Meningitis Flashcards
Define
- inflammation of the menignes
- Diagnosis is confirmed by finding WBCs in the CSF
- Viral infections are the MOST COMMON cause of meningitis- most are self-resolving
- Much of the damaged caused by meningeal infection results from the host response to infection and NOT from the organism itself
The release of inflammatory mediators and activated leukocytes, together with endothelial damage, leads to:
1. Cerebral oedema
2. Raised ICP
3. Decreased cerebral blood flow
The inflammatory response below the meninges causes a vasculopathy leading to cerebral cortical infarction -» hydrocephalus
Causes
< 3 months (GEL acronym)
- GBS
- E. coli
- Listeria monocytogenes
- N. meningitides
- S. pneumoniae
- H. influenzae
3 months- 6 years (NHS acronym)
- N. meningitides
- H. influenzae
- S. pneumoniae
> 6 years - N. meningitides
- S. pneumoniae
Symptoms and signs
- Fever
- Headache
- Neck stiffness
- Photophobia
- Non-blanching rash
- Altered consciousness and seizures
- Shock- hypotension, tachycardia
- Focal neurological signs
- Diarrhoea, abdominal pain/ distension
- Sore throat/ coryza, other ENT symptoms or signs
- Papilloedema (rare)
Neonates and babies present with non-specific signs:
* IRRITABILITY
* Poor feeding
* Drowsy
* Seizures
* Bulging fontanelle
* Opsithotonus (arching of back)
Positive Brudinski’s/ Kernig’s sign (more in older children like after the age of 2)
* Kernig’s sign looks like a K - flex hip and knee at 90 degrees then keep hip flexed and straighten knee will cause pain
* Brudzinki’s test: Flexing head and neck will cause involuntary flexing of knee and hip
- HR starts high to compensate ischaemia in brain
- HR then drops as baroreceptors in heart sense high BP (from HR)
Raised ICP symptoms (late signs) = Cushing’s Triad:
High BP + Low HR + Irregular RR
NOTE: neck stiffness may be seen in some children with tonsillitis and cervical lymphadenopathy
IMPORTANT: purpura in a febrile child of ANY AGE should be assumed to be due to meningococcal sepsis, even if the child does not seem particularly ill at the time
Investigations
A –> E approach
Particularly looking for:
- Signs of shock (low BP, high HR)
- Signs of decreaed consciousness
- Non-blanching rash
- Obs
- AVPU
- Neuro exam to look for any signs of raised ICP
- FUNDOSCOPY FOR ICP - papilloaedema
After A to E:
- LP (CT head before LP if concerns of raised ICP – not routine however) – contraindications
* Midline shift in CT
* Signs of bulging fontanelle
* Coagulopathy/ DIC/ thrombocytopenia
* Local infection @ sign of LP
* Meningococcal septicaemia
* Focal neurological findings, papilloaedema on fundoscopy)
* Coma, papilloedema, Cushing’s reflex (high BP, low HR, low RR)) - Blood culture (an LP would be done before this!)
- FBC, CRP, U&E and glucose
- Coagulation profile
- Rule out other infections:Throat swab, urine, stool (+ LP)- culture and PCR for bacteria or viruses + Urine dip - rule out an UTI
LP
* Lymphocytes can predominate in bacterial meningitis e.g. Lyme disease
* Glucose can be low in viral meningitis e.g. enterovirus meningitis
* Bacterial - neutrophils (polymorphs) are high!
Differentials
DDx
Encephalitis (tend to present more with neuro signs)
UTI
Gastroenteritis
LRTI/ URTI
Management of bacterial meningitis
Admit to hospital and follow sepsis 6 pathway
1) Antibiotics:
Child <3m old:
* IV cefotaxime
* IV amoxicillin / ampicillin
Child >3m old:
- IM benzylpenicillin, STAT (if penicillin allergy -> moxifloxacin & vancomycin)
- IV ceftriaxone for:
- Haemophilus influenzae type b – 10 days
- Streptococcus pneumoniae – 14 days
- Neisseria meningitidis (meningococcal meningitis) – 7 days
2) Steroids (dexamethasone) – if CSF shows…
- Purulent CSF
- WBC >1,000/u
- Raised CSF WCC + protein >1g/L
- Bacteria gram stain
- > 1m old & H. influenzae
- NOT MENINGOCOCCAL
3) Mannitol (reduce ICP)
4)
5) 4) IV saline sodium chloride 0.9% [4-2-1 maintenance]
Notify HPU, review patient 4-6w after discharge, discuss long-term potential complications:
* Hearing loss -> audiological assessment
* Orthopaedic, skin, psychosocial complications
* Neurological/development problems
* Renal failure
* Purpura fulminans = the haemorrhagic skin necrosis from DIC = acute/fatal, thrombotic disorder, manifest as blood spots/bruising/discolouration of skin (needs FFP, debridement or amputation)
o Treat contacts (ciprofloxacin) and offer further support (www.meningitisnow.org)
Complications
Hearing impairment
* Inflammatory damage to the cochlear hair cells may lead to deafness
* All children who have had meningitis should have an audiological assessment done promptly, as children with hearing impairment may benefit from hearing amplification or a cochlear implant
Neuro deficit
* Learning Disabilities
* Memory loss
Local vasculitis
* This may lead to cranial nerve palsies or other focal neurological lesions
Local cerebral infarction
* This may result in focal or multifocal seizures
* May subsequently lead to epilepsy
Subdural effusion
* Particularly associated with H. influenzae and pneumococcal meningitis
* Most spontaneously resolve but some require neurological intervention
Hydrocephalus
* May result from impaired resorption of CSF (communicating hydrocephalus) or blockage of the cerebral aqueduct or ventricular outlets by fibrin (non-communicating hydrocephalus)
* A ventricular shunt may be required
Purpura fulminans = the haemorrhagic skin necrosis from DIC = acute/fatal, thrombotic disorder, manifest as blood spots/bruising/discolouration of skin (needs FFP, debridement or amputation)
Prognosis
Pneumococcal meningitis has poorer outcome than Neisseria meningitidis and Hib
NOTE: In practice, all children with suspected meningitis are usually treated as per meningoencephalitis
Viral meningitis
> 2/3 of CNS infections are VIRAL
Causes:
* Enteroviruses
* EBV
* Adenoviruses
* Mumps
NOTE: mumps meningitis is now rare in the UK due to MMR vaccine
HSV, VZV
* IV Aciclovir- every 8 hours
* Supportive therapy
CMV
* IV Ganciclovir every 12 hours
* Supportive therapy
Treatment course is 7-10 days
PACES
Name of Diagnosis:
* Emma has meningitis
Briefly explain what it is:
* Meningitis is an infection that affects the lining of the brain.
How is it managed:
* It can be a serious infection so it is important that we keep her in hospital and look after her well.
* At the moment she is looking a bit dry so we’re giving her some fluids to rehydrate her.
* Alongside that we are giving her some antibiotics through her vein.
Risks/Safety net:
* In some cases, meningitis can cause problems like deafness
* However, to reduce the risk of this happening, we are also giving her some steroids for 4 days.
* We will also be seeing Emma a month after leaving the hospital to check that her hearing has not been affected.
Leaflets/Offer more information:
Does this all make sense? Do you have any questions?
Other info
Since Meningitis can also spread to other people, we have notified Public Health England.
And they will be in touch with you to find out who Emma has been in contact with over the last week as they would need to have some prophylactic antibiotics to protect themselves from getting the same infection
