Introduction, Organisms Implicated Flashcards
What is pneumonia, and how does it affect the body?
Pneumonia is an acute respiratory infection that inflames the lung parenchyma (alveoli), leading to consolidation.
How is pneumonia typically spread?
Pneumonia can spread via inhaled viruses and bacteria from the nose/throat, airborne droplets from a cough or sneeze, or through the blood.
What are the primary risk factors for developing pneumonia?
Risk factors include immunocompromised status, pre-existing illnesses, age <2 years or >65 years, indoor air pollution, crowded living conditions, and parental smoking.
What distinguishes community-acquired pneumonia (CAP) from other types of pneumonia?
CAP is acquired outside of healthcare facilities or within 48 hours of admission and is typically caused by pathogens like S. pneumoniae, H. influenzae, and S. aureus.
What are the common pathogens responsible for typical community-acquired pneumonia (CAP)?
Typical CAP pathogens include Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, and Klebsiella pneumoniae.
What causes atypical community-acquired pneumonia (CAP), and how is it different?
Atypical CAP is caused by Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella pneumophila, and viruses, with more extrapulmonary symptoms.
What characterizes hospital-acquired pneumonia (HAP)?
HAP is acquired at least 48-72 hours after hospital admission, commonly caused by Gram-negative bacilli, Staphylococcus aureus, including MRSA, and sometimes Legionella from hospital water supplies.
What are the most frequent pathogens causing hospital-acquired pneumonia (HAP)?
Common pathogens include Gram-negative bacilli (Enterobacteriaceae, Pseudomonas spp., Acinetobacter spp.) and Staphylococcus aureus (including MRSA).
How does ventilator-associated pneumonia (VAP) develop, and when is it diagnosed?
VAP is diagnosed at least 48 hours after a patient is connected to a ventilator, often due to biofilm formation on the endotracheal tube, with pathogens such as Streptococcus pneumoniae, Pseudomonas aeruginosa, Acinetobacter spp., and Staphylococcus aureus.
What is aspiration pneumonia, and what pathogens are commonly involved?
Aspiration pneumonia occurs when food, stomach acid, or saliva is inhaled into the lungs, with pathogens like Streptococcus pneumoniae, Pseudomonas aeruginosa, Bacteroides, and Prevotella.
What are some less common pathogens associated with pneumonia?
Less common pathogens include anaerobic bacteria, fungi (e.g., Candida, Aspergillus), and viruses (e.g., Cytomegalovirus, Herpes simplex).
What are some complications associated with pneumonia?
Complications include pleural effusion, lung abscess, empyema, pericardial effusion, meningitis, septicemia with multi-organ failure, and ARDS.
