Pneumonia: Key Concepts and Information

These flashcards cover key concepts, definitions, and facts about pneumonia, its classification, causes, pathogenesis, clinical presentation, diagnosis, and complications.

Define pneumonia.

Microbial invasion of the lung parenchyma and the associated host response.

What are the classification schemes for pneumonia?

Acute or chronic, typical or atypical, community acquired or nosocomial, normal host or immunocompromised, microbial agent, and radiological.

List some common causes of typical bacteria in pneumonia.

Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, Pseudomonas aeruginosa, Enterobacteriaceae.

What viruses are associated with pneumonia?

SARS-CoV-2, RSV, Influenza A & B, parainfluenza viruses.

Identify the pathogens causing pneumonia in neonates.

E. coli and Group B Streptococci.

What pathogens are common in infants (1-6 months) with pneumonia?

Chlamydia trachomatis and RSV.

What are the typical pneumonia pathogens for young adults (16-30 years)?

Mycoplasma pneumoniae and Streptococcus pneumoniae.

What is the role of the mucociliary blanket in lung defenses?

It helps trap and expel airborne particles from the airways.

Describe the pathogenesis of pneumonia.

Failure of host defenses, virulent organism, and sufficient inoculum leads to pneumonia.

What are some extremes of age that can impair host defenses against pneumonia?

Neonates and older adults are at increased risk.

What are clinical symptoms of community-acquired acute pneumonia?

Chills, rigors, productive cough, pleuritic chest pain.

What imaging is used as the most important diagnostic investigation for pneumonia?

Chest X-ray.

What is the definition of atypical pneumonia?

Pneumonia typically caused by bacteria or viruses that present differently from traditional (typical) bacterial pneumonia.

What laboratory findings are typical for atypical pneumonia?

Typically limited leukocyte response and minimal sputum findings.

What is a common pathogenic agent of atypical pneumonia?

Mycoplasma pneumoniae.

What microbiology findings are common in nosocomial pneumonia?

Aerobic Gram-negative bacilli such as Klebsiella pneumoniae, E. coli, and Pseudomonas aeruginosa.

What is the primary pathological pattern seen in bacterial pneumonia?

Suppurative inflammation with lobar or bronchopneumonic patterns.

What are the complications of pneumonia?

Abscess, empyema, disseminated infection, septic shock, respiratory failure.

What is a lung abscess and how does it form?

Aspiration of infective material commonly leads to lung abscess formation.

What X-ray finding is indicative of a lung abscess?

Cavitating lesion in the lung.

What is the common clinical feature of pneumonia in the immunocompromised?

Pneumonia features closely related to immunodeficiency.

What signs are associated with community-acquired acute pneumonia?

Tachypnoea, fever, dullness to percussion, crepitations.

What symptoms indicate impaired drainage of secretions contributing to pneumonia?

Cough suppression, impaired mucociliary apparatus, static fluid in alveoli.

What are the classical stages observed in bacterial pneumonia pathology?

Congestion, red hepatisation, grey hepatisation, resolution.

What laboratory investigations can confirm pneumonia?

Sputum culture, blood culture, microbiological assays for specific antigens.

What are the general host defense mechanisms against pneumonia?

Filtration and humidification of inspired air, cough reflexes, mucociliary transport, innate, humoral, and cellular immunity.

How does pneumonia typically present in terms of symptoms in immunocompromised patients?

Insidious onset with symptoms reflecting specific vulnerabilities depending on the underlying condition.

What X-ray changes occur in bronchopneumonia?

Typically presents as patchy infiltrates on imaging.

What types of microorganisms can cause atypical pneumonia?

Mycoplasma, Chlamydia, and various viral pathogens.

What characterizes the pathophysiological response during pneumonia?

Stimulation of the cough reflex, hypoxaemia, and fever due to inflammatory response.

Define empyema in the context of pneumonia.

A collection of pus in the pleural cavity that can develop as a complication of pneumonia.

What is the effect of age on pneumonia epidemiology?

Increased risk at extremes of age, especially in neonates and elderly populations.

What role do innate immune responses play in pneumonia defense?

Involve alveolar macrophages, neutrophils, and complement responses to pathogens.

What is the significance of altering the hypothalamic thermostat during pneumonia?

It leads to fever as the body attempts to fight off infection.