Meningitis Flashcards
Define meningitis
Inflammation of the meninges covering the brain and the spinal cord
What is the key epidemiology of meningitis?
neonates
Elderly
Immunocompromised are more susceptible
What is the most common cause of meningitis in children?
Gram stain?
Streptococcus pneumonia - gram positive lancet shaped diplococci
What causes of meningitis should be considered in neonates?
Gram stain
Listeria monocytogenes - gram pos cocco bacillus
Group B strep - gram post chains
What are the common causes of bacterial meningitis?
Neissureia meningitis
Streptococcus pneumoniae
Haemophilus influenza
Listeria monocytogenes
E.coi and GBS -> neonates
What are the common viral causes of meningitis?
Enteroviruses
HSV
HIV
Others
What are the rarer causes of meningits?
Fungal - in immunocompromised -> cryptococcus neoformans
Non-infeciouts - drugs, autoimmne, malignancy
What are the risk factors for bacterial meningitis?
Missed immunisations - meningococcal, Hib or pneumococcal
Reduces/absent spleen
Congenital/acquired complement deficiency
Student in further or higher education - large shared accomodation
How does meningitis typically present?
Fever
Severe headache
Neck stiffness
Photophobia (light sensitivity)
Confusion
When should meningococcal disease be considered?
Haemorrhagic non-blanching rash lesions >2mm
Rapidly progressive and/or spreading non-blanching or purpuric rash
When combined with signs/symptoms of bacterial meningitis
What are the signs of meningitis in babies and young children?
Bulging fontanelle
Reduced feeding
Irritability
Lethargy
Unusual behaviour
Weak, high-pitched or continuous cry
What can indicate advanced/severe meningitis?
Seizures
Focal neurological deficits
Signs of raised ICP - papilloedema
What are some key differentials for meningitis?
Encephalitis - altered mental status is key
Subarachnoid haemorrhage - sudden, severe headache, N, V, LOC
What are the key bedside investigations for meningitis?
Throat swab for meningococcal culture
Sepsis screen
Blood glucose for CSF:serum BM ratio
What are the key blood investigations for meningitis?
FBC (assess neutrophils)
Blood cultures
CRP
Meningococcal and pneumococcal PCR
What are the indications for imaging in a meningitis case?
Risk for SOL
New focal neurological features - seizures or posturing
Signs of raised ICP
Abnormal pupillary reactions
GCS of 9 or less -> progressive and sustained or rapid fall in LOC.
What are some contraindications for lumbar puncture in menigitis?
Extensive or rapidly spreading purpura
Infection at the lumbar puncture site
Risk for SOL
Signs of raised ICP - focal neurology, abnormal pupils, GCS 9 or less, fall in consciousness
What tests should be done on CSF in a suspected meningitis?
Total red and white cell count
Total protein
Glucose
Microscopy
Culture and sensitivities
PCR for relevant pathogens
What are the key signs of a bacterial meningitis on a lumbar puncture?
CSF is clear or turgic
Main cell type -> polymorphonuclear (neutrophils)
Culture positive
Raised protein
Reduced glucose
What are the signs of aseptic (viral) meningitis in lumbar puncture?
CSF is clear or slighty turgid
Predominant cell type = lymphocytes
Negative culture
Raised protein
Normal glucose
What are the signs of a tuberculous meningitis on lumbar puncture?
CSF is clear, turgid with(out) fibrin web
Main cell - lymphocytes and polymorphonuclear cells
Culture - negative, acid-fast bacilli positive
Protein raised
Glucose reduced
What immediate treatment should be given in primary care for suspected meningitis?
IM benzylpenicillin/ceftriaxone whilst awaiting ambulance
When should antibiotics be given to a patient with meningitis?
Within 1 hour of arriving to hospital
Ideally after blood tests and LP
What are the typical empirical antibiotics for meningitis?
YOunger than 3m - IV amoxicillin + ceftriaxone
Older than 3 months - IV ceftriazone
