Severe lung disease, such as pneumonia, is not always caused by bacterial flora. Parasites, fungi, drugs, immunodeficiency states, allergic reactions can disrupt homeostasis of the upper and lower respiratory tract. And in such cases, eosinophilic pneumonia develops.
Definition
Eosinophilic pneumonia is a pathological process in the lungs that is characterized by excessive accumulation of eosinophils in the alveoli. There are several types or variants of this pathology that can develop at any age.
Clinically, it is practically indistinguishable from a similar disease caused by bacteria, so the main emphasis in diagnosis is placed on laboratory tests: a general blood test, sputum microscopy. In most cases, after determining the type of disease, they begin therapy with steroid hormones of the adrenal cortex. This helps reduce the inflammatory response and mitigate the symptoms of pneumonia. The prognosis for such patients is usually favorable.
History
Chronic eosinophilic pneumonia, the causes of which were not known at that time, was first described in the mid-twentieth century, in 1969, by a doctor Harrington. He was not very shy, so he assigned his name to the disease, and after publication, the entire scientific world began to call the new pathology Harrington's syndrome.
Prior to this historical article, eosinophilic pneumonia was known as a disease that develops in the lungs when infected with parasites or uncontrolled medication. Twenty years later, in 1989, the term "acute eosinophilic pneumonia" appeared in medicine.
Etiology
There are several factors under the influence of which eosinophilic pneumonia develops. Causes, symptoms are closely related. For example, acute forms of pneumonia are caused by smoking (both active and passive), an allergy to drugs, or a decrease in the body’s defenses in HIV or AIDS. If none of the reasons fits, then pneumonia is considered idiopathic.
Chronic eosinophilic pneumonia can be triggered by a fungal infection (aspergillosis, pneumomycosis), helminthic invasion (ascariasis, echinococcosis), prolonged use of drugs that suppress immunity (glucocorticosteroids, cytostatics), chronic autoimmune diseases of connective tissue (rheumatoid).
Eosinophils perform the protective functions of the body, but since inflammation is a typical pathological process, it can negatively affect a person’s state of health if the course is excessive and violent.
Pathogenesis
The etiological factor largely determines how eosinophilic pneumonia will develop. Causes, symptoms, treatment - it all depends on this. The cornerstone of this type of pneumonia is the accumulation of a large number of eosinophils in the lung tissues. Many diseases, including eczema and bronchial asthma, are caused by an overly violent reaction of the body with the release of biologically active substances.
Taking medications and other toxic substances changes the reactivity of eosinophils, making them more susceptible. Anti-inflammatory substances, antibiotics, drugs cause allergies, which lead to the development of secondary pneumonia. In addition, cigarette smoke and chemical fumes are factors that trigger the appearance of a large number of eosinophils in the tissues.
Parasitic infections
Doctors distinguish three mechanisms for the development of pneumonia during parasitosis. The first is helminthic invasion of the lungs, the second is part of the life cycle of the worms, and the third is random screening with blood flow. To combat them, the body sends eosinophils. They should provoke the release of cytokines, prostaglandins, leukotrienes and other active substances to eliminate worms. But instead they cause pneumonia.
Tapeworms, such as echinococcus and pork tapeworm, as well as pulmonary flukes, are specially introduced into the tissues of the lower respiratory tract . Staying in the lungs and access to atmospheric oxygen is necessary for roundworms, intestinal acne, hookworms and non-catarrh. Eosinophilic pneumonia, which is caused by the above pathogens, otherwise called Leffler's syndrome. Trichinella eggs and schistosomes enter the lungs through the bloodstream.
Clinic
As a rule, it is difficult for a physician, pulmonologist, or even an infectious disease specialist to answer the question at first glance, what kind of patient has eosinophilic pneumonia. Symptoms, even taking into account different etiologies, are very similar to each other. The patient complains of coughing, fever, shortness of breath and sweating at night. After a couple of weeks after coughing, if nothing is done, you will notice symptoms of decompensated respiratory failure. In this case, the patient must be transferred to artificial lung ventilation.
Chronic pneumonia eosinophilic progresses slowly, for months. Patients lose weight, they have shortness of breath, wheezing and coughing, body temperature does not fall below subfebrile numbers. Sometimes the symptoms of the disease mimic bronchial asthma, which makes it difficult to diagnose and choose the wrong treatment tactics.
Many difficulties for diagnosis are caused by drug eosinophilic pneumonia. Symptoms, treatment and prevention strongly resemble aspirin asthma, which is misleading to the doctor. Parasitic infections have a specific prodromal period, which can lead to thoughts about helminthic invasions.
Diagnostics
Since clinically eosinophilic pneumonia is practically no different from other pneumonia, the diagnosis is made on the basis of laboratory and instrumental studies. In the general analysis of blood eosinophilia is pronounced, with the visualization of the lungs on fluoroscopy or computed tomography, characteristic pathological changes are noticeable. To confirm, you can take a biopsy of the lung tissue, as well as a flush from the surface of the bronchi in the process of bronchoscopy.
To identify a connection with taking medication, staying in chemically contaminated areas or cancer, you need to carefully study the patient’s medical history, as well as to collect a detailed history of life and illness. If, after all the investigations, it was still not possible to identify the cause, then the diagnosis is recorded as idiopathic eosinophilic pneumonia.
Be sure to indicate the degree of respiratory failure in the card. Within a week from the onset of the disease, its first signs appear:
- multiple lesions of lung tissue;
- accumulation of fluid in the pleural cavity;
- leukocytosis and increased erythrocyte sedimentation rate in the general blood test;
- increased levels of immunoglobulin E;
- spirometry shows a decrease in the respiratory volume of the lungs.
Treatment
Even before the final diagnosis is made - eosinophilic pneumonia, treatment begins from the moment the patient goes to the doctor.
If pneumonia is secondary, then it is necessary to treat the underlying disease: a tumor or helminthic invasion. This will help reduce pulmonary symptoms and speed up recovery.
If the cause of the disease could not be identified, glucocorticosteroid therapy is prescribed. They well remove the inflammatory reaction, stabilize cell membranes, lower temperature. Remission is achieved quickly - on the third or fourth day. But this does not end with medication. The disappearance of symptoms does not mean that the disease is cured. Therefore, the patient takes corticosteroids for another month, with a gradual dose reduction until the moment when instrumental diagnostic methods do not confirm recovery.
The chronic form of the disease requires therapy for three months or more, even after the disappearance of clinical signs. Relapses of pneumonia are possible against the background of a sharp abolition of corticosteroids. In some cases, the patient may need to switch to mechanical ventilation.
Forecast
If eosinophilic pneumonia is a secondary disease against a background of a cancerous tumor or parasitosis, then the outcome of the disease depends on the course of the underlying pathology. A fatal outcome, with adequate and timely treatment, is unlikely.
Chronic eosinophilic pneumonia prone to recurrence on the background of the abolition of glucocorticosteroids. Therefore, some patients take these medicines all their lives. But this situation has a downside. Side effects from treatment with, for example, prednisone, can greatly impair a person’s quality of life. These include: peptic ulcer, osteoporosis, cushingoid, decreased immunity.
Epidemiology
As a rule, pneumonia caused by parasites is more common in regions endemic to these pathogens. It can be the tropics, the Siberian taiga, the Mediterranean, or the basin of a separate river.
Acute eosinophilic pneumonia can develop at any age, even in very young children, but most often middle-aged people suffer from them: from twenty to forty years. The disease has some kind of sexual discrimination - men get sick more often than women, since the disease is caused by smoking. In modern medical literature there are descriptions of the development of eosinophilic pneumonia after radiation therapy of breast cancer.
Eosinophilic pneumonia in dogs
In animals, eosinophilic pneumonia also occurs. The causes, symptoms, prevention of this disease are very similar to human. Similarly, the causes of the disease: parasites in the lungs, fungi, allergies to pollen and insects, chemicals and medicines.
The dog has an uncontrolled immune response, which causes infiltration of lung tissue by eosinophils. The airiness of the lower sections decreases, pathogenic fungi develop there, which cause pneumonia. The animal dies from acidosis and hypoxia. The clinic is similar to a human: cough, shortness of breath, weakness, fever, lack of appetite, weight loss.
For diagnosis, a blood test, lung radiography, a cytological examination of bronchoalveolar swabs, and a serological examination are used. The radiograph shows pulmonary edema, the presence of cell granulomas, an increase in the lymph nodes of the mediastinum and the root of the lung, and an expansion of the heart’s shadow. After determining the etiology of eosinophilic pneumonia, the veterinarian prescribes a specific treatment aimed at eliminating the primary disease. The most effective are corticosteroids, in combination with antibiotics and bronchodilators. As a rule, animals remain on lifelong therapy.