Emergency: Encephalitis And Meningitis Flashcards
What is encephalitis?
Inflammation of the brain
What are the most common causes of acute encephalitis in the UK?
Herpes simplex virus 1 and 2
Enteroviruses
Varicella zoster
Other than the most common 3 viral causes (herpes simplex, varicella zoster and enteroviruses) what other infective causes are there?
Measles, mumps and rubella Rabies Parvovirus (slapped cheek syndrome) TB Toxoplasmosis Malaria Lyme disease
What are some non infective causes of encephalitis?
Hypoglycaemia DKA Hepatic failure SAH Lead or other poisoning Malignancy Lupus
What signs and symptoms are associated with encephalitis?
Early non specific symptoms:
Fever
Headache
Vomiting
Followed by: Reduced consciousness Odd behaviour Seizures Meningism - stiff neck, photophobia, headache
How should encephalitis be managed?
High dose aciclovir in all cases to cover herpes simplex until investigation results available
EEG and MRI might show characteristic temporal lobe abnormalities
Seizure control and monitoring for raised ICP
What investigations for encephalitis should be done?
CSF MC&S and PCR
Bloods
Stool sample
Urine dipstick and MSU
Is viral or bacterial meningitis more common?
Viral
Is viral or bacterial meningitis more lethal in nature?
Bacterial
A range of bacteria and viruses can cause meningitis. What are some more rarer causes?
TB
Fungal infections
Malignant infiltration
What are the most common bacterial causes of acute meningitis?
Neisseria meningitidis
Streptococcus pneumoniae
Haemophilius influenzae type B
What are the most common bacterial causes of meningitis during the neonatal period?
Group B streptococci
E.Coli
Listeria monocytogenes
What are some common viral causes of meningitis?
Mumps
Enteroviruses
EBV
For bacterial meningitis, under what age is the peak age of incidence?
Under 5
80% of all cases occur in children under 16
What type of bacterial meningitis accounts for over half of the cases in the UK?
Meningococcal meningitis
What is neisseria meningitidis often referred to as?
Meningococcal meningitis
What is the most common variety of meningococcal meningitis in uk?
Group B
Why in the early stages is it difficult to diagnose meningitis, especially in infants?
Early signs are non specific and may be subtle
Where is group B streptococcus usually acquired from?
The mother at birth
What are some non specific symptoms and signs in bacterial meningitis?
Irritability
Poor feeding
Vomiting
Lethargy
What are the more specific signs associated with bacterial meningitis that develop later?
Bulging fontanelle Fever Neck stiffness and photophobia in the older child Seizures Apnoea
Meningococcal infection can present with characteristic non-blanching purpuric rash if septicaemia present
In bacterial meningitis, what are signs of sepsis?
Fever Cold hands/feet/limb/joint pain Abnormal skin colour Odd behaviour Rash DIC Tachycardia Hypotension Tachypnoea
In bacterial meningitis do septic signs or meningeal signs usually present first?
Septic signs
In bacterial meningitis, what are the meningeal signs?
Stiff neck (often absent if less than 18 months old)
Kernig’s sign - resistance to extending knee of hip flexed
Brudzinski’s sign - hips flex on bending head forward
Photophobia
Opisthotonos - spasm occurs muscles causing backward arching of head
What investigations should be done if suspecting bacterial meningitis?
Bloods: FBC, U&E, CRP, LFTs EDTA bottle for PCR Blood sugar Coagulation studies Blood gases Other microbiology samples (urine MSU, nose swab, stool sample, CSF if appropriate)
(In addition to sepsis 6)
Give: oxygen, fluids, abx
Take: blood culture, lactate, urine output)
What signs suggest raised ICP? (And therefore no LP)
Focal neurological signs Papilloedema Significant fontanelle bulging DIC Signs of cerebral herniation
Before admission to hospital, what medication should be given early if suspecting bacterial meningitis?
Parenteral penicillin
Early antibiotic treatment significantly reduces fatality rates
How should bacterial meningitis be managed (before organism known)
High flow oxygen
Fluids
IV antibiotics: if less than 3 months give amoxicillin and cefotaxime, if more than 3 months cefotaxime
Dexamethasone if child more than 3 months and not meningococcal septicaemia
What are some complications of meningitis?
Abscesses Subdural effusion Cerebral oedema Epilepsy Ataxia Paralysis Deafness - steroids may prevent this
Following infection with meningococcus, what should be given to all household contacts?
Rifampicin or ceftriaxone or ciprofloxacin
Describe neisseria meningitidis
Gram neg cocci in pairs
Often within polymorphs
Numerous serogroups -A, B, C, W135 based in the polysaccharide capsule antigen (evades immune response by preventing phagocytosis)
Outer membrane acts as an endotoxin
What vaccinations are there for bacterial meningitis?
Haemophilius influenza type B
Meningococcus C
How is meningococcal meningitis spread?
Aerosols and nasopharyngeal secretions
Most people are harmlessly colonised
Is meningitis a notifiable disease?
Yes
When meningococcal disease is acquired what are the 3 states that can occur?
Clearance
Carriage
Invasion
