Respiratory System Pathologies 3 Flashcards
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.
What does a positive TB skin test indicate?
It indicates latent TB infection (not active). This can be due to:
• Previous exposure to TB-like antigens (prior TB test)
• Previous BCG (Bacillus Calmette-Guérin) vaccine
What further tests may be done after a positive TB skin test?
A chest X-ray and more tests may be carried out.
What can a negative TB skin test indicate?
• No latent TB infection
• Very recent exposure (3–8 weeks)
• Immunosuppression (e.g., HIV infection, active TB)
What test is now available in Canada for diagnosing latent TB infection?
A blood test.
How does TB infection begin and what are the possible symptoms?
It starts with pulmonary TB. It may be asymptomatic or present with:
• Productive cough
• Fever
• Night sweats
• Fatigue
• Weight loss
• Hemoptysis
• Chest pain
Can TB spread beyond the lungs?
Yes, and it may be fatal when it spreads systemically.
What are the symptoms of TB meningitis?
Intermittent or persistent headache, mental status change, coma, and fever.
What is Pott’s disease and what are its symptoms?
TB of the spine. Symptoms: back pain, stiffness, lower extremity paralysis.
What joints are commonly affected by tuberculous arthritis?
Hips and knees.
What are symptoms of genitourinary TB?
• Flank pain
• Dysuria
• Frequency
• In men: epididymitis, scrotal mass
• In women: mimics PID
• May cause sterility in both sexes
What are gastrointestinal symptoms of TB?
Non-healing ulcers (mouth/anus), dysphagia, abdominal pain, malabsorption, diarrhea.
What is TB lymphadenitis (Scrofula) and which area does it affect?
TB affecting lymph nodes in the neck, especially along the SCM.
What are signs of hematogenous spread of TB?
Reddish plaques on skin (lupus vulgaris), tender nodules, or abscesses.
What is miliary TB?
Disseminated TB with calcified granulomas resembling millet seeds, seen in 1–3% of TB cases.
What glands and organs does cystic fibrosis affect?
Sweat glands, digestive glands, liver, pancreas, intestines, and mucus glands of the lungs.
What are lung complications in CF?
Thick mucus production, bronchial destruction, hemoptysis, bronchiectasis, pulmonary hypertension, hypoxia.
What systemic complications can CF lead to?
• Heart failure
• Cirrhosis
• Poor growth
• Pancreatitis
• Infertility
• Malabsorption
• Fat-soluble vitamin deficiency
• Osteoporosis
How is CF diagnosed?
Sweat test in newborns and prenatal screening.
What is the life expectancy for someone with CF?
Typically 20–50 years, but increasing due to better treatments.
What are treatments for CF?
Postural drainage, chest percussion, prompt treatment of respiratory infections.
What is pneumoconiosis?
Lung diseases from inhaling occupational dust, often inorganic.
What happens in the lungs with pneumoconiosis?
Dust particles cause inflammation, destruction of macrophages, fibrous tissue buildup, reduced lung elasticity and surface area.
What are examples of pneumoconiosis and their dust types?
• Silicosis: silicon dust → risk of TB
• Asbestosis: asbestos dust → diffuse fibrosis, 10× higher lung cancer risk (90% if also smoking)
• Anthracosis: carbon dust (“black lung”)
• Byssinosis: cotton dust
• Siderosis: iron dust
What are lesser-known pneumoconioses?
Farmer’s lung (moldy hay)
Bird fancier’s disease (bird dust)
Malt/mushroom/peat moss/mollusk shell worker’s lung
Cheese washer’s lung
Latex (nursing), flour (baking), chemicals (hairdressing, dental lab)
What is bronchiolitis obliterans and what causes it?
A rare, life-threatening obstructive lung disease where bronchioles are plugged with granulation tissue. Caused by inhaling diacetyl (e.g., in “popcorn lung” and vaping).
What percentage of the world smokes, and how deadly is smoking?
~20% smoke. It causes 1 in 10 adult deaths worldwide.
What are Canadian smoking statistics?
~5 million smokers, 37,000 deaths/year—more than all illegal drugs, alcohol, MVAs, murders, and suicides combined.
How many chemicals are in tobacco smoke and how many are carcinogens?
4000 chemicals, 40 carcinogens, plus nicotine, tar, and other irritants.
What percentage of cancer deaths are from smoking?
30%
How is lung cancer risk measured in smokers?
By “pack-years” (packs/day × years smoked).
Which cancers and diseases are linked to smoking?
• Cancers: lung, cervical, leukemia
• Cardiovascular: 20% of CVD deaths; increases MI, angina, stroke, PAD, aortic aneurysm
• Pulmonary: 80% of COPD cases; damage to cilia, mucous plugging, chronic bronchitis, emphysema
• GI: peptic ulcer, GERD
• Reproductive: infertility, prematurity, low birth weight, spontaneous abortion
• Oral: oral cancer, gingivitis, tooth staining
• Other: early menopause, osteoporosis, cataracts, wrinkling, altered drug metabolism
What happens after thrombolytic therapy in smokers?
4× higher risk of re-occlusion compared to non-smokers.
What is second-hand smoke (ETS) classified as?
A Class A carcinogen.
What are its health effects?
• 3000 lung cancer deaths/year
• 150,000–300,000 infant respiratory infections
• 200,000–1,000,000 child asthma cases/year
How does cannabis smoke compare to tobacco smoke?
Has 50–70% more carcinogenic hydrocarbons.
Why does cannabis smoking increase toxin exposure?
Users inhale more deeply and hold breath longer.
What are other risks of cannabis smoke?
• May suppress immunity
• Risk to those with AIDS, transplants, chemo
• Chronic bronchitis, lung inflammation
• Impairs perception, judgment, memory, learning
What are the two main types of lung cancer?
- Bronchogenic Carcinoma
- Mesothelioma
How common is bronchogenic carcinoma?
Accounts for 90% of lung cancers.
Who gets bronchogenic carcinoma?
90% are smokers; 10% are exposed to environmental tobacco smoke.
Where does it originate?
Epithelial lining of the bronchial tree.
What’s its survival rate and behavior?
5-year survival rate is poor; highly metastatic.
How does it metastasize?
Direct invasion (lungs → pleura)
Lymphatics
Bloodstream (lungs → heart → other organs)
Signs and symptoms of bronchogenic carcinoma?
• May be asymptomatic for years
• Persistent low-grade, non-productive cough
• Recurrent infections
• Hemoptysis (when blood vessels are invaded)
What is mesothelioma?
A rare, malignant tumor of epithelium covering serous membranes (pleura, peritoneum, pericardium).
What causes mesothelioma?
Asbestos exposure.
