Lung Diseases

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Lung Diseases

Lung diseases can affect all parts of the lung. In some cases the transfer of gases from the air sacs to the blood (and vice versa) can be slowed down. In other cases the problem is that not enough air gets to the air sacs. This could be due to blockages in the bronchial tree or weakness in the muscles that expand the chest. In some cases the lungs struggle to remove or detoxify dangerous substances – this could be due to problems with mucus such as cystic fibrosis or due to overwhelming toxins such as smoking.

Common Lung diseases include:

Asthma is a chronic lung disease where inflammation of the bronchi and bronchioles prevent enough air getting to the air sacs. Asthma often happens as an attack which can be triggered by many things. Triggers can include:

  • cigarette smoke
  • moulds and pollens
  • infections
  • exercise
  • cold air 

During an attack, the lining of the airways swell and the muscles surrounding the bronchi contract, narrowing the airway. Mucus secretion lining the airways can slow the movement of air making breathing difficult and causing a wheeze. Most episodes do not cause long-term lung damage but it is often necessary to see a doctor since lack of oxygen and build-up of carbon dioxide can be life-threatening. Patients use inhalers to help open up the airways. According to Asthma UK, 1 in 5 households in the UK have a person with asthma.

COPD (chronic obstructive pulmonary disease) is a term used for both emphysema and chronic bronchitis. In 1999 COPD caused about 5% of all deaths in the UK. With chronic bronchitis, the bronchial tubes become inflamed and scarred. With emphysema, the air sacs in the lungs are slowly destroyed. Patients with COPD find it hard to breath out and have long term problems getting enough oxygen to the blood and carbon dioxide out. Smoking causes about 80 to 90 percent of the deaths associated with COPD. Other risk factors include repeated exposure to air pollution.

Pneumonia is a complicated inflammation of the lungs usually caused by bacteria or virus. Pneumonia can affect one area of a lung or both lungs (bilateral). A patient may cough up sputum, have a fever, and feel tired. Doctors can sometimes hear signs of pneumonia when listening with a stethoscope. X-rays can help by showing areas of inflammation (consolidation). Antibiotics are used to treat bacterial pneumonia.

Influenza is an acute illness caused by a virus that affects the whole body and often causes respiratory problems such as a sore throat or cough. In the UK people who are particularly venerable to infection can be given a vaccine which may reduce symptoms. Antibiotics will not help to treat a viral infection.

Tuberculosis (TB) and nontuberculous mycobacteria (NTM) are chronic infections most commonly seen in patients with weakened immune systems (such as patients with HIV/AIDS). The infections caused by mycobacteria develop slowly and can affect the whole of the body as well as the lungs. Treatment for TB requires long term antibiotics.

Pleuritisis caused by inflammation of the lining of the lungs (pleura). It is particularly painful when taking deep breaths or coughing. It can occur with diseases such as pneumonia or pulmonary embolus.

A pleural effusion is a collection of fluid between the lungs and the rib cage. There are many causes including in response to pneumonia, cancer, and heart failure. Some times doctors will take the fluid out with a needle or even a small tube. Looking at the fluid under a microscope can help doctors to find out what caused the fluid accumulation.

Lung cancer is the uncontrolled growth of malignant cells in the lungs. There are two main types, small cell and non-small cell lung cancers. Other cancers may spread to the lungs and are described as metastatic, because the cancer cells do not come from lung tissue originally. The main risk for developing lung cancer is smoking. Symptoms include coughing up sputum with small amounts of blood, long term cough which doesn’t go away, and worsening shortness of breath.

A pulmonary embolism is normally a blood clot that originates in the veins of the legs (DVT) and travels through blood vessels to the lungs where it gets stuck. Pulmonary embolisms cause chest pain, sudden shortness of breath, and coughing (sometimes of blood). This condition can be life-threatening and requires urgent medical attention. Treatment is usually to thin the blood.

Pulmonary fibrosis is a disease with damage and scarring to the tissues between the air sacs, inflammation of the air sacs, and stiffening of the lungs. Causes of pulmonary fibrosis include:

  • Exposure to small particles (often at work). This includes repeated exposure to substances such as asbestos, coal, beryllium, and silica
  • Repeated exposure to organic substances such as moldy hay, animal droppings, and grain dust. This can cause an allergic inflamation pneumonitis) and eventually lead to pulmonary fibrosis
  • Chemicals and drugs that are toxic to the lungs
  • Previous radiation treatment
  • Sarcoidosis
  • Systemic sclerosis, and other autoimmune disorders
  • Idiopathic – cause unknown

Pulmonary hypertension is a rare lung disorder. Narrowing of the blood vessels from the heart to the lungs causes high blood pressure within the lungs. This means the heart has to work harder to transport blood into the lungs. Pulmonary hypertension can occur by itself but often happens with other problems such as rare conditions such as systemic sclerosis.

Bronchopulmonary dysplasia (BPD) is a lung disease that develops mainly in premature babies who have had long-term oxygen and/or been on a ventilator. It may also be seen in those who have experienced oxygen toxicity or had pneumonia. With this disorder airways are inflamed, do not develop normally, and may be damaged.

Respiratory Distress Syndrome (RDS) of the newborn is a life-threatening breathing problem that may develop in babies born before 34 weeks. These premature babies’ lungs are not developed enough to be able to produce much of the protective liquid called surfactant. Without surfactant, the lungs are not able to expand properly and babies have difficulty breathing in enough oxygen. It can occur within a few hours of premature birth.

Acute Respiratory Distress Syndrome (ARDS) is a rapid, severe breathing difficulty due to extensive lung inflammation and the lungs filling with fluid. ARDS can be fatal and may be brought on by many types of injury to the lungs including serious viral or bacterial infection, sepsis, trauma, multiple transfusions, drug overdose, or inhaling substances such as salt water or smoke.

Cystic fibrosis is an inherited disease that affects the lungs, pancreas, and other body systems. Frequent chest infections occur due to problems with mucus. Diarrhoea and low weight are due to pancreatic problems preventing absorption of nutrients. Cystic fibrosis commonly causes infertility in men. 1 in 25 people in the UK have 1 cystic fibrosis gene, but the disease doesn’t occur unless both parents pass the gene onto a child. According to the Cystic Fibrosis Trust 5 babies are born with cystic fibrosis in the UK each week.

Alpha-1 antitrypsin deficiency is an inherited lack of a protein that provides protection to the lungs. Without this protection the lungs slowly become damaged with the patient being at an increased risk of COPD and liver disease at a young age.

Other disorders do not affect the lungs directly, but can impair a person’s ability to breathe properly. These disorders may affect the chest cavity, muscles, nerves, and heart. They include a variety of conditions, such as nerve and muscle (neuromuscular) diseases like muscular dystrophy, polio, myasthenia gravis, Guillain-Barré syndrome, and amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease). Bony problems that result in abnormal spine formation or rib cage movement can restrict lung expansion. [Note: specific testing and treatment for these disorders is not covered in this article.]

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