Emphysema is a lung disease that may develop after long-term exposure to cigarette smoke or other toxins. The cause of most cases of emphysema is cigarette smoking. Symptoms of emphysema may include shortness of breath, coughing, wheezing, and chronic mucus production. Treatment options for the condition include medications (such as corticosteroids) and oxygen therapy; surgery may be necessary in severe cases of emphysema. The key to managing emphysema is to identify the disease as early as possible.