Meningitis

Disclaimer

These guidelines have been produced to guide clinical decision making for the medical, nursing and allied health staff of Perth Children’s Hospital. They are not strict protocols, and they do not replace the judgement of a senior clinician. Clinical common-sense should be applied at all times. These clinical guidelines should never be relied on as a substitute for proper assessment with respect to the particular circumstances of each case and the needs of each patient. Clinicians should also consider the local skill level available and their local area policies before following any guideline. 

Read the full PCH Emergency Department disclaimer.

Aim

To guide staff with the assessment and management of meningitis.

Background

  • Since it may be impossible in the Emergency Department to distinguish clinically between viral and bacterial meningitis, all cases of meningitis should initially be managed as if the cause were bacterial
  • Despite advances in the diagnosis and prevention of meningitis it remains a major cause of morbidity and mortality in children
  • Although a significant reduction in case numbers was achieved by the introduction of the vaccines against Haemophilus influenza type b and Streptococcus pneumoniae, meningitis continues to pose a risk of death or permanent disability to children.

The usual cause of meningitis in children differs according to age:

Age  Organism (in order of likelihood)
0 - 1 month Group B Streptococcus, Escherichia coli, Neisseria meningitidis, Haemophilus influenzae type b (Hib), Streptococcus pneumoniae, Listeria monocytogenes
1 -3 months  Neisseria meningitidis, Haemophilus influenzae type b (Hib),Streptococcus pneumoniae, Group B Streptococcus, Escherichia coli, Listeria monocytogenes
3 months - 5 years Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae type b (Hib) *
6 years and older Neisseria meningitidis, Streptococcus pneumoniae
  * Rare since the introduction of Hib vaccine

Assessment

History

  • Obtain a general medical history.

Important questions to ask early:

  • Immunisation status, ensure immunisations are not 'alternative medicine' or 'homeopathic'
  • Recent antibiotic use - as it could be partially treated meningitis, and recent antibiotic use may also be a risk factor for carriage of relatively resistant pneumococci requiring addition of vancomycin to the treatment regimen.

Examination

  • The child may be obviously unwell, look septic, moribund, floppy and pale with a high pitch cry
  • High fever, vomiting, neck stiffness and photophobia may be evident
  • The child may have an altered conscious level or focal neurological signs - 20% will have seizures sometime during the course of the illness.

Early presentation

  • Child may have less obvious signs of meningitis
  • Fever is common and headache, irritability, anorexia or vomiting may be present.

Neonates and infants

  • May present with non‐specific signs of infection such as poor feeding, irritability, lethargy, vomiting or fever without focus.
  • The clinician should have a high index of suspicion for the possibility of meningitis, and have a low threshold for performing a diagnostic lumber puncture.

Investigations

Lumbar Puncture (LP)

  • LP is the only way to confirm the diagnosis of meningitis
  • It allows identification of the organism and its antibiotic sensitivities, thus ensuring appropriate use of antibiotics
  • LP should (with few exceptions) be performed in every child who may have meningitis
  • A good rule of thumb is that if you are asking yourself "should this child have an LP?" the answer generally is "yes".

Contraindications for LP

  • Coma, decreased conscious state
  • Signs of raised intracranial pressure: altered pupillary responses, absent Doll's eyes reflexes, decerebrate or decorticate posturing, papilloedema, Cushing's Triad (abnormal respiratory pattern, hypertension, bradycardia)
  • Seizures
  • Focal neurological signs
  • Coagulopathy (e.g. disseminated intravascular coagulation in Meningococcal disease)
  • Shock, cardiovascular compromise
  • Respiratory compromise
  • Evolving petechiael/purpuric rash.

Not contraindications for LP

  • Brief tonic‐clonic, myoclonic, absence or atonic seizures, in isolation
  • Drowsiness
  • Irritability
  • Vomiting.

If LP is contraindicated start antibiotic treatment immediately and consider CT head.

CSF Volumes Required

  • An absolute minimum of 500 microlitres (0.5mL) is required, with 750 micro litres preferred
  • One drop of CSF = 30‐40 microlitres, thus a minimum of 15‐20 drops is needed, collected in three bottles.

Other tests

Test Tube - Specimen Container
Blood culture Where possible, a large volume of blood should be cultured
Ideally 5 mL in each of the adult aerobic and anaerobic culture bottles
FBC EDTA tube (purple/lilac top)
C-Reactive Protein Lithium heparin tube (green top)
PCR Meningococcal PCR – requires a second separate EDTA tube (purple/lilac top)
Electrolytes Especially for sodium, lithium heparin tube (green top)
Capillary / venous blood gas
Defines overall metabolic status of child
Clotting Blue top tube filled to and not beyond mark on tube 
Group and hold Pink top tube
Requires hand written patient information on the label, not patient sticker

Throat swab

  • PCR for Meningococcus

Cranial CT

  • This is of limited use in acute bacterial meningitis
  • CT does not reliably exclude raised intracranial pressure, and a normal CT should not reassure one about the risk of coning following an LP
  • CT does have a role when the diagnosis is in doubt (e.g. posterior fossa tumours can also cause meningism), or when complications of meningitis (e.g. brain abscess) are suspected.

Management

  • Time to antibiotics is crucial - early empirical antibiotics will decrease mortality
  • Ideally antibiotics should be given once the septic screen, including the LP is done, but if this is not possible do not delay antibiotic administration.

Antibiotics

Steroids

  • The role of steroids in the treatment of meningitis has been controversial
  • A recent Cochrane review states that steroids may reduce neurological sequelae (particularly hearing loss) in meningitis
  • Current management at PMH is to give IV Dexamethasone 0.2 mg/kg 6 hourly
  • Where possible, give the first dose just prior to or at least concurrently with antibiotics
  • However antibiotics should never be delayed when Dexamethasone is not immediately available.

Fluids

  • Patients with meningitis are at risk of hyponatremia secondary to syndrome of inappropriate antidiuretic hormone hypersecretion (SIADH)
  • Therefore any maintenance or replacement fluid should be isotonic (0.9% saline), with or without glucose (5%)
  • Intravenous fluid rate should be at 30‐70% maintenance
  • Careful management of fluids and electrolytes is essential in the treatment of meningitis
  • Under-hydration, over-hydration, and rapid shifts in cerebral fluid balance are all associated with an adverse neurological outcome
  • Maintaining a normal blood pressure and circulating volume is essential to maintain optimal cerebral perfusion
  • If the child is hypotensive, this should be treated with a bolus of 20 mL/kg of 0.9% saline. If the child remains shocked, a further bolus of 10 mL/kg of 0.9% saline should be given, and advice should be sought from PICU
  • If the child was not initially hypotensive a more cautious approach is needed to avoid precipitating / exacerbating cerebral oedema, and boluses of IV fluid should be avoided.

Admission criteria

  • All children with suspected meningitis will be admitted under the General Paediatric Team.

Bibliography

  1. Cochrane Summary: Corticosteroids for Bacterial Meningitis
  2. Muller, Martha L. "Pediatric Bacterial Meningitis." Medscape.com. Jan. 30, 2014. <http://emedicine.medscape.com/article/961497-overview>
  3. Textbook of Pediatric Emergency Medicine. 6th ed. Fleisher GR, Ludwig S. Philadelphia: Lippincott Williams & Wilkins, 2010
  4. Nelson Textbook of Pediatrics: 20th Edition Robert M. Kliegman, Bonita M.D. Stanton, Joseph St. Geme, Nina F Schor Publisher: Elsevier
  5. Textbook of Paediatric Emergency Medicine 2nd Edition Cameron Elesevier 2012

Endorsed by:  Director, Emergency Department   Date:  Mar 2018


 Review date:   Mar 2021


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