MI: Respiratory Tract Infections Flashcards
List some ways in which the body can be compromised, thereby increasing the risk of respiratory tract infection.
- Poor swallow
- Abnormal ciliary function (e.g. smoking)
- Abnormal mucus (e.g. CF)
- Dilated airways (e.g. bronchiectasis)
- Defect in host immunity
What type of bacterium is Streptococcus pneumoniae?
- Gram-positive cocci in chains
- Alpha-haemolytic and optochin-sensitive
Why is no microbiological identification of the pathogen made in the most cases of CAP?
Difficult to obtain a good sputum sample and early treatment is usually initiated with empirical antibiotics
List the main organisms that cause CAP.
- Streptococcus pneumoniae
- Haemophilus influenzae
- Moraxella catarrhalis
- Staphylococcus aureus
- Klebsiella pneumoniae
List the most prevalent pathogens causing CAP in the following age groups:
- 0-1 months
- 1-6 months
- 6 months - 5 years
- 16 - 30 years
0 - 1 months:
- Escherichia coli
- Group B Streptococcus
- Listeria monocytogenes
1-6 months:
- Chlamydia trachomatis
- Staphylococcus auerus
- RSV
6 months - 5 years:
- Mycoplasma pnaeumoniae
- Influenza
16-30 years:
- Mycoplasma pneumoniae
- Streptococcus pneumoniae
List the causes of CAP that fall into the following two categories:
- Typical
- Atypical
Typical:
- Streptococcus pnaeumoniae
- Haemophilus influenzae
Atypical:
- Legionella
- Mycoplasma
- Coxiella burnetii
- Chlamydia psittaci
What is the CURB-65 score? How is it interpreted?
- Confusion
- Urea > 7 mmol/L
- Respiratory rate > 30/min
- BP < 90 systolic, < 60 diastolic
- Score of 2 = consider hospital admission
- Score of more than 2 = severe pneumonia that may need ITU admission
Outline the presentation of bronchitis.
- Cough
- Fever
- Increased sputum production
- Increased SOB
Which organisms cause bronchitis?
- Viruses
- Streptococcus pneumoniae
- Haemophilus influenzae
- Moraxella catarrhalis
List some bacterial causes of cavitating lung lesions.
- Staphylococcus aureus
- Klebsiella pneumoniae
- TB
What type of bacterium is H. influenzae?
Gram-negative cocci-bacilli
How is Legionella spread?
Inhalation of infected water droplets
What medium is Legionella grown on?
Buffered charcoal yeast extract
Whatis a common feature of bacteria that cause atypical pneumonia?
They have NO cell wall
List four atypical organisms.
- Mycoplasma
- Legionella
- Chlamydia
- Coxiella
Which type of antibiotics do not work on atypical bacteria?
Penicillins
NOTE: this is because they act on cell walls