1.2 - An Infection Model

Question 1

Describe the different types of pathogens

Answer 1

Prokaryotes : Virus, bacterium

Eukaryotes : Fungus (yeast, mould), parasite (Protozoa, helminth)

Question 2

Describe the 7 mechanisms of infection

Answer 2

Contiguous (direct) spread
Inoculation
Haematogenous 
Ingestion
Inhalation
Vector 
Vertical transmission

Question 3

What are the determinants of infections

Answer 3

Person

• age (strength of immune system, behaviours, activities)
• gender (body anatomy, UTI more common in females due to shorter distance of urethra from rectum)
• physiological state (puberty, pregnancy, post menopausal)
• pathological state ( smoking paralysing cilia, predisposing the lungs to infection. Diabetes can result in blood vessel diease, results in amputation of the foot)
• social factors (HIV, tattoos, intravenous drug use)

Time

• calendar time (time of year, clods/flu, seasonal diseases)
• relative time (

Place

• current
• recent

Question 4

How does an infection result in host damage?

Answer 4

Pathogen infects patient resulting in infection. During attachment, the infection interacts with host defences, making the host cell more susceptible to damage. Pathogens may also produce toxins, which induce damage to host cells. Occasionally, the host immune response may be unsuitable, and cause excessive inflammation, causing host cell damage.

Question 5

How can we manage infection

Answer 5

1) Diagnosis
- History
- examination
- investigations

2) Treatment
- specific ( antimicrobials, surgery)
- supportive (symptom relief, physiological restoration)

3) infection prevention
- hospital
- community

Question 6

What forms of surgery is used to treat infection?

Answer 6

Drainage
Debridement
Dead space removal.

Question 7

Describe the infection model

Answer 7

Pathogen interacts with patient. Mechanism of infection can vary. This results in an infection. Management of this infection can vary with the infection type. Outcome can vary from death to cure.

Question 8

What from of outcome can result from management of an infection?

Answer 8

Many infections are not cure able and are chronic infections. For example HIV. Some infections are not treatable and result in death. Others can be surged easily with antimicrobials or by the bodies immune response.

Therefore the outcome can be anywhere between death and cure.