The fourth type is known as paracicatricial emphysema or irregular emphysema that  involves the acinus irregularly and is associated with fibrosis. Though the different types can be seen on imaging they are not well-defined clinically. There are also a number of associated conditions including bullous emphysema, focal emphysema, and Ritalin lung. Only the first two types of emphysema – centrilobular, and panlobular are associated with significant airflow obstruction, with that of centrilobular emphysema around 20 times more common than panlobular. Centrilobular emphysema is the only type associated with smoking.Osteoporosis is often a comorbidity of emphysema. The use of systemic corticosteroids for treating exacerbations is a significant risk factor for osteoporosis, and their repeated use is recommended against. Signs and symptoms
Emphysema is a respiratory disease of the lower respiratory tract. It is commonly caused by tobacco smoking but a significant number of people are affected who either do not smoke, or have never smoked. The presence of emphysema is a clear risk factor for the development of lung cancer, made stronger in those who smoke.Early symptoms of emphysema may vary from person to person. Symptoms can include a cough (with or without sputum), wheezing, a fast breathing rate, breathlessness on exertion, and a feeling of tightness in the chest. There may be frequent cold or flu infections. Other symptoms may include anxiety, depression, fatigue, sleep problems and weight loss. Since these symptoms could also relate to other lung conditions or other health problems, emphysema is often under diagnosed.
Several factors including age, and poor exercise tolerance, using the BODE index need to be taken into account. A transplant is only considered where there are no serious comorbidites. A CT scan or a ventilation/perfusion scan may be useful in surgery considerations to evaluate cases for surgical interventions, and also to evaluate post-surgery responses. A bullectomy may be carried out when a giant bulla occupies more than a third of a hemithorax. History
The terms emphysema, and chronic bronchitis were formally defined in 1959 at the CIBA guest symposium, and in 1962 at the American Thoracic Society Committee meeting on Diagnostic Standards. The word emphysema is derived from Ancient Greek ἐμφύσημα inflation, swelling (referring to a lung inflated by air-filled spaces), itself from ἐμφυσάω emphysao to blow in, to inflate, composed of ἐν en, meaning "in", and φυσᾶ physa, meaning "wind, blast".René Laennec, the physician who invented the stethoscope, used the term emphysema in his book A Treatise on the Diseases of the Chest and of Mediate Auscultation (1837) to describe lungs that did not collapse when he opened the chest during an autopsy. He noted that they did not collapse as usual because they were full of air and the airways were filled with mucus. Early descriptions of probable emphysema include: in 1679 by T. Bonet of a condition of "voluminous lungs" and in 1769 by Giovanni Morgagni of lungs which were "turgid particularly from air". In 1721 the first drawings of emphysema were made by Ruysh.