S2) Infection Model

Question 1

Identify the components in the model of infection

Answer 1

• Pathogen
• Patient
• Mechanism of infection
• Infection
• Management
• Outcome

Question 2

Describe the layout of the infection model

Answer 2

Question 3

Classify pathogens in terms of the infection model

Answer 3

• Virus
• Prokaryotes: bacteria
• Eukaryotes:

I. Fungus – yeast (unicellular) , mould (multicellular)

II. Parasites – protozoa (u) , helminth (m)

Question 4

Why is it a little bit harder to treat fungi and parasites?

Answer 4

• Because they are eukaryotes
• and we have the same physiology and biochemistry as them
• so it makes it very difficult to treat them effectively without poisoning our own cells

Question 5

Describe the ‘patient’ component in the infection model

Answer 5

• Person – age, gender, physiological (e.g. pregnancy) and pathological states (e.g. comorbidities like diabetes), social factors (e.g. where have you been on holiday, how many sexual partners you have)
• Time – calendar time/relative time
• Place – current/recent

Question 6

Identify the 7 different mechanisms of infections

Answer 6

• Contiguous (direct) spread (skin to skin contact or music membrane to mucus membrane like STI)
• Haematogenous (spread through blood stream, e.g. someone who has a boil on skin caused by staphoreus - when you squeeze them, you are squeezing them into the blood stream, which can cause infections else where and you can end up with abcesses)
• Inoculation
• Ingestion (faetal oral transmission)
• Inhalation
• Vector
• Vertical transmission (mother to child)

Question 7

Illustrate the process of infection

Answer 7

Insert image

Question 8

Identify the three parts of the management component in the infection model

Answer 8

• Diagnosis
• Treatment
• Infection prevention

Question 9

Identify the three processes outlined in the diagnosis of an infection

Answer 9

• History
• Examination
• Investigations

We get answers for ‘where is the infection?’ and ‘what is the infection so we can get our treatment

Question 10

Identify the two types of treatment for an infection

Answer 10

• Specific
• Supportive

Question 11

Outline the two types of specific treatments for infections

Answer 11

• Antimicrobials
• Surgery:
• drainage (if someone has big abcess, drain it to get rid of bacterial load)
• debridement (cutting open affected tissue and removing as much affected tissue as can be seen, sometimes a consequence of this is amputation) ,
• dead space removal ( to ensure you don’t leave a big cavity in the body for more infection to accumulate, it needs to be packed with muscle or other tissue)

Question 12

Outline two types of supportive treatment for infections

Answer 12

• Symptom relief
• Physiological restoration (trying to get the body’s biochemistry back to what it should be like)

Question 13

What are the two locations for infection prevention?

Answer 13

• Hospital
• Community

Question 14

Identify 4 different outcomes for infections

Answer 14

• Cure
• Chronic infection
• Disability
• Death

Question 15

Describe the infection component of the infection model

Answer 15

Question 16

Describe a case in which infection prevention is extremely important

Answer 16

It is important to remember that a patient in the hospital setting may have had an operation e.g. hip replacement and may acquire an infection in the process therefore infection prevention is extremely important.