Pulmonary Fibrosis

Generality

Pulmonary fibrosis is a respiratory disease that occurs when scar tissue forms inside the lung instead of normal lung tissue.

Figure: representation of pulmonary fibrosis; note the presence of scar tissue (greenish) in the left lung. From the site: lungsandyou.com

There are two forms of pulmonary fibrosis: the idiopathic form, for which a precise triggering cause has not yet been found, and the secondary form, for which, on the other hand, various determining factors have been identified.

The typical symptoms of pulmonary fibrosis are dyspnea, dry cough, weight loss and fatigue.

Diagnosis requires a fairly long process, consisting of several exams and tests.

Unfortunately, healing from pulmonary fibrosis is impossible. The only treatments currently available serve to alleviate symptoms and improve the quality of life of patients.

What is pulmonary fibrosis?

Pulmonary fibrosis is a respiratory disease, characterized by hardening and scarring of the lung tissue that surrounds and interposes between the alveoli.

A lung with fibrosis is therefore a lung that is not very elastic, hard, and covered with retraent scars that "crush" the alveoli, preventing normal breathing.

What are alveoli?

The alveoli are small cavities in the lungs, where gas exchange occurs between the blood and the atmosphere. Inside them, in fact, the blood is enriched with the oxygen contained in the air breathed and is "freed" of the carbon dioxide discarded by the tissues, after their spraying.

Causes

Pulmonary fibrosis can occur without a precise reason or for well-defined reasons; in the first case one speaks of idiopathic pulmonary fibrosis, in the second of secondary pulmonary fibrosis .

IDIOPATIC PULMONARY FIBROSIS

In medicine, a disease is called idiopathic when it arises without an identifiable reason.

The researchers have proposed various theories about the causes of idiopathic pulmonary fibrosis, but none of these, so far, has been demonstrated with sufficient scientific evidence.

Most investigations concerned:

• Cigarette smoke.
• Particular viral infections, caused by Epstein-Barr virus or hepatitis C virus
• Coal powders and metal powders.
• Genetic / hereditary factors, linked to the transmission of the mutated gene for the so-called surfactant protein C (NB: surfactant is a fundamental substance for the proper functioning of the lungs).

To learn more: Idiopathic pulmonary fibrosis: spread and mortality

SECONDARY PULMONARY FIBROSIS

In medicine, a disease is associated with the secondary term when it appears after the occurrence of a particular condition, which can be pathological or non-pathological.

Secondary pulmonary fibrosis may arise due to:

• Prolonged exposure to toxic substances in the workplace . They are harmful to the health of the lungs: asbestos fibers (which also cause tumors, such as pleural mesothelioma and lung cancer); stone, marble and wood dusts emitted by sandblasters; the excrement of some animals and some birds; powders produced from stored grain and flour; finally, silicon powders.
• Antitumor radiotherapy cycles . Radiotherapy performed for breast and lung tumors can have side effects, especially if it is very prolonged and the amount of ionizing radiation emitted is high. The consequences of radiotherapy may appear even months or years after cancer treatment.
• Drugs used to treat tumors (chemotherapy), heart problems and bacterial infections (antibiotics) . Methotrexate, cyclophosphamide and busulfan are among the chemotherapeutic lung cancer drugs.

  Medicines for heart problems include amiodarone (an anti-arrhythmic) and propranolol (antihypertensive and anti-arrhythmic).

  Finally, among the antibiotics, nitrofurantoin, bleomycin and sulfasalazine are potentially harmful.

• Infectious or autoimmune diseases . The infectious diseases associated with pulmonary fibrosis are tuberculosis and pneumonia (both bacterial and viral). The autoimmune diseases incriminated, on the other hand, are systemic lupus erythematosus, rheumatoid arthritis, sarcoidosis, Wegener's granulomatosis and scleroderma.

RISK FACTORS

According to some statistical surveys, pulmonary fibrosis is more frequent among: the elderly; the big smokers; those who work in farms, mines, carpentry or metallurgical plants; those who have had radiation therapy for lung or breast cancer; those who used chemotherapy drugs; and finally, individuals with a family history of pulmonary fibrosis.

Epidemiology

Pulmonary fibrosis is a disease that is widespread all over the world: in fact, it can affect men and women of any ethnicity.

Its idiopathic form appears to have an annual incidence of 6-16 cases per 100, 000 people. Its secondary form, on the other hand, has an extremely variable incidence from country to country, as it depends on how much people are exposed to the triggering causes.

For both forms, the individuals most affected are those between 50 and 70, although it must be said that the disease can arise at any age.

Pulmonary fibrosis makes no distinction between males and females; in fact, it affects both sexes very similarly.

Symptoms and Complications

To learn more: Symptoms Pulmonary fibrosis

The signs and symptoms typically associated with pulmonary fibrosis are:

• Dyspnea, or difficulty breathing
• Dry cough
• The feelings of fatigue and weakness
• Weight loss for no reason
• Chest pain
• Muscular and joint pains

The severity of these manifestations varies from person to person: in some subjects, the symptomatology is very marked from the beginning, in others it is initially moderate and gradually worsens over several months / years.

The evolution of pulmonary fibrosis would seem to depend on the triggering causes.

COMPLICATIONS

A prolonged situation of pulmonary fibrosis can lead to the onset of serious complications, such as pulmonary hypertension, pulmonary heart, respiratory failure and lung cancer.

Deepening on the complications

Pulmonary hypertension is the increase in pressure within the arterial vessels that carry blood to oxygenate the lungs. In the presence of pulmonary fibrosis, this increase in blood pressure depends on the compression that the scar tissue exerts on alveoli and alveolar capillaries, in which the carbon dioxide-oxygen exchange takes place between blood and atmosphere; this compression causes an obstruction and an obstacle to the free flow of blood. Pulmonary hypertension is a serious problem, which tends to worsen over time and which can lead to death.

The pulmonary heart is a very serious heart disease, triggered by pulmonary hypertension and characterized by an enlargement of the right ventricle of the heart (NB: the right ventricle is the contractile cavity of the heart that pumps blood into the arteries directed to the lungs, or arteries lung). Its appearance causes worsening dyspnea.

Respiratory failure is usually the final consequence of severe pulmonary fibrosis. It causes severe shortage of breath and poor oxygenation of the circulating blood (severe hypoxemia). The lungs, in these situations, become extremely rigid and are covered with numerous retracting scars.

Finally, lung cancer is one of the most common cancers that can occur among patients with pulmonary fibrosis.

To learn more: How does the lung tissue change following pulmonary fibrosis?

Diagnosis

A patient with respiratory problems (dyspnea), for whom pulmonary fibrosis is suspected, undergoes various diagnostic tests.

The process begins with an objective examination and continues with diagnostic imaging tests and with others for the assessment of pulmonary function; finally, it ends with a lung biopsy. The latter, which is based on a rather invasive procedure, is the only test that allows a precise and definitive diagnosis to be made.

EXAMINATION OBJECTIVE

During the physical examination, the doctor visits the patient, collecting from the latter information on the troubles felt and auscultating the chest with a stethoscope.

DIAGNOSTICS FOR IMAGES

The most suitable diagnostic imaging tests, in the case of pulmonary fibrosis, are chest X-rays, CT scans and echocardiograms.

Figure: comparison between radiographic images of healthy lungs (left) and those affected by fibrosis (right)

The chest X-ray (or Rx-thorax ) and the CT scan (or Computerized Axial Tomography ) allow both to visualize the main anatomical structures of the thorax: therefore heart, lungs, main blood vessels, most of the ribs and a portion of the spine . The second, however, is more precise than the first, because it shows with greater clarity the extent of the scar tissue present in the lung.

The echocardiogram is used to evaluate the health of the heart and if the latter is affected by some anatomical anomaly (for example the pulmonary heart).

Warning: chest X-ray and CT scan expose the patient to a certain dose of ionizing radiation (X-rays) harmful to health.

TEST FOR FUNCTIONALITY ASSESSMENT? OF LUNGS

Tests to assess how the lungs work are: spirometry, oximetry and exercise testing.

Spirometry . Fast, practical and painless, spirometry records the inspiratory and expiratory capacity of the lungs, and the patency (ie, opening) of the airways passing through them.

Oximetry . As simple and immediate as spirometry, it measures the saturation of oxygen in the blood. It is achieved with an instrument, called an oximeter, which is applied to a finger or an ear lobe (in both cases, these are highly vascularized areas, therefore particularly suitable for the purpose).

Stress test . It consists in evaluating how the patient's heart rate, blood pressure and breathing vary, while this is performing more or less intense physical activity.

PULMONARY BIOPSY

Lung biopsy consists of taking and analyzing in the laboratory a small sample of lung tissue from the patient. The withdrawal can be done through:

• Bronchoscopy . During bronchoscopy, the doctor collects the lung tissue with an instrument, the bronchoscope, introduced by the nose or mouth. The bronchoscope is basically a very thin tube, rather flexible and equipped with an optical fiber camera for orientation inside the lung cavities.

  The passage of the bronchoscope can irritate the respiratory tract crossed; furthermore, the quantities of tissue taken may not be sufficient for diagnosis.

• Bronchoalveolar lavage . During bronchoalveolar lavage, the doctor always uses a bronchoscope, but, unlike the previous procedure, he injects a saline solution into the lungs which is promptly sucked in a few moments. This operation allows to take a larger sample of cells than just bronchoscopy, although not always sufficient.
• Surgery . Surgery for collecting a lung sample requires general anesthesia and involves performing two or three incisions on the side. Through these micro-openings, the surgeon introduces a camera (connected to an external monitor and indispensable for orientation) and the tools necessary for collection.

  A surgical procedure of this kind is very bloody and dangerous, however it is the procedure that, from the diagnostic point of view, guarantees the most useful information.

Treatment

To learn more: Medications for the treatment of pulmonary fibrosis

Because the scar tissue is permanent and its formation is almost unstoppable, cicatricial fibrosis is an incurable and irreversible disease. However, thanks to some drugs, oxygen therapy and respiratory rehabilitation, it is possible to alleviate the symptoms and slow down the progression, thus also improving the patient's quality of life.

The hypothesis of a lung transplant, which is a very delicate surgical procedure with an uncertain outcome, is only taken into consideration in extreme cases and when the aforementioned treatments have proved to be completely ineffective.

PHARMACOLOGICAL THERAPY

Many patients with pulmonary fibrosis (both idiopathic and secondary) are treated with corticosteroids and immunosuppressants, because these are the only drugs, among the various tested, to have had a certain effect on the symptoms and on the progression of the disease.

Corticosteroids are powerful anti-inflammatories that, when taken for long periods of time and at high doses, can lead to serious side effects (osteoporosis, diabetes, cataracts, hypertension, obesity, etc.).

Immunosuppressants, on the other hand, are medicines particularly indicated in the presence of an autoimmune disease, as they lower the body's immune defenses.

OXYGEN THERAPY

Oxygen therapy is the administration of oxygen through special medical instruments (some of which are also portable). This intervention is necessary when there is a need to increase the amount of oxygen circulating in the blood.

In the case of pulmonary fibrosis, oxygen therapy offers various benefits, as:

• Makes breathing easier
• Reduces the possibility of hypoxemia (low oxygen levels in the blood)
• Reduces blood pressure within the right compartment of the heart (preventing complications such as pulmonary hypertension and pulmonary heart).
• Improves sleep at night, and therefore also the quality of life.

Warning: oxygen therapy improves the symptoms, but unfortunately does not slow down the formation of scar tissue, inside the lung.

RESPIRATORY REHABILITATION

Respiratory rehabilitation consists in having the patient practice a series of motor exercises (exercise bikes, climbing stairs, walking etc.), in order to improve tolerance to efforts and reduce the severity of dyspnea.

Even this treatment, like oxygen therapy, mitigates the symptoms but does not slow down the progression of the disease.

LUNG TRANSPLANTATION

Lung transplantation is the procedure by which the diseased lung is replaced by another healthy one from a compatible donor. Given the considerable invasiveness and the more than fair probability of failure of the operation (rejection of the organ), lung transplantation is an operation practiced only in extreme cases and when all the other solutions mentioned above have not provided any benefit.

SOME ADVICE ON THE LIFESTYLE

For patients with pulmonary fibrosis, doctors recommend:

• Smoking cessation: although a certain connection between cigarette smoking and pulmonary fibrosis has not yet been scientifically demonstrated, tobacco reduces lung function and is the cause of many other lung diseases (such as lung cancer).
• Avoid passive smoking : because it is as harmful as active smoke.
• Contact a dietician for planning a balanced diet . Patients suffering from pulmonary fibrosis, in fact, are subject to a drop in body weight, because, due to respiratory problems, they have difficulty in eating properly.
• Get vaccinated against the flu (flu vaccine) and against pneumonia (pneumococcal vaccine), as they are two respiratory infections that could further worsen the symptoms.

Prognosis

The prognosis of a disease with irreversible consequences is never positive. This also applies to pulmonary fibrosis, which, as mentioned above, causes permanent scarring on the lungs.