicaemia. Discontinue if a cause other than S. pneumoniae or H. influenzae identified
• 2G CefTRIAXone q12h
• Add Amoxicillin 2g q4h iv if Listeria monocytogenes suspected
  • Risks for Listeria: age >50, unsuppressed, pregnancy, alcohol, malignancy
• If penicillin allergy discuss with micro. before:
  • Meropenem 2g q8h iv
  • or
  • Chloramphenicol 25mg/kg q6h iv PULS Vancomycin 25mg/kg (max 2g) loading then 15mg./kg q12h

For patients with meningitis (not septicaemia) give dexamethasone 0.15mg/kg q6h iv

Contacts and admission

• Close contacts should be given prophylaxis if meningococcal infection is likely
• The consultant responsible for the patient's care should be informed of the admission as soon as is reasonable
• If bacterial meningitis is possible the relevant Consultant in Communicable Disease control should be contacted without delay. Prophylaxis in the community should not normally be undertaken by admitting clinicians

CSF findings in acute meningitis

1. If the diagnosis is in doubt, give antibiotics microbiology team review at 48°)
2. In partially treated bacterial meningitis lymphocytes may be predominate. Protein is often high
3. The CSF is usually normal in meningococcal septicaemia and it may be microscopically and biochemically normal in 5-10% of patients in the early stages of meningococcal meningitis subsequently confirmed by culture of the same specimen
4. Microbacterium tuberculosis is seen in the initial CSF in only about 40% of samples from patients who have tuberculous meningitis. Initial suspicion may have to rely on the finding of low cerebrospinal glucose level and a high protein level in patients with a lymphocytic meningitis. However, in early tuberculous meningitis the CSF may show a polymorphonuclear response and even the protein level may occasionally be normal. Consult with the on call microbiologist

Prophylaxis

Bacterial meningitis is a notifiable disease.

Inform Public Health ad complete the Infectious Diseases Notification Booklet available on the wards. Public Health will advise on chemoprophylaxis of contacts.

Vaccination of contacts and index may be indicated if exposed to Neisseria meningitidis Groups B, C, A, Y or W135, Haemophilus influenzae type b or pneumococcal meningitis. Contact Public Health for advice.