Pneumonia Flashcards
What percentage of pneumonia cases are caused by bacteria?
85%
What are clinical features of pneumonia?
Unrelenting cough
Fever and chills
Purulent sputum production - green or yellow
Chest pain (if pleura is inflamed)
Impair gas exchange resulting in dyspnoea and tachypnoea
What is the most common causitive pathogen in community acquired pneumonia?
Streptococcu pneumoniae
What type of bacteria predominate in hospital acquired pneumonia?
Gram negative.
What are the routes of entry of pathogens?
Inspiration of droplets containing pathogens
Aspiration of infective secretion from the URT
Aspiration of infected particles from the gastric tract, food, drink, foreign bodies
Haematogenous spread
How do URT flora cause disease and what are the common ones?
Aspirated into the LRT or travel down when the host immune response in impaired.
Commonly - Strep pneumonia, Staph aureus, and Haemophilus influenzae
What are some exogenous causes of pneumonia
Legionella pneumophilla, TB
What is the term given for common aetological causes of hospital acquired pneumonia
Enteric saprophytes - ie E. coli, pseudomonas - cause pneumonia when they contaminate the airways or blood
What are the two possible patterns of inflammation seen in pneumonia
Alveolar - inflam cells in the alveolar airspaces - neutrophils - causes consolidation - typically caused by bac like streph, staph, gram negs
Interstitial inflammation - macrophages and lymphocytes in the interstitial spaces. Causes atypical pneumonia or viral and bacterial origins
What is consolidation and what is it caused by?
The lung becomes old and firm and loses elasticity.
Due to alveolar being filled with neutrophils.
How does lobar pneumonia appear on at CXR?
White, sharply defined boarders at the fissures.
Describe the appearance of bronchopneumonia
Patchy, sometime focused around a bronchi or small airway. Across fissures.
T/F, a bacterial species will only produce lobar or bronchopneumonia.
False, a given bacteria can produce either. It depends on the immune state of the host and the virulence of the pathogen.
T/F lobar and bronchopneumonia can not overlap.
False. Eg bronchopneumonia can become diffuse and effect a whole lobe.
What is the most common cause of lobar pneumonia?
Strep pneumoniae (90%)
