Chronic respiratory disease has emerged as a major nationwide health problem. Chronic obstructive pulmonary diseases have increased to epidemic proportions and are currently significant causes of morbidity and mortality in this country. These conditions have revolutionized the practice of pulmonary medicine and have promoted the emergence of the allied health specialties, such as respiratory therapy and pulmonary nursing.

There has also developed increasing recognition of the dangers of occupational lung diseases and much has been done to prevent them and promote early diagnosis. Despite these new developments, tuberculosis remains a significant worldwide health problem. Many advances, however, have made treatment much easier (more available drugs and shorter treatment programs).

Lung disease is not restricted to any age group. Each year tens of thousands of children under the age of five die from various pulmonary causes and even more adult deaths occur annually due to chronic lung disease.

As is true in many other organ diseases, prevention and early diagnosis are the keys to ultimate control and cure. Respiratory therapists can play a very important role in assisting physicians in gathering clues in the clinical history, examination and physiologic measurements that may lead to early detection and treatment. To accomplish this end, respiratory therapists must learn about lung disease. Learning involves not only reading and studying didactic information, but devoting time to clinical rounds with a teacher well versed in the spectrum of lung disease.

Upon completion of this module, the student will:

1. Differentiate between the various chronic obstructive pulmonary diseases.
2. Differentiate between the various restrictive pulmonary diseases.
3. Describe the pathophysiology of the infectious respiratory disease processes.
4. Discuss the pathophysiology of pulmonary embolic disease.
5. Summarize the effects of pulmonary pathology due to trauma.

As there are no clinical procedures to perform for this module, the student is expected to spend more time on assigned readings. Because of the wide array of disease states the therapist encounters, familiarity obtained by these readings will aid in proper diagnosis and treatment.

For your own benefit, we highly recommend reviewing the supplemental reading, however it is not required.

Burton and Hodgkin, Respiratory Care - A Guide to Clinical Practice. Philadelphia: J.B. Lippincott Company.

       Unit 1. Introduction:

To cover the entire topic of pulmonary diseases in a single module is a difficult if not impossible task. In order to provide the respiratory therapy student with a sound general concept of the pathophysiology of the majority of pulmonary disease, this module has been broken down into several major categories:

1. Chronic obstructive pulmonary disease
2. Restrictive pulmonary disease
3. Infectious pulmonary disease
4. Pulmonary embolic disease
5. Pulmonary pathology due to trauma

Before beginning the discussion of the individual diseases, it is important for the student to be able to differentiate between obstructive and restrictive disease and acute and chronic disease states. Obstructive pulmonary disease is generally defined as a state in which there is an obstruction to expiratory air flow. This disorder can be determined by simple spirometry. On the other hand, restrictive pulmonary disease is defined as disease processes in which there is a restriction to inspiratory air flow. Both obstructive and restrictive diseases can occur acutely and chronically.

Acute pulmonary disease is defined as one in which the onset of symptoms is rapid and severe. An acute disease usually will follow a shorter course than chronic disease states. Chronic disease is defined as any disease with a long, drawn-out course. Acute and chronic are antonyms.

Each adult pulmonary disease will be further discussed according to certain major characteristics. The following terms will be used in the discussion:

1. Etiology: The cause of the disease.
2. Incidence: The frequency of occurrence of the disease in relation to the population.
3. Pathogenesis: The origin and development of the disease.
4. Pathology: The conditions produced by the disease.
5. Clinical Manifestations: Those manifestations which can be clinically observed by actual patient observation.
6. Radiographic Examination: Data obtained by x-ray.
7. Sputum Examination: Data obtained from sputum collection.
8. Laboratory Findings: Data obtained from laboratory tests.
9. Pulmonary Function Studies: Data obtained from PFT’s.
10. Diagnosis: Establishing the name of the disease by evaluation of the above data.
11. Management: How the disease is treated.
12. Disease Course: The progression of the disease.
13. Prognosis: Prediction of the final outcome of the disease.

An attempt will be made to cover each of these aspects of the individual pulmonary diseases. A great deal of additional information may be obtained from the resource readings and it will be most important for the student to study these sources to obtain in-depth knowledge of pulmonary pathology.

       Unit 2. Chronic Obstructive Pulmonary Disease:

Chronic obstructive pulmonary disease (COPD) is a title given to a number of disease entities that are all similar and often difficult to distinguish from one another. This is due in part to the fact that they often overlap; the patient may well have more than one of the disease entities.

Generally, COPD includes chronic bronchitis, pulmonary emphysema and asthma. Closely associated with these diseases are bronchiectasis, cystic fibrosis, bronchiolitis and small airway disease. Bronchiolitis and cystic fibrosis are predominantly pediatric disorders and should be covered at length in a pediatric module.

The chronic obstructive pulmonary diseases have much in common. They tend to be chronic illnesses and exhibit an obstructive component in pulmonary function studies. Because of these similarities, treatment is often much the same for each of the COPD states.

• Chronic Bronchitis:

Chronic bronchitis is best defined as a chronic productive cough for at least three months of the year for two successive years. The patient with “asthmatic bronchitis” suffers from chronic bronchitis accompanied by frequent bouts of bronchospasm.

Incidence

Chronic bronchitis is found in 10 to 20% of the adult population. It is more common in men than women (a 10:1 ratio).

Etiology

The key factor in the etiology of chronic bronchitis is cigarette smoking. There is also an increased incidence of the disease in areas associated with air pollution. Infection can cause exacerbation of the bronchitis into an acute state. Anything causing prolonged irritation of the bronchial mucosa can cause chronic bronchitis.

Pathology and Pathogenesis

The primary pathological feature of chronic bronchitis is inflammation of the airways. This inflammation leads to hypertrophy of the bronchial mucosal glands and an increase in the number of goblet cells. Increased amounts of mucus are produced. The bronchial mucosa becomes edematous.

The increased mucus production, mucus gland hypertrophy and edematous tissues cause increased airway resistance. This is the cause of the obstructive component of chronic bronchitis.

The above changes are accompanied by mucociliary impairment and some actual loss of cilia. Phagocytic activity is decreased by the increase in mucus production and decreased mucus infection.

Often, chronic bronchitis is accompanied by vascular changes due to the hypoxia that it causes. Pulmonary hypertension and an increase in pulmonary vascular resistance may occur and lead to right ventricular hypertrophy or cor pulmonale.

Clinical Manifestations

The major symptom of chronic bronchitis is the cough accompanied by excessive expectoration. The cough is usually loose and “rattling,” worsening in the morning and at night. Sputum is mucoid and difficult to expectorate. It varies in color from white to yellow or gray.

Respiratory difficulties often appear at about thirty years after the onset of lung injury. Shortness of breath is not marked, however, unless CHF is involved. The chronic bronchitis patient often suffers frequent attacks of acute bronchitis in periods of damp or cold weather.

The physical examination reveals either a normal or “barrel” chest. Rhonchi and wheezes may be heard throughout the lung fields and expiration time is often prolonged. In extreme cases, cyanosis may present, along with clubbing of the digits. In the later stages, pulmonary hypertension may cause neck vein distention and peripheral edema.

Laboratory Findings

Pulmonary function tests indicate obstructive airway disease. The flow rate measurements (including FEV1, FEV1/FVC and FEF25-75) are decreased. The degree of abnormality determines whether the disease state is mild, moderate or severe.

Arterial blood gases may exhibit a carbon dioxide retention accompanied by hypoxemia. A second polycythemia may also be present due to the chronic hypoxemia.

Roentgenographic Findings

The chest x-ray is normal in 20 to 40% of the cases of chronic bronchitis. This usually will occur if mainly the larger airways are affected. If the more peripheral bronchi are involved, hyperinflation and a flattened diaphragm may be observed. Increased bronchovascular markings may be present and, on bronchography, dilated bronchial glands may be seen.

Treatment

The first step in the treatment of chronic bronchitis is to have the patient stop smoking. Air pollution and occupational hazards should also be avoided.

The patient should be taught to maintain good bronchial hygiene. Effective cough methods should be taught, along with postural drainage. A high fluid intake should be encouraged to promote hydration of secretions. If the patient develops an upper respiratory infection, early antibiotic therapy should be instituted.

Bronchodilator therapy and expectorants may be helpful. In the patient with “asthmatic bronchitis,” steroid therapy is often used.

• Pulmonary Emphysema:

Emphysema is a pathological process characterized by an abnormal increase of the respiratory portion of the lung beyond the terminal bronchioles with attenuation and loss of pulmonary septal tissues. It is characterized by dilation and destruction of all or part of the acinus, the tissue distal to the terminal bronchioles.

There are may different types of emphysema. The following types will be discussed:

1. Centrilobular emphysema
2. Panlobular emphysema
3. Focal dust emphysema
4. Paraseptal emphysema
5. Alveolar-duct emphysema
6. Paracitatrical (scar) emphysema
7. Unilateral (Swyer-James’ syndrome, hyperlucent lung syndrome and MacLeod’s syndrome) emphysema

In addition, Alpha-1 antitrypsin deficiency will be discussed.

Emphysema is considered to be an obstructive disorder not because the airways are narrowed, but because there is premature airway closure on expiration due to disruption of the alveolar septum and a subsequent loss of lung elasticity.

Centrilobular emphysema primarily affects the middle of the acinus and the respiratory bronchioles. The centrilobular type of emphysema is often found in patients with chronic bronchitis. It is common for patients with this variety of emphysema to retain secretions and develop respiratory infections. This type of emphysema occurs primarily in the upper two-thirds of the lung fields and is seldom seen in nonsmoking patients.

Panlobular (panacinar) emphysema involves the entire acinus. The alveoli tend to enlarge and appear very similar to the alveolar duct. This type of emphysema is found mainly in the lower lobes. Panlobular emphysema often occurs in the elderly and, like centrilobular emphysema, is more often found in males than in females. However, females with emphysema are more likely to have panlobular emphysema than centrilobular emphysema.

Focal dust emphysema is characterized by inhaled coal dust in the respiratory and terminal bronchioles accompanied by dilation of the bronchioles. There is little, if any, impairment of respiratory function.

Paraseptal (lineal) emphysema is usually a localized, asymptomatic form of emphysema and is thought to be a major cause of spontaneous pneumonthorax. The lung periphery and the pleura are primarily involved. Bullae may develop from disrupted alveoli and it is thought that this type of emphysema may be an element of bullous emphysema.

Alveolar-duct emphysema is commonly found in elderly patients and is characterized by an increase in the diameter of the alveolar ducts. The patient with alveolar-duct emphysema is rarely symptomatic. The cause of the disease is most likely due to airway dilation as a direct result of the aging process.

Paracitatrical (scar) emphysema occurs in areas of pulmonary scarring and is characterized by small areas of alveolar destruction and distention.

Unilateral emphysema is also known as MacLeod’s syndrome, hyperlucent lung and Swyer-James’ syndrome. This disease is characterized by one lung being more radiolucent than the other. The affected lung is often afflicted with bronchitis, bronchiolitis and air trapping. Patients with this disease, however, are often asymptomatic. The hyperlucency is most likely due to decreased vascular markings and widespread emphysema in that lung. The etiology in the majority of cases is most likely infection.

Alpha-1 (a-1) antitripysin deficiency is a genetic abnormality resulting in emphysematous lung tissue. Alpha-1 antitrypsin is the major proteinase inhibitor in normal adult plasma. When a deficiency of this substance is present, the lung parenchyma is destroyed by leukocyte proteases. Panlobular emphysema is usually seen and affects mainly the lower lobes.

Those with severe deficiency are usually homozygous (possess like pairs of genes with the genetic abnormality) and often develop the disease at age thirty five or older. Those with a milder deficiency are usually heterozygous and become symptomatic at approximately fifty years or older.

Alpha-1 antitrypsin deficiency is responsible for less than 5% of the reported cases of emphysema. One-third of the patients thirty five years old or less exhibit an alpha-1 antitrypsin deficiency. Genetic counseling should be given to patients with this disorder to prevent reoccurrence.

Etiology

The etiology of emphysema is questionable, but cigarette smoking and environmental pollutants are definitely key causative factors. Infection, retained secretions in the small airways and subsequent air trapping can all cause destruction and distention of the alveolar tissue. As mentioned earlier in the various types of emphysema, old age, repeated respiratory infections, heredity and congenital anomalies can also be etiologic factors.

Pathology and Pathogenesis

Emphysema begins with small holes or fenestrations in the alveolar membranes. Eventually as these fenestrations increase in number, they become larger; breaking, tearing and rupturing the alveolar membrane. Septal destruction also appears due to frequent coughing, hyperinflation and air trapping.

Unfortunately, this alveolar destruction occurs long before the patient becomes symptomatic. As the alveoli undergo these changes, there is a subsequent loss of surface area available for diffusion of gases. When this occurs, arterial blood gas values become abnormal and hypoxemia and carbon dioxide retention may present. Diffusing capacities decrease and compliance increases as elasticity decreases. The lung tends to over-expand and become larger as the loss of elasticity continues. A “barrel” shaped appearance of the chest results. The ribs have a tendency to separate and the diaphragm flattens to allow for the increased lung expansion.

Clinical Manifestations

Shortness of breath on exertion is the earliest clinical sign of emphysema. Work of breathing is greatly increased as more and more effort is required to exhale, due to airway collapse and air trapping. Cough and expectoration may be present, but are generally not severe in the early stages of emphysema. Eventually, the patient will experience generalized symptoms of orthopnea, weight loss, loss of appetite, inactivity and depression. On physical examination, a prolonged expiratory phase is encountered. End-expiratory wheezing may be present and breath sounds may be decreased to absent. There is hyper-resonance to percussion and a decrease in tactile fremitus. Chest expansion decreases, A-P diameter increases, work of breathing increases and there is often a “barrel” chest appearance.

Roentgenographic Findings

The chest x-ray shows a flattened diaphragm, overall hyperinflation, a vertical heart and a possible decrease in pulmonary vascular markings. There is an overall hyperlucency of the lung fields. The chest x-ray is not a good tool in the diagnosis of emphysema, as these symptoms are also seen in other pulmonary diseases.

Laboratory Findings

Pulmonary function studies, of course, show obstructive pulmonary disease. If an element of bronchitis is present, airway resistance will increase; DLCO decreases, TLC increases (as does FRC and RV) and VC may be normal or decreased. If pulmonary emphysema is the only disease present, there will generally be a poor response to bronchodilator therapy due to the nonreversible components of airway collapse. Helium and nitrogen washout tests show poor distribution of ventilation.

Arterial blood gases usually indicate hypoxemia and possible carbon dioxide retention. The degree of severity of these abnormalities is dependent upon the extensiveness of the emphysema, the presence of other diseases and the occurrence of exacerbations.

Treatment

Emphysema is an irreversible disease state, but with treatment the parenchymal damage may be prevented from going any further. Treatment includes avoidance of smoking and airway irritants. Good bronchial hygiene, nutrition and adequate fluid intake are encouraged. If there is a significant response to bronchodilator therapy, it should be instituted. A good pulmonary rehabilitation program is indicated in the patient with emphysema. If necessary, supplemental oxygen and respiratory therapy may be used in the patient’s home.

Bronchiectasis:

Bronchiectasis is a disease characterized by permanent irreversible dilation of either the bronchi, bronchioles or both. It is diagnosed with bronchography. A cardinal symptom is expectoration of purulent sputum.

Incidence

Since antibiotic therapy has been introduced, bronchiectasis occurs much less frequently than in the past.

Etiology

Bronchiectasis can be caused by a number of pulmonary insults. As a rule, bronchiectasis occurs following a primary insult accompanied by pulmonary infection. The following processes have been implemented as predecessors to bronchiectasis: necrotizing pulmonary infections, repeated pneumonias, cystic fibrosis, immunologic deficiency status, pulmonary neoplasm, tuberculosis, Kartagner’s disease (bronchiectasis and sinus inversus), foreign body aspiration and Agammoglo bulinema.

Pathology and pathogenesis

There are three types of bronchiectasis:
1. Cylindrical bronchiectasis
2. Saccular bronchiectasis
3. Mixed Bronchiectasis

In the cylindrical or tubular type of bronchiectasis, fusiform (tapered at the end) dilations occur within the airway. The dilated airways then fill with purulent secretions. This type of bronchiectasis often occurs as a result of severe bronchitis.

Saccular bronchiectasis is characterized by irregular “grape-like” dilations and narrowing in the airways. Again, these airways fill with pooled purulent secretions.

The third type of bronchiectasis is a mixture of the other two types and is rightfully termed mixed bronchiectasis.

The exact mechanisms causing bronchiectasis are unknown. It is thought that repeated attacks to the airway by various disease states cause damage to the epithelial tissue, inflammation, narrowing of the airway alternating with dilation of the airway and finally erosion of the bronchial wall.

Clinical Manifestations

The patient with bronchiectasis presents with a productive cough of large amounts of foul-smelling purulent sputum. Sputum production peaks in early morning and immediately after the patient rises. In 50% of the cases of bronchiectasis, hemoptysis is present. A characteristic of sputum in severe cases of bronciectasis is its quality of settling into three layers: cloudy on top, saliva in the middle and purulent mucus on the bottom.

Bronchiectasis may be present for a period of time with no symptoms noted. Dyspnea will not normally be present in the bronchiectasis patient. Often in more advanced cases, clubbing, malnutrition, sinusitis, cor pulmonale, rales and hypoxemia may be present.

Laboratory Findings

Pulmonary function studies are nonspecific in the diagnosis of bronchiectasis and usually indicate obstructive airway disease. Significant hypoxemia may be present due to a “shunt effect.”

Roentgenographic Findings

Standard chest x-ray results are generally negative, although increased markings may be present within localized areas. The x-ray may show some cystic spaces with recognizable air-fluid levels and “honeycomb” appearance of fibrosis surrounding emphysematous areas.

The bronchogram, however, is a more definite test for a diagnosis of bronchiectasis. Bronchography is the process of instilling a radio-opaque substance into the lung which will illustrate the size and appearance of the tracheobronchial tree. In bronchiectasis, the narrowing and dilation of the airways can be seen along with pooling of secretions within these areas.

Treatment

The major component of a treatment regimen for bronchiectasis is a good bronchial hygiene program and chest physiotherapy to remove retained secretions. Appropriate antibiotic therapy should be institued to treat pulmonary infections. A good general rule in the treatment of bronchiectasis is to treat it much the same as chronic bronchitis.

• Asthma:

More than twelve million Americans suffer from asthma, a chronic obstructive pulmonary disease that makes the lungs extremely sensitive. In response to allergens or exertion, the airway mucosa becomes inflamed, the smooth muscles spasm, and the secretory cells increase their production. The mechanism behind asthma is a normal reflex of the sentries that protect the human body against invasions by allergens or infection. It’s simply a defense that has become too powerful for the body’s own good. For some reason, the immune cells that guard an asthmatic’s bronchial tubes are in a perpetual state of inflammation. And like jittery soldiers firing at a shadow, the immune cells compound the problem by overreacting to triggers.

Asthma Triggers:
1. Allergies
2. Infections
3. Inhalants
4. Emotions

Upon exposure to these perceived enemies, the cells fire so many antibodies that airways to the lungs become jammed with mucus and squeezed by bands of constricting muscle, triggering an episode.

Asthma can produce severe shortness of breath, inability to perform routine activities, and if improperly treated, can result in respiratory failure and death. Each individual suffers a different level of severity. Almost all patients with asthma do enjoy a reversal of symptoms until something triggers the next episode. Estimates of direct and indirect costs incurred by asthmatics in 1990 totaled $6.2 billion. Asthma related morbidity and mortality have increased in recent years in the United States. The incidence of asthma is rising. Asthma kills fourteen Americans of all ages every day. Asthma is the number one chronic disease afflicting American children.

Between seven and twenty million Americans have asthma, and approximately 5% of all Emergency Room visits are due to asthma (National Asthma Education Program Expert Panel, 1999). Asthma affects 4% to 5% of the population. There are at least two genetic influences. One associated with the capacity to develop allergies (atopy) and the second associated with the tendency to develop hyper-responsiveness of the airways independent of atopy. Genetic researchers have recently identified a region (locus) on chromosome eleven that is associated with atopy. This locus may contain an abnormal gene that encodes a part of the IgE receptor. In asthma, the normal airway function designed to protect the lungs (muscle contraction, mucosal swelling and mucus formation), becomes excessive. For reasons not entirely known, the airways become abnormally sensitive to infection, weather, exercise, irritants and allergens. The muscles tighten (bronchospasam) and the mucosa begins to swell, which reduces the diameter of the airway. In addition, mucus production is increased, sometimes forming sticky plugs in the bronchial tubes.

Asthma is a common chronic lung disease that affects individuals of all ages. It is an inflammatory disease characterized by hyper-responsiveness of the airways and episodic periods of bronchospasm (spasm, or prolonged contractions, of the bronchial smooth muscle). Asthma, is the Greek word for panting, imposing a heavy burden of misery and danger. The disease is characterized by the presence of reversible airway obstruction, airway inflammation, and a variable degree of airway hyper-responsiveness. Allergens, viral illnesses, exercise, cold, weather, certain medications, and stress are all factors that exacerbate intermittent episodes of bronchospasm. Biochemical, autonomic, immunologic, infectious, endocrine, and psychologic factors are involved in varying degrees. Most asthmatic episodes of bronchospasm are short-lived, with freedom from symptoms between episodes; although airway inflammation is present, even in asymptomatic individuals.

The symptoms of asthma arise when the “caliber” of the tiny air passages that conduct the air in and out of the lungs, is reduced. These tubes, or bronchi and bronchioles, are narrowed by the contraction of the thin layer of muscles that sheathes each airway. In addition, the bronchial walls become inflamed or swollen, from the secretion of thick, tenacious mucous in the bronchial tubes. The inflammation resulting in hyperresponsiveness of the airways is the major pathological feature of all types of asthma. The release of inflammatory mediators produces bronchial smooth muscle congestion, microvascular congestion, increased tracheobronchial secretions, and muscosal edema.

Asthma is a unique combination of clinical and pathological findings. It combines bronchial hyperresponsiveness with a distinctive form of airway inflammation associated with increased mucous production. The bronchial biopsy of even the mild asymptomatic individual with asthma demonstrates epithelial disruption, eosinophilic proliferation, actively degranulating mast cells, and an increase in activated T-lymphocytes.

The way the asthmatic inflammatory process manifests itself is disease specific with the eosinophil playing a major role and activated cytokines orchestrating the inflammatory component of this illness. Asthma may be clinically indistinguishable from bronchiolitis in infants and toddlers, becomes a more easily definable illness from childhood to middle age and then blends with a component of chronic obstructive lung disease in older adults.

Allergy in asthma is an immediate or type I hypersensitivity reaction that requires the presence of specific immunoglobulin E (IgE) class of antibodies. This type of reaction occurs in individuals who have atopy, which is a hypersensitivity state with a genetic predisposition characterized by the production of an excessive amount of IgE antibodies and against a variety of antigens. About 10% to 20% of the general population are atopic and have the tendency to develop hay fever, asthma, eczema, and other IgE- mediated allergic reactions. These types of hypersensitivity reactions result from the interaction of antigens (allergens) with their specific IgE antibodies, which tend to attach to the mast cells, basophilic ganulocytes, and perhaps other cells. Mast cells have the highest concentration of IgE molecules on their surface. The cross-linking of two IgE antibody molecules by specific antigen signals the initiation of a series of intracellular biochemical events resulting in the release of several mediators. Some of these mediators are preformed and stored at specially stainable granules, and many others, before being released, are rapidly synthesized as a result of the signal from the antigen-antibody interaction.

Among the many chemical mediators identified thus far, important ones are: histamine, eosinophyil chemotactic factor of anaphylaxis (EFC-A), neutrophil chemotactic factor (NCF), leukotrienes (formerly known as slow-reacting substance of anaphyulaxis, or SRS-A), prostaglandins, and platelet-activating factor. In addition to mast cells, other cells, including macrophages, neutrophils, eosinophils, and endothelial cells, are known to produce many of these mediators as well as many cytokines. Both T lymphocytes and B lymphocytes are also active participants and interact with other cells in causing and maintaining airway inflammation and other heightened reactivity. Plasma cells, made from B-lymphocytes, are responsible from production of IgE antibodies.

The pathophysiologic changes during an asthmatic episode are based on the narrowing of the airways by contraction of smooth muscles, mucosal and submucosal edema, and increased secretions. Increased respiratory airway resistance results in decreased forced expiratory flowrates and hyperinflation. Increased respiratory work load is related to the increase in airway resistance. In addition to mechanical dysfunction, abnormal distribution of both ventilation and perfusion with their mismatching, results in alteration of the arterial blood gases, particularly hypoxemia. More severe and prolonged episodes may culminate in hyercapnia from worsening of ventilation-perfusion mismatching and ventilatory muscle fatigue.

Although the exact mechanism of airway hyperresponsiveness is unknown, several factors, including genetic predispositon, autonomous nervous imbalance and the alteration of adrenergic receptors have been implicated in its development. Since everyone’s asthma is different, asthma medications come in different forms: liquids, pills, powders, vapors, and injections. Medications are given in different ways to different people. Although drug companies sell asthma medications under many brand names, there are only a few major types: inhaled bronchodilatiors, oral bronchodilators, corticosteroids, phosphodiesterace inhibitors, cholinergic blockers, anti-leukotrienes, and prophylactic bronchodilators to prevent the degranulization of the mast cell.

TRIGGERS AND TREATMENTS

Knowing what triggers the asthmatic episode, and following a proper medication plan, even on days when asthma isn’t a problem, are an asthmatic’s keys to maintaining a normal lifestyle.

MEDICATIONS:

AEROSOLIZED MEDICATIONS

Alpha Agonist
      Phenylephrine: NEO- SYNEPHRINE

Catecholamines
      Epinephrine
      Racemic Epinephrine: ASTHMANEFRIN
      Isoproterenol: ISUPREL
      Isoetharine: BRONKOSOL

Beta Agonists
      Bitolterol mesylate: TORNALATE
      Resorcinols
      Metaproterenol: ALUPENT, METAPREL
      Fenoterol
      Terbutaline: BRICANYL, BREATHAIRE
      Saligenins
      Salbutamol (Albuterols): VENTOLIN, PROVENTIL
      Pirbuterol acetate: MAXAIR AUTOHALER
      Sameterol Xinafoate: SEREVENT
      Carbuterol

Cholinergic Blockers
      Atropine
      Ipratropium: ATROVENT

Prophylactic Bronchodilators
      Cromolyn Sodium: INTAL

Corticosteriods
      Beclomethasone Dipropionate: BECLOVENT, VANCERIL
      Betamethasone
      Dexamethasone: DECADRON, RESPIHALER
      Flunisolide: AEROBID, AEROBID-M
      Prednisone: PEDIAPRED
      Triamcinolone: AZMACORT

Asthmatic episodes can be brief and infrequent, or long and debilitating. Most fatalities result from a condition termed “status asthmaticus” in which the airways become completely plugged. The diameter is reduced and the airway resistance is increased.

FOR SUFFERERS, KNOWLEDGE IS POWER

Asthma is now receiving the attention it deserves as a potentially life-threatening but controllable disease.

Asthma is a major public health concern in the United States. As indicated earlier in this monograph, Asthma morbidity and mortality has risen substantially over the past 10 to 15 years, as have costs associated with treatment. Considering the significant clinical and financial implications surrounding this disease, health providers need to recognize that patient education is one of the most powerful tools for helping patients gain more adequate control of their disease. A dedicated, collaborative effort on the part of various members of the health care team to educate patients, will ensure their compliance to self-management and allow for attainment of therapeutic goals.

Laboratory Findings

Arterial blood gases will show hypoxemia with severity dependent on the severity of the attack. Hypercapnia may also be present if the attack is severe. Sputum culture may
show eosinophilia in extrinsic asthma. If the asthma is extrinsic, skin test will be positive for specific antigens.

Pulmonary function studies during an attack will show decreased VC, FVC and flow rates; FRC, TLC and RV, however, will be increased due to air trapping.

Roentgenographic Findings

The chest x-ray will show hyperinflation and an increased A-P diameter. Areas of atelectasis may be present.

Treatment

Treatment of the asthma attack deals mainly with bronchodilation. This consists of a loading dose of aminophylline followed by an intravenous drip, aqueous epinephrine (adrenaline) injection and aerosolized bronchodialators (i.e., Albuterol).

In addition, corticosteroid therapy may be instituted for several days to reduce inflammation in the airways. If infection if present, antibiotic therapy is instituted. Fluid intake should be encouraged to promote secretion hydration.

Arterial blood should be analyzed and, if necessary, intubation and assisted ventilation should be instituted.

Long-term treatment of asthma includes avoidance of contact with specific allergens, inhaled irritants, extremes in humidity and temperature, emotional upset and several medications (aspirin, inderol, indocin and motrin).

Several medications may be used for long-term therapy including bronchodilators, expectorants, antibiotic, corticosteroids, cromolyn sodium, antihistamines and tranquilizers.

• Small Airway Disease:

Small airways disease has also been referred to as early bronchitis or bronchiolitis. It is said to be “early” as there is a pulmonary abnormality present, but it cannot be detected by routine pulmonary function studies.

Etiology

The etiology of small airways disease would be the same as for bronchitis, including such factors as cigarette smoking, air pollution, recurrent infection, or similar conditions capable of causing prolonged irritation of the bronchial mucosa.

Pathology

The small airways less than 2 mm in diameter demonstrate early closure and are inflamed. This early airway closure is increased with inhaled irritants.

Clinical Manifestations

The patient with small airway disease may not even be aware of the problem. Minor symptoms, such as dyspnea on exertion, may be present, along with rales, expiratory wheezing and a prolonged expiration.

Laboratory Findings

Pulmonary function studies show restrictive flow patterns. The chest x-ray will likely be normal with the exception of those patients with small areas of atelectasis.

Treatment

The major treatment of small airway disease is removal of the causative agents, such as cigarettes or irritants in the air.

• Cor Pulmonale:

Cor pulmonale is usually caused by chronic respiratory failure, as seen in the COPD patient. It is defined in the function and structure of the right ventricle of the heart resulting from lung disease.

Pathology and Pathogenesis

Hypoxemia and hypercarbia cause constriction of the pulmonary arterioles and an increased pulmonary vascular resistance. This causes an elevation of the pulmonary artery pressure. A chronic elevation causes a chronic stress to the right ventricle, which could result in hypertrophy due to overwork. Right heart failure ensues.

Clinical Manifestations

Pulmonary artery pressure will be high. Hypoxemia, tachypnea, orthopnea, dyspnea, thoracic pain, cyanosis, neck vein distention, a fourth heart sound and a right ventricular gallop (S-3) are found on clinical examination. The patient will exhibit the clinical signs of severe dyspnea. Wheezing, prolonged expiration and rales will be heard with auscultation.

Laboratory Findings

The EKG is the most valuable diagnostic tool in cor pulmonale. The EKG may indicate right ventricular enlargement. Right heart catheterization will show increased pulmonary arterial pressures and a normal pulmonary capillary wedge pressure. Again, arterial blood gases will show severe hypoxemia and possible hypercapnia.

Roentgenographic Findings

The chest x-ray may be useful in indicating increased pulmonary vascular markings. If the cor pulmonale is long standing, right ventricular enlargement may be viewed.

Treatment

Treatment of cor pulmonale involves decreasing the workload of the right ventricle by decreasing pulmonary artery pressures. If the increased workload is due to hypoxemia and acidosis, these abnormalities should be treated. In other words, if the underlying cause is found and treated, the symptoms should resolve.

• Cystic Fibrosis (mucoviscidosis):

Cystic fibrosis or mucoviscidosis is a hereditary disease characterized by dysfunction of exocrine glands and manifested by chronic pulmonary disease, pancreatic insufficiency, abnormally high electrolyte concentration in sweat, and sometimes abnormalities of other organs. Although characteristically a disease of early childhood, cystic fibrosis is seen more and more in adolescents and young adults because of improvement in early diagnosis and management. With early recognition and institution of proper treatment, pancreatic insufficiency rarely constitutes a serious problem nowadays; whereas, the pulmonary complications of cystic fibrosis escape pulmonary involvement and most patients eventually succumb.

Etiology and incidence

Cystic fibrosis is a hereditary disease transmitted as a Mendelian recessive trait. The single-gene carriers (heterozygotes) have no clinically demonstrable disease. If both parents are carriers, their children, regardless of their sex, would have a 25% chance of having cystic fibrosis and a 50% chance of being carriers. Thus both parents of a child with cystic fibrosis are carriers.

Cystic fibrosis is more common in whites than blacks. Its incidence in whites has been estimated to be 1 in 2000 live births. It is the most frequent lethal hereditary disease in the United States. The basic defect in cystic fibrosis has remained unknown, but it has been postulated to be due to an inborn error in metabolism.

Pathogenesis and pathology

The two separate and distinct pathophysiologic features of cystic fibrosis are high concentration of sweat electrolytes and abnormality of mucus secretion and elimination. Sweat electrolyte abnormality is present at birth and continuously throughout the patient’s life. It has no relationship to severity of disease or extent of involvement of other organs. Chloride and sodium content of sweat are particularly increased, sometimes being several times normal. As a diagnostic tool, the determination of sweat electrolytes has been most valuable. Clinical consequence of this abnormality has not been of significance, ex