Respiratory Diseases

Introduction

The upper respiratory system consists of the structures in the head and neck that are involved in breathing: the nose, sinuses (nasal cavities), throat, and larynx (voice box). Common illnesses of the upper respiratory system include nasal congestion and the common cold.

The lower respiratory system consists of the structures in the chest that are involved in breathing: the trachea, bronchi, bronchioles, and lungs (including alveoli). Common illnesses of the lower respiratory system include cough, asthma, bronchitis, and pneumonia.

 

Nasal Congestion

Key Facts

The family practice physician writes many prescriptions for medications to treat nasal congestion. Nasal congestion results in a feeling of stuffiness and blockage of the breathing mechanism through the nose.

Etiology, Signs, and Symptoms

Nasal congestion may be caused by allergies, viruses, or bacterial infections. Common symptoms are sneezing, stuffiness, runny nose, and postnasal congestion and drip. These symptoms may evolve into chronic nasal or sinus infections.

 

The physician may recommend using a humidifier, to keep the air in the room moist, or a saline nasal spray. If the patient doesn't have any other medical conditions that would contraindicate a decongestant, then one may also be recommended for acute short-term use.

A medication or treatment is contraindicated when it would do more harm than good.

Nasal decongestants provide temporary relief of symptoms by getting rid of the excess fluid in the nose that's causing the congestion. These medications constrict the arterioles in the nose, thereby reducing blood flow in the engorged area.

Since the nasal tissue may be inflamed, corticosteroids can be used to manage the stuffiness. Corticosteroids exert a marked anti-inflammatory  effect on the nasal mucosa when applied topically—that is, when applied directly to the area. They're used alone or with nasal decongestants. Nasal corticosteroids are dispensed as nasal sprays.

 

The following are some of the most common medications that the family physician may recommend for the short-term management of acute nasal congestion:

• Afrin, a nasal decongestant spray
• Sudafed, or pseudoephedrine, tablets
• Beconase, a prescription corticosteroid nasal spray

The physician reviews all of the patient's health conditions prior to recommending any over-the-counter (OTC) preparations or prescribing any drugs. Some conditions, such as narrow angle glaucoma, benign prostatic hyperplasia, and hypertension are contraindications to taking medications like pseudoephedrine. Over-the-counter preparations are for short-term acute use only.

 

The Common Cold and Sinus Congestion

Key Facts

The common cold is a diffuse upper respiratory tract infection caused by any of a wide range of viruses. It's transmitted between individuals through droplets from one respiratory tract to another, as when someone sneezes. The family physician may recommend a variety of remedies to treat the symptoms of the common cold. These remedies usually contain decongestants to relieve nasal stuffiness and sinus congestion and antihistamines to dry the nasal and sinus tissues. Some preparations also contain pain relievers to reduce pain in the sinus cavities. 

 

Etiology, Signs, and Symptoms

The common cold is caused by a viral infection and affects primarily the nose and the throat. Cold symptoms should subside in approximately seven to ten days. Colds are very common in young children. Colds most often occur in the fall and winter months. Diagnosis is made by physical exam. Sinusitis or other secondary bacterial infection can occur as a complication.

Signs and symptoms include the following:

• Rhinorrhea (runny nose)
• Nasal congestion
• Sneezing
• Itchy or scratchy throat
• Watery eyes
• Fatigue

 

The following are some remedies used to treat symptoms of the common cold:

• Increased fluid intake
• Rest
• Humidifier to increase humidity in room
• Gargle
• Saline nasal drops

These are examples of some OTC medications that the physician may suggest to help treat cold symptoms, depending on the patient's other medical conditions.

• Chlorpheniramine (Chlor-Trimeton)
• Diphenhydramine (Bendadryl)
• Brompheniramine (Bromfed)
• Clemastine (Tavist)
• NyQuil Cold & Flu Multisymptom Relief (also contains acetaminophen and dextromethorphan)
• Pseudoephedrine (Sudafed)
• Oxymetazoline (Dristan nasal spray)

*For patients who suffer from a more persistent rhinorrhea, nasal preparations such as Atrovent (ipratropium) may be prescribed by the physician.

 

The lower respiratory system employs defense mechanisms such as mucus, a sticky secretion, and cilia, tiny hair-like structures, to protect the lungs from pathogens.

A respiration, or breath, delivers air to the lower respiratory tract. The contraction and the relaxation of the respiratory muscles move the air in and out of the lungs. Normal respiration is passive. We don't have to think about taking each breath.

The adult lung contains approximately 300 million alveoli, or air sacs. Each one of these alveoli is linked to many capillaries, the smallest blood vessels. Oxygen crosses the alveolar-capillary membrane and enters the bloodstream through a process called diffusion. Then the circulating blood delivers the oxygen to the cells throughout the body for metabolism.

While the blood is circulating, it also picks up metabolic waste and carbon dioxide (CO2) and transports them back to the lungs to be exhaled. When the CO2 reaches the alveolar capillaries, it diffuses across the alveolar-capillary membrane and into the alveoli. The CO2 is then removed from the alveoli during exhalation.

 

Cough

Key Facts

A cough is a symptom, not a disease. Most cough symptoms are caused by disorders in the lower respiratory system. Less commonly, a cough may be caused by other diseases in the head or stomach. 

Etiology, Signs, and Symptoms

A cough may be caused by allergies, respiratory infections, or chronic respiratory diseases. A cough may be productive, meaning the patient is able to expectorate (cough up) mucus, or it may be nonproductive, meaning the patient isn't able to expectorate mucus.

 

When diagnosing the cause of a cough, the physician will listen to the lungs. A chest x-ray may be ordered.

There are numerous prescription and OTC products available to treat coughs, and most of them are taken in liquid form as syrups or elixirs (aqueous mixtures of water and alcohol). Many cough syrup preparations contain expectorants that increase and liquefy the mucus secretions in the respiratory tract, making it easier for the patient to cough up the mucus.

Antitussives are commonly ordered for the dry, hacking, nonproductive cough that keeps the patient up at night. An antitussive helps to suppress the cough. Cough preparations may also contain antihistamines to dry up secretions, decongestants to reduce swelling in the nasal passages, and flavoring to improve the taste.

 

The most effective ingredient in the prescription products is codeine, which is an opioid derived from poppies. Hydrocodone, a synthetic derived from codeine, is also a popular choice. Hydrocodone and codeine are controlled drugs and can't be purchased without a prescription.

Most of the popular anticough preparations that are commonly prescribed by family practice physicians contain one or more of the following ingredients:

• Expectorants, such as guaifenesin (Brand names include Robitussin and Mucinex.)
• Antitussives, such as codeine, hydrocodone (both prescription drugs), or dextromethorphan (OTC) (The brand name Cheracol contains codeine and guaifenesin.)
• Antihistamines, such as chlorpheniramine or brompheniramine 
• Decongestants, such as pseudoephedrine or phenylephrine

 

Asthma

Asthma is a chronic lung disease that inflames and narrows the airways. Asthma affects people of all ages, but it most often starts in childhood.

Key Facts

1. The inflammation caused by asthma makes the airways swollen and very sensitive. When the patient is exposed to a trigger like an allergen, a hypersensitivity to cold air, or strenuous exercise, asthma can be exacerbated. The airway will react and the muscles around the airway will tighten. This results in the airway being further narrowed, meaning less air can flow into the lungs. During the reaction, the swelling can also worsen, making the airway even narrower.

2. Sometimes during a reaction, the cells in the airway will make more mucus than usual, which can further impair and narrow the airway. This chain of events can lead to extremely impaired respiration, or even a complete inability to breathe.

3. The severity of asthma is described as

• Mild intermittent: symptoms occur fewer than two times per week
• Mild persistent: symptoms occur more than two times per week
• Moderate persistent: symptoms occur daily
• Severe persistent: symptoms occur continuously 

 

Etiology, Signs, and Symptoms

Triggers include the following:

• Allergens from dust, pet dander, and pollens
• Irritants like cigarette smoke and air pollution
• Medicines like aspirin, nonsteroidal anti-inflammatory drugs

Signs and symptoms include the following:

• Wheezing (a whistling sound that may be heard on inspiration, expiration, or both)
• Feeling of tightness in the chest
• Shortness of breath
• Cough

Inspiration means inhalation; expiration means exhalation.

 

Not all patients with asthma will have these symptoms, and not all people who have these symptoms have asthma. There are other conditions that can cause patients to experience these symptoms.

The best way for a physician to diagnose asthma is to obtain a thorough medical history and order pulmonary function tests (PFTs). Eosinophils, a type of white blood cell, increase during flare-ups. Skin tests may identify allergens that exacerbate asthma. 

Asthma is chronic disease with no known cure. The goal of treatment is to control it. The physician will work with the patient, especially with children, to develop an asthma action plan. This plan will list the steps for prevention of flare-ups as well as what to do when a flare-up occurs. Some patients may be candidates for allergy injections to help decrease their sensitivity to the trigger substance.

 

Short-term medications called rescue inhalers are used during acute attacks. These medications contain a bronchodilator to dilate (open) the tightened airways. Albuterol (Proventil or Ventolin) is the most commonly ordered rescue inhaler. This medication is to be used to treat acute symptoms only.

Long-term treatment medications are used regularly to maintain and control symptoms. They may be administered via nebulizer, inhalers, tablets, or in liquid form. 

• Theophylline, available in tablet or liquid form, is used most often for long-term control of asthma.
• Montelukast (Singulair), an antileukotriene, comes in tablets.
• Cromolyn can be administered via nebulizer.

Medications delivered by inhaler include 

• Flovent
• Pulmicort
• Symbicort
• Qvar
• Azmacort

 

Complications of asthma are very serious.

Status asthmaticus, an acute, severe asthma attack that doesn't respond to the usual use of inhaled bronchodilators, is associated with symptoms of potential respiratory failure. It's considered a medical emergency.

Respiratory failure is a syndrome in which the respiratory system fails in one or both of its gas exchange functions: oxygenation and carbon dioxide elimination. Acute respiratory failure is also a medical emergency.

 

Chronic Obstructive Pulmonary Disease

Key Facts

Chronic obstructive pulmonary disease (COPD) is a progressive disease that makes it hard to breathe. COPD also includes the diseases emphysema and chronic bronchitis. COPD is a general term for this group of diseases that limit the airflow in the respiratory system, producing symptoms that aren't fully reversible. 

Etiology, Signs, and Symptoms

Cigarette smoking is the leading cause of COPD. Long-term exposure to lung irritants like air pollution, chemical fumes, and a dusty environment may also contribute to the development of the disease. COPD is more prevalent in urban than rural environments and is also related to occupational factors.

In COPD, less air flows through the airways because of several factors:

• The airways and alveoli have lost their elasticity.
• The walls between many of the air sacs have been destroyed.
• The walls of the airway are chronically inflamed and have thickened as the disease progressed.
• The airway makes more mucus than usual, which can clog up the airway.

Signs and symptoms include the following:

• Coughing, which may be accompanied by expectoration of large amounts of mucus
• Wheezing
• Shortness of breath
• Tightness in the chest
• Pursed lip breathing
• Inability to lie flat in bed
• Tripod positioning

 

Treatment consists of monitoring the patient's respiratory status to detect baseline changes, to assess response to treatment, and to prevent and detect complications. The physician should monitor the arterial blood gases, pulmonary function tests, and oxygen saturation levels (SaO2) periodically. Patients with all types of COPD should receive the Pneumococcal vaccine.

 

The following are some of the common drugs that are prescribed for asthma and COPD:

Anticholinergics

• Atrovent nasal spray (ipratropium)
• Spiriva (tiotropium)

Corticosteroids

• Pulmicort (budesonide)
• Aerobid (flunisolide)
• Flovent (Fluticasone)

Antileukotriene Tablets

• Singulair (montelukast)
• Accolate (zafirlukast)

Beta-agonists

• Proventil and Ventolin (albuterol)
• Tornalate (bitolterol)
• Serevent (salmeterol)
• Foradil (formoterol)

 

Bronchodilators are also used to open the airway to allow better air intake. They're usually sprayed into the mouth from a small canister and inhaled. These bronchodilators act immediately and quickly relax the tightened muscles in the airway to allow better airflow. Some bronchodilators are taken as pills to produce longer-lasting effects.

 

Chronic Bronchitis

Key Facts

Chronic bronchitis is a form of COPD. Chronic bronchitis results in inflammation of the bronchi, and it can be caused by irritants or infection. In chronic bronchitis, there's a hypersecretion (excess production) of mucus and chronic productive cough that lasts at least three months of the year and occurs for at least two consecutive years. Children of parents who smoke are at higher risk for respiratory tract infection that can lead to chronic bronchitis. 

Etiology, Signs, and Symptoms

Chronic bronchitis may be caused by several factors:

• Exposure to irritants
• Cigarette smoking
• Genetic predisposition
• Organic or inorganic dusts
• Noxious gases
• Frequent respiratory infections

Signs and symptoms include the following:

• Gray, white, or yellow sputum
• Dyspnea (shortness of breath)
• Cyanosis (bluish coloring in fingers and lips)
• Tachypnea (rapid breathing)
• Pedal edema (swelling of the lower portion of legs and feet)
• Wheezing, rattling sounds

 

Chronic bronchitis is diagnosed by the following tests:

• Chest x-ray will show hyperventilation.
• PFTs will have residual volume, with decreased vital capacity.
• Arterial blood gas (ABG) (a blood test that uses a sample drawn from an artery instead of a vein) shows decreased PaO2 and normal or increased PaCO2.

PaO2 is partial pressure of oxygen in the blood, and PaCO2 is partial pressure of carbon dioxide.

Chronic bronchitis can be treated, but not cured. Treatments include the following:

• Encourage smoking cessation
• Avoidance of air pollutants
• Use of bronchodilators listed for COPD
• Chest physiotherapy to help with drainage and expectoration of secretions
• Nebulizer treatments

Patients with all types of COPD should receive the Pneumococcal vaccine. They should also be warned that exposures to blasts of cold air may bring on a bronchospasm.

*Complications of chronic bronchitis can be very serious:

• Recurrent respiratory tract infections
• Pulmonary hypertension, or high blood pressure in the lungs
• Cor pulmonale, or pulmonary heart disease, is the enlargement and failure of the right ventricle of the heart as a response to increased vascular resistance in the lungs.
• Heart failure
• Acute respiratory failure

 

Emphysema

Key Facts

Emphysema is a form of COPD. Emphysema is an inflammatory response that results in abnormal tissue changes in the lungs, resulting in narrowing of the small airways and breakdown of lung tissue with destruction of alveolar walls. The alveoli lose their elasticity so the lungs can't recoil normally after expanding. This causes the bronchioles to collapse on expiration. The amount of air expired passively is diminished, trapping air in the lungs that can't be exhaled.

Etiology, Signs, and Symptoms

Emphysema is more prevalent in males and risk increases with age. The main causes include:

• Smoking
• Pollution
• Alpha-1 antitrypsin (AAT) deficiency (genetic)

Signs and symptoms include

• Shortness of breath and chronic cough
• Anorexia and feeling of malaise
• Barrel chest (bulging ribcage)
• Breathing through pursed lips
• Decreased breath sounds

 

Diagnosis can be made by a variety of tests:

• Chest x-ray
• ABG
• PFT

Treatment is essentially the same for all types of COPD-related diseases:

• Avoiding smoking and air pollution
• Bronchodilators, as previously listed for COPD
• Mucolytics, which help loosen the mucus to help patients expectorate it
• Corticosteroids

Patients with all types of COPD should receive the Pneumococcal  vaccine.

*Potential complications include the following:

• Cor pulmonale
• Respiratory failure
• Recurrent respiratory tract infections

 

Pneumonia 

Key Facts

Pneumonia is the most common infectious cause of death. Pneumonia occurs throughout the year and affects patients of all ages. The clinical manifestations are more frequently severe in the very young, elderly, and chronically ill.

Etiology, Signs, and Symptoms

For pneumonia to occur, there has to be an opportunity for microorganisms to invade the normally sterile lower respiratory tract. This can occur in three ways:

1. Inhaled as aerosolized particles

2. Spread from a site of infection outside of the lungs

3. Aspiration of foods or liquids

 

Pneumonia is classified based on the types of germs that caused the infection and where an individual acquired it.

Community-acquired pneumonia is contracted through normal social contact outside of healthcare settings. It's the most common type. Bacteria, viruses, fungi, and parasites can cause community-acquired pneumonia.

Bacterial community-acquired pneumonia can occur if a person encounters a bacterial strain that causes pneumonia, or as a secondary infection after a cold or influenza. This type of pneumonia is often called lobar pneumonia because it often affects one area, or lobe, of the lung. Pneumonia caused by some strains of bacteria may result in milder signs and symptoms. The term walking pneumonia is used to describe pneumonia that doesn't require bed rest.

Viruses most commonly cause pneumonia in children younger than two years old. Pneumonia caused by viruses is usually mild, but certain viral strains can become very serious.

Fungi, which can be found in soil and in bird droppings, most commonly cause pneumonia in people with an underlying health problem or weakened immune system. They may also cause pneumonia in people who have inhaled an especially large quantity of the organisms.

Hospital-acquired pneumonia is usually a bacterial infection. People exhibit signs of this type of pneumonia about 48 hours or more after being hospitalized for a different condition. This type of pneumonia can be caused by antibiotic-resistant bacteria, so it can be more serious.

Healthcare-associated pneumonia is also usually a bacterial infection. It affects people who live in long-term care facilities or who have been treated in outpatient clinics such as a dialysis center. Similar to hospital-acquired pneumonia, healthcare-associated pneumonia can be antibiotic-resistant.

Aspiration pneumonia occurs when a person inhales food, drink, vomit, or saliva into his or her lungs. The item inhaled irritates the lungs and can cause the person to become sick. Whether aspiration pneumonia is caused by a true infection or an inflammatory process remains the subject of debate.

 

There are several factors that may predispose a patient to develop pneumonia:

• Decreased immune resistance
• Infection
• Alteration in cough reflex
• A mucosal injury 
• Pulmonary edema (fluid in the lungs)
• Obstructions

Signs and symptoms include the following:

• Fever
• Chills
• Cough
• Rust-colored sputum
• Dyspnea 
• Pleuritic chest pain (a sudden, sharp stabbing, burning, or dull pain in the chest caused by inflammation of the membrane surrounding the lungs)
• Elevated white blood cell (WBC) count

*Potential complications include the following:

• Acute respiratory distress syndrome (ARDS), which consists of flooding of the alveoli and lung collapse
• Pleural effusion (fluid around the lung)
• Lung abscesses 
• Respiratory failure (requiring ventilator)
• Sepsis (may lead to organ failure)

 

Diagnosis is made by obtaining the patient's medical history, reviewing the patient's signs and symptoms, and performing a chest x-ray (CXR). A CT scan may be ordered if a definitive diagnosis can't be made with a chest x-ray.

Lobar pneumonia will show consolidation confined to the lobes of the lungs. Bronchopneumonia will show patchy consolidations, usually in the bases of both lungs.

The goal of treatment is to eradicate the microorganism. If the pneumonia is caused by bacteria, an appropriate antibiotic needs to be selected. If it's caused by a viral infection, antivirals may be ordered along with supportive care. If the pneumonia is caused by a fungal infection, antifungals would be ordered.

Supportive care for pneumonia includes the following:

• Humidified O2
• Bronchodilators (albuterol)
• Chest physiotherapy with postural drainage
• Adequate hydration
• Expectorants
• Analgesic/antipyretic for pleuritic chest discomfort and fever

 

Key Points

• The upper respiratory system consists of the structures in the head and neck that are involved in breathing: the nose, sinuses, throat, and larynx.
• The common cold affects primarily the nose and throat; signs and symptoms include rhinorrhea, nasal congestion, sneezing, itchy or scratchy throat, watery eyes, and fatigue.
• Sinusitis or other secondary bacterial infections can occur as a complication of the common cold.
• The lower respiratory system consists of the structures in the chest that are involved in breathing: the trachea, bronchi, bronchioles, and lungs.
• Asthma is a chronic lung disease that inflames and narrows the airways; inflammation makes the airways swollen and very sensitive.
• Chronic obstructive pulmonary disease (COPD) is a progressive disease that makes it hard to breathe; it includes emphysema and chronic bronchitis.
• Pneumonia is the most common infectious cause of death and is classified based on the types of germs that caused the infection and where the infection was acquired.