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Respiratory tract disorders or Respiratory Disease is the term for diseases of the respiratory system in interferes with the process of respiration. These include disorders of the larynx lung, pleural cavity, bronchial tubes, trachea, upper respiratory tract and of the nerves and muscles of breathing. Of particular interest to psychologists are:
Respiratory diseases 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 death. In the US, people suffer 1 billion colds per year. One in seven people in the UK is affected by some form of chronic lung disease, most commonly chronic obstructive pulmonary disease and asthma. Respiratory disease is responsible for over 10% of hospitalizations and over 16% of deaths in Canada. The study of respiratory disease is known as pulmonology. A doctor who specializes in respiratory disease is known as a pulmonologist, a chest medicine specialist, a respiratory medicine specialist, a respirologist or a thoracic medicine specialist.
The symptoms of respiratory disease differ depending on the disease. Common symptoms are:
- Shortness of breath or dyspnea which usually occurs with exercise and can interfere with daily activities. In severe cases, shortness of breath can occur while resting.
- Cough with or without the production of sputum.
- Coughing blood (haemoptysis).
- Chest pain. This may or may not be pleuritic chest pain (that is pain that worsens with the movements of breathing).
- Noisy breathing, either wheeze or stridor.
- Loss of appetite.
- Weight loss.
- Cyanosis, a bluish discoloration of the lips, tongue or fingers.
In some cases respiratory disease is diagnosed without symptoms in the investigation of another disease or through a routine check.
Respiratory diseases may be investigated by performing one or more of the following tests
- Chest x-ray
- Pulmonary function test
- Computed tomography scan
- Culture of microorganisms from secretions such as sputum
- Biopsy of the lung or pleura
- Ventilation - perfusion scan
- Ultrasound scanning can be useful to detect fluid such as pleural effusion
Treatment of respiratory disease depends on the particular disease being treated, the severity of disease and the patient. Lifestyle factors such as regular exercise and healthy nutrition are important in preventing and treating respiratory disease. Vaccination can prevent some respiratory diseases. In addition, the following treatments are often used for respiratory diseases:
- Medication, often given in an inhaled form
- Liquid ventilation (or Liquid breathing)
- Surfactant Replacement Therapy
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
Restrictive lung diseases
Restrictive lung diseases (also known as interstitial lung diseases) are a category of respiratory disease characterised by a loss of lung compliance, causing incomplete lung expansion and increased lung stiffness. E.g. in infant respiratory distress syndrome (IRDS)
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 in is pneumonia, a lung infection. Pneumonia is usually caused by bacteria, particularly Streptococcus pneumoniae in Western countries. Worldwide, tuberculosis is an important cause of pneumonia. Other pathogens such as viruses and fungi can cause pneumonia for example 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.
Tumours of the respiratory system are either malignant or benign.
Malignant tumours, or cancers of the respiratory system, particularly lung cancers, are a major health problem responsible for 15% of all cancer diagnoses and 29% of all cancer deaths. The majority of respiratory system cancers are attributable to smoking tobacco.
The major types of respiratory system cancer are:
- Small cell lung cancer
- Non-small cell lung cancer
- Large cell undifferentiated carcinoma
- Other lung cancers (carcinoid, Kaposi’s sarcoma, melanoma)
- Head and neck cancer
- Mesothelioma, usually caused by exposure to asbestos dust.
In addition, since many cancers spread via the bloodstream and the entire cardiac output passes through the lungs, it common for cancer metastases to occur the lung. Breast cancer may invade directly through local spread, and through lymph node metastases. After metastasis to the liver, colon cancer frequently metastasizes to the lung. Prostate cancer, germ cell cancer and renal cell carcinoma may also metastasize to the lung.
Treatment of respiratory system cancer depends on the type of cancer. Surgery (usually removal of part of the lung, a lobectomy or an entire lung, a pneumonectomy), chemotherapy and radiotherapy are all used. The chance of surviving lung cancer depends on the cancer stage at the time the cancer is diagnosed and is only about 14-17% overall. In the case of metastases to the lung, treatment can occasionally be curative but only in certain, rare circumstances.
Benign tumours are relatively rare causes of respiratory disease. Examples of benign tumours are:
- Pulmonary hamartoma
- Congenital malformations such as pulmonary sequestration and congenital cystic adenomatoid malformation (CCAM).
Pleural cavity diseases
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 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. A number of other substances can also embolise to the lungs but they are much more rare: fat embolism (particularly after bony injury), amniotic fluid embolism (with complications of labour and delivery), air embolism (iatrogenic).
- 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
- Central sleep apnea
- Amyotrophic lateral sclerosis
- Guillan-Barre syndrome
- Myasthenia gravis
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.
- ↑ National Institutes of Health – common cold. URL accessed on 2008-05-07.
- ↑ British Lung Foundation - Facts about respiratory disease. URL accessed on 2008-04-19.
- ↑ Public Health Agency of Canada - Centre for Chronic Disease Prevention and Control Chronic Respiratory Diseases. URL accessed on 2008-05-06.
- ↑ Sharma, Sat. Restrictive Lung Disease. URL accessed on 2008-04-19.
- ↑ LungCancer.org. URL accessed on 2008-05-07.
- ↑ Canadian Lung Association – Lung Cancer. URL accessed on 2008-05-07.
Pathology of respiratory system (J, 460-519)
|Acute upper respiratory infections|
|Influenza and Pneumonia|
|Other acute lower respiratory infections|
|Other diseases of upper respiratory tract|
|Chronic lower respiratory diseases|
|Lung diseases due to external agents|
| Other, principally affecting|
| Suppurative and necrotic conditions|
of lower respiratory tract
Respiratory system, physiology: respiratory physiology
lung volumes - vital capacity - functional residual capacity - respiratory minute volume - closing capacity - dead space - spirometry - body plethysmography - peak flow meter - thoracic independent volume - bronchial challenge test
ventilation/perfusion ratio (V/Q) and scan - zones of the lung - gas exchange - pulmonary gas pressures - alveolar gas equation - hemoglobin - oxygen-haemoglobin dissociation curve (2,3-DPG, Bohr effect, Haldane effect) - carbonic anhydrase (chloride shift) - oxyhemoglobin - respiratory quotient - arterial blood gas - diffusion capacity - Dlco
|Control of respiration|
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