Meningitis + encephalitis Flashcards
Categories of CNS infections
- encephalitis: infections of parenchyma
- meningitis: infections of meninges
What is the triad of meningism?
Headache
Neck stiffness
Photophobia
Presentation of meningitis
- triad of meningism with fever
- joint pain
- meningococcal non blanching rash
- reduced GCS
- flu like symptoms
Presentation for babies in meningitis
- listen to parents
- inconsolable crying/high pitched
- reduced feeds
- floppy
- bulging fontanelle
What commonly causes meningitis rash?
Meningococcal meningitis/septicaemia
Describe meningeal rash
Non balancing
Often on trunk, legs, mucous membranes, conjunctivae
What is meningitis commonly due to in neonates?
E. coli
Group B streptococcus
Listeria monocytogenes
What is meningitis commonly due to in children?
Haemophilias influenzae type B
Neisseria meningitidis
What is meningitis commonly due to in eldery?
Streptococcus pneumoniae
Listeria monocytogenes
Risk factors of meningitis
- CSF defects e.g. spina bifida
- spinal procedures e.g. surgery, lumbar puncture
- diabetes
- alcoholism
- endocarditis
- splenectomy
- crowded housing
Pathophysiology of meningitis
- nasal commensals enter circulation > bacteraemia
- damages vessel walls in brain + meninges
- allowing pathogens to enter subarachnoid space
- pathogen multiply rapidly > purulent CSF + meningeal inflammation
- cerebral oedema + raised ICP
Complications of meningitis
- septic shock
- disseminated intravascular coagulation
- coma
- seizures
- hearing loss
- hydrocephalus
- focal paralysis
What is Kernig sign?
- supine patient with thigh flexed at 90°
- extension of knee met with resistance
What is Brudzinki’s neck sign?
When neck is flexed there is involuntary flexion of knees and hips
What are two tests signs of meningitis?
Kernig sign
Brudzinski
Investigations of meningitis
- lumbar puncture
- blood cultures
- meningococcal PCR if indicated
- viral PCR if indicated
- head CT if raised ICP
What signs would delay a lumbar puncture?
Decreasing consciousness
Brainstem signs
Recent seizure
Lumbar puncture findings of bacterial meningitis
- cloudy CSF
- high protein
- high white cells (especially neutrophils)
- low glucose (bacteria metabolise it)
Lumbar puncture findings of viral meningitis
- clear or cloudy
- protein level normal or raised
- high white cells (especially lymphocytes)
- normal glucose
Treatment of meningitis
- analgesia
- antipyretics
- fluids
- IV benzylpenicillin or ceftriaxone if confirmed meningococcal
- dexamethasone
- vancomycin if penicillin resistance
- aciclovir if viral
Why is dexamethasone given in treatment of meningitis?
To prevent hearing loss
Viral causes of meningitis
herpes simplex virus
varicella zoster virus
What is used in post exposure prophylaxis of meningitis?
single dose of ciprofloxacin given ASAP after contract tracing
What must happen after a diagnosis of meningitis?
Notify public health england
bacterial meningitis + menigococcal infection are notifiable diseases
Treatment of bacterial meningitis in children
IM or IV benzylpenicillin
- under 1: 300mg
- 1-9 years: 600mg
- over 10: 1200mg
Presentation of encephalitis
- headache
- confusion/drowsiness
- seizures
- N+V
- behavioral changes
- fever
- loss of consciousness
Causes of encephalitis
- autoimmune
- herpes simplex virus
- varicella zoster virus
- rarely bacterial or fungal infection
- could be spread by mosquitos, ticks or from mammals with rabies
Prevention of encephalitis
- MMR vaccine
- encephalitis vaccines for travelers
- rabies vaccine
Diagnosis of encephalitis
- CT or MRI head
- lumbar puncture
- EEG
- FBCs, LFTs, urinalysis
Treatment of encephalitis
- antiviral/antibiotics/antifungal medications depending on cause
- steroid injections if due to the immune system
- painkillers
- plasmapheresis
- anticonvulsants
Complications of encephalitis
- amnesia
- personality or behavioral changes
- dysphagia
- epilepsy
- balance + coordination problems
