Meningitis

Question 1

The meninges

Answer 1

Three layers of protective tissue that covers and protects the cells

Question 2

Three layers to the meninges

Answer 2

Dura mater
Arachnoid layer
Pia mater

Question 3

Dura mater

Answer 3

Double layered external covering, tough connective tissue

Question 4

Arachnoid layer

Answer 4

Middle, web like layer

Question 5

Pia mater

Answer 5

Internal layer, clings to the surface of the brain

Question 6

Meningitis

Answer 6

An inflammation of the meninges

Question 7

Leptomeninges

Answer 7

The two inner layers: arachnoid layer and pia mater

Question 8

Subarachnoid space

Answer 8

Where cerebrospinal fluid is kept

Question 9

Cerebrospinal fluid

Answer 9

Pumped around the CNS, cushions for impact and bathes them in nutrients

Question 10

Levels of CSF in the body

Answer 10

500ml is made a day, 150ml in the body. Any excess is absorbed into the blood

Question 11

Direct spread of meningitis

Answer 11

The pathogen gets into the skull of spinal column through overlying skin or an anatomical defect such as a skull fracture and penetrates the meninges

Question 12

Hamatogenous spread

Answer 12

Enters the blood stream by adhering to epithelial cells. They then bind to surface receptors on the endothelial cells or find areas of damage to get access.

Question 13

What happens in the meninges when the pathogens enter

Answer 13

The white blood cells notice the pathogens and release cytokines, which recruit more white blood cells. They attract more fluid to control the infection, CSF and protein levels increase and glucose levels decrease, and pressure levels rise.

Question 14

Why is the CSF an ideal medium for the spread of bacteria

Answer 14

It provides enough nutrients for multiplication and has few phagocyte cells, and low levels of antibodies

Question 15

Common microbes of meningitis for 30+ years

Answer 15

Streptococcus pneumoniane

Question 16

Treatment for meningitis

Answer 16

Airway and ventilation, nurse in head up position, 20-30 degrees from horizontal, IV access and antibiotics, IV anti osmotic agents and vaccines

Question 17

Symptoms of meningitis

Answer 17

Excessive drowsiness, confusion, vomiting, severe headache, nuchal rigidity, photophobia, phonophobia, blurred vision, seizures, high BP, bradycardia

Question 18

Cushing’s Triad

Answer 18

Occurs when the medulla of the brain is directly compressed. When ICP has reached a similar level as the mean arterial pressure, the capillaries that supply the medulla are compressed and become ischaemic. A sympathetic response is initiated, causing a rise in BP and vasoconstriction. The arterial pressure overcomes the ICP and blood supply is resorted.

Question 19

Monro-Kellie Hypothesis

Answer 19

ICP is usually between 5-15mmHm. CSF is 15%, blood is 15% and brain is 70%. An increase in volume of any of these leads to an increased pressure in the brain.

Question 20

Differences in anatomical features

Answer 20

Greater compressibility of the brain, greater pliability of the skull, lower ICP, open fontanelle

Question 21

Brain herniation/coning

Answer 21

Occurs when the intracranial vault has reached maximum capacity, the brain shifts to the area of least reistance

Question 22

Viral meninigits

Answer 22

Normally recover without treatment in five days to two weeks. There is no effective treatment.

Question 23

Most common type of bacterial meningitis

Answer 23

Meningococcus bacterial

Question 24

Why is meningococcal bacteria very dangerous?

Answer 24

Alongside meningitis, it usually causes infection of the blood, septicaemia which can cause a non blanching rash

Question 25

How is a non blanching rash caused?

Answer 25

The infection can damage blood vessels, causing blood to leak out into the tissues, and causing the rash

Question 26

How is bacterial meningitis transmitted?

Answer 26

Prolonged contact with an infected person or direct contact with their oral secretions

Question 27

Why does meningitis cause a headache?

Answer 27

Swelling of the blood vessels puts pressure on the surrounding nerves, sending a rush of pain to the brain which brings on a headache

Question 28

Why does meningitis cause high BP?

Answer 28

The walls of the blood vessels become inflamed, leading to narrowing of the walls, resulting in increased vascular pressure.

Question 29

Why does meningitis cause blurred vision?

Answer 29

Can cause swelling of the optic nerve which is responsible for sight and is located at the back of the brain