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PulmonaPulmonary ry

fibrosisfibrosis

Pulmonary fibrosis is the formation or development of excess fibrous connective tissue (fibrosis) in the lungs. It can be described as "scarring of the lung“

A chest X-ray demonstrating pulmonary fibrosis due to amiodarone .

CausePulmonary fibrosis may be a secondary effect of other diseases, most of them being classified as interstitial lung diseases, lung diseases affecting the interstitium. e.g. autoimmune disorders, viral infections or other microscopic injuries to the lung. However, it may also appear without any known cause, then termed "idiopathic". In either case, there is a growing body of evidence which points to a genetic predisposition in a subset of patients. For example, a mutation in Surfactant protein C (SP-C) has been found to exist in some families with a history of pulmonary fibrosis

•Diseases and conditions that may cause pulmonary fibrosis as a secondary effect include:

•Inhalation of environmental and occupational pollutants .

–Hypersensitivity pneumonitis, allergic alveolitis… most often resulting from inhaling dust contaminated with bacterial, fungal, or animal products.

•Cigarette smoking can increase the risk or make the illness worse.

•connective tissue diseases•Infections

•Certain medications•Radiation therapy to the chest

Pathogenesis

•Pulmonary fibrosis involves gradual replacement of normal lung parenchyma with fibrotic tissue. The replacement of normal lung with scar tissue causes irreversible decrease in oxygen diffusion capacity

•In addition, decreased compliance makes pulmonary fibrosis a restrictive lung disease. It is the main cause of restrictive lung disease that is intrinsic to the lung parenchyma. In contrast, quadriplegia. and kyphosis .are examples of causes of restrictive lung disease that do not necessarily involve pulmonary fibrosis

Signs and symptoms•Symptoms of pulmonary fibrosis are

mainly:•Shortness of breathe .

•Chronic dry, hacking coughing •Fatigue and weakness

•Chest discomfort•Loss of appetite and rapid weight loss

•Pulmonary fibrosis is suggested by a history of progressive shortness of breath (dyspnea) with exertion. Sometimes fine inspiratory crackles can be heard at the lung bases on auscultation. A chest x-ray may or may not be abnormal, but high Resolution CT will frequently demonstrate abnormalities.

Diagnosis

•The diagnosis can be confirmed by lung biopsy under general anesthesia. This kind of biopsy involves placement of several tubes through the chest wall, one of which is used to cut off a piece of lung to send for evaluation. For a large proportion of the patients, change of therapy and then clinical improvement can be achieved after surgical lung biopsy.

•Pulmonary Function Tests. Pulmonary function tests are tests performed to make measurements of how your lungs and airways function. Results from pulmonary function tests enable your physician to evaluate your breathing, make diagnosis, recommend treatment and follow your progress

•Walking and Stress Tests Six-minute walk test for the evaluation of pulmonary disease severity

•Misdiagnosis is common because while overall, pulmonary fibrosis is not rare, each individual type of pulmonary fibrosis is uncommon and the evaluation of patients with these diseases is complex and requires a multidisciplinary approach.Terminology has been standardized but difficulties still exist in their application.

Types of Pulmonary fibrosis

•common Types of Pulmonary fibrosis

•Cystic fibrosis

•Idiopathic Pulmonary Fibrosis

•Interstitial lung fibrosis (type of Interstitial lung disease)

Treatment and prevention

•Treatment options for idiopathic pulmonary fibrosis are very limited.Though research trials are ongoing, there is no evidence that any medications can significantly help this condition. Lung transplantation is the only therapeutic option available in severe cases .

•Since some types of lung fibrosis can respond to corticosteroids (such as Prednisone) and/or other medications that suppress the body's immune system, these types of drugs are sometimes prescribed in an attempt to slow the processes that lead to fibrosis .

•Responses to treatment are variable. Those whose conditions improve with immune suppressive treatment probably do not have idiopathic pulmonary fibrosis, for idiopathic pulmonary fibrosis has no significant treatment or cure. There are pharmacological agents in the experimental phase intended to prevent scarring.Anti-inflammatory agents have only limited success in reducing the fibrotic progress.

•Some of the other types of fibrosis, such as nonspecific interstitial pneumonitis (NSIP), may respond to immunosuppressive therapy such as corticosteroids. However, only a minority of patients respond to corticosteroids alone, so additional immunosuppressants, such as cyclophosphamide, azathioprine, methotrexate, penicillamine, and cyclosporine may be used.

•Hypersensitivity pneumonitis ,a less severe form of pulmonary fibrosis, is prevented from becoming aggravated by avoiding contact with the causative material .

• Oxygen supplementation improves the quality of life and exercise capacity.

Prognosis•Hypoxia caused by pulmonary

fibrosis can lead to pulmonary hypertension, which, in turn, can lead to heart failure of the right ventricle. This can be prevented with oxygen supplementation.

•Pulmonary fibrosis may also cause increased risk for pulmonary emboli, which can be

prevented by anticoagulants.

•Complications and sequelae of Pulmonary fibrosis from the Diseases Database include :

•Cardiac failure, right sided •Interstitial lung disease

•Cough •Tracheal shift towards lesion

•Pulmonary hypertension •Right ventricular hypertrophy

•Breathlessness

Epidemiology

•Five million people worldwide are affected by pulmonary fibrosis. In the United States there are over 500,000 patients with pulmonary fibrosis. The actual numbers may be significantly higher due to misdiagnosis. Typically, patients are in their forties and fifties when diagnosed while the incidence of idiopathic pulmonary fibrosis increases dramatically after the age of fifty. However, loss of pulmonary function is commonly ascribed to old age, heart disease or to commoner lung diseases.