Meningitis Flashcards
What are the predominant causative agents in meningitis?
- Streptococcus pneumoniae
- Neisseria meningitides
- Haemophilus influenzae type b (Hib)
What has helped decrease the cases of meningitis?
- Hib vaccine has helped decreases cases
- Pneumococcal vaccine also helpful in older people
What is common epid of meningitis?
mostly >60 as impaired or waning immunity
What are social RF for meningitis?
- Age
- Crowding: e.g. college, military
- Exposure to others with it
- Immunocompromised ppl
What are medical RF for meningitis?
- Cranial anatomical defects, ventriculoperitoneal shunt
- Cochlear implants
- Sickle cell disease
- Contiguous infection
- Genetic predisposition
What are common symptoms of meningitis?
- Headache
- Neck stiffness
- Fever
- Altered mental status
- Vomiting
- Confusion
- Photophobia
- Seizures
What are the two signs in meningitis?
- Brudzinski’s signs
2. Kernig sign
What is Brudzinski’s sign?
- Passive flexion of neck
- Elicits hip and knee flexion to avoid pain
What is Kernig sign?
- Knee flexed to 90 degrees
- Hip if flexed to 90 degrees
- Extension of the knee is painful or limited in extension
Why is Kernig painful?
- lie child on back, flex knee to right angle to body and completely extend leg at knee joint
- causes stretching of meninges leading to pain which positive sign
What is possible DDx for meningitis?
- Encephalitis
- Viral meningitis
- Drug-induced menigitis
- TB meningitis
- Fungal meningitis
- Malaria
How can you tell the difference between viral and bacterial meningitis in CF?
For Viral:
- CSF pressure normal
- CSF glucose normal
- CSF protein high
- Bacterial culture negative
- Procalcitonin is usually normal
What is the most important test in meningitis?
lumbar puncture
How quickly do you need to do an LP?
Within 1 hour
What bloods do you do in meningitis?
- Blood culture
- Serum pneumococcal and meningcoccal OCR
- Blood glucose
- FBC and differential
- U+Es and electrolytes
- VBG
- LFTs
- Coagulation screen
- Serum HIV
- Serum procalcitonin
How quickly should you do a blood culture?
Within 1 hour
What may the FBC with differential show in meningitis?
- leucocytosis
2, anaemia - thrombocytopenia
What would shock show up as in a VBG?
lactate >4mmol/L
What would a coagulation screen in meningitis show?
sometimes DIC
What do you look for in the CSF analysis?
- Protein
- Glucose
- Lactate
- Microscopy, gram stain, culture, snesitivities
- Cell count
- PCR for pneumoccocus
What would the protein in CSF be like in BM?
elevated 0.5g/L
What would a lactate be like in BM?
> 35mg/dL suggests bacterial rather than viral
What would glucose be like in BM CSF?
<2.5mmol/L in BM
What may show up of metabolic screen for BM?
bacterial meningitis often have metabolic abnormalities
What is the management plan for BM if below 3yo?
IV cefotaxime + amoxicillin
What is the management plan for BM ages 3-50?
IV ceftotaxime
What is the management plant for BM >50?
IV cefotaxime + amoxicillin
What is the management plan for Meningococcal meningitis?
IV benzylpenicillin or ceftotaxime
What is the management plan for Pneumococcal meningitis
IV cefotaxime
What is the management plan of Meningitis caused by haemophilus influenzae?
IV cefotaxime
What is the management plan of Meningitis caused by listeria?
IV amoxicillin + gentamicin
What is the general management of meningitis?
- Empirical antibiotics and supportive care and corticosteroid: dexamethasone 10mg/6h IV
- When know pathogen give specific antibiotics
- Presume bacterial until proven viral: then stop and supportive care (if ongoing viral consider antiviral therapy)
What are possible complications of meningitis?
- Shock
- Elevated ICP
- Hydrocephalus
- Seizures
- Subdural effusion
- Hearing loss
- Septic DVT
What is the mortality rate of BM?
- Community acquire BM: 20% and 30% for pneumococcal meningitis
- Mortality increases with age
What are LT effects of meningitis?
1/3 of adults with BM may have cognitive impairement
What are the properties (colour, predominant cell, cell count, glucose and protein) of BM CSF?
- Turbid
- Polymorphs (predominant cell)
- Cell count 90-1000 or more
- <1/2 plasma glucose
- > 1.5 protein
- Bacteria in smear and culture
What are the properties (colour, predominant cell, cell count, glucose and protein) of TB CSF?
- Fibrin web
- Mononuclear predominant cell
- 10-1000 cell count
- <1/2 plasma glucose
- 1-5 protein
- Often no bacteria in smear
What are the properties (colour, predominant cell, cell count, glucose and protein) of Viral CSF?
- Clear
- Monocular predominant cell
- 50-1000 cell count
- > 1/2 plasma
- <1 protein
- No bacteria seen or cultured
What layers does meningitis affect?
infection that affects the leptomeninges – the arachnoid and pia layer of the brain
What are two way in which pathogens can infect the leptomeninges?
- direct spread
2. haematogenous spread
What is direct spread for meningitis?
- Pathogens can enter either through overlying skin,
2. p through the nose or through an anatomical defect (such as spina bifida or skull fracture)
What is haematogeous spread for meningitis?
- when pathogens enters the bloodstream and moves through the endothelial cells in the blood vessels that make up the blood-brain barrier
- pathogen spreads in the CSF and white blood cells enter, release cytokines and recruit even more white blood cells
What bacteria usually causes meningitis in neonates?
E.coli
What bacteria usually causes meningitis in childrens?
- H. influenze
2. strep. Pneumoniae
What bacteria usually causes meningitis in teenagers/young adults?
Neisseria meningitidis
What bacteria usually causes meningitis in elderly?
- strep. Pneumoniae
2. Listeria monocytogenes
What viruses commonly cause meningitis?
- Enteroviruses
- HSV
- VZV
- HIV
OR TB OR FUNGAL
What can neisseria mengitides cause?
meningococcal disease which can be very SEVERE
How can meningococcal disease present?
- rapid onset fever and malaise progressing rapidly to signs and symptoms of sepsis and/or meningitis
- non-blanching rash should make you worried about meningococcal disease
What is the skin rash in meningitis called?
petechial or purpuric rash is typically associated with meningococcal meningitis
If you suspect meningitis at GP what do you give?
benzylpenicillin IM & URGENT REFERAL TO THE HOSPITAL
What broad spectrum antibtioics may be given initally?
- ceftriaxone IV
- benzylpenicillin IM
- acyclovir if viral
What does dexamethasone do?
to be reduce cerebral oedema
What investigation is done firast?
- CT head: if reduced conciousness or neurological deficet
2. If neither of those lumbar puncture first
What are the common bacterial causes of meningitis?
- Neisseria meningitidis
2. Streptococcous penumoniae
What sort of bacteria is NM?
- Gram negative
2. Diplocci
What sort of bacteria is streptococcus pneumoniae?
- Gram positive
2. (usually di-) Cocci
What are other bacterial causes of meningitis?
- Haemophilus influenzae type B: gram negative rod/coccobacilli
- Listeria: gram +ve
- E. coli
- Group B strep.
What are viral causes of meningitis?
- Cocksackie virus
- Herpes virus (HSV2 > HSV1 )
- Enteroviruses
- Measles
- Mumps
What are other causes of meningitis?
- Borrelia Burgdorferi (causes Lyme disease)
- Tuberculosis mycobacterium
- Fungi (immunocompromised)
What conditions can cause meningitis?
- Otitis media
- Sinusitis
- CSF leak after head trauma or neurosurgery
- Maternal group B streptococcal infection during birth
- Sepsis
What are the causative organisms in neonates?
- Group B streptococcus
- E.coli
- Listeria monocytogenes
What are RF for meningitis in neonates?
- Extended labour, infection in previous pregnancy
2. Late neonatal infection
What are RF for children and teenagers for meningitis?
- Gram -ve diplococci
2. Unvaccinated
What are the causative organisms of meningitis in the children and teenagers?
- Neisseria meningitides
2. Haemophilus infeluzae
What are RF for meningitis in adults and elderly?
- Gram +ve cocci
2. Elderly, cheese/unpasturied milk, alcoholics
What are the causative organisms in meningitis for adults and elderly?
- Streptococcus pneumoniae
2. Listeria monocyogenes
What is the meningial triad?
- Headache
- Photophobia
- Neck stiffness
What is the rash like?
non-blanching
When should you avoid LP?
- Neurological signs suggesting raised ICP
- Superficial infection over LP site
- Coagulopathy
Do you give antibiotics or do an LP first?
If patient is stable and no LP contraindications, then perform LP ASAP before starting empiric antibiotics
What antibiotics are used in bacteria meningitis?
IV Ceftriaxone (3rd generation cephalosporin)
What other medications can be given in bacterial meningitis?
- Consider corticosteroids – Dexamethasone for bacterial meningitis BUT not if meningococcal septicaemia is suspected
(cover Listeria with ampicillin) - If consciousness affected, consider IV acyclovir to cover encephalitis
- Prophylaxis to close contacts: Rifampicin or ciprofloxacin
When is amoxicillin used?
Listeria (As cephalosporins are ineffective against Listeria species)
What is meropenem?
extended spectrum beta lactamase
What is bacterial meningitis and meningococcal disease?
notifiable diseases