Session 3

Question 1

Define Photophobia

Answer 1

Eye pain on exposure to light

Question 2

What is Purpura?

Answer 2

Spontaneous bleeding into the skin that appears as a rash

Question 3

What are the clinical features of Sepsis?

Answer 3

Temperature 38
Heart rate >90/min
Respiratory rate >20/min
WBC 12 x 10(9)L

Question 4

Define Bacteraemia

Answer 4

The presence of bacteria in the blood

Question 5

Define Septicaemia

Answer 5

Generalised Sepsis

Question 6

What is severe sepsis?

Answer 6

Systemic Inflammatory Response Syndrome and organ dysfunction/hypoperfusion

Question 7

What is septic shock?

Answer 7

Severe sepsis and persistently low blood pressure despite administration of IV fluids

Question 8

What is Systemic Inflammatory Response Syndrome?

Answer 8

Inflammatory state affecting the whole body frequently due to the immune system responding to an infection

Question 9

What is characteristic of a meningitis caused by Neisseria Meningitidis?

Answer 9

A non blanching rash

Question 10

What part of the Niesseria Meningitidis causes an inflammatory response?

Answer 10

The lipopolysaccharide endotoxin

Question 11

How does the Pilus help Niesseria Meningitidis?

Answer 11

It enhances attachment

Question 12

How does the polysaccharide capsule aid Niesseria Meningitidis?

Answer 12

Promotes adherence

Prevents phagocytosis

Question 13

How are cytokines pro thrombotic?

Answer 13

They promote coagulation

The inhibit fibrinolysis

Question 14

What happens if the coagulation cascade is overactive?

Answer 14

Microvascular thrombosis occurs (Disseminated Intravascular Coagulation) which can cause organ ischaemia/failure

Question 15

How can patients end up loosing extremities during sepsis?

Answer 15

Low BP causes blood to be diverted away from the extremities for extended periods of time causing them to become ischaemic

Question 16

What are the Sepsis six?

Answer 16

Deliver high O2
Take blood cultures (Before treating)
Administer empirical IV antibiotics
Measure serum lactate
Start IV fluid resuscitation
Commence accurate urine output measurement

Question 17

Why is serum lactate measured in patients with sepsis?

Answer 17

It shows how much anaerobic respiration is occuring which is a good indicator of how much blood is reaching the tissues

Question 18

What are some life threatening complications of sepsis?

Answer 18

Irreversible Hypotension
Respiratory failure
Acute renal failure
Raised intracranial pressure
Ischaemic necrosis of extremities

Question 19

How can you confirm a diagnosis?

Answer 19

Blood cultures
PCR
Gram stain
Lumbar puncture (for Meningitis)

Question 20

What are the 3 outcomes when someone comes into contact with meningitis causing pathogens?

Answer 20

Clearance
Carriage
Invasion

Question 21

How can you prevent meningitis?

Answer 21

Vaccinations (Only available for serogroup C)

Antibiotic Prophylaxis

Question 22

How is the spleen important immunologically?

Answer 22

It filters the blood and can detect any pathogens. It then attracts lymphocytes to defend against the infection

Question 23

When can you have decreased neutrophil number?

Answer 23

Chemotherapy
Certain drugs
Leukaemia
Lymphoma

Question 24

When can you have decreased neutrophil function?

Answer 24

Chronic granulomatomous disease

Very rare as not many issues with the innate immune system

Question 25

Define Immune system

Answer 25

Cells and organs that contribute to immune defences against infectious and non infectious substances

Question 26

Define Infectious disease

Answer 26

When the pathogen succeeds in evading and/or overwhelming the host's immune defences

Question 27

What does activation of the adaptive immune system depend on?

Answer 27

Activation of the innate immune system | Takes a few days to begin

Question 28

What are some of the Physical barriers to infection?

Answer 28

Skin Mucous membranes Bronchial cells

Question 29

What are some of the physiological barriers to infection?

Answer 29

Diarrhoea Vomitting Coughing Sneezing

Question 30

What are some of the chemical barriers to infection?

Answer 30

``` Low pH (Skin, stomach, vagina) Antimicrobial molecules (IgA, Lysosomes) ```

Question 31

What are some of the Biological barriers to infection?

Answer 31

Normal flora (They compete for space and resources with pathogens so infection does not occur) They are located at strategic places eg openings.

Question 32

When do issues begin to arise with normal flora?

Answer 32

When it is displaced from its normal location to a sterile location. Dental work Normal flora overgrows due to host being immunocompromised Normal flora being removed by antibiotics

Question 33

Give some examples of normal flora on the skin

Answer 33

Staphylococcus aureus | Staphylococcus epidermidis

Question 34

Give some examples of normal flora in the nasopharynx

Answer 34

Streptococcus pneumoniae | Neisseria meningitidis

Question 35

What are some of the ways normal flora can be displaced?

Answer 35

Breaching of the skin's integrity Fecal-oral route Fecal-perineal-urethral route

Question 36

What does PAMP stand for?

Answer 36

Pathogen-associated molecular pattern

Question 37

What are PAMPs?

Answer 37

Molecules that act as markers for certain pathogens

Question 38

How do PAMPs interact with the immune system?

Answer 38

They are recognised by PRRs (Pattern recognition receptor) and when this interaction occurs there is an inflammatory response

Question 39

How do Opsonins aid the immune system?

Answer 39

Bacteria that are encapsulated (eg streptococcus pneumoniae and neisseria meningitidis) are difficult to clear, but opsonins aid by marking them

Question 40

What are the 2 pathways of the complement system?

Answer 40

Alternative pathway | MBL pathway

Question 41

How does the alternative pathway work?

Answer 41

It is initiated by cell surface microbial constituents to release C3a & C5a (Recruits phagocytes) C3b & C4b (Opsonisation of pathogens)

Question 42

How does the MBL pathway work?

Answer 42

It is initiated when MBL binds to mannose containing residues of proteins (found on salmonella) to release C5-C9 (Kill pathogen membrane. Attack complex)