MENINGITIS

Question 0

Mode of spread of brain infection?

Answer 0

Haematogenous  I.e. Systemic 
Local cranial site of infection 
- OM
- mastoiditis
- sinusitis
Direct from
- neurosurgery
- penetrating TBI

Question 1

What is meningitis?

What is encephalitis?

Answer 1

Infection of sub-arachnoid space, CSF and meninges

Direct Viral Infection of brain tissue

Question 2

Pathogens of bacterial meningitis? 2-50? Elderly? Immunosuppressed? <1month? 1-23 months?

Viral?

Answer 2

2-50

• strep pneumoniae
• neisseria meningitides

Elderly - listeria

Immunosuppressed

• listeria
• klebsiella
• TB if HIV +

<1month

• E. coli
• klebsiella
• listeria

1-23 months

• strep pneumoniae
• neisseria meningitides
• haemophilus influence

Enteroviruses
HSV2
HIV

Question 3

Clinical presentation of meningitis?

Answer 3

Preceding URTI

Triad of headache, neck stiffness and photophobia.

Altered mental state
+/- Seizures, raised ICP and focal neurological deficit

Question 4

Physical exam signs of meningitis?

Answer 4

Evidence of URTI

Meningeal irritation

• brudzinskis sign: passive flexion of neck -> flexion of hip
• kernigs sign: passive extension of hip causes pain

Meningococcal rash
- diffuse erythema toys maculopapular rash (viral exanthem)

Raised ICP

• cushings triad: hypertension, bradycardia, abnormal respiration
• papiloedema

Question 5

Ix for meningitis?

Answer 5

Start ABx if high clinical suspicion

CBE EUC LFT CRP BGL urinalysis

Blood cultures
LP if no raised ICP
- bacterial: WBC: neutrophils, increased proteins, reduced glucose, purulent CSF
- viral: WBC lymphocytes, normal glucose, moderately elevated proteins

CT/MRI for raised ICP

Question 6

What risk is there with LP and raised ICP?

Answer 6

Removal of CSF below brain -> tonsillar herniation

Question 7

Rx of meningitis?

Answer 7

4 steps

1. Dexamethasone
2. Empirical ABx
   - IV ceftriaxone
3. Specific ABx
   - strep pneumoniae: benpen or ceftriaxone +/- vancomycin
   - neisseria: benzylpenicilin
   - hib: ceftriaxone
   - listeria: benpen
4. Treat contacts of meningococcal meningitis
   - meningococcal: PO ciprofloxacin
   - pneumococal: no chemoprophylaxis

Question 8

Complications of meningitis?

Answer 8

Neurological

• hydrocephalus
• seizures
• raised ICP

Non-NEURO

• SIADH
• sepsis