Farmer’s lung occurs primarily in people who handle plant debris for a living. This includes hay, straw, and dried fodder, for example. If left untreated, it can become chronic and lead to death.
What is farmer’s lung?
Farmer’s lung is an inflammation of the alveoli caused by bacterial and mold spores (exogenous allergic alveolitis). In this case, the immune defense system identifies the inhaled (“exogenous”) spores and their components (allergens) as foreign to the body. The triggered allergic reaction is an “exuberant response” of the organism. As a result, inflammation of the alveoli occurs, which can be acute or chronic. Chronic inflammation of the alveoli eventually progresses into what is known as pulmonary fibrosis:
Increased formation of connective tissue impairs the expandability of the lungs and thus breathing. The connective tissue also makes the lungs less and less able to supply the blood with sufficient oxygen. The decrease in oxygen content caused in this way manifests itself in lower physical and mental resilience. As pulmonary fibrosis progresses, shortness of breath occurs even at rest.
Causes
When plant debris is stored, bacteria and molds can proliferate. This process is promoted by warm and humid conditions. For example, if mild and rainy weather prevails after mowing grass, mold deposits will form inside the stored hay after a short time. When the mown grass is moved again, the fungal spores easily become airborne and can be inhaled. However, the spread of fungal and bacterial spores is also possible during grain harvesting, spreading bedding in barns, and making feed in silos. Other sources include turning compost piles and obtaining and storing wood chips. Their small size allows the spores to penetrate the alveoli and provoke inflammatory processes.
Symptoms, complaints, and signs
The acute form of farmer’s lung usually manifests as cough, shortness of breath, chills, and fever. Tightness in the chest, runny nose, and general feeling of weakness are also described. The fever, with temperatures up to 40 °C, may occur in attacks. Some patients complain of brownish yellow sputum and burning in the throat. Less commonly, bright red, frothy blood is coughed up. These symptoms occur only a few hours after contact with the spores that cause inflammation. They usually subside overnight, only to reappear the next time the allergens are exposed. In some affected persons, however, this symptom, which is sometimes described as flu-like, is not very noticeable (subacute). It is observed, for example, in people whose organism is less sensitive to the fungal and bacterial spores. Others are exposed to only a low load of spores, so that the symptoms are correspondingly weaker or even unspecific. Complaints such as loss of appetite, sleeplessness and coughing irritation can be an expression of many diseases. If the spores act regularly over many years, the inflammatory processes triggered by them manifest themselves in a further deterioration of the general condition and in weight loss. It is an indication of the progressive formation of connective tissue in the lungs (pulmonary fibrosis) and thus of the transition of farmer’s lung into the chronic phase.
Diagnosis
The blood of diseased individuals shows a marked increase in white blood cells (leukocytosis). T lymphocytes are found in greater numbers in the lungs, which is an expression of the inflammatory process taking place there. As so-called killer cells, they serve to recognize invading foreign substances and eliminate them. An important symptom of farmer’s lung is the presence of so-called immunoglobulin G (IgG) antibodies in the blood. These are also formed when viruses, bacteria or foreign substances have entered the body. The lung function test reveals a reduction in the distensibility of the lungs and chest – restrictive ventilation disorder. It is explained by the increasing formation of connective tissue between the alveoli and scarring of the alveoli walls. Acute farmer’s lung is manifested by collections of fine patches on X-ray. The reduction in diffusion capacity of the lungs indicates that less oxygen can be absorbed by the organ and delivered to the blood.Computer tomography of the lungs (thoracic CT) and bronchoscopy (lungoscopy) are also used. Between 1 and 17% of patients die as a result of farmer’s lung disease. Cardiovascular stress threatens heart failure.
Complications
Farmer’s lung can result in death in the worst case scenario. However, this course only occurs if farmer’s lung is not treated. In most cases, patients suffer the symptoms of a common cold or those of fever. These include chills and fever. However, there is severe shortness of breath and coughing associated with severe phlegm. The flu symptoms also cause a feeling of weakness. Physical work is hardly possible anymore. The fever can reach very high temperatures and become extremely dangerous for the body. Temperatures of up to 40 degrees Celsius are possible. In severe cases, hemoptysis occurs, which leads to a panic attack in most sufferers. Farmer’s lung also causes loss of appetite and sleep problems. This can lead to underweight and dehydration. Both conditions are very dangerous for the body and must be avoided. Farmer’s lung usually develops over several years and is manifested by increasingly frequent problems with the lungs. There is no specific treatment available. However, the symptoms can be prevented if contact with the triggering substances is avoided. Farmer’s lung improves on its own over time, but complete recovery does not occur.
When should you see a doctor?
In any case of farmer’s lung, a doctor must be consulted. This disease must always be treated by a medical professional, as there is no self-healing. In severe cases, farmer’s lung can also lead to the death of the affected person. The doctor should be consulted if the patient suffers from high fever and continues to have chills. Very severe cough with bloody sputum may also indicate farmer’s lung and should be examined by a physician. The symptoms often do not occur permanently, but return again and again. Insomnia or loss of appetite may also indicate the disease and should be investigated if they occur over a long period of time. An examination should always be performed, especially if the symptoms are chronic. Farmer’s lung can usually be identified by an internist or by a general practitioner. Further treatment is then carried out by taking medication. To prevent further discomfort, the affected person should always wear respiratory protection. In some severe cases, patients may also require psychological treatment.
Treatment and therapy
There is currently no cure by medication or surgical intervention. The shorter the exposure time to the allergens, the lower the risk of permanent changes in the lung tissue. The disease can be brought to a standstill by this so-called allergen abstinence. This can be, for example, the immunoglobulins mentioned. Cortisone can be administered to alleviate inflammation that has already occurred. Representatives of this substance class promote the formation of white blood cells, which are increasingly produced during inflammatory processes. At the same time, however, they inhibit the release of substances in the body’s cells that are directed against foreign proteins (i.e. allergens). The latter enter the human organism via inhaled fungal and bacterial spores. The immunosuppressive (suppressing the body’s own immune system) and anti-allergic effects of cortisone play the decisive role in alleviating the symptoms described. The drug has a decongestant effect on the mucous membranes of the respiratory tract, relaxes the bronchial muscles and reduces the formation of bronchial mucus. However, the positive effects sometimes only set in with a time delay of several days. For patients in whom the disease has progressed to a chronic stage or pulmonary fibrosis, therapeutic measures to actively improve respiratory performance are recommended: These include exercise, conditioning and strengthening programs. A healthy diet and psychotherapeutic treatment are also beneficial. Lung transplantation for severe pulmonary fibrosis results in a five-year survival rate of about 50%. It is recommended under certain conditions.
Outlook and prognosis
Patients who develop farmer’s lung generally have a good prognosis. If the disease is detected and treated early, symptoms can improve rapidly. Coughing, shortness of breath and other symptoms usually subside as soon as the cause of the disease is corrected and drug treatment is initiated. Acute farmer’s lung can lead to heart failure in some cases, resulting in the patient’s death. Chronic disease develops insidiously and also places a significant burden on the cardiovascular system. Symptoms such as breathing difficulties and pain increase in intensity as the disease progresses and permanently impair well-being. In the long term, untreated chronic farmer’s lung is also fatal. Coughing up blood and high fever can trigger a panic attack in the affected person and cause psychological problems. Farmer’s lung can also cause loss of appetite and sleep problems, which further worsen the general condition. Nevertheless, the outlook and prognosis are generally positive. Assuming early treatment, farmer’s lung usually progresses well and does not result in further health problems for those affected. Any damage already done to the lungs must be treated symptomatically.
Prevention
As a general rule, the time spent handling plant debris should be kept as short as possible. Certified respirators with P2 protection level also help keep any dust that may be stirred up away from the lungs. The FFP2/3 particle filter mask is recommended. Commercially available protective masks are not effective enough. Combine harvester operators should keep the control cabins closed at all times. Their ventilation must be provided only by systems capable of keeping out dust contaminated with spores. Before hay stored in meadows is brought in, it should be turned several times. This is especially true after wet and mild weather conditions. One possible measure to reduce dust when handling dry forage is to mix it with a little vegetable oil.
Aftercare
In most cases of farmer’s lung, there are no aftercare options available to the affected person. The disease can thereby also not be treated completely and reduces in most cases significantly the life expectancy of the affected person. There is also no self-healing, so that farmer’s lung can only be treated symptomatically. The triggers of the disease should be avoided at all costs so as not to put additional strain on the patient’s lungs. In many cases, those affected are dependent on taking cortisone. However, this leads to severe side effects, which should also be treated. When taking cortisone, it is therefore important to ensure that the correct dosage is used and that it is taken regularly in order to prevent further complications. The airways must be relieved, so the affected person should also not smoke. To restore the performance of the lungs, patients can perform various exercises, and in general, a healthy lifestyle with a healthy diet can have a positive effect on the course of farmer’s lung. In the case of severely pronounced or severe symptoms, those affected are not infrequently also dependent on the help of their fellow human beings in everyday life. In this case, loving care by one’s own family has a particularly positive effect on recovery.
What you can do yourself
Farmer’s lung is a dangerous disease that can lead to death if left untreated. Affected persons should therefore not treat the symptoms themselves, but should consult a doctor promptly. The best form of self-help is complete allergen abstinence. The disorder usually develops slowly over a period of years and its progression can be halted by consistent avoidance of the causative substances. Very often, the symptoms improve considerably over time, even if a complete regeneration of the damaged lungs cannot be expected. Simple measures can often help to reduce exposure. Farmers should be sure to wear a high-quality P2 level protective mask when working with hay, straw and other dried grasses. Those who handle dried forage can lightly moisten it or apply vegetable oil to it to prevent excessive dusting. However, if avoidance of the allergens is not possible, at least in severe cases, timely consideration must be given to occupational reorientation.Since farmer’s lung is a recognized occupational disease, those affected are relatively well covered socially. Self-employed farmers can seek advice from their association, and dependent helpers in agriculture from their employers’ liability insurance association.