Eosinophilic pneumonia

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Eosinophilic pneumonia
Specialty Respirology

Eosinophilic pneumonia is a disease in which an eosinophil, a type of white blood cell, accumulates in the lungs. These cells cause disruption of the normal air spaces (alveoli) where oxygen is extracted from the atmosphere. Several different kinds of eosinophilic pneumonia exist and can occur in any age group. The most common symptoms include cough, fever, difficulty breathing, and sweating at night. Eosinophilic pneumonia is diagnosed by a combination of characteristic symptoms, findings on a physical examination by a health provider, and the results of blood tests and X-rays. Prognosis is excellent once most eosinophilic pneumonia is recognized and treatment with corticosteroids is begun.

Contents

Classification

Eosinophilic pneumonia is divided into different categories depending upon whether its cause can be determined or not. Known causes include certain medications or environmental triggers, parasitic infections, and cancer. Eosinophilic pneumonia can also occur when the immune system attacks the lungs, a disease called eosinophilic granulomatosis with polyangiitis. When a cause cannot be found, the eosinophilic pneumonia is termed "idiopathic". Idiopathic eosinophilic pneumonia can also be divided into acute and chronic forms, depending on the symptoms a person is experiencing. [1]

Signs and symptoms

Most types of eosinophilic pneumonia have similar signs and symptoms. Prominent and nearly universal signs and symptoms include cough, fever, difficulty breathing, and night sweats. Acute eosinophilic pneumonia typically follows a rapid course. Fever and cough may develop only one or two weeks before breathing difficulties progress to the point of respiratory failure requiring mechanical ventilation. Chronic eosinophilic pneumonia usually follows a slower course. Symptoms accumulate over several months and include fever, cough, difficulty breathing, wheezing, and weight loss. Individuals with chronic eosinophilic pneumonia are often misdiagnosed with asthma before the correct diagnosis is made.

Eosinophilic pneumonia due to medications or environmental exposures is similar and occurs after an exposure to a known offending agent. Eosinophilic pneumonia due to parasitic infections has a similar prodrome in addition to a host of different symptoms related to the variety of underlying parasites. Eosinophilic pneumonia in the setting of cancer often develops in the context of a known diagnosis of lung cancer, cervical cancer, or other certain types of cancer.

Pathophysiology

Eosinophilic pneumonia can develop in several different ways depending on the underlying cause of the disease. Eosinophils play a central role in defending the body against infection by parasites. Many diseases, such as asthma and eczema, are caused when eosinophils overreact to environmental triggers and release an excess of chemicals, e.g., cytokines and histamine. The common characteristic among different causes of eosinophilic pneumonia is eosinophil overreaction or dysfunction in the lungs.

Medications and environmental exposures

Medications, substance abuse, and environmental exposures may all trigger eosinophil dysfunction. Medications such as nonsteroidal anti-inflammatory drugs (e.g., ibuprofen), nitrofurantoin, phenytoin, L-tryptophan, daptomycin [2] and ampicillin, and drugs of abuse such as inhaled heroin and cocaine may trigger an allergic response which results in eosinophilic pneumonia. Chemicals such as sulfites, aluminum silicate, and cigarette smoke can cause eosinophilic pneumonia when inhaled. A New York City firefighter developed eosinophilic pneumonia after inhalation of dust from the World Trade Center on September 11, 2001. [3]

Parasitic infections

Parasites cause eosinophilic pneumonia in three different ways. Parasites can either invade the lungs, live in the lungs as part of their life cycle, or be spread to the lungs by the bloodstream. Eosinophils then migrate to the lungs in order to fight the parasites, and cause eosinophilic pneumonia when they release their contents. Important parasites that invade the lungs include Paragonimus lung flukes and the tapeworms Echinococcus and Taenia solium . Important parasites which inhabit the lungs as part of their normal life cycle include the worms (helminths) Ascaris lumbricoides , Strongyloides stercoralis and the hookworms Ancylostoma duodenale and Necator americanus . When eosinophilic pneumonia is caused by helminths, it is often called "Löffler's syndrome". The final group of parasites cause eosinophilic pneumonia when their eggs are carried into the lungs by the bloodstream. This can include Trichinella spiralis , Strongyloides stercoralis, Ascaris lumbricoides, the hookworms, and the schistosomes. [4]

Acute and Chronic Eosinophilic Pneumonia

The causes for both acute and chronic eosinophilic pneumonia are unknown as of 2005. There is some suspicion that at least the acute form is the result of the body's response to some unidentified environmental agent.

Diagnosis

Eosinophilic pneumonia is diagnosed in one of three circumstances: when a complete blood count reveals increased eosinophils and a chest X-ray or computed tomography identifies abnormalities in the lungs, when a biopsy identifies increased eosinophils in lung tissue, or when increased eosinophils are found in fluid obtained by a bronchoscopy (bronchoalveolar lavage fluid). Association with medication or cancer is usually apparent after review of a person's medical history. Specific parasitic infections are diagnosed after examining a person's exposure to common parasites and performing laboratory tests to look for likely causes. If no underlying cause is found, a diagnosis of acute or chronic eosinophilic pneumonia is made based upon the following criteria. Acute eosinophilic pneumonia is most likely with respiratory failure after an acute febrile illness of usually less than one week, changes in multiple areas and fluid in the area surrounding the lungs on a chest X-ray, and eosinophils comprising more than 25% of white blood cells in fluid obtained by bronchoalveolar lavage. Other typical laboratory abnormalities include an elevated white blood cell count, erythrocyte sedimentation rate, and immunoglobulin G level. Pulmonary function testing usually reveals a restrictive process with reduced diffusion capacity for carbon monoxide. Chronic eosinophilic pneumonia is most likely when the symptoms have been present for more than a month. Laboratory tests typical of chronic eosinophilic pneumonia include increased levels of eosinophils in the blood, a high erythrocyte sedimentation rate, iron deficiency anemia, and increased platelets. A chest X-ray can show abnormalities anywhere, but the most specific finding is increased shadow in the periphery of the lungs, away from the heart.

Differential diagnosis

This includes:

Treatment

When eosinophilic pneumonia is related to an illness such as cancer or parasitic infection, treatment of the underlying cause is effective in resolving the lung disease. When due to acute or chronic eosinophilic pneumonia, however, treatment with corticosteroids results in a rapid, dramatic resolution of symptoms over the course of one or two days. Either intravenous methylprednisolone or oral prednisone are most commonly used. In acute eosinophilic pneumonia, treatment is usually continued for a month after symptoms disappear and the X-ray returns to normal (usually four weeks total). In chronic eosinophilic pneumonia, treatment is usually continued for three months after symptoms disappear and the X-ray returns to normal (usually four months total). Inhaled steroids such as fluticasone have been used effectively when discontinuation of oral prednisone has resulted in relapse. [5] Because eosinophilic pneumonia affects the lungs, individuals develop difficulty breathing. If enough of the lungs are involved, it may not be possible for a person to breathe without support. Non-invasive machines such as a bilevel positive airway pressure machine may be used. Otherwise, placement of a breathing tube into the mouth may be necessary and a ventilator may be used to help the person breathe.

Prognosis

Eosinophilic pneumonia due to cancer or parasitic infection carries a prognosis related to the underlying illness. Acute and chronic eosinophilic pneumonia, however, have very little associated mortality as long as intensive care is available and treatment with corticosteroids is given. Chronic eosinophilic pneumonia often relapses when prednisone is stopped; therefore, some people require lifelong therapy. Long-term use of prednisone has many side effects, including increased infections, osteoporosis, stomach ulcers, Cushing's syndrome, and changes in appearance. [6]

Epidemiology

Eosinophilic pneumonia is a rare disease. Parasitic causes are most common in geographic areas where each parasite is endemic. Acute eosinophilic pneumonia can occur at any age, even in previously healthy children, though most patients are between 20 and 40 years of age. Men are affected approximately twice as frequently as women. Acute eosinophilic pneumonia has been associated with smoking. Chronic eosinophilic pneumonia occurs more frequently in women than men and does not appear to be related to smoking. An association with radiation for breast cancer has been described. [7]

History

Chronic eosinophilic pneumonia was first described by Carrington [8] in 1969, and it is also known as Carrington syndrome. Prior to that, eosinophilic pneumonia was a well-described pathologic entity usually associated with medication or parasite exposures. Acute eosinophilic pneumonia was first described in 1989. [9] [10]

See also

Related Research Articles

Cough Sudden expulsion of air from the lungs as a reflex to clear irritants

A cough is a sudden expulsion of air through the large breathing passages that can help clear them of fluids, irritants, foreign particles and microbes. As a protective reflex, coughing can be repetitive with the cough reflex following three phases: an inhalation, a forced exhalation against a closed glottis, and a violent release of air from the lungs following opening of the glottis, usually accompanied by a distinctive sound.

Shortness of breath Feeling of difficulty breathing

Shortness of breath (SOB), also known as dyspnea, is a feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity", and recommends evaluating dyspnea by assessing the intensity of the distinct sensations, the degree of distress involved, and its burden or impact on activities of daily living. Distinct sensations include effort/work, chest tightness, and air hunger. The tripod position is often assumed.

Sputum Mucus that is coughed up from the lower airways

Sputum is mucus that is coughed up from the lower airways. In medicine, sputum samples are usually used for naked eye exam, microbiological investigation of respiratory infections and cytological investigations of respiratory systems. It is crucial that the specimen not include any mucoid material from the nose.

Eosinophilia Blood condition

Eosinophilia is a condition in which the eosinophil count in the peripheral blood exceeds 5×108/L (500/μL). Hypereosinophilia is an elevation in an individual's circulating blood eosinophil count above 1.5 x 109/L (i.e. 1,500/μL). The hypereosinophilic syndrome is a sustained elevation in this count above 1.5 x 109/L (i.e. 1,500/μL) that is also associated with evidence of eosinophil-based tissue injury.

Eosinophilic granulomatosis with polyangiitis Medical condition

Eosinophilic granulomatosis with polyangiitis (EGPA), formerly known as allergic granulomatosis, is an extremely rare autoimmune condition that causes inflammation of small and medium-sized blood vessels (vasculitis) in persons with a history of airway allergic hypersensitivity (atopy).

Chemical pneumonitis is inflammation of the lung caused by aspirating or inhaling irritants. It is sometimes called a "chemical pneumonia", though it is not infectious. There are two general types of chemical pneumonitis: acute and chronic.

Pneumonitis General inflammation of lung tissue

Pneumonitis describes general inflammation of lung tissue. Possible causative agents include radiation therapy of the chest, exposure to medications used during chemo-therapy, the inhalation of debris, aspiration, herbicides or fluorocarbons and some systemic diseases. If unresolved, continued inflammation can result in irreparable damage such as pulmonary fibrosis.

Löfflers syndrome Medical condition

Löffler's syndrome is a disease in which eosinophils accumulate in the lung in response to a parasitic infection. The parasite can be Ascaris, Strongyloides stercoralis, or Dirofilaria immitis which can enter the body through contact with the soil. The symptoms of Löffler's syndrome include those of a parasitic infection such as abdominal pain and cramping, skin rashes and fatigue. Löffler's syndrome itself will cause difficulty breathing, wheeze, coughing as well as a fever.

Respiratory disease Disease of the respiratory system

Respiratory diseases, or lung diseases, are pathological conditions affecting the organs and tissues that make gas exchange difficult in air-breathing animals. They include conditions of the respiratory tract including the trachea, bronchi, bronchioles, alveoli, pleurae, pleural cavity, the nerves and muscles of respiration. Respiratory diseases range from mild and self-limiting, such as the common cold, influenza, and pharyngitis to life-threatening diseases such as bacterial pneumonia, pulmonary embolism, tuberculosis, acute asthma, lung cancer, and severe acute respiratory syndromes, such as COVID-19. Respiratory diseases can be classified in many different ways, including by the organ or tissue involved, by the type and pattern of associated signs and symptoms, or by the cause of the disease.

Acute severe asthma, also known as status asthmaticus, is an acute exacerbation of asthma that does not respond to standard treatments of bronchodilators (inhalers) and corticosteroids. Asthma is caused by multiple genes, some having protective effect, with each gene having its own tendency to be influenced by the environment although a genetic link leading to acute severe asthma is still unknown. Symptoms include chest tightness, rapidly progressive dyspnea(shortness of breath), dry cough, use of accessory respiratory muscles, fast and/or labored breathing, and extreme wheezing. It is a life-threatening episode of airway obstruction and is considered a medical emergency. Complications include cardiac and/or respiratory arrest. The increasing prevalence of atopy and asthma remains unexplained but may be due to infection with respiratory viruses.

Pneumonia is an irritation of the lungs caused by different sources. It is characterized by an inflammation of the deep lung tissues and the bronchi. Pneumonia can be acute or chronic. This life-threatening illness is more common in cats than in dogs and the complication “Kennel Cough” can occur in young pets.

Allergic bronchopulmonary aspergillosis (ABPA) is a condition characterised by an exaggerated response of the immune system to the fungus Aspergillus. It occurs most often in people with asthma or cystic fibrosis. Aspergillus spores are ubiquitous in soil and are commonly found in the sputum of healthy individuals. A. fumigatus is responsible for a spectrum of lung diseases known as aspergilloses.

Loeffler endocarditis is a form of heart disease characterized by a stiffened, poorly-functioning heart caused by infiltration of the heart by white blood cells known as eosinophils. Restrictive cardiomyopathy is a disease of the heart muscle which results in impaired diastolic filling of the heart ventricles, i.e. the large heart chambers which pump blood into the pulmonary or systemic circulation. Diastole is the part of the cardiac contraction-relaxation cycle in which the heart fills with venous blood after the emptying done during its previous systole.

Lungworms are parasitic nematode worms of the order Strongylida that infest the lungs of vertebrates. The name is used for a variety of different groups of nematodes, some of which also have other common names; what they have in common is that they migrate to their hosts' lungs or respiratory tracts, and cause bronchitis or pneumonia. The lungworm will gradually damage the airways or lung tissue by inciting an inflammatory reaction inside the tissue. Ultimately, the parasites survive and reproduce in the respiratory tissues. The category is thus more a descriptive than a precisely taxonomic one.

White blood cell Type of cells of the immunological system

White blood cells, also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and derived from multipotent cells in the bone marrow known as hematopoietic stem cells. Leukocytes are found throughout the body, including the blood and lymphatic system.

Eosinophilic bronchitis Medical condition

Eosinophilic bronchitis (EB) is a type of airway inflammation due to excessive mast cell recruitment and activation in the superficial airways as opposed to the smooth muscles of the airways as seen in asthma. It often results in a chronic cough. Lung function tests are usually normal. Inhaled corticosteroids are often an effective treatment.

Tropical (pulmonary) eosinophilia, or TPE, is characterized by coughing, asthmatic attacks, and an enlarged spleen, and is caused by Wuchereria bancrofti, a filarial infection. It occurs most frequently in India and Southeast Asia. Tropical eosinophilia is considered a manifestation of a species of microfilaria. The filariasis is transmitted by a vector, specifically the bite of a Culex, Anopheles, or Aedes mosquito, and the microfilariae (larvae) take up residence in the lung tissue, hindering respiration and causing chest pain as the disease progresses.This disease can be confused with tuberculosis, asthma, or coughs related to roundworms.

Classification of pneumonia Medical condition

Pneumonia can be classified in several ways, most commonly by where it was acquired, but may also by the area of lung affected or by the causative organism. There is also a combined clinical classification, which combines factors such as age, risk factors for certain microorganisms, the presence of underlying lung disease or systemic disease and whether the person has recently been hospitalized.

Eosinophilic myocarditis is inflammation in the heart muscle that is caused by the infiltration and destructive activity of a type of white blood cell, the eosinophil. Typically, the disorder is associated with hypereosinophilia, i.e. an eosinophil blood cell count greater than 1,500 per microliter. It is distinguished from non-eosinophilic myocarditis, which is heart inflammation caused by other types of white blood cells, i.e. lymphocytes and monocytes, as well as the respective descendants of these cells, NK cells and macrophages. This distinction is important because the eosinophil-based disorder is due to a particular set of underlying diseases and its preferred treatments differ from those for non-eosinophilic myocarditis.

Chronic cough is long-term coughing, sometimes defined as more than several weeks or months. The term can be used to describe the different causes related to coughing, the three main ones being upper airway cough syndrome, asthma and gastroesophageal reflux disease. It occurs in the upper airway of the respiratory system. Generally, a cough lasts around one to two weeks; however, chronic cough can persist for an extended period of time defined as six weeks or longer. People with chronic cough often experience more than one cause present. Due to the nature of the syndrome, the treatments used are similar; however, there are a subsequent number of treatments available, and the clinical management of the patients remains a challenge.

References

  1. ↑ Bain GA, Flower CD (1996). "Pulmonary eosinophilia". European Journal of Radiology. 23 (1): 3–8. doi:10.1016/0720-048X(96)01029-7. PMC   1574763 . PMID   8872069.
  2. ↑ Research, Center for Drug Evaluation and. "Postmarket Drug Safety Information for Patients and Providers - FDA Drug Safety Communication: Eosinophilic pneumonia associated with the use of Cubicin (daptomycin)". www.fda.gov.
  3. ↑ Rom WN, Weiden M, Garcia R, et al. (2002). "Acute eosinophilic pneumonia in a New York City firefighter exposed to World Trade Center dust". American Journal of Respiratory and Critical Care Medicine. 166 (6): 797–800. doi:10.1164/rccm.200206-576OC. PMID   12231487.
  4. ↑ Weller PF (1994). "Parasitic pneumonias". In Pennington, James (ed.). Respiratory infections: diagnosis and management (3rd ed.). New York: Raven Press. p. 695. ISBN   0-7817-0173-2.
  5. ↑ Jantz MA, Sahn SA (1999). "Corticosteroids in acute respiratory failure". American Journal of Respiratory and Critical Care Medicine. 160 (4): 1079–100. doi:10.1164/ajrccm.160.4.9901075. PMID   10508792.
  6. ↑ Naughton M, Fahy J, FitzGerald MX (1993). "Chronic eosinophilic pneumonia. A long-term follow-up of 12 patients". Chest. 103 (1): 162–5. doi:10.1378/chest.103.1.162. PMID   8031327.
  7. ↑ Cottin V, Frognier R, Monnot H, Levy A, DeVuyst P, Cordier JF (2004). "Chronic eosinophilic pneumonia after radiation therapy for breast cancer". European Respiratory Journal. 23 (1): 9–13. doi: 10.1183/09031936.03.00071303 . PMID   14738224.
  8. ↑ Carrington CB, Addington WW, Goff AM, et al. (1969). "Chronic eosinophilic pneumonia". New England Journal of Medicine. 280 (15): 787–98. doi:10.1056/NEJM196904102801501. PMID   5773637.
  9. ↑ Badesch DB, King TE, Schwarz MI (1989). "Acute eosinophilic pneumonia: a hypersensitivity phenomenon?". American Review of Respiratory Disease. 139 (1): 249–52. doi:10.1164/ajrccm/139.1.249. PMID   2912347.
  10. ↑ Allen JN, Pacht ER, Gadek JE, Davis WB (1989). "Acute eosinophilic pneumonia as a reversible cause of noninfectious respiratory failure". New England Journal of Medicine. 321 (9): 569–74. doi:10.1056/NEJM198908313210903. PMID   2761601.
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