lung fibrosis

Lung fibrosis

Introduction
Pulmonary (lung) fibrosis, is a scarring of the lungs, and is the consequence of untreated pulmonary inflammation (alveolitis). It is often also referred to as interstitial lung disease.
Interstitial lung disease is sometimes also known as "interstitial pulmonary fibrosis." The terms interstitial lung disease, pulmonary fibrosis and interstitial pulmonary fibrosis are often used to describe the same condition.
40% of patients who get the Acute Respiratory Distress Syndrome
Patient who is diagnosis with idiopathic lung fibrosis may only live for another three years; lu7ng fibrosis is currently without effective treatment.
Also, lung fibrosis is relatively rare condition and affect small number of people. Pulmonary fibrosis usually develops slowly (over 20 to 30 years) and is asymptomatic in the early stages.
PATHOPHYSIOLOGY
While the progress and symptoms of these diseases may vary from person to person; there is one common link between the many forms of ILD. They all begin with an inflammation. The inflammation may affect different parts of the lung, as explained below:
1. The walls of the bronchioles (small airways). When inflammation involves the bronchioles, it is called bronchiolitis.
The diagram below shows the changes that happen in lung tissue with interstitial lung disease.

2. The walls and air spaces of the alveoli (air sacs). When inflammation involves the alveoli, it is called alveolitis.
3. The small blood vessels (capillaries) of the lungs. When inflammation involves the small blood vessels, it is called vasculitis.
Inflammation of these parts of the lung may heal or may lead to permanent scarring of the lung tissue. When scarring of the lung tissue takes place, the condition is called pulmonary fibrosis.
Fibrosis, or scarring of the lung tissue, results in permanent loss of that tissue's ability to transport oxygen. The level of disability that a person experiences depends on the amount of scarring of the tissue. This is because the air sacs, as well as the lung tissue between and surrounding the air sacs, and the lung capillaries, are destroyed by the formation of scar tissue. If this happens, your doctor may prescribe oxygen to help you breathe easier.


KNOWN CAUSES OF PULMONARY FIBROSIS

Several causes of pulmonary fibrosis are known. They include:
1. Occupational and environmental exposures. Many jobs - particularly those that involve mining or that expose workers to asbestos or metal dusts -- can cause pulmonary fibrosis. Workers doing these kinds of jobs may inhale small particles (like silica dusts or asbestos fibers) that can damage the lungs, especially the small airways and air sacs, and cause scarring (fibrosis).
Agricultural workers also can be affected. Some organic substances, such as moldy hay, cause an allergic reaction in the lung. This reaction is called Farmer's Lung and can cause pulmonary fibrosis. Other fumes found on farms are directly toxic to the lungs.
2. Sarcoidosis. A disease characterized by the formation of granulomas (areas of inflammatory cells), which can attack any area of the body but most frequently affects the lungs.
3. Drugs. Certain medicines may have the undesirable side effect of causing pulmonary fibrosis. Check with your doctor about the medicines you are taking and ask about any possible side effects.
4. Radiation. (Treatment for breast cancer)
4. Connective tissue or collagen diseases such as rheumatoid arthritis and systemic sclerosis.
5. Genetic/familial. This is not as common as the other causes listed.
IDIOPATHIC PULMONARY FIBROSIS (IPF)

When all known causes of interstitial lung disease have been ruled out, the condition is called "idiopathic" (of unknown origin) pulmonary fibrosis (IPF).
There are several theories as to what may cause IPF; including viral illness and allergic or environmental exposure (including tobacco smoke). These theories are still being researched. Bacteria and other microorganisms are not thought to be the cause of IPF.
There is also a familial form of the disease, known as familial idiopathic pulmonary fibrosis. Additional research is being done to determine whether there is a genetic tendency to develop the disease, as well as to determine other causes of IPF.
Small number of people affected by lung
Clinical Manifestations
1. Shortness of breath (dyspnea) on exertion.
2. Chest Pain, Chronic.
3. Pleural effusion in interstitial lung disease.
4. Chronic cough; productive in silicosis.
5. Susceptibility to lower respiratory tract infections.
6. Bibasilar crackles in asbestosis.
7. Dyspnea on exertion; progressive and irreversible in asbestosis.

Diagnostic Evaluation
Diagnostic Tests That May Be Used to Identify Pulmonary Fibrosis or Interstitial Lung Disease
1. Blood Tests 2. Pulmonary Function Tests
3. Chest X-ray 4. CT scan
5. Bronchoscopy 6. Bronchoalveolar Lavage
7. Lung Biopsy 8. CT scan

1. Chest x-ray—Nodules of upper lobes in silicosis and CWP; diffuse parenchymal fibrosis, especially of lower lobes, in asbestosis.
2. Pulmonary Function Tests (PFTs) primarily shows restrictive pattern.
3. Bronchoscopy with lavage to identify specific exposure.
4. CT, sputum examination, and lung biopsy may be needed to rule out other disorders.

Complications
1. Acute respiratory failure.
2. Infections and sepsis.
3. Cardiac dysfunction, hypotension.
4. Hepatorenal failure.
5. Hemorrhage.

Management
1. Oral or rectal administration of lactulose (Cephulac) to minimize formation of ammonia and other nitrogenous by-products in the bowel.
2. Rectal administration of neomycin (Myciguent) to suppress urea-splitting enteric bacteria in the bowel and decrease ammonia formation.
3. Low-molecular-weight dextran or albumin followed by a potassium-sparing diuretic (spironolactone) to enhance fluid shift from interstitial back to intravascular spaces.
4. Pancreatic enzymes, if diarrhea and steatorrhea are present, to permit better tolerance of diet.
5. Mannitol (Osmitrol) IV for management of cerebral edema when indicated.
6. Cholestyramine (Questran) to promote fecal excretion of bile salts to decrease itching.
7. Antacids and histamine-2 (H2) antagonists to reduce the risk of bleeding from stress ulcers.
8. Restriction of dietary protein and sodium while maintaining adequate caloric intake with diet or hypertonic dextrose solutions.
9. Supplemental vitamins (A, B complex, C, and K) and folate.
10. Infusion of fresh-frozen plasma to maintain prothrombin time; cryoprecipitate as needed.
11. Additional medical interventions, depending on the patient’s condition, may include: hemodialysis, hemofiltration, hemoperfusion, or plasmapheresis.
12. Liver transplantation has become the treatment of choice.