Lower Respiratory Infections Flashcards
What is the leading cause of death in older adults in those with impaired resistance?
pneumonia caused by strep. pneumoniae (Gram + cocci)
infections by this pathogen are most common in IV drug users, older adults, in people with recurrent influenza virus infection, and individuals with cystic fibrosis. What is?
staphylococcus aureus (Gram + cocci) - can cause severe necrotizing pneumonia
what are the top three bacterial causes of community acquired pneumonia?
- Streptococcus pneumonia! most common by farrrr
- Haemophilus influenza.
- Staphylococcus aureus
to what family of viruses do influenza virus type A/B and respiratory syncytial virus (RSV) belong to and what kind of viruses are these? (what are the features of this family)
Paramyxoviridae: single stranded, negative sense, helical, enveloped
both viral causes of community acquired pneumonia
what kind of illness does parainfluenza virus cause and in whom?
human parainfluenza viruses type 1-4: confined to the respiratory tract, influenza like symptoms
—> pneumonia, croup, bronchiolitis
Mainly in infants and children
What are the three most common bacterial causes of atypical pneumonia?
- mycoplasma pneumoniae
- Chlamydia pneumoniae
- Legionella pneumophila
(more common than viruses)
mycoplasma pneumonia is the most common cause of what illness? what protein allows mycoplasma pneumoniae to cause infection?
mycoplasma pneumoniae: most common cause of atypical/walking pneumonia, most common in older children/young adults
P1 cytoadhesin allows M. pneumoniae to adhere to ciliated bronchial epithelial cells - inhibiting cilia reaction —> patches of affected mucosa desquamate
this bacterial cause of atypical pneumonia replicates in cells of the monocyte–macrophage system in the alveoli, causing a necrotizing multifocal pneumonia. In the environment this bacteria replicate in amoebas. what is?
Legionella pneumophila (Gram - rod)
This virus is known to cause outbreaks of lower respiratory tract infections (which can progress to pneumonia) in crowded environments such as military bases. Infected infants most commonly suffer from febrile pharyngitis. What is?
adenovirus: double stranded, non-enveloped
what kinds of infections result from the follow immunological defects:
a. MYD88 mutation adaptor protein
b. defective IgA production
c. defective TH1 cell-mediated immunity
a. MYD88 mutation adaptor protein —> severe necrotizing, pneumococcal infections
b. defective IgA production —> pneumonias from encapsulated organisms (H. influenza, pneumococcus)
c. defective TH1 cell-mediated immunity —> infections with Intracellular organisms (atypical mycobacteria)
define the following types of pneumonia:
a. Patchy distribution with inflammation from bronchioles to alveoli (patchy consolidation)
b. intra-alveolar exudate (consolidation of a lobe)
c. Diffuse, patchy inflammation localized to interstitial areas and alveolar walls.
a. Patchy distribution with inflammation from bronchioles to alveoli (patchy consolidation): bronchopneumonia
b. intra-alveolar exudate (consolidation of a lobe): lobar pneumonia
c. Diffuse, patchy inflammation localized to interstitial areas and alveolar walls: interstitial pneumonia
how do you reticular versus nodular interstitial opacities caused by pneumonia appear radiographic Lee?
reticular interstitial opacities = lines
Nodular interstitial opacities = dots
how do you alveolar opacities versus interstitial opacities caused by pneumonia appear radiographically?
alveolar opacities – lobar/segmental distribution, fluffy
Interstitial opacities – no respect for boundaries, reticular/nodular
what do the following colors of patient sputum indicate?
a. Yellow/green.
b. Pink/red/bloody.
c. White
d. Charcoal/gray.
e. Brown
a. Yellow/green: infection
b. Pink/red/bloody: infection or cancer
c. White: allergies, asthma, or viral infections.
d. Charcoal/gray: environmental, common in people who work in coal mines/factories or heavy smokers
e. Brown: chronic lung disease, cystic fibrosis or bronchiectasis.
*note this isn’t actually very reliable in clinical practice (but remember for boards!)
You are examining a blood sample from your patient who is presenting with community acquired pneumonia (more reliable than sputum). You identify a gram-positive lancet-shaped diplococci. What is it?
Streptococcus pneumoniae: most common cause of community acquired pneumonia
On rounds, you encounter a five year old child with community acquired pneumonia and concurrent epiglottitis. The child has not yet received their vaccinations. You identify an aerobic gram-negative bacteria in their sputum sample. What is the most likely cause of their pneumonia?
Haemophilus influenzae: aerobic, gram-negative bacteria, usually seen in infants and children or individuals with COPD/cystic fibrosis/bronchiectasis
Causes epiglottitis in suppurative meningitis in children
Uncommon in the US because of vaccination (Hib)
What kind of illness is Moraxella catarrhalis known to cause?
gram-negative bacteria, second most common cause of COPD exacerbation
Seen more in elderly, can cause community acquired pneumonia
Also commonly causes otitis media in children
use of IV drugs leading to right-sided endocarditis following pneumonia is associated with what bacteria?
Staphylococcus aureus: often causes secondary bacterial infections in children and adults
Associated with high incidence of complications - lung abscess, emphysema