Meningitis

Question 1

Definition of meningitis

Answer 1

Inflammation of the meninges, most commonly due to infection
• Can be due to Bacterial (more COMMON), Viral or fungal infection

Question 2

Aetiology of meningitis

Answer 2

BACTERIAL:
• Most common causes of bacterial meningitis are:
◦ Neisseria Meningitidis (Meningococcal)-> MORE COMMON
◦ Streptococcus Pneumoniae (Pneumococcal)
◦ Haemophilus Influenzae
◦ Group B streptococci (more common in neonates)

Viral:
◦ Enterovirus
◦ Mumps
◦ HSV

Fungal:
◦ Cryptococcus

Question 3

Risk factors for meningitis

Answer 3

• Close communities (e.g uni halls)
• Basal skull fractures
• Sinusitis
• Inner ear infections
• Immunodeficiency
• Mastoiditis

Question 4

Pathophysiology of meningitis

Answer 4

• Bacteria commonly reach the CNS via haematogenous spread.
• The bacteria rapidly multiply once they’re in the subarachnoid space.
• The inflammatory cascade leads to cerebral oedema and increased ICP, which contributes to neurological damage

• In meningococcal disease, there is a risk of meningococcal septicaemia

Question 5

History and examination findings for meningitis

Answer 5

• Headache
• Fever
• Neck stiffness
• Nausea/Vomiting
• Altered mental state: Confusion, delirium and impaired consciousness
• Photophobia
• Rash: Typically petechial/maculopapular (non-blanching)
• Abnormal skin colour: pallor or mottled skin can be a sign of meningococcal septicaemia
• Seizures: can be present in some patients
• Shock: hypotension, delayed CRT

• Kernigs sign: Pain and stiffness when knee is extended whilst hips flexed at 90 degrees
• Brudzinski’s sign: pain and stiffness when legs brought to stomach whilst neck is flexed

Question 6

Investigations for meningitis

Answer 6

• VBG: can check for lactate levels
• U&Es: May show associated AKI
• FBC,CRP
• Coagulation screen: check for DIC (caused by severe sepsis due to clots forming and depleting the coagulation factors)
• CT scan: to check for raised ICP before attempting LP, CT is contraindicated in kids, do neuro exam instead
• LUMBAR PUNCTURE: Check for glucose levels, MC&S, WCC, protein etc
• BLOOD CULTURES: Take 2 ASAP before giving antibiotics
• PCR or throat swab: To help detect pathogen

Question 7

Treatment for bacterial meningitis in the COMMUNITY

Answer 7

1) Urgent hospital transfer
+ 1.2g IM Benzylpenicillin: Only give if evidence of non-blanching rash, septicaemia or delay in transport. Check for penicillin allergy

Question 8

Treatment of bacterial meningitis in SECONDARY care

Answer 8

1) ABCDE: Support the airway and give fluid if dehydrated or haemodynamically unstable
+ Empirical antibiotics: IV 3rd gen cephalosporin (e.g Ceftriaxone, cefotaxime). Give ASAP within an hour ideally after cultures (but antibiotics take priority)

CONSIDER IV dexamethasone: give before or during antibiotic course. Do NOT give if septic or evolving rash

Continue to monitor ICP, GCS. Change antibiotics to more specific ones when organism is identified.
Isolate for 1st 24 hours and notify Public Health

Question 9

Prevention of meningitis

Answer 9

Pneumococcal and meningococcal vaccination
Report all cases

Question 10

Complications of meningitis

Answer 10

• Shock
• Elevated ICP
• Seizures
• Cognitive impairment

Question 11

Prognosis of meningitis

Answer 11

Prognosis usually good with prompt and adequate treatment of the infection
Older age, low GCS at presentation etc associated with poorer prognosis
Risk of cognitive impairment
Meningococcal septicaemia has higher mortality rates than meningococcal meningitis