Immunopathogenesis

Question 1

immunopathogenesis

Answer 1

pathologies caused by immune reactions, following an infection, rather than the pathogen itself

Question 2

viral bronchiolitis: definition and aetiological agents

Answer 2

inflammation of the bronchioles following viral infection

respiratory syncytial virus (RSV), rhinovirus, influenza virus, human metapneumovirus

Question 3

Risk factors for severe immunopathological disease in infants

Answer 3

prematurity (more than 4 wks early), 
chronic lung disease or congenital heart disease, 
low birth weight, 
other kids at home, 
bad living conditions,
 attending nursery etc

Question 4

RSV induced diseases - descending infection

Answer 4

rhinitis
otitis media
tracheobronchitis
bronchiolitis
pneumonia
asthma

Question 5

• RSV bronchiolitis and pneumonia - pathology and clinical signs

Answer 5

o Pathology – necrosis and sloughing of small airway epithelium, oedema, increased mucous secretion, interstitial infiltration, alveolar filling
Clinical – hyperinflation, atelectasis (collapsed lung), wheezing

Question 6

pathogenesis of RSV

Answer 6

virus replication causes immune response in lungs.
cyto/chemokine release, neutrophil infiltration, lymphocytes and eosinophils
perivascular and peribronchiolar cuffing occur, trapping air in lower lungs
= lung hyperinflation
removal of RSV doesn’t stop the pathway.

Question 7

systemic inflammatory response syndrome (SIRS)

Answer 7

Temperature >38ºC or <36ºC
Heart rate >90bpm
Resp rate >20 breaths/min or PaCO2 of <32 mmHg
WBCc >12,000 cells/mm3, <4000 cells/mm3, or >10% immature forms

Question 8

Sepsis

Answer 8

presence of SIRS associated with a confirmed infectious process

Question 9

severe sepsis

Answer 9

sepsis with either hypotension or systemic manifestations of hypoperfusion (lactic acidosis, oliguria, altered mental status)

Question 10

septic shock

Answer 10

sepsis with hypotension despite adequate fluid resuscitation, associated with hypoperfusion abnormalities

Question 11

bacterial causes of septicaemia in previously healthy adult - Skin

Answer 11

staphylococcus aureus and other gram positive cocci

Question 12

bacterial causes of septicaemia in previously healthy adult - urinary tract

Answer 12

escherichia coli and other aerobic gram negative rods

Question 13

bacterial causes of septicaemia in previously healthy adult - respiratory tract

Answer 13

streptococcus pneumoniae

Question 14

bacterial causes of septicaemia in previously healthy adult - bladder or bowel

Answer 14

enterococcus faecialis, e. coli and other gram negative rods, bacteroides fragilis

Question 15

bacterial causes of septicaemia in previously healthy adult - pelvic organs

Answer 15

nesseria gonorrhoeae, anaerobes

Question 16

bacterial causes of septicaemia in hospitalised patients - urinary catheter

Answer 16

E. coli
Klebsiella spp.
Proteus spp.
Serratia spp.
Pseudomonas spp.

Question 17

bacterial causes of septicaemia in hospitalised patients - Intravenous catheter

Answer 17

Staphylococcus aureus
Staph. epidermidis
Klebsiella spp.
Pseudonomas spp.
Candida albicans

Question 18

bacterial causes of septicaemia in hospitalised patients - peritoneal catheter

Answer 18

staph epidermidis

Question 19

bacterial causes of septicaemia in hospitalised patients - wound/deep infection

Answer 19

staph. aureus, e. coli, sometimes anaerobes

Question 20

bacterial causes of septicaemia in hospitalised patients - burns

Answer 20

gram positive cocci, pseudonomonas spp. candida albicans

Question 21

sepsis - pathophysiology

Answer 21

ACTIVATION of host defence mechanisms by endotoxins (gram -ve, lead to cytokine release) and exotoxins (gram +ve)
INFLAMMATION - neutrophils, monocytes are activated, –> vasodilation, diffuse endothelial permeability, activation of coagulation pathways
SEPSIS - fever, vascular collapse/shock. cna lead to septic shock

Question 22

consequenses of septic shock caused by the coagulation pathway

Answer 22

capillary microthrombi

end organ ischaemia

Question 23

consequenses of septic shock caused by the dysfunction of capillary endothelium

Answer 23

vasodilation
capillary leakage
global tissue hypoxia
organ dysfunction and failure