Meningitis & Encephalitis Flashcards
What bacteria causes meningococcal septicaemia?
Neisseria meningitidis
What is meningococcal septicaemia?
Refers to the meningococcus bacterial infection in the bloodstream.
This is the cause of the classic “non-blanching rash”.
The rash indicates the infection has caused disseminated intravascular coagulopathy (DIC) and subcutaneous haemorrhages.
What are the 2 most common causes of bacterial meningitis in children & adults?
1) Neisseria meningitidis (meningococcus)
2) Strep. pnuemoniae (pneumococcus)
In neonates, what is the most common cause of bacterial meningitis?
Group B strep (GBS) (Strep. agalactiae)
How is GBS contracted in the neonates?
During birth from GBS bacteria that live harmlessly in the mother’s vagina.
Clinical features of bacterial meningitis?
- headache
- fever
- nausea/vomiting
- photophobia
- drowsiness
- seizures
- neck stiffness
- purpuric rash (particularly with invasive meningococcal disease)
Presentation of bacterial meningitis in neonates?
Non-specific signs e.g. hypotonia, poor feeding, lethargy, hypothermia, and a bulging fontanelle.
When is a lumbar puncture indicated in children?
1) Under 1 month presenting with fever
2) 1 to 3 months with fever and are unwell
3) Under 1 year with unexplained fever and other features of serious illness
What 2 special tests can be done to look for meningeal irritation?
1) Kernig’s test
2) Brudzinski’s test
What does Kernig’s test involve?
Lying the patient on their back, flexing one hip and knee to 90 degrees and then slowly straightening the knee whilst keeping the hip flexed at 90 degrees.
This creates a slight stretch in the meninges.
Where there is meningitis it will produce spinal pain or resistance to movement.
What does Brudzinski’s test involve?
Lying the patient flat on their back and gently using your hands to lift their head and neck off the bed and flex their chin to their chest.
In a positive test this causes the patient to involuntarily flex their hips and knees.
Investigations in suspected meningitis?
- FBC
- CRP
- Coagulation screen
- Blood culture
- Whole blood PCR
- Blood glucose
- Blood gas
- Lumbar puncture (if no signs of raised intracranial pressure)
Give some contraindications to LP
Any signs of raised ICP:
1) Focal neurological signs
2) Papilloedema
3) Significant bulging of the fontanelle
4) DIC
5) Signs of cerebral herniation
Also LP is contraindicated in meningococcal septicaemia.
What should be obtained instead of a LP for patients with meningococcal septicaemia?
Blood cultures & PCR for meningococcus
CSF findings in bacterial meningitis:
a) appearance
b) glucose
c) protein
d) white cells
a) cloudy
b) low (<1/2 plasma)
c) high (>1g/l)
d) high (neutrophils)
1st line management of children seen in the primary care setting with suspected meningitis AND a non blanching rash?
Urgent stat injection (IM or IV) of benzylpenicillin prior to transfer to hospital.
Dose dependent on age.
1st line management of PENICILLIN ALLERGIC children seen in the primary care setting with suspected meningitis AND a non blanching rash?
Where there is a true penicillin allergy, transfer should be the priority rather than finding alternative antibiotics.
I.e. Giving antibiotics should not delay transfer to hospital.
What is the most common cause of bacterial meningitis in neonates (<3 months)?
GBS
What are the 3 most common causes of bacterial meningitis in children aged 3 months to 6 years?
1) Neisseria meningitidis
2) Streptococcus pneumoniae
3) Haemophilus influenzae
What are the 2 most common causes of bacterial meningitis in people aged 6-60 years?
1) Neisseria meningitidis
2) Streptococcus pneumoniae
What are the 3 most common causes of bacterial meningitis in people aged >60 years?
1) Streptococcus pneumoniae
2) Neisseria meningitidis
3) Listeria monocytogenes
What are the 3 most common causes of bacterial meningitis in nenoates (aged <3 months)?
1) Group B Streptococcus (most common cause in neonates)
2) E. coli
3) Listeria monocytogenes
Who does listeria cause meningitis in?
Extremes of age i.e. >65 y/o or <3 months.
Also immunosuppressed.
What is the 1st line management of bacterial meningitis in neonates <3 months?
IV amoxicillin + IV cefotaxime
Note - amoxicillin is to cover listeria contracted during pregnancy.
What is the 1st line management of bacterial meningitis in children >3 months?
IV ceftriaxone (or cefotaxime)
What should be added to the Abx treatment of bacterial meningitis if there is a risk of penicillin resistant pneumococcal infection e.g. recent foreign travel or prolonged antibiotic exposure?
Vancomycin
Steroids can also be used in the management of bacterial meningitis.
What is their role?
Reduce frequency and severity of hearing loss and neurological damage.
Which steroid is indicated in bacterial meningitis?
Dexamethasone
When are steroids advised in bacterial meningitis?
If child is >3 months old.
If LP reveals any of the following:
1) frankly purulent CSF
2) CSF white blood cell count >1000/microlitre
3) raised CSF white blood cell count with protein concentration greater than 1 g/litre
4) bacteria on Gram stain
What Abx is used for PROPHYLAXIS of bacterial meningitis for contacts?
Single dose of ciprofloxacin
When do cases of meningitis need to be reported to public health?
Bacteria meningitis and meningococcal infection are notifiable diseases.
Is viral or bacterial meningitis more severe?
Bacterial
Viral meningitis tends to be milder than bacterial and often only requires supportive treatment.
What is the most common viral cause of meningitis?
Non-polio enteroviruses e.g. Coxsackie virus
Give some causes of viral meningitis
1) Enterovirus e.g. Coxsackie virus
2) HSV
3) VZV
4) Mumps
What clinical features would indicated meningoencephalitis?
- Significant change in behaviour
- Seizures
- Disorientation
- Marked deterioration in mental state
CSF analysis in viral meningitis:
a) appearance
b) protein
c) glucose
d) white cell
a) clear
b) mildly raised or normal
c) normal
d) high (lymphocytes)
Management of viral meningitis?
Generally speaking, viral meningitis is self-limiting, with symptoms improving over the course of 7 - 14 days and complications are rare in immunocompetent patients.
Aciclovir can be used to treat suspected or confirmed HSV or VZV infection.
What can be used to treat suspected or confirmed HSV or VZV meningitis?
Aciclovir
Where is the needle usually inserted in a LP?
L3-L4 intervertebral space (as the spinal cord ends at L1-L2).
What is the most common complication of meningitis?
sensorineural hearing loss
What is given to reduce risk of hearing loss in meningitis?
Steroids (dexamethasone)
What are some complications of meningitis?
- hearing loss
- seizures
- neurological deficit
- sepsis
- intracerebral abscess
- cerebral palsy: with focal neurological deficits such as limb weakness or spasticity
- pressure: herniation, hydrocephalus
Patients with meningococcal meningitis are at risk of Waterhouse-Friderichsen syndrome.
What is this?
Adrenal insufficiency secondary to adrenal haemorrhage
What syndrome are patients with meningococcal meningitis at risk of?
Waterhouse-Friderichsen syndrome
What is encephalitis?
Inflammation of the brain.
This can be the result of infective (e.g. HSV) or non-infective (autoimmune) causes.
What is the most common cause of encephalitis?
Viral –> HSV
What is the most common cause of encephalitis in children vs neonates?
Children: HSV-1 (from cold sores)
Neonates: HSV-2 (from genital herpes, contracted during birth)
Give 5 viral causes of encephalitis
1) HSV
2) VZV
3) CMV
4) Epstein-Barr virus
5) Enterovirus
Why is it important to ask about vaccination history in encephalitis?
As the polio, mumps, rubella and measles viruses can cause encephalitis as well.
What lobe does HSV encephalitis characteristically affect?
Temporal lobes
Patients may demonstrate temporal lobe signs e.g. aphasia.
Clinical features of encephalitis?
- Fever, headache, seizures, vomiting,
- Altered consciousness
- Altered cognition
- Unusual behaviour
- Focal features e.g. aphasia
What investigations are indicated in encephalitis?
1) LP for CSF viral PCR testing
2) CT scan (if a LP is contraindicated)
3) MRI scan (after the LP to visualise the brain in detail)
4) EEG recording
5) HIV testing: recommended in all patients with encephalitis
Give some contraindications to a LP
- GCS <9
- Haemodynamically unstable
- Active seizures
- Post-ictal
- Signs of raised ICP e.g. papilloedema
What will CSF show in HSV encephalitis?
Lymphocytosis & elevated protein
Management of HSV encephalitis?
IV aciclovir
Management of VZV encephalitis?
IV aciclovir
Management of CMV encephalitis?
Ganciclovir
What is usually performed to ensure successful treatment prior to stopping antivirals in encephalitis?
Repeat LP
What is usually started empirically in suspected encephalitis until results are available?
Aciclovir
What are some complications of encephalitis?
- Lasting fatigue and prolonged recovery
- Change in personality or mood
- Changes to memory and cognition
- Learning disability
- Headaches
- Chronic pain
- Movement disorders
- Sensory disturbance
- Seizures
- Hormonal imbalance
- High mortality rate if left untreated
