Pulmonary Medicine:
- What is Pulmonary Medicine?
- How are Pulmonary Diseases diagnosed?
- How are Pulmonary Diseases treated?
- Procedures – Preparation and what to expect.
- What is Pulmonary Medicine?
Pulmonary medicine is a medical specialty that focuses on the diagnosis and treatment of diseases of the lung and lower respiratory tract. A physician who specializes in this field is called a pulmonologist or pulmonary physician.
About the respiratory system:
— The Nose - Usually air will enter the respiratory system through the nostrils. The nostrils then lead to open spaces in the nose called the nasal passages. The nasal passages serve as a moistener, a filter, and to warm up the air before it reaches the lungs.
— Pharynx and Larynx - Air travels from the nasal passages to the pharynx, or more commonly known as the throat. When the air leaves the pharynx it passes into the larynx, or the voice box. The voice box is constructed mainly of cartilage, which is a flexible connective tissue. Food and liquids are blocked from entering the opening of the larynx by the epiglottis.
— Trachea - The larynx goes directly into the trachea or the windpipe. The trachea is a tube approximately 12 centimeters in length and 2.5 centimeters wide. The trachea is kept open by rings of cartilage within its walls.
— Bronchi - Around the center of the chest, the trachea divides into two cartilage-ringed tubes called bronchi (bronchus-singular). The bronchi enter the lungs and spread into a treelike fashion into smaller tubes called bronchial tubes.
— Bronchioles - The bronchial tubes divide and then subdivide. By doing this their walls become thinner and have less and less cartilage. Eventually, they become a tiny group of tubes called bronchioles.
— Alveoli - Each bronchiole ends in a tiny air chamber that looks like a cluster of grapes. Each chamber contains many cup-shaped cavities known as alveoli (alveolus-singular). They are thin, moist, and are surrounded by capillaries. The exchange of oxygen and carbon dioxide between blood and air occurs through the aveoli. The estimation is that lungs contain about 300 million alveoli. Their total surface area would be about 70 square meters.
About respiratory diseases:
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 - Obstructive lung diseases are 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 - Restrictive lung diseases (also known as interstitial lung diseases) are a category of respiratory disease characterized by a loss of lung compliance,[4] 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.
— Respiratory tumors - Tumors of the respiratory system are either malignant or benign.
- Malignant tumors - Malignant tumors, 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[5]. 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- Adenocarcinoma
- Large cell undifferentiated carcinoma
• Lymphoma
• 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[6]. In the case of metastases to the lung, treatment can occasionally be curative but only in certain, rare circumstances.
- Benign tumors - Benign tumors are relatively rare causes of respiratory disease.
Examples of benign tumors are:
• Pulmonary hamartoma
• Congenital malformations such as pulmonary sequestration and congenital cystic adenomatoid malformation (CCAM).— Pleural cavity diseases - Pleural cavity diseases include empyema and mesothelioma which are mentioned above.
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. 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 gravisObesity 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.
References
1. "National Institutes of Health – common cold". http://www3.niaid.nih.gov/topics/commonCold/. Retrieved on 2008-05-07.
2. "British Lung Foundation - Facts about respiratory disease". http://www.lunguk.org/media-and-campaigning/media-centre/lung-stats-and-facts/factsaboutrespiratorydisease.htm. Retrieved on 2008-04-19.
3. "Public Health Agency of Canada - Centre for Chronic Disease Prevention and Control Chronic Respiratory Diseases". http://www.phac-aspc.gc.ca/ccdpc-cpcmc/crd-mrc/facts_gen_e.html. Retrieved on 2008-05-06.
4. Sharma, Sat. "Restrictive Lung Disease". http://www.emedicine.com/med/topic2012.htm. Retrieved on 2008-04-19.
5. "LungCancer.org". http://www.lungcancer.org/reading/about.php. Retrieved on 2008-05-07.
6. "Canadian Lung Association – Lung Cancer". http://lung.ca/diseases-maladies/cancer-cancer/treatment-traitement/index_e.php. Retrieved on 2008-05-07.
Courtesy of www.wikipedia.org –respiratory diseases
- How are Pulmonary Diseases diagnosed?
Common diagnostic testing for pulmonary disease include:
Imaging
- Chest radiographs or chest x-rays can be used to diagnose many conditions in the chest cavity. Examples include pneumonia, pneumothorax or collapsed lung, and pleural effusion (fluid buildup between the lung and chest wall). It can also be used to screen for occupational exposures to dust, metal particles, etc.
- Computed axial tomography scans (CAT or CT scans) of the chest can be used to visualize parts of the chest that cannot be seen on a chest x-ray. This scan produces a 3-dimensional image of the chest so the physician is able to assess the condition of the lungs in greater detail.
- Positron emission tomography scan (PET scan) is most commonly used to diagnose and stage cancer in pulmonology.
- Echocardiography is an ultrasound of the heart. This test is generally used to diagnose conditions of the heart but it is a significant test in pulmonary medicine because it can be used to diagnose diseases that are related to the supply of blood to and from the lungs.
Pulmonary Function Testing
- Spirometry is the most common type of pulmonary function testing. It measures the capacity of the lungs or how much volume the lungs can hold, and also the speed in which the air moves in and out of the lungs. This test can be used to evaluate for asthma and COPD.
- Pulmonary stress test or 6 minute walk test is a test that evaluates the lungs’ ability to deliver oxygen to the body under exertion.
Laboratory
- Specimens such as blood and/or sputum can be collected to help diagnose conditions of the lungs.
Surgery
- Bronchoscopy is procedure where the airways inside the lungs are visualized through a camera or scope. The bronchoscope is usually inserted into the mouth and guided down into the lungs while the patient is under anesthesia. The physician can then assess for tumors, inflammation, and/or foreign bodies. Tissue samples of the lungs can also be taken for biopsy.
- How are Pulmonary Diseases treated?
Treatment may involve -
- Medications such as steroids and/or bronchodilators may be used to help open air passages. Antibiotics may be prescribed to fight any bacterial infection.
- Supplemental oxygen therapy may be administered to individuals with decreased lung function.
- Pulmonary rehabilitation is a treatment where an individual with worsening chronic lung disease receives education and instruction on how to improve the quality of his/her life by reducing symptoms of the lung condition.
- Surgery- certain conditions can be improved or resolved through surgical intervention. Examples of procedures include thoracentesis and/or PleurX catheter placement to resolve a collapsed lung, and right heart catherization to treat pulmonary hypertension.
- Procedures – Preparation and what to expect.
Spirometry testing - Patients are asked to withhold their bronchodilator the morning of testing, as tolerated. Patient Handout (pdf)
Bronchoscopy - This is usually an outpatient procedure. Patients will be given specific directions from the facility where the procedure was scheduled but in general, sedation is involved so patients are asked to withhold from eating and drinking the night before the procedure. Patients may be asked to temporarily withhold certain medications such as blood thinners.