Chapter 20 – Respiratory Inflammation and Infection

Which part of the respiratory tract contains normal flora?

The upper respiratory tract (nose, mouth, throat) is colonized with normal flora

Does the lower respiratory tract have normal flora

No, the lower respiratory tract and alveoli do not have normal flora

What mechanism helps keep the lower respiratory tract free of infectious agents

Mucoiliary movement

What type of cells line the bronchioles and move mucus and particles

Ciliated pseudostratified epithelial cells and goblet cells

What affects cilia movement and increases infection risk?

Respiratory infections and smoking

Which lung has a higher risk for pulmonary aspiration and why

The right lung — its right bronchus is straighter, allowing easier entry of material

What does the diaphragm do during inspiration and expiration?

Inspiration: moves downward

Expiration: moves upward

What is gas exchange dependent on?

Partial pressure of oxygen (PaO₂)

What is SaO₂?

The percentage of hemoglobin saturated with oxygen

What PaO₂ level provides maximal SaO₂?

90-100 mmHg

What is the function of the pleural membranes

They line the chest cavity and envelop the lungs, lubricated by a thin film of fluid to enable easy movement

What happens if air or fluid enters the pleural space?

Lung expansion becomes more difficult

What causes bronchodilation and bronchoconstriction

Smooth muscle control by the autonomic nervous system

Which nervous system causes bronchodilation

Sympathetic (beta-2 adrengenic receptors)

Which nervous system causes bronchoconstriction

Parasympathetic

What chemical mediators cause bronchoconstriction?

Leukotrienes and histamine

What happens during chronic hypoxia?

Increases ventilation, increased erythropoietin (EPO) from kidneys, increased RBC production, pulmonary vasoconstriction, and possible right-sided heart failure (Cor pulmonale)

What happens during chronic hypercapnia

Central chemoreceptors become insensitive to CO₂; low oxygen becomes the main drive to breathe (hypoxic drive).

What is dyspnea

Shortness of breath — can be cardiac or pulmonary in origin

What is expectoration

Coughing up sputum

What does yellow or green sputum indicate

Infection

What does pink-tinged sputum indicate

Minor bleeding

What is hemoptysis

Blood-containing sputum (bright red), not to be confused with hematemesis (coffee-colored blood)

What is atelectasis

Collaspe of alveoli, reducing gas exchange; common post-op complication

What are signs of atelectasis

Shallow breathing, risk for pneumonia, need for incentive spirometer

What are adventitious breath sounds

Extra lung sounds such as crackles, wheezes, or rhonchi

What causes a “barrel chest”

Long term COPD — chest width and depth become equal

What is clubbing of the fingers a sign of

Chronic hypoxia

What are crackles (rales)

Noncontinuous sounds of the alveoli opening and closing against fluid (seen in heart failure or pneumonia)

What are wheezes

High-pitched, whistling sounds due to narrowed airways

What are rhonchi

Low-pitched, snore-like sounds from inflamed brochi

What causes a friction rub

Inflammation of pleural surfaces

What is Acute bronchitis

Inflammation of bronchi and bronchioles caused by infection or irritation

What are common causes of Acute bronchitis

Virusese, bacteria, or toxic inhalation (smoking increased risk)

How is Acute bronchitis diagnosed and treated

By symptoms and sputum culture; treated with antibiotics, expectorants, mucolytics, bronchodilators, and cough suppressants at night

What is pneumonia

Inflammation of lung tissue where alveoli fill with fluid

What are types of pneumonia

Community-acquired (CAP), hospital-accquired (HAP), and ventilator-associated (VAP)

What are risk factors for pneumonia

Influenza infection, immunosuppression (HIV, AIDS)

What are symptoms of pneumonia

Sudden onset cough, fever, chills, pleuritic chest pain, dyspnea, hemoptysis, tachypnea, accessory muscle use

How is pneumonia diagnosed and treated

Chest X-ray (most important), sputum culture; treated with antibiotics, Fowler’s position, oxygen, analgesics, antipyretics, bronchodilators

What is tuberculosis (TB)

Chronic infection caused by Mycobacterium tuberculosis; can be active or latent

What forms after TB infection

Tubercles (granulomas) — walled-off collections of WBCs, bacteria, and fibrotic tissue

What are symptoms of TB

Chronic cough, purulent sputum, hemoptysis, weight loss, anorexia, low-grade fever, night sweats

What diagnostic tests confirm TB

Mantoux test (PPD), chest X-ray (granulomas), and sputum culture (acid fast positive)

What does a positive PPD mean

Induration (raised, hardened area) — requires chest X-ray follow-up

What does a negative PPD mean

No induration at injection site