Infectious Disease Flashcards
What is infection
When barriers are broken such as epithelial barrier
What is the upper respiratory tract and name some pathogens related
Oral and nasal cavity
Streptococcus, influenza
What is the area called in the lower respiratory tract affected by things like TB
Parenchyma (alveoli and bronchioles)
What are the 2 main bacteria which affect the parenchyma
Pneumonia - strep, staph
TB
How does TB bacteria in parenchyma cause tubercles to form
They can grow inside of macrophages in lungs
What does Tb have in cell wall which makes it resistant
Mycolic acid
What are the 3 causes of gastroenteritis
Viral cause
Parasite (waterborne)
Bacterial
What 2 types of gastroenteritis is there and their wbc count
1- secretory diarrhoea (low WBC)
2- inflammatory diarrhoea (high wbc)
What can cause secretory diarrhoea gastroenteritis
Cholera or enterotoxins
What kind of things cause inflammatory gastroenteritis
Shigella
Salmonella
Which strand of salmonella is asymptomatic
Salmonella enterica
What toxin does ecoli release and what happens
Vero cytotoxin- causes haemolytic uraemia syndrome HUS
What kind of toxin is cholera which causes inflammatory diarrhoea
AB exotoxins
What happens in cholera infect ants
B toxin binds to epithelial cells
A can enter via gangliosides and causes activation of adenylate cyclase
A lot of camp is produced which blocks NA movement from intestines to blood
This causes flood of Cl to move into intestines along with water
= dehydration
Which types of pathogens cause skin infections
Opportunistic pathogens - organisms which are present in absence of others
Which 3 bacteria produce skin infections
Streptococcus
Staphylococcus
S pyogenes
Why is streptococcus immune
Coated in a capsule
What type of things can streptococcus infect
Skin (impetigo, Scarlett fever)
Lungs (pneumonia)
What type of things can staphylococcus infect
Skin
Brain
Lungs(pneumonia)
What is inflammation induced by
Cytokine release
Neutrophil accumulation
What are the 5 signs of acute infection (innate response)
1- rubor(redness)
2- calor (Heat)
3- Tumor(swelling)
4- dalor (pain)
5- change in function - change in tissue structure due to pain
Why does rubor and calor occur
Increased blood flow to area of infection
Why does tumor occur
Movement of plasma to the tissue affected causes swelling
What causes dalor
Tumour which stretches skin pressing on nerves and pain receptors
What does adaptive immunity refer to
Humoral immunity - producing
antibodies from B cells
Cellular immunity - T cell attack
Memory and specificity - targeted response
Antibody dependant cytotoxicity
What is bacteremia
Bacteria presence in the blood
Use host mechanisms to attach eg via fim H
What is septicaemia
The response to bacteraemia
It causes septic shock which is an inflammatory response
What happens in septic shock for it to be more dangerous than infection
Excess cytokine release
Causes damage to organs due to blood vessel leakage
Which other illness is similar to septicaemia but inflammatory response is in brain
Meningitis
What 3 ways to bacteria, viruses, parasites enter
Wounds
Orally
Bites
