Drugs
What enzymes does Moxifloxacin inhibit?
DNA topoisomerase II and IV
A patient with pneumonia also has hyponatremia. Which bacteria is likely responsible for this?
Legionella
What are physicians looking for in an x-ray to identify if S. Pneumoniae is present?
lobar consolidation -- dense, homogenous opacity of a single lobe or lung segment
What type of vaccine is PCV15/20?
conjugate
Where in the lung does pneumonia infection start?
alveoli
What class of drug is moxifloxacin?
fluoroquinolones
Why does S. Pneumoniae cause rust-colored sputum? Describe the mechanism.
1. Alveolar inflammation
2. Capillary damage from pneumolysin
3. RBC breakdown
4. mix with purulent exudate --> red/brown sputum
Define egophony
When a patient says “E” and you hear it as a nasal or bleating “A” sound
How do you calculate absolute risk reduction?
ARR = control event rate - experimental event rate
Contrast the sensitivity and specificity of chest radiography vs sputum culture in diagnosing pneumonia.
chest radiograph - more sensitive
sputum culture - more specific
Liver - through glucuronide and sulfate conjugation (phase II reactions), NOT cytochrome P450.
List 2 similarities and 2 differences between S. Pneumoniae and Legionella immune evasion.
Both: avoid immune clearance to prevent being killed by innate immune cells + disrupt host cytokine signaling
Differences: S. Pneumoniae is extracellular, legionella lives intracellularly inside macrophages. S. Pneumoniae can be transmitted person-to-person, legionella is transmitted via bodies of water.
Explain how PCR works to detect S. Pneumoniae infection.
PCR detects DNA that is specific to S. Pneumoniae in a sample (such as sputum, blood) and amplifies it.
Between PCV15/20 and PPSV23 vaccines, which induces a stronger immunity, and why?
PCV15/20 because they are T-cell dependent.
Compare and contrast typical vs atypical pneumonia.
typical: sudden onset, caused by bacteria like S. Pneumoniae, productive cough w rust colored sputum
atypical: gradual onset, caused by fungi, less common bacteria like legionella, dry cough
What cardiac side effect is associated with moxiflocaxin (and its class of drugs)?
lengthened QT leading to torsade de pointes
List the features of S. Pneumoniae, including gram +/- and at least 3 other identifying traits.
S. Pneumoniae is gram positive, alpha-hemolytic, found as lancet-shaped diplococci, bile-soluble and optochin sensitive.
Bonus: what does this mean?
What does the S. Pneumoniae urine antigen test look for? (specific)
Cell wall polysaccharide of S. Pneumoniae, which is released during infection and can pass into urine.
The vaccine has highest benefit for those populations, and may not justify side effects for younger/healthier people.
Explain why pneumonia often produces pleuritic chest pain even though alveoli themselves lack pain fibers.
Pneumonia leads to inflammation outside of the alveoli, including the pleura (especially parietal, which has a lot of nerves)
What are some precautions to taking Moxifloxacin?
myasthenia gravis, neurotoxicity, peripheral neuropathy, psychiatric event, tendinitis, tendon rupture
Which (2) interleukins do S. Pneumoniae inhibit, and what do these interleukins do?
IL6: pleiotropic effects, mediates innate and adaptive immunity
IL8: attracts and activates neutrophils
Why might a physician prefer to use a urine antigen test instead of sputum culture?
sputum culture can take 3-5 days, urine antigen test is faster
A new pneumococcal vaccine trial shows incidence of pneumonia is 6% in the placebo group and 3% in the vaccine group. Calculate the ARR (absolute risk reduction), RRR (relative risk reduction), and NNT(number needed to treat). Interpret each.
ARR = CER - EER = 0.06 -0.03 = 0.03
RRR = ARR/CER = 0.5
NNT = 1/ARR = 33.3 ~ 34
Which microorganism(s) are likely to cause community acquired pneumonia? Which microorganisms cause hospital acquires pneumonia?
CAP: mostly S. Pneumoniae
HAP: aerobic gram negative bacteria, staph aureus