22.10 Lung diseases

Chronic Obstructive Pulmonary Disease (COPD) -

Key feature is irreversible decrease in ability to force air out of lungs

• History of smoking in 80% of patients 

• Coughing and frequent pulmonary infections

• Most patients develop hypoventilation accompanied by respiratory acidosis, hypoxemia

Emphysema: 

Permanent enlargement of alveoli and destruction of alveolar walls result in decreased lung elasticity, with three consequences:

Trapped air causes

hyperinflation

- flattens diaphragm and causes expanded barrel chest,

• both of which reduces ventilation efficiency

bronchitis

-Inhaled irritants cause chronic excessive mucus 

• Mucosae of lower respiratory passageways become inflamed and fibrosed

• Results in obstructed airways that impair lung ventilation and gas exchange

  Symptoms include frequent pulmonary infections

“Pink puffers”:

patient usually thin because they burn large amount of energy breathing;

- near-normal blood gases are maintained, so skin color is normal

“Blue bloaters”:

patient usually stocky; cyanosis is due to hypoxia, so skin color takes on bluish hue

Treatment for COPD

bronchodilators, corticosteroids, oxygen, sometimes lung volume reduction surgery; oxygen must be administered carefully

Asthma:

sometimes classified as COPD, but episodes are acute, not chronic, with symptom-free periods

• Characterized by coughing, dyspnea, wheezing, and chest tightness

Airway inflammation is

an immune response caused by release of interleukins, production of IgE, and recruitment of inflammatory cells

Tuberculosis (TB)

Infectious disease caused by bacterium Mycobacterium tuberculosis 

• Symptoms: fever, night sweats, weight loss, racking cough, coughing up blood

• Treatment: 12-month course of antibiotics

treatment for lung cancer

• If metastasis has not occurred: surgery to remove diseased lung tissue

• If metastasis has occurred: radiation and chemotherapy

• Sleep apnea -

• common disorder characterized by temporary cessation of breathing during sleep

• Person usually not aware of problem

• Leads to excessive daytime sleepiness due to  waking up several times each night (up to 30 an hour)

Obstructive sleep apnea –

most common type caused by collapse of upper airway

• Pharynx muscles relax during sleep and sag causing obstruction

• Central sleep apnea –

caused by reduced drive from respiratory centers of brain stem

-Increase in chronic illnesses such as hypertension, heart disease, stroke, diabetes

• Obstructive sleep apnea can be treated by using CPAP (continuous positive airway pressure) device

• ^ Pressure from CPAP holds airway open, preventing collapse