2.1 CNS Infective diseases

Question 1

what are the types of organisms that can cause infectious diseases of the CNS 4

Answer 1

bacterial
viral
fungal
parisitic

Question 2

which is more severe viral or bacterial meningitis

Answer 2

bacterial

Question 3

what is the most common causes of meningitis 2

Answer 3

streptococcus pneumoniae
neisseria meningitides

Question 4

patho of meningitis 7

Answer 4

bacteria replicate in CSF
release endotoxins
trigger inflammation recruiting neutrophils
increased BBB permeability
allows albumin to enter
water follows

Question 5

key clinical features of neisseria meningitis 2

Answer 5

petechial rash w purpura

severe skin injury due to diffuse intravascular coagulation

Question 6

encephalitis macro and microscopically

Answer 6

macro: diffuse inflammation of the brain parenchyma
micro: severe necrosis, astrocytosis and lymphocytes around blood vessles

Question 7

what does encephalitis look like microscopically 3

Answer 7

severe necrosis
astrocytosis
lymphocytes surrounding blood vesels

Question 8

most common cause of encephalitis

Answer 8

herpes simple virus

Question 9

most common bacterial cause of encephalitis

Answer 9

mycobacterium tuberculosis

Question 10

other causes for encephalitis spanning viruses, parasites and fungal 5

Answer 10

adenoviruses
HIV
arboviruses - need vectors
parasite - cerebral malaria
fungal - cryptococcal

Question 11

what is the features of a brain abscess 4

Answer 11

brain lesions which are well demarcated w a fibrous wall or capsule

central liquefactive necrosis w a pus filled cavity

neovascularisation resulting in oedema

reactive astrocytes

Question 12

the three stages of cerebral abscess formation

Answer 12

early cerebritis
intermediate cerebritis
final abcess formation

Question 13

features of early cerebritis 3 + immune cells involved 3

Answer 13

acute inflammation
necrosis
oedema

immune cells: neutrophils, microglia, astrocytes

Question 14

features of intermediate cerebritis 2

Answer 14

macrophages and lymphocytes

BBB becomes comprised due to cytokine release

Question 15

features of final abscess formation 2

Answer 15

neovascularisation

continual tissue destruction

Question 16

most common viral cause of meningitis

Answer 16

enterovirus

Question 17

clinical features of meningitis 6

Answer 17

neck pain
fever
photophobia
back and abdomen pain
stiff neck
altered mental state

Question 18

what are the two signs which also indicate meningitis

Answer 18

Kernig sign
Brydzinski sign

Question 19

what is kernigs sign

Answer 19

inability to extend the knee when hip flexed at 90degree angle

Question 20

what is brydzinskis sign

Answer 20

flexion of the neck causes flexion of the knee and hip

Question 21

complications of meningitis 4

Answer 21

vascular congestion
meningeal thickening
hydrocephalus
cerebral oedema

Question 22

what does vacular congestion involve as a complication of meningitis 2

Answer 22

inflammation cuasing thrombophlebitis - blood clots

can result in blockage and ischemia

Question 23

what does meningeal thickening and adhesions involve as a complication of meningitis 2

Answer 23

results in cranial nerve palsies

and can impaire CSF reabsorption

Question 24

does meningitis result in communicating or non communicating hydrocephalus

Answer 24

communicating

Question 25

investigations for meningitis

Answer 25

bloods including: CBE ,CRP, immunohistochemistry blood cultures and PCR gram stain CSF CT Lumbar puncture

Question 26

what is the relevance of CRP and immune histochemistry in our bloods test

Answer 26

neutrophils and high CRP = more likely bacterial atypical lymphocytes = more likely viral

Question 27

what can we conduct pcr for in meningitis investigations 3

Answer 27

strep pneumonia n meningitides enterovirus note how these are our top causes of meningitis

Question 28

where does the meningitis bug often live in the body prior to the brain

Answer 28

nasopharynx

Question 29

what other features would a blood test show in a bacterial meningitis 2

Answer 29

decreased glucose increased protein concentration

Question 30

key physical exams we would do in meningitis and reason for each 3

Answer 30

ENT - look for source of infection Skin to look for rashes in the case of neisseria meningitis neuro exam

Question 31

clinical features of encephalitis 7

Answer 31

very similar to meninigitis fever altered mental state headache nausea vomitting psychiatric symptoms seizures

Question 32

complications of encephalitis (and how these differ to meningitis) 2

Answer 32

In encephalitis it affects brain parenchyma so complications are permanent these include impairements to memory, hearing, speech, muscle control, sensation

Question 33

what are two predisposing conditions to getting brain abscesses

Answer 33

bacterial endocarditis chronic pulmonary sepsis

Question 34

clinical features of brain absessesn 5

Answer 34

fever headache altered mental state focal neurological symptoms ICP symptoms

Question 35

complication specific to brain absesses and then ur generic

Answer 35

abscess rupture resulting in meningitis or ventriculitis raised icp, herniation

Question 36

investigations for encephalitis 3

Answer 36

MRI - detects hyperintensities Lumbar puncture - to determine viral or bacterial bloods - if current sepsis, CRP, leukocytes, PCR

Question 37

investigations for brain abseccesses 3

Answer 37

MRI w contrast is gold standard - enhances lesions CT contrast next Bloods

Question 38

whcih part of the brain does encephalitis most commonly affect

Answer 38

temporal lobe - hence you commonly get impairements in speech, hearing, memory

Question 39

do you perform lumbar puncture in brain absesses

Answer 39

generally contraindicated due to mass effect and risk of herniation