Meningitis

Question 1

Key symptoms:

Answer 1

headache, seizures, altered conscious state

Question 2

classic triad—

Answer 2

headache, photophobia, neck stiffness

Others: malaise, vomiting, fever, drowsiness

Question 3

Causes

Answer 3

Bacterial causes:

• Strep. pneumoniae
• H. influenza (esp. children)
• Neisseria meningitides (can take form of meningitis, septicaemia (meningococcaemia) or both)

Also—

• Listeria monocytogenes
• M. tuberculosis, Group B Strep
• Strep. agalactiae (esp. newborn)
• Staph spp, Gm–ve bacilli
• Treponema pallidum

Viral causes:

• enteroviruses (Coxsackie, echovirus, poliovirus)
• mumps
• HSV type 1, 2 or 6
• Varicella zoster
• EBV
• HIV

Fungi:

• cryptococcus
• Histoplasma capsilatum

Autoimmune encephalitis

Question 4

Common age?

Answer 4

Basically a childhood infection (↑ risk 6–12 mths).

Question 5

Infancy (clinical features)

Answer 5

Fever, pallor, vomiting ± altered conscious state

Lethargy

Increasing irritability with drowsiness

Refusal to feed, indifference to mother

Neck stiffness (not always present)

Cold extremities (a reliable sign)

May be bulging fontanelle

Question 6

Children over 3 years, adolescents, adults

Answer 6

Meningeal irritation more obvious e.g.

• headache
• fever
• vomiting
• neck stiffness

Later:

• delirium
• altered conscious state
• ± Kernig sign

or

• Brudzinski sign (more reliable sign)

Antibiotics may mask symptoms.

Suspect meningitis if fever >3 days in reasonably well child on antibiotics.

Question 7

Kernig / Brudzinski signs

Answer 7

(left) Kernig sign:

• pain in hamstrings on passive knee extension with hip flexed at 90°
• https://www.youtube.com/watch?v=rJ-5AFuP3YA

(right) Brudzinski sign

• passive neck flexion by examiner causes involuntary flexion of hip and knee
• https://www.youtube.com/watch?v=jO9PAPi-yus

Question 8

Fulminating

Answer 8

Dramatic sudden-onset shock, purpura (does not blanch on pressure) ± coma

Usually due to;

• meningococcal septicaemia
• H. influenza type B
• Streptococcus pneumoniae

Septic shock may ensue without signs of meningitis.

Question 9

Treatment (suspected meningitis)

Answer 9

First: oxygen + IV access and consult

Take blood for culture (within 30 minutes of assessment)

For child give bolus of 10–20 mL/kg of N saline with additional boluses up to 60 mL/kg if signs of hypoperfusion

Admit to hospital for lumbar puncture (preliminary CT scan to assess safety of LP in adults)

Dexamethasone 0.15 mg/kg up to 10 mg IV (shown to improve outcome)

Start with antibiotic: antibiotics of proven value—ceftriaxone, cefotaxime, penicillin, meropenem

• Ceftriaxone 2 g (child: 50 mg/kg up to 2 g) IV statim then 12 hrly for 4 days

or

• Cefotaxime 2 g (child: 50 mg/kg up to 2 g) IV 6 hourly for 3–5 days

Question 10

Treatment (meningococcaemia—all ages)

Answer 10

Rx is extremely urgent once suspected (e.g. petechial or purpuric rash on trunk and limbs).

It should be given before reaching hospital.

Empirical treatment:

benzylpenicillin 60 mg/kg IV (max. 2 g) statim (continue for 5 days)

• if IV access not possible, give IM

or

• ceftriaxone IV or IM 2g (child > 1 mth 50mg/kg up to 2g) 12 hrly for 5 days

A simple plan with benzylpenicillin:

• infants <1 yr: 300 mg IV or IM
• 1–9 yrs: 600 mg
• >10 yrs: 1200 mg

Question 11

Prevention

Answer 11

Meningococcal ACWY and B vaccines

Question 12

Viral meningitis

Answer 12

Can mimic bacterial meningitis but milder and most cases self-limiting

Common causes: HHV 6 (cause of roseola infantum), enteroviruses, mumps

Lumbar puncture for diagnosis

Treatment is symptomatic—analgesics, rehydration, etc.

Acyclovir for herpes meningitis