RS15 - Respiratory Diseases Part II

Where do pulmonary infections typically center in the lungs?

On the alveoli and bronchioles or on the interstitium.

What type of organisms tend to damage the interstitium and cause interstitial pneumonitis?

Viruses.

What type of organisms tend to affect alveoli and bronchioles and cause bronchopneumonia or lobar pneumonia?

Bacteria.

What is pneumonia?

Infectious inflammation and consolidation of the lung where alveolar air spaces fill with fluid, pus, or blood.

What is the microscopic finding in pneumonia?

Acute inflammation.

How does pneumonia typically heal?

By resolution and/or focal fibrosis.

What is the ranking of pneumonia as a cause of death in the United States?

Fifth leading cause of death.

What is bronchopneumonia?

An infection of the bronchi that spreads to alveoli in multiple sites.

Which age groups are most susceptible to bronchopneumonia?

Age extremes and immobile patients.

How do areas affected by bronchopneumonia appear grossly?

Consolidated, firm, airless, dark red or gray, and may contain pus.

What are the most common causes of bronchopneumonia?

Streptococcus pneumoniae and Hemophilus influenzae.

What is lobar pneumonia?

A pneumonia that spreads rapidly through alveoli and bronchioles and consolidates an entire lobe.

Which populations are at higher risk for lobar pneumonia?

Homeless individuals, alcoholics, and severely ill patients.

What allows organisms in lobar pneumonia to spread rapidly?

Their capsule protects against phagocytosis and provokes intense exudation.

How can lobar pneumonia heal?

By resolution restoring normal structure or by fibrosis with lung scarring.

What occurs during the congestion stage of lobar pneumonia?

Edema with alveoli filled with fluid and bacteria for 1 to 2 days.

What occurs during the red hepatization stage of lobar pneumonia?

The lung becomes firm and red with exudate containing erythrocytes, PMNs, and fibrin for 2 to 4 days.

What occurs during the gray hepatization stage of lobar pneumonia?

Less hyperemia with fewer erythrocytes and more macrophages and fibrin for 4 to 8 days.

What occurs during the resolution stage of lobar pneumonia?

Lysis and removal of fibrin via sputum, lymphatics, and macrophages over 1 to 3 weeks.

What is hospital-acquired pneumonia also called?

Nosocomial pneumonia.

What percentage of hospital admissions develop nosocomial pneumonia?

About 5 percent.

What organisms commonly cause hospital-acquired pneumonia?

Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae, and MRSA.

What is the most common anatomic type of hospital-acquired pneumonia?

Bronchopneumonia.

What is aspiration pneumonia caused by?

Regurgitation while unconscious or neuromuscular disease leading to chemical and infective damage.

How can gastric acid contribute to aspiration pneumonia?

It can cause ARDS.

How can food particles contribute to aspiration pneumonia?

They cause a foreign body reaction.

Why is atypical pneumonia called "walking pneumonia"?

Because it is less severe than broncho- or lobar pneumonia.

What bacteria commonly cause atypical pneumonia?

Mycoplasma pneumoniae, Chlamydia pneumoniae, Rickettsia, and Legionella pneumophila.

What viruses can cause atypical pneumonia?

COVID-19, RSV, SARS, and measles.

What are the typical symptoms of atypical pneumonia?

Fever, dry cough, and dyspnea.

Is leukocytosis present in atypical pneumonia?

No.

Does atypical pneumonia produce consolidation on clinical exam?

No, infection is localized to limited areas.

What type of inflammation is commonly produced in atypical pneumonia?

Interstitial inflammation.

What is interstitial pneumonia?

A pneumonia affecting the walls of the alveoli rather than the air spaces.

Is interstitial pneumonia usually unilateral or bilateral?

Usually bilateral and symmetrical.

What is the most common cause of interstitial pneumonia?

Mycoplasma pneumoniae.

What can interstitial pneumonia progress to?

Interstitial pulmonary fibrosis.

What organism most commonly causes Legionellosis?

Legionella pneumophila, a Gram-negative aerobe.

Is Legionella resistant to beta-lactam antibiotics?

Yes.

What are the two forms of Legionellosis?

Legionnaire's disease and Pontiac fever.

Which form of Legionellosis produces pneumonia?

Legionnaire's disease.

Which form of Legionellosis resembles the flu and does not cause pneumonia?

Pontiac fever.

How is Legionnaire's disease transmitted?

By inhaling aerosolized bacteria from contaminated water systems.

What antibiotics are used to treat Legionnaire's disease?

Levofloxacin and azithromycin.

What is the approximate mortality rate of Legionnaire's disease?

About 25 percent.

Who is most affected by fungal infections of the lung?

Immunosuppressed patients.

Name common fungi that infect the lung?

Aspergillus, Candida albicans, Histoplasmosis, Coccidioidomycosis, Sporotrichosis, and Cryptococcus.

What causes tuberculosis?

Mycobacterium tuberculosis most commonly.

What is tuberculosis also historically called?

Consumption (wasting disease)

What type of inflammation characterizes tuberculosis?

Granulomatous inflammation.

What are granulomas in tuberculosis called?

Tubercles.

What type of necrosis is found at the center of tubercles?

Caseous necrosis.

What are the microscopic features of tuberculosis?

Granulomatous inflammation, giant cells, and caseation.

What are the first-line treatments for tuberculosis?

Isoniazid, Rifampin, and Pyrazinamide.

(RIPE)

What is a Ghon focus in primary tuberculosis?

A small focus of tuberculous pneumonia in the mid-lung.

What is a Ghon complex?

A Ghon focus plus regional lymph nodes.

How does primary tuberculosis usually heal?

With calcification.

Can tuberculosis remain latent after primary infection?

Yes.

What is secondary tuberculosis?

Reactivation of latent tuberculosis in the lung.

Who commonly develops secondary tuberculosis?

Immunosuppressed patients.

What is miliary tuberculosis?

Diffuse blood dissemination of tuberculosis.

Why is it called miliary tuberculosis?

Because the lesions resemble millet seeds.

What is a lung abscess?

A localized focus of suppuration with necrosis of lung tissue.

What is the number one cause of lung abscess?

Aspiration.

What lobes are commonly affected by aspiration abscesses?

Right middle and lower lobes.

What are major complications of lung abscess?

Rupture into pleura, hemorrhage, bacteremia, and cerebral abscess.

What percentage of lung cancers are related to smoking?

Over 80 percent.

What age group is most commonly affected by lung cancer?

Ages 40 to 70.

What environmental exposures increase lung cancer risk?

Asbestos, nickel, chromium, iron oxides, coal gas, radioactivity, and radon.

What is the risk of lung cancer in passive smokers?

Twice the risk.

What is the most common type of lung cancer?

Adenocarcinoma.

Where is adenocarcinoma usually located in the lung?

At the periphery.

Does adenocarcinoma usually obstruct the airway?

No.

Which type of lung cancer is strongly linked to smoking and is highly malignant?

Small cell carcinoma.

What is the overall five-year survival rate for small cell carcinoma?

About 7 percent.

Which lung cancer commonly causes hypercalcemia as a paraneoplastic syndrome?

Squamous cell carcinoma.

Which lung cancer commonly causes SIADH and Cushing syndrome?

Small cell carcinoma.

What are common symptoms of lung cancer?

Cough, hemoptysis, dyspnea, chest pain, wheeze, weight loss, anorexia, and malaise.

What is pleural effusion?

Fluid in the pleural space.

What is empyema?

Pus in the pleural space.

What is hemothorax?

Blood in the pleural space.

What is pneumothorax?

Air in the pleural space causing lung collapse.

What is pleurisy?

Acute inflammation of the pleura causing sharp stabbing pain with breathing.

What is mesothelioma associated with?

Asbestos exposure.

What is the latent period for malignant mesothelioma?

Up to 20 years.

What virus is strongly linked to nasopharyngeal carcinoma?

Epstein-Barr virus (EBV).

Where is nasopharyngeal carcinoma most common geographically?

Southeast Asia.

What is a common presenting sign of nasopharyngeal carcinoma?

A lump in the neck due to early metastasis.

What benign laryngeal tumors are associated with HPV?

Papillomas and juvenile laryngeal papillomatosis caused by HPV 6 and 11.

What is the most common malignant laryngeal tumor?

Squamous cell carcinoma.

What is the strongest risk factor for laryngeal carcinoma?

Smoking.

What is a classic symptom of laryngeal carcinoma?

Persistent hoarseness.