Meningitis Flashcards
What is the definition of meningitis?
An inflammation of the leptomeningeal (pia and arachnoid mater) coverings of the brain, most commonly due to infection
What are the bacteria that cause meningitis and which groups do they cause it in?
Neonates:-Group B streptococci
- Escherichia coli
- Listeria monocytogenes
Children:
- Haemophilus influenzae
- Neisseria meningitidis
- Streptococcus pneumoniae
Adults:
- Neisseria meningitidis
- Streptococcus pneumoniae
- Tuberculosis
Elderly:
- Streptococcus pneumoniae
- Listeria monocytogenes
What are the viral causes of Meningitis?
Enteroviruses
Mumps
HSV
VZV
HIV
What are the fungal causes of meningitis?
Cryptococcus (common cause of meningitis in HIV patients)
What are the other causes of meningitis?
Aseptic meningitis (not due to microbes)
Mollaret’s meningitis (recurrent benign lymphocytic meningitis)
What are the risk factors involved with meningitis?
- Close communities (e.g. college halls)
- Basal skull fractures
- Mastoiditis
- Sinusitis
- Inner ear infections
- Alcoholism
- Immunodeficiency
- Splenectomy
- Sickle cell anaemia
- CSF shunts
- Intracranial surgery
Summarise the epidemiology of meningitis
2500 in the UK per year
What are the presenting symptoms of meningitis?
- Severe headache
- Photophobia
- Neck or backache
- Irritability
- Drowsiness
- Vomiting
- High-pitched crying or fits (common in children)
- Reduced consciousness
- Fever
What is important to ask about in the history a patient with suspected meningitis?
IMPORTANT: take a good travel history and exposure history and take not of exposure to any of the following
- Rodents (lymphocytic choriomeningitis virus)
- Ticks (Lyme borrelia, Rocky Mountain spotted fever)
- Mosquitoes (West Nile virus)
- Sexual activity (HSV-2, HIV, syphilis)
- Travel
What are the signs of meningitis on physical examination?
- Photophobia
- Neck stiffness
- Kernig’s Sign +ve - with the hips flexed, there is pain/resistance on passive knee extension
- Brudzinski’s Sign +ve - flexion of the hips when the neck is flexed
Also be aware of signs of infection (fever, tachycardia, hypotension, skin rash and altered mental state)
What are the possible investigations for meningitis?
- Bloods
- Imaging
- Lumbar puncture
What bloods do you do when suspecting meningitis?
Two sets of blood cultures
What imaging do you do when suspecting meningitis?
CT scan - exclude mass lesion or raised ICP before LP
What may you find when conducting a lumbar puncture when suspecting meningitis?
-MC&S
Bacterial meningitis:
- Cloudy CSF
- High neutrophils
- High protein
- Low glucose
Viral meningitis:
- High lymphocytes
- High protein
- Normal glucose
TB meningitis:
- Fibrinous CSF
- High lymphocytes
- High protein
- Low glucose
How would you manage meningitis?
- IMMEDIATE IV Antibiotics (before LP)
- First choice: 3rd generation cephalosporin (e.g. cefotaxime or ceftriaxone)
- Benzylpenicillin may be used as an initial blind therapy - Dexamethasone IV
- Given shortly before or with the first dose of antibiotics
- Associated with a reduced risk of complications - Resus:
- Manage in ITU
- Notify public health services
