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.
Gastric distention is the enlargement of the stomach, and can be due to a number of causes.Physiologic (normal) gastric distension occurs when eating. Distension of the upper stomach stimulates the secretion of stomach acid, while distension of the lower stomach stimulates gastrin secretion. Distension of the stomach also stimulates the secretion of ghrelin.Other causes include:

binge eating associated with bulimia nervosa
tumors causing obstruction
diabetic neuropathy
scarring due to pyloric gastritis
delayed gastric emptyingTo identify the cause of gastric distention, an upper endoscopy or barium upper GI imaging should be done. == References ==