Lecture 7 - Cerebral Infections - Bacterial and Viral Meningitis

Question 1

What is meningitis?

Answer 1

An inflammation of the lining that covers the brain and spinal cord (The meninges). It can be caused by a bacterial or viral infection. Sometimes you can have both encephalitis and meningitis at the same time.

Question 2

What is encephalitis?

Answer 2

Inflammation of the brain itself. Can be due to a direct infection OR due to the immune systems response to infection.

Question 3

What are common symptoms of meningitis & encephalitis?

Answer 3

• Headache (difficulty to dx in young children)
• Fever
• Neck stiffness
• Vomiting / nausea / loss of appetite
• Photophobia (esp. meningitis)
• Lethargy
• Confusion
• Can progress to seizures, coma and death unless early and aggressive treatment administered

Question 4

Is viral or bacterial meningitis more common?

Answer 4

Viral

Question 5

Describe the general features of viral meningitis.

Answer 5

• Viral is more common than bacterial
• Viral more difficult to diagnose (huge range of viral pathogens)
• Viral meningitis has a mixed picture of outcomes, not generally life threatening, less pronounced sequelae compared to bacterial meningitis.
• Not associated with neuro-anatomical changes
• Some adult studies: mild cognitive impairment in acute and recovery stages of illness, particularly processing speed.
• —- IN CHILDREN: Attention, concentration, behavioural difficulties (e.g., irritability, reduced frustration tolerance).

Question 6

Is viral or bacterial meningitis more likely to result in death and impairment.

Answer 6

Bacterial

Question 7

In newborns, what is the most common pathogens implicated in bacterial meningitis?

Answer 7

Group B streptococcus, Escherichia coli, Listeria monocytogenes

Question 8

In Infants & younger children, what is the most common pathogens implicated in bacterial meningitis?

Answer 8

Streptococcus pneumoniae, Neisseria meningitidis (decreasing), Haemophilus influenzae type b.

Question 9

In younger adults, what is the most common pathogens implicated in bacterial meningitis?

Answer 9

Neissereia meningitidis, Streptopcoccus pneumoniae

Question 10

In older adults, what is the most common pathogens implicated in bacterial meningitis?

Answer 10

Streptococcus pneumoniae, Neisseria meningitidis, Listeria monocytogenes.

Question 11

What are the symptoms of Bacterial Meningitis in children?

Answer 11

Sudden onset of:

• Fever and/or
• Severe headache and/or
• Stiff neck
• Meningococcal: rash (purplish, non-blanching [don’t go white when pressed]

Additional common symptoms in children:
- Vomiting/nausea/loss of appetite
- dislike of bright lights (photophobia)
tiredness or drowsiness (lethargy) or hard to wake
- Listlessness, hypotonia (especially babies)
iritability and hight pitch cry (especially in babies)
- Babies: fontanelle may bulge, babies may also hold their head back or arch their back + high-pitched screaming.

May progress to:
- Seizures, visual disturbances, hearing problems, nerve palsies, ataxia.

Question 12

What is the mortality of bacterial meningitis?

Answer 12

5-10% (used to be 90% before the advent of antibiotics).

Question 13

What groups are most at risk of bacterial meningitis?

Question 14

What psychosocial factor can make young kids twice as likely to have bacterial meningitis?

Answer 14

Living in the home with a smoker.

May be because smoker is more susceptible to infection and thus more opportunity for infection to be passed onto a child.

Question 15

What is the treatment for bacterial meningitis?

Answer 15

Treat with antibitotics, specific NSAIDS or steroids

Fluid restriction (to reduce hyponatrinium [low sodium]) , anticonvulsants when necessary

Question 16

What are the acute physiological and neurological complications associated with bacterial meningitis?

Answer 16

Approximately half of children with bacterial meningitis have neurological deficits in the acute phase (1-2 weeks duration) including:

Raised ICP
Hypoxia
Seizures
Hydrocephalus
Hemiparesis and ataxia
Cranial nerve damage, cranial nerve palsy, vision and hearing problems

Question 17

Why are the cranial nerves susceptible to the effects of bacterial meningitis? What can be affected? and which doesn’t always resolve?

Answer 17

because they are enveloped by arachnoid meninges.

3rd - occulomotor (strabismus, diplopia)
4th - Trochlear - diplopia, vertical strabismus
6th - abducens - eye deviates medially
7th facial - facial expression, taste
8th - vestibulocochlear - hearing and balance

Question 18

What are the LONG TERM neurological/neuropsychological effects of bacterial meningitis?

Answer 18

neuropsychology:

has an effect on neurodevelopmental in at least 40%.
@ 5 years-post, over 1/2 have at least 1 persisting symptom.

12-years post, BM group scores consistently lower than controls for IQ and academic functioning

• 27% required education support (twice as many as controls)
• Specific high level language deficit (even w/o hx of hearing impairment) – e.g., comprehension, abstract reasoning, making inferences.
• improvement in lower order skills over time (attention, speed of processing) BUT chronic difficulty with higher-order skills e.g., memory and executive functioning.
• Higher incidence of significant behavioural problems.

ALSO physiologically:

• ongoing seizures
• hearing impairment
• gross or fine motor problems (e.g., palsy)
• visual deficitis

Question 19

What are the neuropsychological findings after bacterial meningitis in adults?

Answer 19

Cognitive slowing (increased decision making time, reduced verbal fluency, reduced mental flexibility, slowed RT)

• increased rates of depression
• increased subjective perception of poorer quality of life.

Question 20

What are some predictors of poorer outcomes in Bacterial meningitus?

Answer 20

• less than 12 months at illness = increased risk of persisting cognitive deficits
• > 24 hours symptoms before diagnosis
• prolonged or complicated seizures
• focal neurological signs, ataxia
• Pneumococcal infection (bacteria remain for time after treatment)
• reduced QOL associated with academic and/or behavioural problems (not age, gender, presence of neurological symptoms or hearing impairment).

Question 21

What should you look for when doing a neuropsychological assessment on a child who has had bacterial meningitis?

Answer 21

• Processing speed and “higher-level’ abilities e.g., executive function
• mood assessment (some increased mood disorders indicated in studies)
• Behaviour assessment
• regular monitoring over time (e.g., every 2 years) long-term as up to 12 years later still see effects.