Respiratory System Pathologies 3 Flashcards
(70 cards)
What are the two main types of infection-related respiratory pathologies?
- Pneumonia (Lobar and Bronchopneumonia)
- Tuberculosis (Primary and Secondary)
What is pneumonia and what characterizes it?
Pneumonia is an infection leading to inflammation of the lung parenchyma. It is characterized by vascular permeability and hyperemia, resulting in exudate that fills the alveolar spaces and distal bronchioles.
Who is especially at risk of pneumonia-related death and hospitalization?
The elderly, particularly due to influenza-related pneumonia.
What are the causes of pneumonia?
• Infection (bacterial, viral, fungal, or parasitic) via:
• Aspiration of contaminated secretions
• Inhalation of infected airborne droplets
• Direct spread from adjacent infections (e.g. flu)
• Bacteremia (bacteria in the blood)
• Opportunistic disease when body defenses are down (especially in elderly)
What is lobar pneumonia?
A pneumonia that affects an entire lobe or large part of a lung lobe, usually caused by streptococcal bacteria (pneumococcus) and has a rapid onset in healthy individuals.
What are the signs and symptoms of lobar pneumonia?
High fever, chills, fatigue, loss of appetite
Acute, violent productive cough
Severe pleuritic pain or dyspnea
Possible hemoptysis (coughing blood)
Complications: endocarditis, meningitis, pleural adhesion, chronic bronchitis
Now fully treatable with antibiotics
What are the 4 stages of lobar pneumonia?
- Congestion (48 hrs):
• Inflammation and congestion
• Vascular congestion, intra-alveolar fluid, few neutrophils, many bacteria
• Lung is heavy and hyperemic - Red Hepatization:
• Persistent vascular congestion
• Capillary rupture → RBCs leak into alveoli
• ↑ Neutrophils & fibrin
• Alveoli filled with exudate, lobe looks red and solid like liver - Grey Hepatization:
• RBCs disintegrate
• Neutrophils & fibrin remain
• Solid pale lobe with a dry surface - Resolution (days–weeks):
• Enzymes break down exudate
• Cleared by macrophages or cough reflex
What causes bronchopneumonia and how does it present?
Caused by staph or strep (can also be viral/fungal). It presents as bilateral, patchy inflammation around terminal bronchioles and alveoli in one or more lung lobes.
Who is most likely to be affected by bronchopneumonia?
Debilitated or immunosuppressed individuals like the elderly, infants, AIDS patients.
What are the signs and symptoms of bronchopneumonia?
• Low-grade fever
• Fatigue
• Mild cough
• Slowly increasing lung congestion
How does bronchopneumonia differ from lobar pneumonia?
• Slower, insidious onset
• Rarely resolves fully—becomes chronic
• May lead to death in already compromised patients
• May be hard to distinguish from other pathologies in debilitated patients
What are possible complications of pneumonia?
• Abscess formation
• Spread to pleural cavity (pleuritis)
• Exudate replaced by fibroblasts (fibrosis)
What causes tuberculosis and how is it spread?
Caused by Mycobacterium tuberculosis bacilli, spread via airborne transmission. Risk is higher in densely populated, low-hygiene, malnourished, or impoverished areas.
What is the global impact of TB?
TB is the most common infectious disease-related cause of death worldwide.
Who is at higher risk of TB in Canada?
First Nations peoples and immigrants from high-incidence countries.
What are global challenges in TB control?
TB-HIV co-epidemic
Spread of drug-resistant TB strains
What is primary TB and how does it develop?
It develops in people with no prior exposure. TB bacilli are inhaled, then multiply in alveoli. Macrophages ingest them but fail to destroy them, triggering T-cell sensitization and macrophage enzyme release.
What does primary TB cause in lung tissue?
Caseous necrosis (cheese-like destruction) and granuloma formation to contain the infection. Most develop a latent infection.
What happens in latent TB?
The body controls the bacteria, which become dormant but not destroyed. Infected people are asymptomatic and not contagious.
What is a Ghon Focus?
A visible granuloma (calcified lesion) on chest X-ray formed when bacteria are surrounded by fibrous tissue.
What is a Ghon Complex?
The combination of a Ghon Focus (pulmonary lesion) and granulomas in regional lymph nodes.
What is secondary TB and how does it occur?
Reactivation of latent TB when the Ghon Focus ruptures, typically due to weakened immunity (e.g. AIDS, chemotherapy, radiation).
What are the medical treatments for TB?
• Long-term multi-drug antibiotic therapy (1–2 years)
• Surgery (resection) in MDR-TB to reduce bacterial load
• Despite treatment, TB can still be fatal
What is the Mantoux test, also known as the TB skin test?
It’s a test where a small amount of TB antigen is injected under the skin of the forearm. After 48–72 hours, the skin is examined for a reaction.