pulmonary fibrosis

Pulmonary fibrosis: description

Pulmonary fibrosis can arise as a result of various lung diseases. These sometimes have completely different causes, but ultimately lead to similar structural changes in the lungs. The lung consists on the one hand of air-carrying parts, on the other hand of a connective tissue supporting framework. Airborne areas include, for example, the bronchi, which branch out further into the smaller bronchioles and finally into the smallest functional unit of the lung – the alveoli. The alveoli are surrounded by a fine vascular network. About thin membranes, which line the alveoli from the inside, the so-called gas exchange takes place. The oxygen from the air gets into the blood, carbon dioxide is released from the blood into the breath.

Between the air-conducting areas is connective tissue, which supports the lungs and gives them elasticity. The pulmonary connective tissue is also known as interstitium. Diseases that take place in this area, doctors call accordingly as interstitial lung diseases. Especially chronic inflammation can lead to a strong increase of the pulmonary connective tissue. As a result, among other things, the wall of the alveoli thickened and the distance between the air and the surrounding blood vessels becomes larger. As a result, the blood is no longer well oxygenated. The causes of interstitial lung disease are very diverse and in about half of the cases the exact cause of pulmonary fibrosis is unknown.

Pulmonary fibrosis: symptoms

The symptoms of pulmonary fibrosis are often less specific at first. Over time, the symptoms increase in severity and become more pronounced. Often sufferers notice that their physical capacity decreases. Everyday activities that used to be effortlessly accomplished make them faster out of breath. In the course of the disease, the shortness of breath is finally without any effort. Since more and more connective tissue forms in the lungs as part of the disease, the membrane thickened between alveoli and blood vessels. The oxygen from the air must therefore overcome a thicker layer to get into the blood. As a result, the oxygen content in the blood drops. The body tries to balance this condition by increasing the number of breaths per minute. Often also indicates a longer existing dry irritating cough, a disease of the lung.

In the advanced stage of pulmonary fibrosis, the skin in some patients turns bluish (cyanosis) as a result of the lack of oxygen. A long-lasting oxygen deficiency can also lead to changes on the fingers. The bone thickness at the finger end members increases, the fingertips thereby look round and distended. Doctors also refer to her as a drumstick finger because of her appearance. Frequently, the fingernails are conspicuously bulging at the same time (glass clock nails). However, these symptoms are not exclusive to pulmonary fibrosis; they may also be an expression of other lung or heart diseases.

Pulmonary fibrosis: causes and risk factors

In general, physicians classify pulmonary fibrosis into two categories: interstitial lung diseases of known cause and so-called idiopathic pulmonary fibrosis, the cause of which is unknown. Both forms hold their scales in relation to their frequency.

The following causes of pulmonary fibrosis are known:

• infections: e.g. by viruses or parasites
• Inhalation of harmful substances: If harmful, inorganic dusts such as fumed silica or asbestos are inhaled, a so-called black lung can form. Often this form is occupational diseases, e.g. with miners. Certain gases or vapors, as well as cigarette smoke can cause lasting damage to the lung tissue.
• medications: These include certain drugs for cancer therapy such as bleomycin or busulfan, as well as the drug amiodarone against cardiac arrhythmias
• Weedkillers: e.g. the herbicide paraquat
• Ionizing radiation: Radiation therapy for the treatment of cancer, if carried out in the thoracic region, can damage the lung tissue.
• Heart disease: In a so-called left heart failure (left ventricular failure), the blood accumulates in the lungs, in the long run, thereby causing a lung damage.
• Adult respiratory distress syndrome: The condition can be due to a variety of damaging factors and is the result of prolonged reduced perfusion of the lung tissue.
• Chronic renal failure: A disturbed elimination of water can cause fluid to accumulate in the lungs, thereby damaging them.
• Certain diseases: These include diseases of the connective tissue, such as sarcoidosis or collagenosis, as well as rheumatoid arthritis, various vascular and storage diseases.

Of the interstitial lung diseases of unknown cause, interstitial pulmonary fibrosis is the most common form. In addition, other variants are known, they differ in terms of their course and their severity in some cases significantly from each other.

Pulmonary fibrosis: examinations and diagnosis

Most complaints such as shortness of breath and irritated cough give rise to a visit to the doctor. However, such symptoms not only occur in pulmonary fibrosis but can also be caused by many other diseases. In order to delimit these from each other, the doctor with the patient first of all a detailed conversation (anamnesis). He asks, for example, how long the symptoms already exist and whether there are known comorbidities. Also information about the professional environment – such as whether the person concerned is regularly exposed to harmful gases or dusts – provide the physician with important information for the diagnosis of pulmonary fibrosis. During the physical examination, the doctor listens to the chest of the patient with a stethoscope. A crackle or creaking sounds – as if corks rub against each other – are typical signs of pulmonary fibrosis.

A pulmonary function test shows how severely the respiratory function is impaired. For example, the doctor measures the lung volume and checks how much air the patient can inhale or exhale. The examination of the lung function is relatively simple: usually the patient has to inhale and exhale through a mouthpiece into a device. In addition, the measurements are also made for certain commands (for example, sudden strong exhalation as long as the breath lasts). An important statement also provides the determination of the so-called diffusion capacity (DCO). It measures the ability of the lungs to carry the oxygen from the air into the blood.

In order to further narrow down the diagnosis, usually also follow imaging examinations, such as a computed tomography of the chest. If the suspicion of pulmonary fibrosis becomes more pronounced, the lungs are finally reflected (bronchoscopy). In the context of this examination, the physician can also gain cells via a flushing of the bronchi (bronchial lavage) or remove a tissue sample (biopsy). The samples are then examined under the microscope histopathologically.

Since the diagnosis of the exact form of pulmonary fibrosis as well as its possible underlying disease is very complex, mostly doctors of different disciplines work hand in hand.

Pulmonary fibrosis: treatment

The aim of treating pulmonary fibrosis is to halt the course of the disease or at least slow down further fibrosis (fibrosis) as much as possible. If a triggering underlying disease (for example rheumatoid arthritis) is known, it must be treated accordingly. Other causes, such as harmful substances in the air or smoking, should be avoided as far as possible. It may also require a career change.

Often an excessive reaction of the immune system and inflammatory processes in the lung tissue contribute to the disease. Therefore, physicians often use medications for the treatment of pulmonary fibrosis, which have an anti-inflammatory effect and reduce the immune system (immunosuppressants). For example, one of the best-known representatives of this group is cortisone. The patient can either inhale the drug directly or receive it in the form of tablets or syringes. A newer agent with the active ingredient pirfendione inhibits the fibrosis and also counteract inflammation. If the oxygen level in the blood falls below a certain level, those affected receive additional oxygen via a probe – preferably over many hours a day. If the treatment does not take place and pulmonary fibrosis is already very advanced, the last treatment option is a lung transplantation.

Pulmonary fibrosis: prevention

Lung fibrosis can be caused by many different causes, so there is no specific way to prevent it. However, in order to reduce the risk of lung diseases such as pulmonary fibrosis, it is advisable not to avoid smoking and other pollutants in the air. This includes, for example, appropriate occupational safety (such as respiratory filters) for people who are often exposed to pollutant or dust-laden air. In idiopathic pulmonary fibrosis, however, no prevention is possible.

Pulmonary fibrosis: disease course and prognosis

The course of the disease and the prognosis of pulmonary fibrosis depend on many different factors and can not be generally predicted. The connective tissue remodeling of the lung tissue can not be undone. The extent to which the course of the disease can be slowed down by treatment varies with the individual forms of pulmonary fibrosis. In particular, idiopathic pulmonary fibrosis can be aggressive and often can hardly be influenced by medication. Life expectancy is then significantly shortened in many cases, a lung transplant here may life extending.

Forms of Pulmonary fibrosis, which are caused by external harmful substances – such as dusts or smoking – improve in many cases well, if the trigger is avoided. These forms usually also respond to anti-inflammatory drugs.