Respiratory Tract medications

Emphysema

Emphysema is a lung disease, characterized by an abnormal, permanent enlargement of air spaces distal to the terminal bronchioles. The disease is coupled with the destruction of walls, but without obvious fibrosis. It is often caused by exposure to toxic chemicals, including long-term exposure to tobacco smoke.

Emphysema is characterized by loss of elasticity (increased pulmonary compliance) of the lung tissue caused by destruction of structures feeding the alveoli, in some cases owing to the action of alpha 1-antitrypsin deficiency. This causes the small airways to collapse during forced exhalation, as alveolar collapsibility has decreased. As a result, airflow is impeded and air becomes trapped in the lungs, in the same way as other obstructive lung diseases. Symptoms include shortness of breath on exertion, and an expanded chest. However, the constriction of air passages isn't always immediately deadly, and treatment is available.

Signs of emphysema include pursed-lipped breathing, central cyanosis and finger clubbing. The chest has hyper resonant percussion notes, particularly just above the liver, and a difficult to palpate apex beat, both due to hyperinflation. There may be decreased breath sounds and audible expiratory wheeze. In advanced disease, there are signs of fluid overload such as pitting peripheral edema. The face has a ruddy complexion if there is a secondary polycythemia. Sufferers who retain carbon dioxide have asterixis (metabolic flap) at the wrist.

Prognosis and treatment

Emphysema is an irreversible degenerative condition. The most important measure to slow its progression is for the patient to stop smoking and avoid all exposure to cigarette smoke and lung irritants. Pulmonary rehabilitation can be very helpful to optimize the patient's quality of life and teach the patient how to actively manage his or her care. Patients with emphysema and chronic bronchitis can do more for themselves than patients with any other disabling disease.

Emphysema is also treated by supporting the breathing with anticholinergics, bronchodilators, steroid medication (inhaled or oral), and supplemental oxygen as required. Treating the patient's other conditions including gastric reflux and allergies may improve lung function. Supplemental oxygen used as prescribed (usually more than 20 hours per day) is the only non-surgical treatment which has been shown to prolong life in emphysema patients. There are lightweight portable oxygen systems which allow patients increased mobility. Patients can fly, cruise, and work while using supplemental oxygen. Other medications are being researched, and herbal organic remedies are being offered by companies.

Lung volume reduction surgery (LVRS) can improve the quality of life for certain carefully selected patients. It can be done by different methods, some of which are minimally invasive. In July 2006 a new treatment, placing tiny valves in passages leading to diseased lung areas, was announced to have good results, but 7% of patients suffered partial lung collapse. The only known "cure" for emphysema is lung transplant, but few patients are strong enough physically to survive the surgery. The combination of a patient's age, oxygen deprivation and the side-effects of the medications used to treat emphysema cause damage to the kidneys, heart and other organs. Transplants also require the patient to take an anti-rejection drug regimen which suppresses the immune system, and so can lead to microbial infection of the patient. Patients who think they may have contracted the disease are recommended to seek medical attention as soon as possible.

A study published by the European Respiratory Journal suggests that tretinoin (an anti-acne drug commercially available as Retin-A) derived from vitamin A can reverse the effects of emphysema in mice by returning elasticity (and regenerating lung tissue through gene mediation) to the alveoli.

While vitamin A consumption is not known to be an effective treatment or prevention for the disease, this research could in the future lead to a cure. A follow-up study done in 2006 found inconclusive results ("no definitive clinical benefits") using Vitamin A (retinoic acid) in treatment of emphysema in humans and stated that further research is needed to reach conclusions on this treatment.