CNS Infections

Question 1

What composes the CNS?

Answer 1

Brain, Spinal Cord

Question 2

Function of CNS?

Answer 2

master controller and coordinator of almost
all bodily functions

Question 3

What encloses the brain?

Answer 3

cranial meninges
(membranous covering) and neurocranium (bony
case)

Question 4

3 parts of the brain?

Answer 4

cerebrum,
cerebellum, and the brain stem

Question 5

What is the cerebrum?

Answer 5

Main brain parenchyma

Question 6

What composes the meninges?

Answer 6

Calvaria and duria

Question 7

Parts of cerebral cortex observed when meninges are removed?

Answer 7

Gyri, sulci, fissures

Question 8

Differentiate gyri, sulci, fissures

Answer 8

Gyri (folds), sulci (grooves), fissures (clefs)

Question 9

membranous coverings of the
brain that lie internal to the cranium

Answer 9

cranial meninges

Question 10

Three membranous connective tissues of meninges (describe).

Answer 10

1) Dura matter/dura: outermost layer; tough,
thick, external fibrous layer

2) Arachnoid matter: middle layer; thin and
intermediate

3) Pia mater/pia: innermost layer; delicate
internal vasculated layer

Question 11

Name for arachnoid and pia mater (and why)

Answer 11

Leptomeninges (associated together)

Question 12

Separates pia mater from arachnoid mater

Answer 12

Subarachnoid space

Question 13

What is contained in subarachnoid space?

Answer 13

CSF

Question 14

clear liquid, similar to blood plasma in
constitution

Answer 14

CSF

Question 15

CSF function

Answer 15

provides nutrients, but it has less
protein and a different ion concentration as
compared to the blood plasma

Question 16

Separates cerebral hemispheres; within longitudinal fissure

Answer 16

Falx cerebri

Question 17

What is falx cerebri?

Answer 17

continuation of the dura
mater, lying within the great longitudinal fissure

Question 18

Divided into different lobes with different functions

Answer 18

Cerebrum

Question 19

When cerebrum lobe functions
are disrupted, they are ___.

Answer 19

correlated to the location of
a corresponding neurological deficit at the brain

Question 20

clear liquid that fills the subarachnoid space of the central nervous system; Continuously generated and reabsorbed

Answer 20

CSF

Question 21

Production of CSF made in ___.

Answer 21

choroid plexus and
ependymal cells in the ventricles of the brain

Question 22

Amount of CSF produced

Answer 22

400 to 500 mL/day

Question 23

Contains choroid plexus

Answer 23

Ventricles

Question 24

Site of CSF reabsorption

Answer 24

arachnoid villi

Question 25

Functions of CSF

Answer 25

Provides buoyant force ■ CSF surrounds the brain ■ It dissipates a lot of downward force that would normally act on the organ → hence it reduces the stress on the brain and allows for it to maintain its shape ○ Protects the brain from damage secondary to sudden head movement → acts as a cushion and shock absorber ○ Regulates intracranial pressure ○ Clears CNS metabolites → since CSF is circulated, traveling through the different ventricles of the brain

Question 26

Cells in CNS? (NGMAO)

Answer 26

Neurons, Glial cells (Oligoendrocytes, Astrocytes, Microglia)

Question 27

function as tissue macrophages within the CNS; resident dendritic cells in the CNS

Answer 27

Microglia

Question 28

Structures for protection of brain (NMBB)

Answer 28

Neurocranium, Meningeal barrier, Blood-brain barrier, Blood-CSF barrier

Question 29

One of most important sites for the control of the CNS microenvironment in homeostasis

Answer 29

Blood-Brain Barrier

Question 30

Blood-Brain Barrier composed of?

Answer 30

endothelial cells of the blood vessels

Question 31

Location of endothelial cells?

Answer 31

inline or near the astrocytes, neurons, and pericytes

Question 32

How is pathogen penetration prevented in BBB

Answer 32

mechanical separation by the presence of specialized endothelial cells tightly attached to each other

Question 33

Mortality in CNS infections?

Answer 33

100%

Question 34

Mortality depends on what?

Answer 34

Agent, age, immune status of individual

Question 35

Tropism or preponderance in invading neural tissue

Answer 35

neurotropism

Question 36

CNS infections categorized according to?

Answer 36

location

Question 37

CNS Infections (MERMBFR):

Answer 37

Meningitis, Encephalitis, Rhomboencephalitis, Myelitis, Brain Abscess, Focal Lesions, Radiculitis

Question 38

localized infection; associated with immunocompromised individuals

Answer 38

Focal lesions and brain abscess

Question 39

Locations of brain abscess:

Answer 39

Directly on brain parenchyma; depending on location with regards to dura

Question 40

intracranial focal collection of purulent material located between the dura mater and arachnoid matter

Answer 40

Subdural empyema/abscess

Question 41

intracranial focal collection of purulent material located between the cranium and the dura

Answer 41

Epidural abscess

Question 42

Inflammation of the brain parenchyma

Answer 42

Encephalitis

Question 43

Clinical manifestations of Encephalitis (ADLPUSFFHNV)

Answer 43

○ Altered mental status (decreased level of consciousness, lethargy, personality change, unusual behavior) lasting at least 24 hours, ○ Seizures, and/or ○ Focal neurologic signs, ○ Fever, headache, nausea, and vomiting

Question 44

Inflammation of the meninges

Answer 44

Meningitis

Question 45

Clinical Manifestations of Meningitis (FHNVPS)

Answer 45

○ Fever ○ Headache ○ Nausea ○ Vomiting ○ Photophobia ○ Stiff neck aka nuchal rigidity

Question 46

Difference of meningitis vs encephalitis

Answer 46

Non altered sensorium

Question 47

Brainstem encephalitis

Answer 47

Rhomboencephalitis

Question 48

Clinical Manifestations of rhomboencephalitis (MTACRSC)

Answer 48

(mainly involved with balance and respiratory functions) ○ Myoclonic jerks, tremor, ataxia, cranial nerve involvement, respiratory abnormalities, shock, and coma

Question 49

Inflammation of the spinal cord

Answer 49

Myelitis

Question 50

Clinical Manifestation of Myelitis (WBFR)

Answer 50

Weakness, bladder dysfunction, flaccid paralysis, and reduced or absent reflexes

Question 51

Inflammation of the nerve roots

Answer 51

Radiculitis

Question 52

Clinical Manifestations of Radiculitis (WSDD)

Answer 52

Weakness, shooting pain, dysesthesia, and diminished reflexes

Question 53

Why is diagnosis of CNS based on diagnostic tests?

Answer 53

A lot of pathogens infect different parts of CNS