Eosinophilic pneumonia includes a group of disorders characterized by an accumulation of eosinophilic infiltrates in the pulmonary parenchyma with/without peripheral blood eosinophilia. These include a broad range of lung conditions which occur due to infectious or non-infectious causes. The two common pulmonary eosinophilic syndromes are :
Abnormally increased eosinophils in lung parenchyma occurs due to infectious and non-infectious causes.
Non-infectious causes include-
Idiopathic acute eosinophilic pneumonia can occur at any age but is more common in males of age 20-40 years. Associations for the condition also exist with CML, HIV infection and smoking.
The most common cohort for chronic eosinophilic pneumonia is Caucasian women with a peak incidence between 30-40 years. Asthma is present in 50 percent of these patients.
Eosinophils are granulocytic white blood cells (WBCs) which are primarily tissue-dwelling cells. The main functions of eosinophils include host defense, inflammation modulation, and tissue destruction. Eosinophils play an important role in killing parasites, tumor cells, and respiratory epithelial cells.
The normal absolute eosinophil count in the peripheral blood is 0 to 500 cells/microL. Eosinophilia is predominantly due to polyclonal expansion (reactive expansion) as compared to hematopoietic clonal stem cell expansion which is rare. A count of over 1500 increases the risk of tissue damage. However, it can also occur at low eosinophil count. In eosinophilic lung diseases, eosinophils commonly affect parenchyma and airways. Based on the increase in eosinophils, eosinophilia can be:
Eosinophilic pneumonia occurs secondary to lung tissue damage by the activated eosinophils. The substances and chemical mediators released by these activated macrophages damage the tissues and contribute to the disease pathology. These include 
In acute eosinophilic pneumonia, there is a marked infiltration of eosinophils in the alveolar spaces, bronchial walls and, to a lesser extent in the interstitium. Acute and/or organizing diffuse alveolar damage is present. However, granulomas or hemorrhage are absent.
In chronic eosinophilic pneumonia, leukocytic infiltrates in alveolar air spaces and interstitium. The infiltrates are predominantly eosinophilic with macrophages, lymphocytes, and occasional plasma cells.
Common symptoms include a cough, fever, dyspnea, night sweats.
Acute eosinophilic pneumonia follows a rapid course with symptoms developing within 2 weeks. Myalgias and pleuritic chest pain with dyspnea may also be present, which can progress to respiratory failure. These patients can present with apparent acute lung injury or ARDS without any antecedent illness. However, extrapulmonary failure and shock are absent which differentiates it from ARDS. On auscultation, diffuse crackles are present.
Chronic eosinophilic pneumonia follows a progressive course. The presentation is subacute with symptoms present for months before diagnosis. These patients present with moderate weight loss besides the common symptoms. Over time, dyspnea progresses and presents with wheezing especially in those with adult-onset asthma.
Idiopathic Acute eosinophilic pneumonia- is usually a diagnosis of exclusion.
Chronic eosinophilic pneumonia - the diagnosis is based on clinical, radiographic and BAL findings and on the inability to document pulmonary or systemic infection.
Supportive care with supplemental oxygen and glucocorticoids are the initial management in acute cases. While waiting for the culture results, staring mechanical ventilation and empiric antibiotics are valid therapeutic measures.
Systemic glucocorticoid therapy (intravenous or oral) is recommended for all and started as soon as possible for rapid improvement within 12-48 hours. However, the dose depends on the severity. Without glucocorticoid therapy, there is a risk of progressive respiratory failure in acute eosinophilic pneumonia patients. Once the respiratory failure resolves, oral prednisone continued for 2-4 weeks with subsequent slow taper over the next few weeks.
There is a dramatic response to corticosteroids with rapid resolution of symptoms within an hour and complete resolution of infiltrates within a month.
For chronic eosinophilic pneumonia, prednisone (40-60 mg) until 2 weeks after the resolution of symptoms and x-ray abnormalities. Treatment is maintained for at least 3 months and optimally for 6 to 9 months. Some patients may require longer maintenance. Later, inhaled corticosteroids can be started allowing discontinuation of oral steroids.
Once the diagnosis of acute eosinophilic pneumonia is established, and corticosteroid treatment started, the prognosis is excellent with dramatic response to therapy.
Sometimes prolonged glucocorticoid therapy may be required when there is a risk of recurrence; the prognosis is generally good for chronic eosinophilic pneumonia patients.
Eosinophilic pneumonia affects the lung and is predominantly idiopathic. It requires interprofessional care and the involvement of more than one subspecialty. This patient-centered approach involving a physician with a team of other health professionals, physiotherapists, respiratory therapists, nurses, pharmacists, and support groups working together for the patient plays a vital role in improving the quality of care in pneumonia patients. The timely diagnosis and treatment are crucial especially in patients with an acute presentation, as left untreated, it can progress to respiratory failure.
We are looking for contributors to author, edit, and peer review our vast library of review articles and multiple choice questions. In as little as 2-3 hours you can make a significant contribution to your specialty. In return for a small amount of your time, you will receive free access to all content and you will be published as an author or editor in eBooks, apps, online CME/CE activities, and an online Learning Management System for students, teachers, and program directors that allows access to review materials in over 500 specialties.
This is an academic project designed to provide inexpensive peer-reviewed Apps, eBooks, and very soon an online CME/CE system to help students identify weaknesses and improve knowledge. We would like you to consider being an author or editor. Please click here to learn more. Thank you for you for your interest, the StatPearls Publishing Editorial Team.
Click Your Answer Below
Would you like to access teaching points and more information on this topic?
Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.
Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.
|Allen J,Wert M, Eosinophilic Pneumonias. The journal of allergy and clinical immunology. In practice. 2018 Sep - Oct; [PubMed]|
|Salahuddin M,Cherian SV, Pulmonary Eosinophilia 2018 Jan; [PubMed]|
|Bartal C,Sagy I,Barski L, Drug-induced eosinophilic pneumonia: A review of 196 case reports. Medicine. 2018 Jan; [PubMed]|
|Weissler JC, Eosinophilic Lung Disease. The American journal of the medical sciences. 2017 Oct; [PubMed]|
|Xiaohong C,Yiping XU,Meiping LU, [Clinical characteristics and etiology of children with hypereosinophilia]. Zhejiang da xue xue bao. Yi xue ban = Journal of Zhejiang University. Medical sciences. 2016 May 25; [PubMed]|
|Blavier N,Thimmesch M,Lebrun F,Bodart E, [Acute idiopathic eosinophilic pneumonia in a teenager]. Revue medicale de Liege. 2018 Sep; [PubMed]|
|Higashi Y,Nakamura S,Tsuji Y,Ogami C,Matsumoto K,Kawago K,Tokui K,Hayashi R,Sakamaki I,Yamamoto Y, Daptomycin-induced Eosinophilic Pneumonia and a Review of the Published Literature. Internal medicine (Tokyo, Japan). 2018 Jan 15; [PubMed]|
|Fayyaz B, Acute eosinophilic pneumonia associated with smoking: a case report. Journal of community hospital internal medicine perspectives. 2018; [PubMed]|
|Bhatt NY,Allen JN, Update on eosinophilic lung diseases. Seminars in respiratory and critical care medicine. 2012 Oct; [PubMed]|
|Bjerrum OW,Fassi DE,Madsen G,Stentoft J,Vestergaard H,Rønnov-Jessen D,Pedersen PT,Pulczynski S,Overgaard UM,Andersen CL, [Eosinophilia]. Ugeskrift for laeger. 2018 Sep 10; [PubMed]|
|Felton JM,Lucas CD,Rossi AG,Dransfield I, Eosinophils in the lung - modulating apoptosis and efferocytosis in airway inflammation. Frontiers in immunology. 2014; [PubMed]|
|De Giacomi F,Vassallo R,Yi ES,Ryu JH, Acute Eosinophilic Pneumonia. Causes, Diagnosis, and Management. American journal of respiratory and critical care medicine. 2018 Mar 15; [PubMed]|
|Seifert M,Gerth J,Gajda M,Pester F,Pfeifer R,Wolf G, [Eosinophilia--a challenging differential diagnosis]. Medizinische Klinik (Munich, Germany : 1983). 2008 Aug 15; [PubMed]|
|Curtis C,Ogbogu PU, Evaluation and Differential Diagnosis of Persistent Marked Eosinophilia. Immunology and allergy clinics of North America. 2015 Aug; [PubMed]|
|Martin N,Brightling CE,Pavord ID, Eosinophils best marker of steroid response. Thorax. 2011 Aug; [PubMed]|
The intent of StatPearls is to provide practice questions and explanations to assist you in identifying and resolving knowledge deficits. These questions and explanations are not intended to be a source of the knowledge base of all of medicine, nor is it intended to be a board or certification review of Allergy and Immunology. The authors or editors do not warrant the information is complete or accurate. The reader is encouraged to verify each answer and explanation in several references. All drug indications and dosages should be verified before administration.
StatPearls offers the most comprehensive database of free multiple-choice questions with explanations and short review chapters ever developed. This system helps physicians, medical students, dentists, nurses, pharmacists, and allied health professionals identify education deficits and learn new concepts. StatPearls is not a board or certification review system for Allergy and Immunology, it is a learning system that you can use to help improve your knowledge base of medicine for life-long learning. StatPearls will help you identify your weaknesses so that when you are ready to study for a board or certification exam in Allergy and Immunology, you will already be prepared.
Our content is updated continuously through a multi-step peer review process that will help you be prepared and review for a thorough knowledge of Allergy and Immunology. When it is time for the Allergy and Immunology board and certification exam, you will already be ready. Besides online study quizzes, we also publish our peer-reviewed content in eBooks and mobile Apps. We also offer inexpensive CME/CE, so our content can be used to attain education credits while you study Allergy and Immunology.