Infection S2 - An Infection Model & Antimicrobials (incomplete)

Question 0

Describe and give examples of contiguous spread of infection

Answer 0

Spread from one area of the body to another eg UTIs, perotinitis, endocarditis, meningitis

Question 1

What are the mechanisms of infection?

Answer 1

Contiguous
Inoculation
Haematogenous
Ingestion
Inhalation
Vector
Vertical transmission

Question 2

Describe and give examples of inoculation as a mechanism of infection

Answer 2

When a pathogen is introduced to the body by an external object eg if a branch scratched an eye, a fungal eye infection may occur as a result

Question 3

Describe and give examples of heamatogenous spread of infection

Answer 3

When pathogens spread via the blood eg infective endocarditis commonly occurs as a result of dental bacteria entering the blood

Question 4

Describe and give examples of ingestion as a mechanism of infection

Answer 4

When the pathogen is eaten/drunk from an infected source eg salmonella, E.coli, foot&mouth disease

Question 5

Describe and give examples of inhalation as a mechanism of infection

Answer 5

When the pathogen enters the body via air taken into the lungs. Can occur by droplet (eg the common cold) or aerosol transmission (TB)

Question 6

Describe and give examples of vectors as a mechanism of infection

Answer 6

When pathogens are transmitted between patients by a third party, eg Mosquitos can carry malaria and tsetse flies can carry sleeping sickness

Question 7

Describe and give examples of vertical transmission as a mechanism of infection

Answer 7

This occurs from mother to child. Seen in syphilis, HIV and hepatitis B

Question 8

What about your patient might you consider?

Answer 8

Factors about the person: age, gender etc
The time they became ill
The place(s) they have been and where they became ill

Question 9

What about your patient as a person would you consider?

Answer 9

Age
Gender
Physiological state
Pathological state
Social factors

Question 10

Why should a patient’s age be considered?

Answer 10

Many illnesses can become more or less likely at different ages eg meningitis has peaks in the early 20s and at ~3-6 months

Question 11

Why should a patient’s gender be considered?

Answer 11

Some illnesses are much more/less likely in different genders (eg UTIs) and some infections may be symptomatic in one gender but not the other (seen in several STIs)

Question 12

Why should a patient’s physiological state be considered?

Answer 12

Big physiological factors like pregnancy can come with increased risks for different infections

Question 13

Why should a patient’s pathological state be considered?

Answer 13

Pre existing conditions like HIV, AIDS and cystic fibrosis can make patients more vulnerable to different infections

Question 14

Why should a patient’s social factors be considered?

Answer 14

There are strong links with lower social class and several diseases, particularly TB

Question 15

Why should the timings of an infection be considered?

Answer 15

Calendar time - some microbes have peak months or seasons, eg norovirus is particularly active in winter
Relative time - some infections have very specific incubation times eg Ebola is 3-21 days

Question 16

Why should current and recent locations of a patient be considered?

Answer 16

Firstly so that if anyone else has been infected with a dangerous microbe, they can be identified and offered screening/treatment
Also so you know if the patient has been to any countries which may have common malaria infections or other diseases uncommon to the current location