Fluid or other substances can accumulate in the pleural cavity in the case of volume overload or infections in the body. The buildup of water in the pleural cavity is called hydrothorax.

When there is an accumulation of lymph in the cavity, it is called chylothorax. A buildup of blood is called hemothorax, and when there is pus in the cavity due to an infection such as pneumonia, it is called pyothorax. This fluid can be removed and examined with a procedure called pleuracentesis (pleural tap).

A puncture of the thoracic wall or the lung can result in the elimination of the negative pressure to keep the lung expanded. The air that enters the cavity causes the lung to collapse on itself; this is called pneumothorax.

Similar to a pneumothorax is a tension pneumothorax, in which the air that enters cannot leave, therefore the pressure inside the pleural space builds up. This will displace the structures in the thoracic cavity and mediastinum to the opposite side from the entry wound. Symptoms of a pneumothorax are chest pain, and shortness of breath. To treat, a chest tube can be inserted on the side that is injured.

Infections of the lungs are possible in any age group, but predispositions such as problems in the immune system can make it easier to get an infection. Tuberculosis is a contagious lung disease, and is caused by the bacteria Mycobacterium tuberculosis. It involves formation of granulomas in the lungs. Pneumonia is an inflammatory process in the lungs caused by a bacteria, virus, or mycoplasma. It presents with fever, cough, chest pain, sputum, and shortness of breath. Pulmonary aspergillosis is a fungal infection by Aspergillus fumigatus in the lungs. It will most likely manifest in individuals with weak immune systems and is characterized by fever, cough, wheezing, and fatigue.

Asthma is not considered an infection, but rather an obstruction due to narrowing of the airways. Symptoms are shortness of breath, cough, and wheezing. This constriction is brought on by irritation of the airways due to factors in the environment.

Many diseases can affect the lungs and the lung tissue. When air accumulates in the alveolar sacs chronically due to loss of elastic tissue in the alveolar walls, it is called emphysema. This results in reduced surface area for exchange of oxygen and carbon dioxide, leading to hypoxia and a buildup of carbon dioxide in the blood.

Asthma is a result of a non-patent airway, presenting with shortness of breath and wheezing. Bronchiectasis is the dilation of the bronchi and bronchioles over a period of time, usually due to an underlying disease such as pneumonia or tuberculosis. Symptoms are chronic cough with copious amounts of sputum. Chronic bronchitis is a type of chronic obstructive pulmonary disease (COPD) and is caused by inflammation of the airways due to an irritant, such as tobacco. The individual will present with a chronic cough and shortness of breath and some sputum.

Cystic fibrosis is a genetic disease that affects many organs in the body. It is usually detected in newborns by their mother, who will state that the baby has salty skin. Symptoms of cystic fibrosis are centered around the respiratory, endocrine, and gastrointestinal systems. Imbalance in the sodium chloride channels found on the cells of the body produces excessively thick mucus, which can cause complications in the ducts of the pulmonary, gastrointestinal, and pancreatic regions. Obstruction of the pancreatic ducts can result in inflammation of the pancreas, which is called pancreatitis. Children with cystic fibrosis tend to get many infections, such as pneumonia and bronchiectasis. Symptoms are managed with antibiotics and the mean survival age is around 40s to 50s years of age.

Lung cancer is not associated with cystic fibrosis.

The thoracic outlet is the area between the clavicle and the first rib. If there is compression of the vessels and nerves in this area, it is called thoracic outlet syndrome. The structures in this area are the subclavian artery and the nerves in the brachial plexus, which supply the upper limb. Symptoms include pain, numbness, weakness, and ischemia if the artery is affected. Common causes of compression in the area are the presence of a cervical rib or abnormal placement of the scalene muscles of the neck.

Cystic fibrosis is an inherited disease that affects the secretory glands. While mucus is normally slippery and watery, those who have cystic fibrosis often have thick and sticky mucus, which primarily affects the function of the respiratory system. This mucus is difficult to clear and provides a breeding ground for bacteria, leading to secondary infections. 

Cystic fibrosis causes sweat to become very salty, which can lead to numerous secondary issues. Some of the issues caused by this include dehydration, increased heart rate, and fatigue. It can also lead to heat stroke or death.

Pleurisy is an inflammation of the pleura, or a membrane that wraps around the lungs and chest cavity. The inflammation causes the membrane layers to rub against each other and causing sharp pain. Many things can cause pleurisy, including viral infections.

Pneumothorax is when air or gas builds up in the pleural space. This can be caused by lung disease or an acute lung injury. The symptoms are a sudden sharp pain in one side and shortness of breath. Pneumothorax can also cause the lungs to collapse.