Infections Flashcards
What is meningitis
Inflammation of the meninges usually caused by infection
Who does meningitis mainly affect
Infants
Children
Elderly (>60)
Give 4 RFs of meningitis
- Immunocompromised
- Crowding
- IVDU
- Pregnancy
Give 2 causes of bacterial meningitis in adults
- Strep pneumoniae
- Neisseria meningitidis
Give 4 groups of patients that are more likely to be affected by bacterial meningitis that is caused by listeria monocytogenes
- Elderly
- Immunocompromised
- Alcohol misuse
- DM
Give 5 causative pathogens of viral meningitis
- Enterovirus, e.g. coxsackievirus - mc
- Herpes simple virus and herpes zoster virus
- measles and mumps
- HIV
Give 2 causative pathogens of fungal meningitis
- Cryptococcus neoformans
- Cryptococcus gattii
Give 2 non-infective causes of meningitis
- Paraneoplastic syndromes
- Autoimmune conditions
Give 5 typical symptoms of meningitis
- Fever and vomiting
- Neck stiffness
- Photophobia
- Headache
- Altered mental state - drowsiness/ seizures
Give 2 clinical signs that are indicative of inflammation of the meninges
- Kernig’s sign
- Brudzinski
What is kernig’s sign
- hip and knee of one leg flexed to 90
- Knee is then slowly straightened
+ve sign = pain on knee extension
What is Brudzinski’s sign
Forced flexion of the neck causes flexion of the hips and knees
Give 3 ways meningitis is investigated
- Lumbar puncture - cultures, glucose, protein, PCR and microscopy
- CT head - if signs of raised ICP
- Bloods: FBC, lactate, CRP and U+Es
Describe a CSF analysis that would indicate bacterial meningitis
- Cloudy appearance
- High protein (>1g/l)
- Low glucose - <2.5mmol/L or <50% of serum glucose)
- High neutrophils
Describe a CSF analysis that would indicate viral meningitis
- Clear appearance
- Normal or mildly raised protein
- Typically normal or >60% of plasma glucose
- High lymphocytes
When is lumbar puncture contraindicated/ delayed in the invesigation of meningitis
- signs of raised ICP
- signs of severe sepsis or rapidly evolving rash
- Coagulopathy - signficant bleeding risk
- severe cardio/ resp compromise
How is meningitis initially treated if the patient presents to primary care
- 1.2g IM/ IV benzylpenicillin then immediate transfer to hospital
- OR IV cefotaxime/ ceftriaxone
How should suspected bacterial meningitis be managed
- IV access - take bloods and cultures
- Lumbar puncture within one hour
- < 60y: IV cefotaxime or ceftriaxone for 10 days
- > 60y: IV cefotaxime/ ceftriaxone + amoxicillin/ ampicillin
- IV dexamethasone - reduce neuro sequelae
What should be done if a lumbar puncture can’t be done within the first hour in the case of suspected bacterial meningitis
IV antibiotics should be given after blood cultures have been taken
When is IV dexamethasone avoided in the management of bacterial meningitis
- septic shock
- meningococcal septicaemia
- immunocompromised
What is the treatment for bacterial meningitis caused by L. monocytogenes
- IV amoxicillin for 21 days
- OR IV trimethoprim/sulfamethoxazole (penicillin allergy)
When would vancomycin be given in combination with the typical Abx for bacterial meningitis
If there is a risk of penicillin-resistant pneumococcal infection (e.g. recent foreign travel or prolonged Abx exposure)
Describe contact tracing in bacterial meningitis and state what prophylaxis is given
- Close prolonged contact within the 7 days before onset
- Single dose of oral ciprofloxacin or rifampicin guided by local health protection team
How is viral meningitis managed
- whilst awaiting results of LP, if bacterial meningitis or encephalitis are suspected, patient should start broad-spectrum antibiotics (e.g. IV ceftriaxone and aciclovir)
- typically self-limiting over 2 weeks
- Aciclovir if meningitis secondary to HSV
Give 5 complications of meningitis
- sensorineural hearing loss (mc)
- Seizures
- pressure: brain herniation, hydrocephalus
- focal neurological deficit
- infective: sepsis, intracerebral abscess
What type of bacteria is N. meningitidis
Gram negative diplococcus
What type of bacteria is L. monocytogenes
Gram positive bacillus
What type of bacteria is strep. pneumoniae
Gram positive diplococci
What is encephalitis
Inflammation of the brain parenchyma associated with neuro dysfunction
Give 3 causes of encephalitis
- HSV-1 (mc)
- HSV-2 (neonates from genital herpes)
- West Nile virus
- Enterovirus
Give 3 RFs of encephalitis
- Age <1 or >65
- Immunodeficiency
- Animal/ insect bites
Give 5 typical symptoms of encephalitis
- Fever
- headache
- Altered mental state - consciousness, cognition
- Focal neuro deficits: aphasia
- seizures
- vomiting
How is encephalitis investigated
- FBC - raised WCC
- CSF (LP): high WCC, raised proteins, PCR for HSV, VZV and enteroviruses
- MRI brain - medial temporal and inferior frontal changes, may be normal
- Electroencephalogram
What is the treatment for encephalitis
IV Aciclovir for 14-21 days
* repeat LP before stopping antivirals
What lobe of the brain does herpes simplex encephalitis typically affect
temporal lobes
Which type of HSV is responsible for most cases of herpes simplex encephalitis in adults
HSV-1
