Meningitis Flashcards
How does meningitis cause hydrocephaly?
The release of inflammatory mediators and activated leucocytes, together with endothelial damage, leads to cerebral oedema, raised intracranial pressure, and decreased cerebral blood flow.
The inflammatory response below the meninges causes a vasculopathy resulting in cerebral cortical infarction, and fibrin deposits may block the resorption of CSF by the arachnoid villi, resulting in hydrocephalus.
What causative organisms from 0-3 months?
Group B Streptococcus (most common cause in neonates) - acquired from mother
E. coli
Listeria monocytogenes
Causative organisms from 3m to 6y
Neisseria meningitidis
Streptococcus pneumoniae
Haemophilus influenzae
Causative organisms from 6y to 60y
Neisseria meningitidis
Streptococcus pneumoniae
Causative organisms > 60y
Streptococcus pneumoniae
Neisseria meningitidis
Listeria monocytogenes
Causative organism in immunosuppressed
Listeria monocytogenes
Risk factors for GBS infection?
Low birth weight
Prolonged rupture of membranes
What are clinical features of meningitis?
Headache Fever Nausea/vomoting Photophocia Drowsiness Seizures Neck stiffness Purpuric rash
What does purpura in a febrile chil likely indicate?
Meningococcal sepsis
What is Brudzinski’s sign?
Flexion of the neck with the child supine causes flexion of the knees and hips
What is Kernig’s sign?
With the child lying supine with the hips and knees flexed, there is back pain on extension of the knee
What investigations in meningitis?
FBC Blood glucose Blood gas for acidosis Coagulation screen CRP U&E LFT
Blood culture
Throat swab
Urine
Stool for bacteria
Rapid antigen test for menignitis orgnaisms - blood, CSF or urine
Samples for vital PCT - throat swab, NPA, conjunctiva swab, stool
Lumbar puncture for CSF unless CI
Serum for compareison of titres
PCR of blood and CSF
CXR and Mantoux if TB suspected
CT/MRI
EEG
What are contraindications to LP?
Cardiorespiratory instability Focal neurological signs Signs of RICP - coma, high BP, low heart rate, papilloedema Bulging of fontanelle DIC Coagulopathy Thrombocytopenia Local infection at the site of LP If it causes delay instating ABX
MEningococcal septicaemia
CSF Normal - Appearance, Glucose, Protein, WBC
Appearance - Clear
Glucose - >= 50% of blood
Protein - 0.14-0.4g/L
WBC - 0-5/mm^3
CSF - Bacterial meningitis: Appearance Glucose Protein WBC
Appearance: Turbid
Glucose: LowLow <1/2 plasma
Protein: HighHigh > 1g/L
WBC: Raised polymorphs 10-5000/,,^3
CSF - Viral meningitis
Appearance: Clear
Glucose: Normal/Low
Protein: Normal/High
WBC: Lymphocytes raised 15-1000/mm^3
CSF - Tuberculosis
Appearance: Turbid/clear/viscous - slightly cloudy, fibrin web
Glucose: LowLowLow < 1/2 plasma
Protein: High High High > 1g/L
WBC: Raised lymphocytes 10-1000/mm^3
Management of meningitis?
Antibiotics
Steroids:
If > 1 month and Haemophilus influenzae give dexamethasone
Fluids
Treat shock
Cerebral monitoring
Mechanical ventilation if respiratory impairment
Public health notifications and antibiotic prophylaxis of contacts:
Ciprofloxacin
What antibiotics if < 3months? > 3 months > 50 years Meningococcal meningitis Listeria menignitis
IV amoxicillin + IV cefotaxime
> 3m
IV Cefotaxime
> 50 years
IV cefotaxime + IV amoxicillin
Meningococcal meningitis
IV benzylbenicillin or cefotazime
Listeria
IV amoxicillin + gentamicin
Chloramphenicol of pen allergic
Management of meningitis if in pre-hospital setting
Transfer to hospital urgently
Give IM benzylpenicillin while waiting - don’t delay transfer
Why should steroids be given?
IV dexamethasone to reduce risk of neurological sequelae
What management of contacts
Prophylaxis to household and close contacts - Ciprofloxacin
People who have been exposed to patient if they have had close contact within 7 days before onset
Meningococcal vaccination offered to close contacts when serotype results are available including booster doses to those who had vaccine in infancy
What are neurological sequelae of meningitis?
Deafness/hearing impairment - audiology assessment Local vasculitis - focal neurological lesions Local cerebral infarction Subdural effusion Hydrocephalus Brain herniation Cerebral abscess sepsis
What are causes of viral meningitis?
Enteroviruses
Epstein Barr virus
Adenovirsues
Mumps
Diagnose by culture or PCR of CSF, stool, urine nasopharyngeal aspirate, throat swabs and serology
When are Meningitis B vaccinations given?
Men ACWY
2 months
4 months
12-13 month
ACWY - 13-18 years and to students up to 25
