You may take breathing for granted, thinking that it is just another involuntary bodily function or reflex action. For the millions of people who suffer from respiratory diseases, each breath is a major accomplishment. These include diseases of the lung, pleural cavity, bronchial tubes, trachea, upper respiratory tract and of the nerves and muscles of breathing. They range from mild and self-limiting such as the common cold to life-threatening such as bacterial pneumonia or pulmonary embolism. They are a common and important cause of illness and even death.
Respiratory diseases can be classified in many different ways; by the organ involved, by the pattern of symptoms or by the cause of the disease.
Obstructive lung diseases:
Diseases of the lung where the bronchial tubes become narrowed making it hard to move air in and especially out of the lung.
Restrictive lung diseases:
Also known as interstitial lung disease is a category of respiratory diseases characterized by a loss of lung compliance, causing incomplete lung expansion and increased lung stiffness.
Respiratory tract infections:
Infections can affect any part of the respiratory system. They are traditionally divided into upper respiratory tract infections and lower respiratory tract infections.
Upper respiratory tract infection:
The most common upper respiratory tract infection is the common cold, however, infections of specific organs of the upper respiratory tract such as sinusitis, tonsillitis, otitis media, pharyngitis and laryngitis are also considered upper respiratory tract infections.
Lower respiratory tract infection:
The most common lower respiratory tract infection is pneumonia, a lung infection. Pneumonia is usually caused by bacteria. Other pathogens such as viruses and fungi can cause pneumonia, severe acute respiratory syndrome and pneumocystis pneumonia. A pneumonia may develop complications such as a lung abscess, a round cavity in the lung caused by the infection or an empyema, the spread of the infection to the pleural cavity.
Chronic Obstructive Pulmonary Disease
From the National Heart, Lung and Blood Institute
COPD, or chronic obstructive pulmonary disease, is a progressive disease that makes it hard to breathe. “Progressive” means the disease gets worse over time. COPD includes two related conditions of the respiratory system: Emphysema and Chronic Bronchitis. Cigarette smoking is the leading cause of COPD. Long term exposure to other lung irritants, such as air pollution, chemical fumes, or dust, also may contribute to COPD. In rare cases, a genetic condition called alpha-1 antitrypsin deficiency may play a role in causing COPD.
COPD can cause coughing that develops into a chronic cough that produces large amounts of colorless sputum. The cough will become more frequent and more effort is needed to get air into and out of the lungs. Eventually, the heart may be affected. Eventually death occurs when the function of the lungs and heart is no longer adequate to deliver oxygen to the body’s vital organs and tissues.
COPD is a major cause of disability and it’s the fourth leading cause of death in the United States. More than 12 million people are currently diagnosed with COPD. An additional 12 million likely have the disease and don’t even know it.
COPD develops slowly. Symptoms often worsen over time and can limit your ability to do routine activities. Severe COPD may prevent you from doing even basic activities like walking, talking, or taking care of yourself.
Most of the time, COPD is diagnosed in middle-aged or older people. The disease isn’t passed from person to person. You can’t catch it from someone else.
COPD has no cure yet, and doctors don’t know how to reverse the damage to the airways and lungs. However, treatments and lifestyle changes can help you feel better, stay more active and slow the progress of the disease.
If you have mild COPD, you may:
Experience breathlessness only during high energy activities (like exercise)
Cough occasionally
If you have moderate COPD, you may:
Become breathless during daily activities (like climbing stairs)
Experience breathlessness that makes you feel less active
Cough more often as the disease progresses
If you have severe COPD, you may:
Be constantly breathless at rest
Need oxygen (if more severe)
Become incapacitated and unable to perform simple activities
Cough even more frequently (often with mucus or phlegm)
Emphysema
From Wikipedia
One of two major diseases of the lung grouped under COPD. Emphysema is often caused by exposure to toxic chemicals, including long term exposure to tobacco smoke.
Emphysema is characterized by loss of elasticity of the lung tissue caused by destruction of structures feeding the alveoli, owing to the action of alpha-1 antitrypsin deficiency. This causes the small airways to collapse during forced exhalation, as alveolar collapsibility has decreased. As a result, airflow is impeded and air becomes trapped in the lung, in the same way as other obstructive lung diseases. Symptoms include shortness of breath on exertion, and an expanded chest. However, the constriction of air passages isn’t always immediately deadly, and treatment is available.
Signs of emphysema include pursed-lipped breathing, central cyanosis and finger clubbing. The chest has hyper resonant percussion notes, particularly just above the liver, and a difficult to palpate apex beat, both due to hyperinflation. There may be decreased breath sounds and audible expiratory wheeze. In advanced disease, there are signs of fluid overload such as pitting peripheral edema. The face has a ruddy complexion if there is a secondary polycythemia. Sufferers who retain carbon dioxide have asterixis (metabolic flap) at the wrist.
Chronic Bronchitis
From Wikipedia
The other of the two major diseases of the lung grouped under COPD. Chronic bronchitis is a chronic inflammation of the bronchi (medium size airways) in the lungs. It is defined clinically as a persistent cough that produces sputum (phlegm) and mucus, for at least three months in two consecutive years.
Bronchitis may be indicated by an expectorating cough (also known as a productive cough, i.e. one that produces sputum), shortness of breath (dyspnea) and wheezing. Occasionally chest pains, fever, and fatigue or malaise may also occur. Mucus is often green or yellowish green and also may be orange or pink, depending on the pathogen causing the inflammation.
A physical examination will often reveal diminished breath sounds, wheezing and prolonged expiration. Most doctors rely on the presence of a persistent dry or wet cough as evidence of bronchitis.
Asthma
From Wikipedia
Asthma is a predisposition to chronic inflammation of the lungs in which the airways are reversibly narrowed. During asthma attacks, the smooth muscle cells in the bronchi constrict, and the airways become inflamed and swollen. The National Heart, Lung and Blood Institute defines asthma as a common chronic disorder of the airways characterized by variable and recurring symptoms, airflow obstruction, bronchial hyperresponsiveness (bronchospasm), and an underlying inflammation. Attacks can be prevented by avoiding triggering factors and by drug treatment. Drugs are used for acute attacks and long-term prevention. Prognosis is good with treatment. In contrast to chronic obstructive pulmonary disease and chronic bronchitis, the inflammation of asthma is reversible.
Sarcoidosis
From Wikipedia
Sarcoidosis is a multisystem disorder characterized by non-caseating granulomas (small inflammatory nodules). The cause of the disease is unknown. Virtually any organ can be affected; however, granulomas most often appear in the lungs or the lymph nodes.
Cystic Fibrosis
From Wikipedia
Cystic Fibrosis is a genetic disorder known to be an inherited disease of the secretory glands, including the glands that make mucus and sweat. Lung disease results from clogging the airways due to mucosa build-up and resulting inflammation. Inflammation and infection cause injury and structural changes to the lung, leading to a variety of symptoms. In the early stages, incessant coughing, copious phlegm production, and decreased ability to exercise are common. Many of these symptoms occur when bacteria that normally inhabit the thick mucus grow out of control and cause pneumonia. In later stages of CF, changes in the architecture of the lung further exacerbate chronic difficulties in breathing.
Other symptoms include coughing up blood (hemoptysis), changes in the major airways in the lungs, high blood pressure in the lung (pulmonary hypertension, heart failure, difficulties getting enough oxygen to the body (hypoxia), and respiratory failure.
Tuberculosis
From Wikipedia
This is a common and often deadly infectious disease caused by mycobacteria. Tuberculosis usually attacks the lungs, but can also affect the central nervous system, the lymphatic system, the circulatory system, the genitourinary system, the gastrointestinal system, bones, joint, and even the skin. Tuberculosis is spread through the air, when people who have the disease cough, sneeze, or spit. Most infections in human beings will result in asymptomatic, latent infection, and about one in ten latent infections will eventually progress to active disease, which, if left untreated, kills more than half of its victims. The classic symptoms of tuberculosis are a chronic cough with blood-tinged sputum, fever, night sweats, and weight loss.
Pleural Cavity Diseases
Pleural cavity diseases include empyema and mesothelioma. A collection of fluid in the pleural cavity is known as a pleural effusion. This may be due to fluid shifting from the bloodstream into the pleural cavity due to conditions such as congestive heart failure and cirrhosis. It may also be due to inflammation of the pleura itself as can occur with infection, pulmonary embolus, tuberculosis, mesothelioma and other conditions.
A pneumothorax is a hole in the pleura covering the lung allowing air in the lung to escape into the pleural cavity. The affected lung collapses like a deflated balloon. A tension pneumothorax is a particularly severe form of this condition where the air in the pleural cavity cannot escape, so the pneumothorax keeps getting bigger until it compresses the heart and blood vessels, leading to a life threatening situation.
Pulmonary Vascular Diseases
Pulmonary vascular diseases are conditions that affect the pulmonary circulation. Examples of these conditions are:
Pulmonary embolism, a blood clot that forms in a vein, breaks free, travels through the heart and lodges in the lungs (thromboembolism). Large pulmonary emboli are fatal, causing sudden death.
Pulmonary arterial hypertension, elevated pressure in the pulmonary arteries. It can be idiopathic or due to the effects of another disease, particularly COPD. This can lead to strain on the right side of the heart, a condition known as cor pulmonale.
Pulmonary edema, leakage of fluid from capillaries of the lung into the alveoli (or air spaces). It is usually due to congestive heart failure.
Pulmonary hemorrhage, inflammation and damage to capillaries in the lung resulting in blood leaking into the alveoli. This may cause blood to be coughed up. Pulmonary hemorrhage can be due to auto-immune disorders such as Wegener’s Granulomatosis and Goodpasture’s syndrome.
Disorders of Breathing Mechanics
The brain co-ordinates breathing and sends messages via nerves to the muscles of respiration. The muscles produce the movements of breathing. Disorders of the brain’s control of breathing, the nerves or the muscles of respiration can affect the respiratory system. Common disorders of breathing mechanics are:
Obstructive Sleep Apnea
The most common category of sleep disordered breathing. The muscle tone of the body ordinarily relaxes during sleep and at the level of the throat the human airway is composed of collapsible walls of soft tissue which can obstruct breathing during sleep. Mild, occasional sleep apnea, such as many people experience during an upper respiratory infection, may not be important, but chronic, severe obstructive sleep apnea requires treatment to prevent low blood oxygen (hypoxemia, sleep deprivation, and other complications. The most serious complication is a severe form of congestive heart failure called cor pulmonale.
Central Sleep Apnea
In pure central sleep apnea or Cheyne-Stokes respiration, the brain’s respiratory control centers are imbalanced during sleep. Blood levels of carbon dioxide and the neurological feedback mechanism that monitors them do not react quickly enough to maintain an even respiratory rate, with the entire system cycling between apnea and hyperpnea, even during wakefulness. The sleeper stops breathing and then starts again.
In central sleep apnea, the basic neurological controls for breathing rate malfunction and fail to give the signal to inhale, causing the individual to miss one or more cycles of breathing. If the pause in breathing is long enough, the percentage of oxygen in the circulation will drop to a lower than normal level (hypoxaemia) and the concentration of carbon dioxide will build to a higher than normal lever (hypercapnia). In turn, these conditions of hypoxia and hypercapnia will trigger additional effects on the body. Brain cells need constant oxygen to live, and, if the level of blood oxygen goes low enough or long enough, the consequences of brain damage and even death will occur.
Obesity is often associated with sleep apnea and can cause either an obstructive or a restrictive pattern on spirometry. Obesity reduces the movement of the chest wall which can, in extreme cases, result in the obesity-hypoventilation syndrome a cause of respiratory failure
Guillan-Barre Syndrome
This disease is an acute inflammatory demyelinating polyneuropathy, an autoimmune disorder affecting the peripheral nervous system, usually triggered by an acute infectious process. It is frequently severe and usually exhibits as an ascending paralysis noted by weakness in the legs that spreads to the upper limbs and the face along with complete loss of deep tendon reflexes and respiratory difficulties. With prompt treatment by plasmapheresis or intravenous immunoglobulins and supportive care, the majority of patients will regain full functional capacity.
Myasthenia Gravis
The hallmark of myasthenia gravis is fatigue. Muscles become progressively weaker during periods of activity and improve after periods of rest. Muscles that control eye and eyelid movement, facial expression, chewing, talking and swallowing are especially susceptible. The muscles that control breathing and neck and limb movements can also be affected.
Obesity is often associated with sleep apnea and can cause either an obstructive or a restrictive pattern on spirometry. Obesity reduces the movement of the chest wall which can, in extreme cases, result in the obesity-hypoventilation syndrome a cause of respiratory failure.