What is the most common cause of death in viral influenza epidemics?
Superimposed bacterial pneumonia
What are 2 acute phase markers made in the liver that are specific for bacterial infection and can be useful in pneumonia diagnosis?
Which serotype of the encapsulated H. influenzae is most virulent?
What will the sputum culture of a patient with community-acquired bacterial pneumonia caused by Streptococcus pneumoniae show morphologically?
Lancet-shaped gram (+) diplococci in pairs and chains
Which patient population is at a high risk for development of invasive infection by H. influenzae?
Neonates and children w/ comorbidities
What is the 1st and 2nd most common bacterial cause of acute exacerbation of COPD?
- Most common = H. influenzae
- 2nd = M. catarrhalis
Pneumonia caused by what bacteria is a pediatric emergency due risk of acute epiglottitis w/ high mortality rate?
What is the pulmonary consolidation associated w/ H. influenzae typically like?
Lobular and Patchy
Which patient population is especially susceptible to bacterial pneumonia by Moraxella Catarrhalis?
S. aureus pneumonia is associated with a high incidence of which 2 complications?
- Lung abscess
- Empyema (aka pus in the pleural space)
What is the most frequent cause of gram-negative bacterial pneumonia and who does it most commonly afflict?
- Klebsiella pneumoniae
- Debilitated and malnourished people, particularly chronic alcoholics
What type of sputum is characteristic of Klebsiella pneumoniae?
Thick, mucoid (blood-tinged) --> "currant jelly"
Pseudomonas aeruginosa is a common cause of pneumonia in whom and in what setting?
- Hospital acquired
- Cystic Fibrosis and Immunocompromised
Which bacteria cause of pneumonia flourished in warm freshwater (i.e., AC units, misters, hot tubs); what does it live inside?
- Legionella pneumophila
- Lives in amoebas
What are the 2 common modes of transmission for Legionella pneumophilia?
- Inhalation of aerosolized organisms
- Aspiration of contaminated drinking water
What is the gram stain and morphology of Legionella pneumophila?
Gram NEGATIVE bacillus
Pt's with what predisposing conditions are most at risk for Legionella pneumonia?
- Pt's w/ cardiac, renal, immunologic, or hematologic diseases
- Organ transplant recipients****
- Elderly smokers
How is rapid diagnosis of Legionella pneumophila done and what is the gold standard?
- Legionella Ags in the urine
- (+) fluorescent Ab test on sputum samples
- CULTURE = gold standard
Which bacterial cause of pneumonia is associated with hypokalemia, elevated CPK, and lobar infiltrates?
What is the gram stain, shape, and O2 dependency of Pseudomonas aeruginosa?
AEROBIC Gram NEGATIVE; bacillus
Mycoplasma pneumoniae infections are common in which age groups and occur most often how?
- Children and young adults
- Sporadically or as local epidemics (i.e., schools, military camps, prisons)
Patchy consolidation of the lung is the dominant characteristic of what type of bacterial pneumonia?
Air-fluid level within cystic space seen on CXR associated with pneumonia suggests what?
What are the 4 stages of the inflammatory response which have been classically described for lobar pneumonia?
1) Congestion: vascular engorgement; intra-alveolar fluid
2) Red hepatization: massive exudation of alveolar spaces w/ lots of neutrophils; red, firm, airless lobe; liver-like consistency
3) Gray hepatization: disintegration of red cells w/ fibrinosuppurative exudate
4) Resolution: fibrosis and macrophage clean-up
Congested septal capillaries due to massive confluent exudation w/ numerous intra-alveolar neutrophils is characteristic of what stage of lobar pneumonia?
Which inflammatory stage of lobar pneumonia is characterized by progressive disintegration of red cells and the persistence of a fibrinosuppurative exudate?
Exudates within alveolar spaces converted into fibromyxoid masses rich in macrophages is characteristic of which inflammatory stage of lobar pneumonia?
Which pattern of bacterial pneumonia is often multilobular and frequently bilateral and basal?
Which cause of bacterial pneumonia is classically seen in military recruits or college student i.e., those living in close quarters?
Histologically, the rxn associated with bronchopneumonia shows areas of acute suppurative inflammation rich in what type of immune cell?
Neutrophilic exudate filling bronchi, bronchioles, and adjacent alveolar spaces