Objectives • To define bacterial meningitis • To discuss the causative pathogens • To discuss clinical presentation • To discuss diagnosis and lumbar puncture • To discuss management including antibiotics and dexamethasone • To discuss outcomes and follow up • To discuss Meningococcal disease • To discuss prevention
What is meningitis ? • Meningitis • Encephalitis • Meningoencephalitis
Bacterial Pathogens • Depends on Age • Depends on underlying conditions • Depends on vaccination status • Depends on Geographical location
Bacterial Pathogens Neonatal period • Group B Strep. 49% • E.Coli 18% • Listeria 7% • Misc. Gram. Neg. 10% • Misc. Gram. Pos. 10%
Bacterial Pathogens Older than 1 month • Neiserria Meningitidis(Meningcoccus) • Strep. Pneumoniae (Pneumococcus) • H.influenzae ( Now rare )
Bacterial Pathogens V-P Shunt • Staph. Epidermidis • Staph. Aureus • Coliforms Post Head injury • Strep. Pneumoniae most common if CSF leak ( Consider s.aureus/Pseudomonas)
Symptoms of Meningitis Depends on Age Older Child • Fever, Chills, vomiting, photophobia & severe headache • Seizures Younger Child • More subtle – poor feeding, drowsy, quiet, ‘Not herself’
Clinical Signs of Meningitis Signs of infection: Fever, pallor. Raised ICP: Elevated BP with decreased Heart rate. Papilloedema Nuchal Rigidity: Neck stiffness – not soreness
Clinical Signs of Meningitis Kernigs: “If one attempts to extend the patient’s knees one will succeed only to an angle of approximately 135°. In cases in which the phenomenon is very pronounced the angle may even remain 90°.” Brudzinskis: With the patient lying on the back: if the neck is forcibly bended forward, there occurs a reflexive flexion of the knees.
Role of Lumbar Puncture (LP) • CSF analysis and culture is the definitive method of diagnosis • Identifying pathogen allows rationalisation of antibiotic treatment and collection of epidemiological information • Definitive diagnosis allows better outcome prediction.
Role of Lumbar Puncture When to LP? • When meningitis is suspected • When its safe ! • ? Role of CT • Sterilisation of CSF after antibiotics • Molecular techniques
Contraindications to Lumbar Puncture Signs of cerebral herniation • GCS < 8 • Abnormal pupillary signs • Abnormal tone / posture • Papilloedema Focal neurological signs Cardiorespiratory compromise Obvious signs of Meningococcaemia
Management Airway Breathing Circulation Drugs
Circulation How much fluid? • Fluid restriction no longer recommended in meningitis • Consider SIADH in later management • Massive fluid resuscitation may be required for meningococcal sepsis
Antibiotics Choice depends on • Causative Pathogen • Resistance of Local pathogens • Penetrance of CSF
The role of Steroids • Dexamethasone now recommended for all types of bacterial meningitis. • Improved neurological outcome – especially hearing. • Must be given early – with initial antibiotics. • Some concern over use with resistant pneumococcus
Complications Early & Late include • Circulatory collapse – not just meningococcal • Focal neurological abnormalities • Hydrocephalus • Brain abscess • Seizures
Outcome from Bacterial Meningitis Mortality - Less than 10% • Reports of less than 2% in infants and children • Reports of up to 30% in Neonates and Adults Morbidity – 15% (10-30%) • Hearing • Seizures • Learning problems • Lower IQ when compared with sibs
Meningococcal Disease • May present as meningitis or as sepsis (Meningococcaemia) or both. • Significant differences in management depending on presentation. • Endotoxins trigger “Sepsis Syndrome” • Meningococcaemia may cause profound shock and may require significant fluid resuscitation. • Also associated with Disseminated intravascular coagulation (DIC). • Mortality reduced by early recognition and administration of IM Penicillin
Prevention of Bacterial Meningitis Vaccination • H.Influenzae – incidence decreased by > 99% • Meningococcal A & C – Problems with B • Polyvalent pneumococcal • New vaccines Perinatal Screening • HVS for Group B Strep. • Antepartum penicillin Chemoprophylaxis • House hold contacts of children with meningococcus or H. influenza • Usual treatment Rifampicin for 2/7
Conclusions • Significant infection • Pathogen usually depends on age of the child • Choice of antibiotic is based on the likely pathogen • Meningococcal disease may manifest as meningitis or sepsis – separately or combined • Prevention is still better than cure
References • Bacterial meningitis in children Xavier Sáez-Llorens, George H McCracken Jr The Lancet. Volume 361 Issue 9375 Page 2139 • Diagnosis and treatment of bacterial meningitisH El Bashir, M Laundy, and R BooyArch. Dis. Child., Jul 2003; 88: 615 - 620.