Encephalitis and Meningitis Flashcards
How does encephalitis present?
Flu like prodrome Reduced consciousness Vomiting Fits Raised temperature Meningism
What infective agents often cause encephalitis?
Herpes simplex virus Mumps (oarotiditis and testicular pain) Varicella zoster Rabies Parvovirus (slapped cheek) If immunocompromised then CMV, EBV Influenza
What can cause non infective encephalitis?
Hypoglycaemia DKA Kernicterus Poisoning Haemorrhage or tumour
How should suspected encephalitis be investigated?
CSF and PCR – lymphocytosis and elevated protein if herpes
Test stool, urine and blood
CT head (but MRI better)
EEG
How does herpes simplex encephalitis present?
Easiest to treat cause of encephalitis think of it in a febrile child with focal or general seizures and CNS signs with reduced consciousness. Usually affects temporal lobes giving focal signs such as aphasia. Most commonly as a result of HSV-1
How is herpes simplex encephalitis managed?
Treat with Aciclovir
Monitor Us and Es and urine output
What is meningitis?
Infection of the meninges surrounding the brain. Do not confused with meningococcal septicaemia and non-blanching rash.
How can meningitis present?
Symptoms
Fever, irritability lethargy, high pitched crying, loss of consciousness, poor feeding, vomiting, apnoea and photophobia
Signs
Fever, irritable, difficult to examines, altered LOC, neck stiffness, bulging fontanelles, papilledema, opisthotonos (muscle spasms), positive Brudzinski sign (flexion of neck with child supine causes flexion of knees and hips) and positive Kernig sign (child supine and hips and knees flexed, back pain on knee extension).
What investigations are important in suspected meningitis?
CT
LP and CSF analysis
What contraindications are there to a LP?
Contraindications to LP (signs of raised ICP) Focal neurological signs Papilloedema Significant bulging of the fontanelles DIC Signs of cerebral herniation Meningococcal septicaemia
What is the normal appearance of CSF?
Clear and colourless
Protein level
0.2-0.4 g/L (neonates < 1.7g/L)
Glucose level
>50% of blood
Cell count
<5 lymphocytes
Organisms
None
What is the appearance of CSF when a bacterial infection is present?
Cloudy and turbid
Protein level
Raised protein
Glucose level
Low glucose
Cell count
Raised
Organisms
H. influenzae
Neisseria meningitidis
Strep pneumoniae
Neonates – Gram -ve Group B strep and Listeria
What is the appearance of CSF when a viral infection is present?
Clear
Protein level
Normal or slightly raised
Glucose level
Normal or slightly low
Cell count
Slightly raised lymphocytes
Organisms
Enterovirus
Parechovirus
Herpes virus
How do different organisms that commonly cause meningitis in children present?
Neisseria Meningitidis – rash (+/-) at any age with a film showing gram -ve cocci in pairs
Haemophilus influenzae – rare in vaccinated, usually <4yrs film showing gram -ve rods
Strep Pneumoniae – any age with previous LRTI, or skull fracture – gram +ve cocci
Escherichia Coli – neonates with feeding problems, apnoea’s and seizures
Group B strep – from mother’s vagina, can be delayed a month
Listeria Monocytogenes – soon after birth, rare unless immunocompromised
What organisms usually cause meningitis at different ages?
0-3 months – GBS, E. coli and Listeria
3 months – 6 years – Neisseria meningitidis, strep pneumoniae and haemophilus influenzae
6 years to 60 years – Neisseria meningitidis and strep pneumoniae
