Respiratory System Diseases: Common Types, Causes, and Symptoms

8.6.2025 0 comments

Author: Trisha Houghton, CNS, ASIST

The human respiratory system is one of the most crucial systems in the body.

Its primary function is to absorb oxygen into the bloodstream and expel carbon dioxide wastes. Without this gas exchange, our cells would lack the oxygen required to function and the amount of carbon dioxide would build up to fatal quantities.

However, there are a number of conditions that can impair an otherwise normally functioning respiratory system and cause health problems.

In this article, we’ll take a deep dive into illnesses and diseases of the respiratory system and look at what is most likely to impair respiratory function. We’ll examine the most common diseases, what causes them, and how they manifest.

We’ll also look at simple preventative measures you can take to reduce your risk of and manage any existing respiratory conditions.

By the end, you’ll have a much greater understanding of your respiratory system and how to keep it healthy and functioning optimally.

Introduction to Respiratory System Diseases

The respiratory system’s primary function is, “gas exchange in which oxygen is transferred from the environment to the blood and carbon dioxide is moved in the opposite direction.” [1]

The body absorbs oxygen into the blood and expels the carbon dioxide waste that builds up in the bloodstream after being expelled by cells.

Other functions of the respiratory system include:

• Thermoregulation, maintaining your body’s internal temperature (heating and cooling);
• Working with the kidneys on acid-base regulation (pH balance);
• Metabolizing nitric oxide, eicosanoids, and other metabolically active substances;
• Immune response to inhaled toxins and pathogens.

A healthy respiratory system provides your body with enough oxygen to function normally, expels carbon dioxide wastes, and maintains healthy homeostasis through this gas exchange and its other functions.

However, diseases of the respiratory system can impair lung function and have a serious impact on the body.

Common Types of Respiratory System Disorders

The following paragraphs summarize and describe the most common disorders of the human respiratory system, along with their types, symptoms, and specifics.

Asthma

Asthma is a chronic respiratory condition that’s believed to affect around 25 million adults in the USA alone.

With asthma, the airways narrow, swell, and/or increase mucus production.

The combination of these factors can cause a number of symptoms, including:

• Wheezing;
• Breathing difficulties;
• Shortness of breath;
• Chest pain or tightness;
• Sleeping difficulties (caused by breathing difficulties or shortness of breath).

There are a number of different types of asthma: exercise-induced asthma, which is brought on by strenuous exercise, and may worsen when the air is dry and cold; allergy-induced asthma, the most common type, which is triggered by pollen, spores, pet dander, mold, and other airborne substances; and occupational asthma, which is triggered by exposure to dust, toxic chemicals, fumes, gases, and other workplace irritants.

Asthma may be a nuisance with only minor symptoms. However, in some cases, it can become a serious problem that requires the use of medications (provided via an inhaler). In serious cases, it can become life-threatening if an asthma attack is severe.

Chronic Obstructive Pulmonary Disease (COPD)

Chronic Obstructive Pulmonary Disease, or COPD, is a progressive lung disease that causes airflow blockage and breathing problems, typically due to chronic bronchitis and/or emphysema. This airway obstruction and inflammation limits the amount of air that can flow in and out of the lungs, reducing oxygen uptake and carbon dioxide expulsion.

The two most common types of COPD are chronic bronchitis (inflammation in the lining of the tubes that bring air to the lungs) and emphysema (damage to and inflammation of the alveoli, the small air sacs in the lungs).

They often occur together and can lead to symptoms like:

• Breathing difficulties or trouble catching your breath;
• Whistling or wheezing;
• Heaviness or tightness in the chest;
• Frequent lung infections;
• A persistent cough, often accompanied by mucus (which may be greenish, yellow, white, or clear);
• Edema (swelling) in the legs, feet, and/or ankles;
• Low energy levels, frequent fatigue;
• Unexplained and unintentional weight loss.

Tobacco smoking is the #1 cause of COPD around the world. However, it may also develop in people exposed to fumes emitted by burning fuel, chemical fumes, or vapor or dust.

Pneumonia

Pneumonia is a condition wherein your lungs are infected by germs (virus or bacteria), leading to inflammation in the air sacs in your lungs (one or both).

The air sacs fill with pus or fluid, causing a wide range of symptoms:

• Fatigue;
• Shaking chills, fever, and sweating;
• Chest pain when coughing or even breathing;
• Phlegmy cough;
• Confusion, mental awareness changes;
• Shortness of breath;
• Diarrhea;
• Vomiting and/or nausea;
• Lowered body temperature.

Pneumonia is most commonly acquired in the community, from harmful bacteria like Streptococcus pneumoniae and Mycoplasma pneumoniae, or caused by viruses like SARS-CoV-2.

However, while less common than community-acquired pneumonia, hospital-acquired pneumonia, aspiration pneumonia, and healthcare-acquired pneumonia are all likely to occur especially in the elderly and those with reduced immune response.

Tuberculosis (TB)

Tuberculosis, or TB, is a condition wherein the Mycobacterium tuberculosis bacteria infects your respiratory tract. Exposure to TB-contaminated droplets (expelled by people who are coughing, sneezing,) can cause a primary infection.

This leads to symptoms like:

• Low fever;
• Tiredness;
• Cough.

If the body can respond to the threat effectively, it builds walls around the TB germs and the lung cells they infect. This neutralizes the TB and stops them from causing further harm.

However, if the body can’t neutralize the TB infection, it becomes active TB, which is characterized by symptoms like:

• Coughing, which may involve expulsion of blood or mucus;
• Fever, chills, and night sweats;
• Chest pain or pain when coughing and/or breathing;
• Weight loss and appetite loss;
• Fatigue, tiredness, and general malaise.

Active TB can spread outside the lungs and affect other body parts. This condition is called extrapulmonary tuberculosis and can affect the fluid surrounding your brain and spinal cord, your kidneys, liver, voice box, genitals, skin, blood vessels, and even your heart.

Some forms of TB are drug-resistant. TB is also highly infectious.

Pulmonary Fibrosis

Pulmonary fibrosis is a condition wherein lung damage (caused by autoimmune diseases, environmental exposure, or unknown (idiopathic) reasons) causes scarring of the lung tissue. The scar tissue is thick and stiff, and reduces lung function.

Scarring can worsen over time, causing existing symptoms to worsen and leading to complications like respiratory failure, right-sided heart failure, and pulmonary hypertension. In some cases those with pulmonary fibrosis may have an increased risk of developing lung cancer especially if there are other risk factors.

Symptoms of pulmonary fibrosis include:

• Dry cough;
• Aching joints and muscles;
• Shortness of breath;
• Extreme fatigue and tiredness;
• Clubbing (widening/rounding) of the fingers and toes.

Symptoms may worsen quickly (in a matter of weeks) or may take months or years and may remain largely moderate. However, when the shortness of breath worsens quickly, it may become life-threatening.

Lung Cancer

Lung cancer is the result of malignant tumors forming in the lungs. It’s most commonly caused by smoking and secondhand cigarette smoke exposure, but may be the result of exposure to environmental toxins.

Symptoms of lung cancer include:

• Chest pain;
• A persistent cough;
• Wheezing;
• Shortness of breath;
• Hoarseness;
• Coughing up blood.

Lung cancer may spread to other parts of the body, leading to symptoms like:

• Headaches;
• Swelling in the neck or face;
• Appetite loss and unintentional weight loss;
• Bone pain.

Others

Beyond the conditions above, a number of other disorders can affect the respiratory system.

Here are several notable examples at a glance:

• Acute bronchitis: A short-term inflammation of the bronchial tubes (airways in the lungs), most often caused by a viral infection. It leads to a nagging cough, usually producing mucus, and often follows a common cold or similar illness. Symptoms typically improve within a week or two, though the cough can linger for several weeks. Most cases resolve on their own with rest and fluids.
• Bronchiectasis: A chronic lung condition where repeated inflammation or infections have permanently damaged and widened the bronchi (airways). Because of this damage, mucus is not cleared effectively from the lungs, allowing bacteria to grow. This leads to a chronic productive cough (coughing up sputum often containing pus) and frequent lung infections. Bronchiectasis is irreversible, but treatments (like airway clearance techniques and antibiotics) can help manage symptoms and reduce infections.
• Cystic fibrosis: An inherited genetic disorder that causes the body to produce unusually thick, sticky mucus, especially in the lungs and digestive system. In the lungs, this viscous mucus clogs the airways and promotes frequent respiratory infections, leading to progressive lung damage (bronchiectasis and scarring) over time. It is typically diagnosed in childhood and managed with airway clearance, medications, and other supportive therapies.
• Pulmonary embolism (PE): A blood clot that lodges in an artery of the lung, suddenly blocking blood flow. This medical emergency usually causes abrupt onset of shortness of breath and sharp chest pain (especially with deep breaths). In severe cases, it can lead to lightheadedness, fainting, or circulatory collapse due to strain on the heart.
• Obstructive sleep apnea (OSA): A sleep-related breathing disorder in which the upper airway repeatedly collapses or becomes blocked during sleep, leading to pauses in breathing. This causes loud snoring and frequent awakenings (often with choking or gasping) as the person briefly arouses to reopen the airway. OSA sufferers typically experience non-refreshing sleep and excessive daytime sleepiness or fatigue. Treatment may include lifestyle changes, CPAP therapy (a mask that provides air pressure to keep the airway open), or other interventions.
• Sarcoidosis (pulmonary): An inflammatory disease characterized by the formation of tiny clumps of immune cells called granulomas in various organs. When it affects the lungs (pulmonary sarcoidosis), these granulomas develop in lung tissue (and often in the chest lymph nodes). This can lead to a persistent dry cough, chest discomfort or mild chest pain, and shortness of breath on exertion. Many cases are mild and may even resolve on their own, but others can cause lung scarring if inflammation is severe or long-lasting.
• Pleural effusion and pleurisy:Pleurisy (pleuritis) refers to inflammation of the pleura, the thin lining around the lungs and inner chest wall. It causes a sharp, stabbing chest pain that is typically worse with deep breathing, coughing, or sneezing. People with pleurisy often take shallow breaths or “guard” their breathing to reduce the pain. Pleural effusion is a related condition where excess fluid builds up in the pleural space (the cavity between the lung and chest wall). A pleural effusion can cause difficulty expanding the lungs fully, leading to shortness of breath; it may also cause chest heaviness or pleuritic pain if inflammation is present.
• Pneumothorax: A pneumothorax occurs when air leaks into the pleural space between the lung and chest wall, causing pressure that makes the lung collapse partially or completely. It usually strikes suddenly, often in a previously healthy person or due to chest injury. The classic symptoms are sudden, sharp chest pain on one side and acute shortness of breath. Small pneumothoraxes may resolve on their own, but larger ones or those causing symptoms need prompt medical treatment because a large collapse can be life-threatening.
• Acute respiratory distress syndrome (ARDS): A severe, life-threatening lung condition where the lungs become acutely inflamed and fill with fluid in the air sacs (alveoli). This often happens in the context of critical illness or major injuries – for example, severe pneumonia, sepsis (widespread infection), major trauma, or aspiration of vomit. The fluid leakage into alveoli prevents proper oxygen exchange, leading to dangerously low blood oxygen levels despite breathing support. People with ARDS experience extreme shortness of breath and often need mechanical ventilation in an ICU. ARDS develops rapidly (within hours to days of the triggering event) and requires urgent care.
• Pulmonary hypertension: High blood pressure in the arteries of the lungs. This means the blood vessels in the lungs are narrowed or stiffened, so the heart must work much harder to pump blood through the lungs. Over time, this increased strain causes the right side of the heart (which sends blood into the lungs) to enlarge and weaken – a condition called right-sided heart failure or cor pulmonale. Pulmonary hypertension often causes progressive shortness of breath (especially during exercise at first, and later at rest) and fatigue. Other signs can include chest pain, lightheadedness or fainting episodes, and leg swelling in advanced cases. It is a serious chronic disease that requires specialist management to improve symptoms and slow its progression.
• Alpha-1 antitrypsin deficiency: An inherited genetic disorder in which the body produces too little of a protein called alpha-1 antitrypsin (AAT). AAT’s normal role is to protect the lungs from damage; without enough AAT, people are predisposed to early-onset emphysema (a form of COPD where air sacs in the lungs are destroyed, leading to breathing difficulty). This condition typically causes COPD-like lung symptoms at a younger age (often 30s-40s), especially if the individual smokes.

These conditions range from self-limited illnesses to emergencies and chronic diseases. If new or persistent respiratory symptoms arise, prompt medical evaluation helps guide testing and treatment.

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Causes of Respiratory System Illnesses

Next, we’ll note the primary causes and risk factors for respiratory system diseases.

Smoking

Smoking is the leading cause of lung cancer, and has also been linked to higher rates of COPD and other lung conditions (including, but less common, pulmonary hypertension and obstructive sleep apnea).

The damage done by both smoking and secondhand exposure to smoke can alter the DNA of the lung cells and make them more likely to turn cancerous (multiplying, growing, and spreading at an abnormal rate).

In 2020, it was estimated that roughly 18% of the cancer deaths in the world were caused by lung cancer[2].

Environmental and Occupational Exposures

Environmental and occupational exposures are another major cause of respiratory distress and pulmonary diseases – most commonly COPD, pulmonary fibrosis, and lung cancer.

A number of hazards can cause lung disease, including:

• Air pollution;
• Toxins;
• Fumes;
• Vapors;
• Dust and other irritants;
• Coal dust;
• Silica;
• Radon;
• Asbestos;
• Fungal spores;
• Animal droppings.

Early action to improve ventilation, provide proper protective gear, and enforce strong safety rules can greatly reduce the risk of lung disease caused by environmental or workplace exposure. Clean air protects health now and supports long-term well-being.

Genetic and Hereditary Factors

Some people inherit predispositions to certain respiratory conditions – for example, asthma or some types of pulmonary fibrosis. Due to genetics, they are at a greater risk of developing chronic or acute respiratory health issues.

However, carrying a genetic risk does not guarantee illness. It simply lowers the body’s “buffer” against harm. People with these inherited vulnerabilities are more likely to become sick when they encounter triggers like tobacco smoke, workplace dust, severe infections, or heavy air pollution.

Infections

Viral, fungal, and bacterial infection are the direct cause of some respiratory conditions like tuberculosis, pneumonia, chronic and acute bronchitis.

However, any infection may weaken the immune systemand make you more susceptible to respiratory infections, or cause existing infections to worsen or spread.

Lifestyle and Behavioral Factors

A sedentary lifestyle reduces lung function. As respiratory muscles weaken, overall respiratory health declines.

Especially in cases of COPD, asthma, or other lung diseases, it can be a risk factor.

Autoimmune and Idiopathic Factors

A number of autoimmune conditions (including rheumatoid arthritis, scleroderma, and lupus) can lead to or manifest as respiratory issues. While it’s not known why this is, there is a great deal of evidence to link the two—what is known as “autoimmune lung disease”[3].

However, some lung diseases (particularly pulmonary fibrosis) are caused by no known factors—no direct links to infections, toxins, exposures, etc. These are called “idiopathic”, and may be even harder to treat than lung conditions with known causes.

Common Symptoms of Respiratory System Diseases

Across almost all respiratory diseases, there are a few common general symptoms:

• Coughing;
• Shortness of breath;
• Wheezing;
• Fatigue;
• Chest pain or tightness.

However, each disease also has specific symptoms that are indicators of what the particular respiratory problem may be.

Examples include:

• Asthma is typically characterized by wheezing, chest tightness, breathing problems, and coughing.
• COPD is typically characterized by a persistent cough, excess mucus, and breathlessness.
• Pneumonia is typically characterized by fever, productive cough, and chest pain.
• Tuberculosis is typically characterized by a chronic cough, night sweats, and weight loss.
• Pulmonary Fibrosis is typically characterized by shortness of breath, dry cough, and fatigue.
• Lung Cancer is typically characterized by a persistent cough, chest pain, unintentional weight loss, and in advanced cases, coughing up blood. Other signs include hoarseness, shortness of breath, and frequent respiratory infections.

Learning to recognize these signs will help you to identify and seek out help for specific conditions. Early treatment and management is particularly important with conditions that can be eradicated, which worsen over time, or which are highly contagious.

Prevention and Health Maintenance Strategies

In the paragraphs below, you’ll learn more about how to protect yourself from respiratory disease through proper prevention and health maintenance.

Avoiding Risk Factors

Stop smoking. This is the #1 thing you can do to reduce your risk of lung cancer, COPD, and other smoking-related lung conditions.

Limit your exposure to secondhand smoke, too, as well as other pollutants, fumes, and environmental toxins.

You are also advised to try and reduce your exposure to environmental toxins, such as industrial pollutants, smog, and smoke. The less toxic air you inhale, the less damage you do to your lungs.

Healthy Lifestyle and Diet

Exercise and daily activity are crucial for maintaining healthy lungs and reducing your risk of lung disease. Not only do they promote effective circulation and respiratory function, but they will also boost your immunity and increase your resilience against infections.

Eating a balanced, healthy diet and managing your weight are vitally important in maintaining health including protecting your lungs. A diet full of antioxidants, vitamins, and minerals will fortify your body against infections.

Obesity can increase both the risk and severity of lung infections, dampen your immune system, and increase inflammation. Working to stay at a healthy weight will improve your respiratory health significantly.

Regular Medical Check-ups and Screenings

Frequent health checkups are absolutely crucial for higher risk individuals, those who are more commonly exposed, suffer from frequent infections, or who are genetically predisposed. However, everyone should get checked out regularly just in case.

Many lung conditions—from lung cancer to COPD to TB—can be better managed or treated successfully when caught early. This is possible thanks to screenings, check ups, and if needed, treatment.

Vaccinations and Preventive Measures

Staying up-to-date on your vaccinations against pneumonia and influenza will fortify your body against infections that could lead to more serious lung damage or put you at risk of respiratory conditions.

Wrapping Up

When it comes to your lungs, there should be no second-guessing or half-measures. Your lungs serve the crucial function of absorbing the oxygen needed by every cell in your body and expelling the carbon dioxide wastes – without this function, survival isn’t possible!

Any impairment to your respiratory system can lead to widespread, and possibly permanent, consequences for the rest of your body. Understanding these respiratory conditions and learning how to identify them is just the first step.

Now, it’s up to you to put into practice the information we shared. A few simple preventative countermeasures can significantly support and even improve your respiratory health simultaneously decreasing your risk of lung infections and lung disease.

Because your lungs are one of the primary points of contact with environmental toxins—from air pollution to chemical irritants—it’s essential to not only protect them directly but also support the body’s natural detoxification systems that process and eliminate these harmful substances. Your liver and kidneys play a crucial role in filtering out toxins that can damage your respiratory and overall health, which is why reinforcing these organs with the right nutrients is just as important as avoiding exposure in the first place.

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Frequently Asked Questions

Do lungs ever fully heal?

A great deal of damage caused by cigarette smoking, toxin exposure, and infection can be repaired by the body over time. In fact, some lung tissue can regenerate! However, in many cases, even as lung function improves, the damage remains in the form of scar tissue or greater susceptibility to infection. While the lungs may show significant recovery, some damage like scarring or structural changes may l never fully heal.

What lung diseases cannot be cured?

A number of lung diseases are considered “incurable” because the damage they cause can never be reversed or full lung function restored. These diseases include cystic fibrosis, pulmonary fibrosis, interstitial lung disease, and chronic obstructive pulmonary disease (COPD).

What is the deadliest lung disease?

COPD is the deadliest lung disease, killing roughly 3.23 million people around the globe every year [4]. Lung cancer is the #1 most lethal form of cancer and accounts for around 1.82 million deaths annually. Tuberculosis is responsible for around 1.6 million deaths each year, particularly in low and middle-income countries.

Resources

Respiratory Disorders

Chronic respiratory diseases

About Respiratory Illnesses

Lung Diseases

Diseases of the Respiratory System

Asthma

COPD

Pneumonia

Tuberculosis

Pulmonary fibrosis

Lung cancer

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