Lung diseases Symptoms and Causes

Lungs Overview

The lungs are part of the respiratory system and are located in the chest, inside the rib cage and above the diaphragm. The lungs have a spongy, flexible tissue and are complex organs designed for oxygen uptake and carbon dioxide removal.

When we breathe, oxygen enters the lungs. It is distributed into the lungs by a system called the bronchial tree, which has gradually narrowing branches ( called bronchi and  bronchioles ). The bronchial tree carries oxygen to the alveoli deep in the lungs. Here, inhaled air enters the blood circulation from the lungs, while carbon dioxide, a by-product of metabolism, passes from the blood to the lungs to be exhaled. Oxygen uptake and its delivery to the tissues by blood are necessary for the function of every cell in our body. As part of the acid-base balance system, carbon dioxide must be removed in order for the body to maintain the pH of the blood.

Since the air we breathe contains many elements from the environment such as dust, pollen, bacteria, viruses, smoke and volatile chemicals, the lungs maintain a defense system against these potentially toxic invaders. The lungs’ defense system includes immune cells and mucus secretion to absorb and remove these unwanted elements in the lungs.

About lung diseases

  • Lung diseases

    In lung diseases, some of the functions of the lungs are adversely affected. In some cases, the problem concerns the gas exchange process in the membrane between the alveoli and the blood, preventing effective oxygen uptake and carbon dioxide excretion. In other cases, the problem is that the bronchial system is blocked, or that the chest muscles are unable to expand and contract sufficiently to move air from the bronchial tree into the alveoli. Sometimes the problem is impaired ability of the lungs to expel or detoxify foreign materials, perhaps because of an underlying deficiency or because these substances overwhelm the lungs’ defense systems.

    Common Lung Diseases:

    Asthma is  a chronic inflammation of the bronchi  and  bronchioles  characterized by episodes of airway obstruction. lung disease. People with asthma are sensitive to various substances that do not cause a similar reaction in others. Smoking, other particles in the air, dust, mold, allergens, exercise, cold weather and other factors can trigger attacks. Triggering agents can be different for each person. During an asthma attack, the inner surface of the airways swells, the muscles surrounding the bronchi contract, and the airway narrows. The increase in slime (mucus) can further obstruct airflow, making breathing difficult and causing wheezing in the affected person. Because oxygen deficiency and carbon dioxide accumulation can be life-threatening, most attacks do not cause permanent lung damage, but often require emergency medical treatment.

    Chronic obstructive pulmonary disease (COPD):  A term used for  both  emphysema and chronic bronchitis. In chronic bronchitis, the bronchi become inflamed and scar tissue forms. In emphysema, the air sacs within the lungs are gradually destroyed. In both disorders, patients have more and more difficulty exhaling and getting enough oxygen. About 80-90% of COPD-related deaths are caused by smoking. Other risk factors include frequent exposure to air pollution.

    Lung fibrosis  is a lung disease characterized by damage and scarring of the tissues between the air sacs, inflammation of the air sacs, and hardening of the lungs. Causes of fibrotic disease of the lungs :

    • Occupational or environmental exposure to small particles; It includes frequent exposure to non-organic (inorganic) materials such as asbestos, coal, beryllium, and silica.
    • Repeated exposures to organic materials such as moldy straw, animal droppings and grain dust can cause hypersensitivity  pneumonitis  and eventually lead to lung fibrosis.
    • Chemicals and drugs toxic to the lungs
    • radiation therapy
    • Sarcoidosis
    • Systemic sclerosis and other  autoimmune disorders
    • Idiopathic

    Infections: Infections  that can occur primarily in the lungs can affect the whole body, including the lungs, or can   develop in  the pleura , the membranes that surround the lungs. They can be acute  or chronic. Bacteria ,  viruses ,  and more rarely  fungi  cause these infections. Pneumonia (pneumonia)  is an acute lung inflammation caused by various microbes.  Influenza infection (Influenza) is an acute systemic disease caused by viruses, which also shows respiratory symptoms.  cause chronic infections, which are most common in patients with compromised immune systems (such as HIV/AIDS patients)Tuberculosis  and  non-tuberculous mycobacteria (NTM)  . Infections caused by mycobacteria may develop gradually, be systemic, or be limited to the lungs.

    Lung cancer: It   is the uncontrolled growth of malignant cells in the lungs . There are major types of small cell and non-small cell lung cancer. Although other types of cancer can spread to the lungs, they are considered metastatic because cancer cells do not come from the lungs. In recent years, while the number of women who have died from lung cancer has increased, the number of men has decreased. Lung cancer is still the leading cause of cancer death in   women, killing more women than ovarian, breast ,  and  cervix cancer . Lung cancer risks include smoking and exposure to radon. 

    Hypertension associated with lung disease:  Blood pressure rises as a result of narrowing of the blood vessels in the lungs, causing the heart to work harder to deliver blood to the lungs. This condition can accompany or aggravate various lung diseases, as well as lead to heart failure.

    Pulmonary embolism:  A blood clot, usually originating from the veins of the legs or pelvis, travels to the lungs and blocks a blood vessel, causing chest pain, severe shortness of breath and coughing. This disease requires immediate medical treatment as it can be life-threatening.

    Bronchopulmonary dysplasia (BPD):   Although it is a lung disease that develops primarily in babies born prematurely and who have received oxygen therapy and/or mechanical ventilation for a long time, it can also be seen in babies with oxygen toxicity or pneumonia. In this disease, the airways are inflamed, unable to develop normally and become damaged.

    Respiratory Distress Syndrome (RDS):  It is a life-threatening respiratory problem of the newborn and may develop in babies born more than 6 weeks before term. Babies born before this term (premature) are not developed enough to produce sufficient amounts of a protective fluid called surfactant in their lungs. Without surfactant, the lungs cannot perform their proper expansion or inflation functions, and babies have difficulty breathing to get enough oxygen. It is a condition that can occur a few hours after birth before term.

    Acute Respiratory Distress Syndrome (ARDS):  Severe breathing difficulties occur rapidly due to diffuse lung inflammation and fluid filling of the lungs. Many causes of damage to the lungs such as serious viral or bacterial infections of the lungs, blood poisoning ( sepsis ), trauma, multiple blood transfusions, drug overdose, salt, water or smoke inhalation lead to death.

    Cystic fibrosis  :  An inherited disease that negatively affects the lungs, pancreas, and other systems. Salty sweat is characterized by a thick slimy secretion (mucus) that can block the airways, and a decreased ability to digest fats and proteins, resulting in malabsorption and  malnutrition   . It is usually diagnosed in infancy.

    Alpha-1 Antitrypsin deficiency:  An inherited deficiency of a protein that provides protection to the lungs. Without this protection, the lungs suffer more and more damage.  The patient has a significantly increased risk of developing early-onset emphysema and liver disease . 

    Other diseases do not directly affect the liver, but impair a person’s ability to breathe properly. These extrapulmonary disorders can adversely affect the thoracic cavity, muscles, nerves, and heart. These include malformations, polio, myasthenia gravis,  Guillain-Barré syndrome  , and amyotrophic lateral sclerosis (ALS or Lou Gehrig’s disease), and abnormal spine formation or rib cage movements that can limit the expansion of the lungs. [Note: Specific testing and treatments for these disorders are not discussed in this article.]

  • Symptoms and Causes

     The signs  and  symptoms associated with lung disease   will vary from person to person and over time.  Symptoms in chronic  diseases often appear gradually and gradually worsen. In acute  cases, symptoms can be mild or severe. Some can be life-threatening if not promptly treated. Although each disease will have its own characteristics, there are common signs and symptoms seen in many lung diseases. These include persistent cough and shortness of breath. People may sneeze, cough up blood or  phlegm may cause chest pain. People with obstructive pulmonary disease, such as COPD, may have difficulty exhaling. Some describe it as “trying to breathe through a drinking straw”. Lack of oxygen turns the patient’s skin a bluish color. Over time, lack of oxygen can cause blunt fingertips and abnormal growth of fingernails in some people.

  • Tests

    The purposes of testing are to diagnose lung diseases, identify their causes, if possible, and assess their severity. Many doctors will order lung or pulmonary function tests (PFTs) to evaluate oxygen and carbon dioxide levels, help diagnose and monitor lung function, chest x-rays or CT (computed tomography) scans to examine the anatomy of the lungs. Other tests are also used to aid in the diagnosis of specific diseases.

    Laboratory Tests

    • Blood gases  – a blood sample is taken from an artery (artery) to assess blood pH, oxygen, and carbon dioxide.
    • Complete blood count  –  for anemia  investigation
    • Cystic Fibrosis Tests –  CF Gene Mutation Test  ,  Sweat chloride  test  , Immunoreactive trypsin (IRT),   Fecal trypsin  test – used to  investigate hereditary changes (mutations) of  cystic fibrosis  and to diagnose the disease.
    •  Alpha-1 antitrypsin  – requested to determine if the patient has AAT deficiency.
    • Sputum culture  –  requested to diagnose lung infections caused by bacteria .
    • ARB smear preparation and culture  –  requested to diagnose tuberculosis   and  non-tuberculous mycobacteria (NTM)  infections
    • Blood cultures  – ordered to diagnose bacterial and sometimes yeast infections that have spread to the bloodstream.
    • Influenza tests  – ordered to diagnose influenza infection.
    • Lung  biopsy  – used to evaluate lung tissue for lung damage and cancer
    • Sputum  cytology  – evaluates lung cells for abnormal changes and cancer.
    • Fetal Lung Maturation (FLM) tests – they are used to assess fetal lung maturation and include tests such as the lecithin/sphingomyelin (L/S) ratio, phosphatidylglycerol (PG), foam stability index (FSI), or lamellar body count (LBC). It can be used to determine gestational  age before a cesarean delivery or when a pregnant woman shows signs of preterm labor  .
    • Drug screening  – used to identify drugs that cause decreased respiration or acute respiratory distress and that are used in overdoses.

    Lung Function Tests (Pulmonary Function Tests, PFT)
    Listed below are some of the most frequently performed tests.

    • Spirometry – Measures the amount and velocity of exhaled air as the patient blows into a tube. It is applied to evaluate narrowed or obstructed airways.
    • Measurement of Maximal Airflow – measures exhalation rate. It can be used to help people with asthma monitor their condition at home.
    • Lung Volume – a measurement of the amount of air a person inhales into their lungs and how much air remains in the lungs after exhalation. It helps to assess the flexibility of the lungs, the mobility of the rib cage, the strength of the muscles associated with breathing.
    • Measurement of Diffusion Capacity – measures how much of small amounts of inhaled carbon monoxide (but not harmfully) is absorbed to assess oxygen transfer from the lung air sacs into the bloodstream. 

    Imaging studies

    • Chest X-ray – is requested to examine the lung structure and chest cavity.
    • CT (computed tomography) scan – applied for a more detailed assessment of lung structure.
    • MRI (Magnetic resonance imaging) – applied to show the organs and vessels in the chest in detail.
    • Ultrasonography – Used to determine the fluid between the lung membranes ( pleura ).
    • Nuclear lung scan – used to help detect pulmonary embolism and, rarely, to evaluate the effectiveness of lung cancer treatment.
    • Positron emission tomography (PET) scans – used to help diagnose lung cancer.

     Other tests

    • Electrocardiography  (ECG) – taken to examine the heart rhythm,  to determine if heart disease  is affecting breathing.
    • Sleep studies – used to help determine normal breathing during a patient’s sleep.
  • Treatments

    The goals of lung disease treatment are to prevent disease whenever possible, treat infections and prevent their spread to others, relieve inflammation, stop or slow the progression of lung damage, relieve symptoms, ease breathing, minimize the side effects of some treatments, and make sure the affected person is getting enough oxygen. consists of being

    Many cases of lung disease can be prevented by not smoking, having a radon test, and minimizing exposure to particles such as asbestos, coal, beryllium, silica, molds, grain dust, air pollution, chemicals, and chemicals and drugs that are known to adversely affect the lungs.  People with compromised immune systems,  those with lung disease, the very young, or the elderly  should discuss with their doctor whether to get   an annual flu or pneumonia  vaccine to minimize their risk of getting  flu  and  pneumonia .

    New treatments for lung diseases are being developed and the treatment of patients requires changes over time. Patients should periodically talk to their doctor about treatments that are right for them.


Sources of the article

 (2006 November). Cystic Fibrosis Fact Sheet. American Lung Association [On-line information]. Available online at through Accessed on 6/10/07.

(2006 August). Chronic Obstructive Pulmonary Disease (COPD) Fact Sheet [33 paragraphs]. American Lung Association [On-line information]. Accessed on: 6/10/07 Available FTP:

Weinmann, G., et. al. (2006 March). Lung Disease, Frequently Asked Questions. National Women’s Health Information Center [On-line information]. Available online at through Accessed on:6/10/07.

Rauscher, M. (2007). COPD Seen to be a Growing, Neglected Epidemic. Medscape Reuters Health Information [On-line information]. Available online at through Accessed on 6/10/07.

Goodridge, D. (2007 January 29). COPD as a Life-Limiting Illness: Implications for Advanced Practice Nurses. Medscape Topics in Advanced Practice Nursing eJournal 2007;6(4) [On-line information]. Available online at through Accessed on 6/10/07.

Kaufman, D. (2006 November 13). Lung disease. MedlinePlus Medical Encyclopedia [On-line information]. Available online at “” target=”_blank”> Accessed on 6/10/07.

Mal, H. (2007 February 28). Prevalence and Diagnosis of Severe Pulmonary Hypertension in Patients with Chronic Obstructive Pulmonary Disease [On-line information]. Available online at through Accessed on 6/10/07.

Sharma, S. (2006 June 5, Updated). Restrictive Lung Disease. emedicine [On-line information]. Available online at through Accessed on 6/10/07.

Lympany, P. and du Bois, R. (2000 January 31). Interstitial Lung Disease: Pathophysiology and Genetic Predisposition. Medscape General Medicine 2(1), 2000 [On-line information]. Available online at through

Brain, J. (2006 August, Revision). Biology of the lungs and airways. Merck Manual of Medical Information – Second Home Edition [On-line information]. Available online at through Accessed on 6/6/07.

Mayo Clinic Staff (2005 July 11). Interstitial Lung Disease. [On-line information]. Available online at through Accessed on 6/10/07.

(2006). Flavorings-Related Lung Disease. National Institute for Occupational Safety and Health [On-line information]. Available online at through Accessed on 6/10/07.

O’Reilly, K. et. al. (2007 March 1). Asbestos-Related Lung Disease. American Family Physician [On-line information]. Available online at through Accessed on 6/10/07.

(2004 February 12). High-Risk Newborn, Chronic Lung Disease (Bronchopulmonary Dysplasia). University of Virginia [On-line information]. Available online at through Accessed on 6/10/07.

(© 2000 – 2007). Pulmonary Function Testing. Harvard Health Publications, Pulmonary Function Testing [On-line information]. Available online at through Accessed on 6/16/07.

(© 2002 – 2003). Pulmonary Function Laboratory. John Hopkins Medicine [On-line information]. Available online at through Accessed on 6/16/07.

Kaufman, D. (2006 February 27, Reviewed). Pulmonary Function Tests. University of Maryland Medical Center [On-line information]. Available online at through Accessed on 6/16/07.

(2005). Pulmonary Function Tests in COPD. American Thoracic Society, Patient Education [On-line information]. Available online at through

(2006 June 29, Review). Detailed Guide: Lung Cancer – Non-small Cell. American Cancer Society [On-line information]. Available online at through Accessed on 6/10/07.

(2006 November 23, Review). Detailed Guide: Lung Cancer – Small Cell. American Cancer Society [On-line information]. Available online at through Accessed on 6/10/07.

Pagana, Kathleen D. & Pagana, Timothy J. (© 2007). Mosby’s Diagnostic and Laboratory Test Reference 8th Edition: Mosby, Inc., St. Louis, MO. Pp 790-795.

Thomas, Clayton L., Editor (1997). Taber’s Cyclopedic Medical Dictionary. FA Davis Company, Philadelphia, PA [18th Edition]. Pp 1133–1135.

(2006 August). Asthma and Children Fact Sheet. American Lung Association [On-line information]. Available online through Accessed on 6/23/07.

(2006 August). Asthma in Adults Fact Sheet. American Lung Association [On-line information]. Available online through Accessed on 6/23/07.

(2006 November). Alpha-1 Antitrypsin Deficiency Emphysema. American Lung Association [On-line information]. Available online through Accessed on 6/23/07.

(2004 December). Bronchopulmonary Dysplasia (BPD) Fact Sheet. American Lung Association [On-line information]. Available online through Accessed on 6/23/07.

(May 2007) What is Respiratory Distress Syndrome? National Heart, Lung and Blood Institute, Diseases and Conditions (Online information). Available online at through Accessed August 2007.

(November 2006) Respiratory Distress Syndrome of the Newborn Fact Sheet, American Lung Association (Online information). Available online at through Accessed August 2007.

(November 2006) Adult (Acute) Respiratory Distress Syndrome (ARDS) Fact Sheet. American Lung Association (Online information). Available online at through Accessed August 2007.

Kasper D, Braunwald E, Fauci A, Hauser S, Longo D, Jameson J, eds. Harrison’s Principles of Internal Medicine, 16th edition, McGraw-Hill, 2005.

Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Burtis CA, Ashwood ER, Bruns DE, eds. 4th edition, St. Louis Louis: Elsevier Saunders; 2006.

Leave a Comment