Infectious disease introduction

Question 1

infections occur because of

Answer 1

exogenous or endogenous bacteria

Question 2

what are infections with endogenous bacteria (NF) usually secondary to?

Answer 2

alteration in tissue structure or function

• organisms go where don’t normally go-> perforation of intestine (G-)
• obstruction of draining pathways with overgrowth-> ear infections, sinus infections, obstructive pneumonia (strep. pneumoniae)
• alteration in host defense (candida infections)

Question 3

what is the difference between infection from normal flora versus exogenous organisms?

Answer 3

NF infections are result of another pathological process which must be considered as part of approach of disease.
-NF infections rarely caused by contagion (except in environmental cases)

Question 4

what is characteristic of bacterial respiratory infections with normal flora?

Answer 4

often follow viral infections due to tissue swelling and obstruction
-otitis media, sinusitis, pneumonia

Question 5

most common causes of Pneumonia

Answer 5

strep. pneumoniae, h. influenza, Staph aureus, moraxella catarrhalis

Question 6

what are some organisms NOT commonly found in oropharynx

Answer 6

• beta-hemolytic streptococci (S. pyogenes)
• H. influenza (type B)
• Neisseria meningitids
• DO NOT need pre-existing tissue injury or alteration

Question 7

what are some important features for endogenous or exogenous?

Answer 7

1. ) site of production
2. )presence or absence of exotoxins, endotoxins
3. ) presence or absence of capsules, other methods of evading the immune system
4. )specialized mechanism for invading host
5. ) time course
6. ) special host features (age, immune status, pre-existing or concurrent disease)

Question 8

what are the four major routes in which humans become infected?

Answer 8

1. ) come in contact with virulent organism
2. ) colonize organism gets past a barrier
3. ) changes in local conditions cause overgrowth of a colonizing organism
4. ) combination of a,b,c

Question 9

inability to produce IG puts humans at risk of?

Answer 9

encapsulated organisms

Question 10

lack of cellular immunity puts humans at risk of?

Answer 10

intracellular organisms such as viruses and rickettsia

Question 11

lack of neutrophils function puts humans at risk of?

Answer 11

staph, strep

Question 12

lack of phagocytic clearing mechanisms puts humans at risk of?

Answer 12

encapsulated organisms

Question 13

what are the 2 concepts of contagion

Answer 13

1. ) limiting exposure to virulent organisms
2. ) not allowing colonizing (or virulent) organisms to go where they don’t belong
   - NOSOCOMIAL infections by both

Question 14

protection from virulent organisms requires what?

Answer 14

1. ) enhancement of natural body defenses

2. ) avoidance of exposure

Question 15

patients who have an altered immune response or vascular insufficiency may not?

Answer 15

show TYPICAL signs and SYMPTOMS

Question 16

what are therapeutic interventions in infectious diseases besides antibiotics?

Answer 16

• treating underlying disease
• prevent contagious spread
• shore up natural barriers
• alter the immune response