Meningitis Flashcards
What is meningitis?
It is inflammation of the leptomeninges (arachnoid and pia mater)
What is encephalitis?
It is inflammation of the brain
What is the pathogenesis of meningitis?
The host body produces cytokines like tumor necrosis factor and interleuki-1 which results increased ice, permeability of BBB, vasogenic, cytotoxic and interstitial oedema and decreased cerebral flow
What are the most common symptoms of meningitis?
- Fever
- Headaches or nausea/vomiting(signs of raised ICP)
- Stiff neck or kernigs or brudzinki’s sign
What are the neonatal signs of meningitis?
Difficult to tell in neonates
- poor feeding
- lethargy
- bulging fontanelle
- hypothermia/hyperthermia
- irritability
What are the things that cause an increase in risk for meningitis in babies?
- Low birth weight
- Prolonged delivery
- Premature rupture of membrane
- Male
What specific pathogens cause meningitis in neonates?
- E. Coli
- Listeria
- Group B streptococcus
What specific pathogens cause meningitis in infants? (1 month to 2 years)
- Group B streptococcus
2. Streptococcus penumoniae
What specific pathogens cause meningitis in children and teens?
- Neisserra meningitidis
2. Streptococcus pneumoniae
What kind of organism is streptococcus pneumoniae?
Gram positive diplococci
Why do children with sickle cell have higher changes of streptococcus pneumonia meningitis?
They have functional asplenia
Which patients are most likely to get streptococcus pneumonia meningitis?
-skull fractures, paranasal sinuses, frontal bone fractures that lead to CSF leak and ottorhea
What kind of organism is Neissera meningitidis?
Gram negative
How does neissera meningitidis present in babies?
- with petechiae or purport
- we can scrape the rash to find the organism
- they release endotoxins which can cause shock, bilateral adrenal haemorrhage and DIC
What is the histology of haemophillus influenza?
Gram negative pleomorphic bacillus
How can haemophillus influenza present?
- slow onset
- usually in children who come from overcrowding, children with splenectomies
What does haemophillus influenza meningitis cause?
- hearing loss
- epileptic fits
- mental retardation
- subdural effusions
How do we diagnose meningitis?
- LP
- make sure the child is not comatose before doing the LP because there could be a space occupying lesion
- Rather do a CT/MRI scan
In which situations would we do an MRI/CT?
- Prolonged coma
- Decreased level of consciousness
- Altered mental status
- Hydrocephalus
- Purulent otitis media-possible brain abscess
What makes it difficult to diagnose meningitis?
- Partially treated meningitis with AB
- TBM diagnosis because the neutrophils occur early and then turn into lymphocytes
- Early viral encephalitis
- Recurrent meningitis
What causes recurrent meningitis?
-it is rare firstly
-but causes include some anatomical, surgical or medical disorder
Examples include: organism resistant to AB and sickle cell anaemia and splenectomies
What complications can meningitis cause?
- Epileptic fits
- Thrombosis of veins and small arteries
- Subdural effusions
- Hydrocephalus
- Cranial nerve palsy-sensorineural hearing loss
- Hemiplegia
- Cerebral oedema
- Syndrome of inappropriate ADH secretion
- Cerebral oedema
What organisms contribute more to subdural effusions?
- H. Influenza, strep pneumonia, N meningitidis
Why should we be careful of giving benzodiazepines and phenobarbitone in patients with epileptic fits?
-this can cause respiratory and CNS depression
Which group gets hydrocephalus more?
Neonates get hydrocephalus more than older kids
What are the symptoms of syndrome of inappropriate ADH secretion?
Irritability and convulsions which occurs in 15-20% of patients
Hyponatraemia
What can we expect in a normal child when we do an LP?
- 0 neutrophils and 1-6 lymphocytes
- Glucose- 3,6 to 5,6
- 0,15-0,45 protein
What can we expect on LP in a child with bacterial meningitis?
- 100-50 000 neutrophils predominantly
- Glucose 1,1-1,6
- Protein mild or moderately increased
What can we expect on LP in viral meningitis?
- 25-500 lymphocytes predominantly
- Glucose normal
- Protein mildly increased
What can we expect in LP in TBM?
- Neutrophils predominate early
25-100 lymphocytes - Glucose 2,2-2,7 but usually below 0,5
- Protein-moderately increased
What is the treatment for meningitis?
It is categorized according to whether the child <2 months or >2 months
1. <2 months
Cefotaxime 50mg/kg AND ampicillin 50 mg/kg AND gentamycin
- > 2 months
Give ceftriaxone 100mg/kg OR cefotaxime 75 mg/kg AND dexamethesone 0,6mg/kg
Make sure to give dexa 30 minutes before the antibiotic
Supportive Rx: oxygen and nebuliser
How long do we give the treatment in group B streptococcus
14 days
Which meningitis has the worst prognosis’s?
Pneumococcal meningitis, has a mortality of >10% and neurological sequelae
What prophylaxis do we need to do?
This is for family and nursery school contacts
N. Meningitidis we give rifampicin and ceftriazone
H. Influenza we give (usually <5 year old family members)
We give rifampicin 20mg/kg
