L3: An infection model

Question 1

What is needed to cause an infection?

Answer 1

Pathogens and patient

Pathogens–> mechanism of action –> release chemical (cytokines)–> response–> infection by reproducing

Question 2

How are infections removed/treated?

Answer 2

Management–> self such as coughs and colds–> get better over time
–> Dr provide medical intervention
Outcome–> remove/kill infection –> person gets better

Question 3

What are the different types of pathogens?

Answer 3

Virus
Prokaryotes (16s)–> bacteria
Eukaryotes (18s)–> fungus (yeast, mould) and parasite (protozoa and helminth (worm))

Question 4

What variation in the patient can determine how they respond to a pathogen?

Answer 4

Person–> age, gender, physiological state (pre or post puberty, pregnancy), pathological states (co-morbiditeis- weakened immune system more susceptible, diabetes ↑risk, surgery) and social factors (contact with people and the environment, behaviours)
Time–> calendar time (time of year), relative time (incubation period of infection)
Place–> current, recent (where you have been, travel, restaurants)

Question 5

What are the different mechanisms of infection?

Answer 5

Contingous (direct) spread–> touching, contact
Inoculation (vaccination)–> introduce pathogen into body
Haematogenous–> carried by blood
Ingestion–> eating or drinking it
Inhalation –> breathing it in
Vector–> 3rd party transmits infection
Vertical transmission–> mother to child

Question 6

How does the infection actually cause damage?

Answer 6

Attachment to host
Interaction with host defence and/or toxin production
Inflammation (host response neutrophil–> respiratory burst or NETs)–> host damage
or direct damage via toxins

Question 7

How are infections managed?

Answer 7

Diagnosis–> taking history (name, age, gender, where they’ve been etc), examination, and investigations
Treatment–> specific–> target specific organisms
–> supportive–> treat the symptoms of disease
Infection prevention–> if in hospital or community –> isolate infectious patients

Question 8

What are Drs trying to determine with diagnosis?

Answer 8

Where the infection is
What the infection is
So they can give appropriate treatment

Question 9

What is the difference between specific and supportive treatments?

Answer 9

Specific–> treat the infection–> antimicrobials, surgery (drainage, debridement, dead space removal)
Supportive–> treat the symptoms, physiological restoration (seriously ill–> ventilators, kidney failure or heart failure–> dialysis)

Question 10

What is the outcome?

Answer 10

Either cure or death

Chronic infection can lead to +/- disability e.g. live with HIV and TB but requires continuous treatment