Meningitis

Question 1

What happens to the body during acute meningitis?

Answer 1

• Inflammation of the meninges
• Infection of the subarachnoid space
• Exudate/pus over the spinal cord and brain
• Cerebrospinal fluid with inflammatory changes (pleocytosis = abnormal cells in the CSF)

Question 2

How do pathogens enter the CSF?

Answer 2

1 Paracellular passage
2 Transcellular Transport
3 Invasion within WBCs during diapedesis

Question 3

What factors predispose one to meningitis?

Answer 3

1. Altered immune status
2. functional or congenital asplenia (sickle cell)
3. chronic disease
4. Bacteremia
5. contiguous focus of infection
6. head trauma
7. neurosurgery/instrumentation
8. Household contacts, military barracks, college dorms

Question 4

What two ways can one acquire meningitis?

Answer 4

1. Hematogenous spread (blood –> brain) most common
2. Direct spread or extension (less common)
   - - neighboring infection, postsurgical or cranial injury, secondary to congenital malformation

Question 5

What are the 3 types of brain edema?

Answer 5

Vasogenic edema
Cytotoxic edema
Interstital edema

Question 6

What is vasogenic edema?

Answer 6

Disruption of the BBB and leakage of capillary vessels

Question 7

What is cytotoxic edema?

Answer 7

Increased intracell. fluid, secondary to injury

Question 8

What is interstitial edema?

Answer 8

Exudate in arachnoid space –> interferes with absorption of CSF/obstruction of flow

Question 9

What are the pathological signs of bacterial meningitis?

Answer 9

1. Purulent exudate over brain/spinal cord/in ventricles
2. Spinal nerve/root inflammation
3. Hydrocephalus
4. Thrombosis/occulsion of cerebral vessels
5. Subdural effusions

Question 10

What viruses are commonly associated with aseptic meningitis?

Answer 10

Enterovirus
Herpes viruses
Arbovirus
Mumps
HIV
LCV