eosinophilic pneumonia (redirected from Idiopathic acute eosinophilic pneumonia)

Eosinophilic Pneumonia 

Definition

Eosinophilic pneumonia is a group of diseases in which there is an above normal number of eosinophils in the lungs and blood.

Description

Eosinophilia is an increase in the number of eosinophils. Eosinophilic pneumonia is characterized by a large number of eosinophils in the lungs, usually in the absence of an infectious disease. Eosinophils are one of the white blood cells and are classified as a granulocyte. They are part of the non-specific immune system and participate in inflammatory reactions. Eosinophils contain cationic molecules that are useful for destroying infectious agents, especially heiminthic parasites (worms). There are several types of eosinophilic pneumonia. Loffler's pneumonia is a temporary infiltration of eosinophils into the lungs. The patient will feel tired, have a cough, spasms of the bronchial airway, and difficulty breathing. Loffler's pneumonia will clear spontaneously, but slowly over the course of about a month. Another form of eosinophilic pneumonia, pulmonary infiltrates with eosinophilia (PIE), is a more serious and potentially fatal disease. In PIE, the patient experiences asthma, pulmonary infiltrates, disorders of the peripheral nervous system, central nervous systems symptoms, and periarteritis nodosa.

Causes and symptoms

Pneumonia with eosinophils occurs as part of a hypersensitivity reaction. A hypersensitivity reaction is an over-reaction of the immune system to a particular stimulus. As part of the hypersensitive reaction, cells of the immune system are produced in increased numbers and migrate into areas targeted by the hypersensitivity reaction. In the case of eosinophilic pneumonia, the lungs are the target. Generally, eosinophilia pneumonia is not a reaction to an infection. There is a correlation between asthma and eosinophilic pneumonia. Eosinophilic pneumonia can also be caused by drugs and, in some people, by polluted air. The symptoms range from mild (coughing, wheezing, and shortness of breath) to severe and life threatening (severe shortness of breath and difficulty getting enough oxygen). The symptoms may resolve spontaneously or can persist for long periods of time. In a few cases, the disease may rapidly produce life-threatening pneumonia.

Diagnosis

Since eosinophilia is common to a number of conditions, the physician must rule out asthma and infection by helminths when diagnosing eosinophilic pneumonia. A whole blood count will reveal an increased number of eosinophils in the blood. An x ray of the lungs may show the presence of infiltrates (the eosinophils and fluid). If sputum is produced in coughing, eosinophils will be seen instead of the more normal profile of granulocytes seen when an infectious agent is present.

Treatment

Eosinophilic pneumonia may not respond to drugs used to treat asthma. Eosinophilic pneumonia is usually treated with steroids, particularly glucocorticosteroids. Steroids are not effective against infectious agents, but the main disease process in eosinophilic pneumonia is an inflammatory reaction, not a response to infection. When eosinophilia is produced as a consequence of asthma or an infection by helminths, treatment of the asthma or helminths will reduce the eosinophilia.

Resources

Books

Berkow, Robert, editor. Merck Manual of Medical Information. Whitehouse Station, NJ: Merck Research Laboratories, 2004.

Key terms

Infiltrates — Cells or body fluids that have passed into a tissue or body cavity.

Sputum — Material coughed up from the throat or lungs.

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eosinophilic pneumonia

n.

A disorder characterized by radiologic evidence of infiltrates accompanied by either peripheral blood eosinophilia or eosinophilic infiltrates in lung tissue.

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eosinophilic pneumonia,

inflammation of the lungs, characterized by infiltration of the alveoli with eosinophils and large mononuclear cells, pulmonary edema, fever, night sweats, cough, dyspnea, and weight loss. The disease may be caused by a hypersensitivity reaction to fungi spores; plant fibers; wood dust; bird droppings' porcine, bovine, or piscine proteins; Bacillus subtilis enzyme in detergents; or certain drugs. Treatment consists of removal of the offending allergen and symptomatic and supportive therapy. Compare bronchopneumonia. See also asthmatic eosinophilia.

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eosinophilic

staining readily with eosin; pertaining to eosinophils or to eosinophilia.

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cartilaginous eosinophilic streaks

streaks of eosinophilic matrix in cartilage. Some are normal zones of development, others represent areas of matrix degeneration and osteochondrosis.

eosinophilic chemotactic factor

a primary mediator of type I anaphylactic hypersensitivity, it is an acidic peptide (molecular weight 500) released by mast cells, which attracts eosinophils to areas where it is present.

equine eosinophilic chronic dermatitis

acanthosis and hyperkeratosis accompanied by eosinophilic granulomas in pancreas and other epithelial organs.

feline eosinophilic granuloma complex

a collective name given to the lesions of eosinophilic ulcer, eosinophilic plaque (below), and linear granuloma because of similarities in histopathology, clinical course and occasionally simultaneous occurrence in the cat.

eosinophilic granuloma

nodules or plaques that occur on skin or oral mucosa of dogs. Usually not pruritic, but oral lesions can cause some difficulties in eating. The cause is unknown. See also feline eosinophilic granuloma complex (above), equine nodular collagenolytic granuloma.

eosinophilic intestinal granuloma

see angiostrongyluscostaricensis.

eosinophilic lung disease

see pie syndrome.

eosinophilic meningitis

see gnathostomaspinigerum.

eosinophilic meningoencephalitis

see sodium chloride poisoning, angiostrongyluscantonensis.

eosinophilic myocarditis

in cattle may be observed in normal animals at slaughter. Histologically there is a predominant eosinophil invasion of the heart muscle. May be accompanied by similar lesions in skeletal muscles.

eosinophilic plaque

well-defined, raised, ulcerated and extremely pruritic lesions that occur on the skin of cats, usually on the abdomen or hindlegs. There are large numbers of eosinophils present in the dermis and sometimes peripheral blood. See also eosinophilic granuloma (above), feline eosinophilic granuloma complex (above).

eosinophilic pneumonia

see pie syndrome.

eosinophilic ulcer

a well-defined ulceration, usually on the upper lip of cats overlying the canine tooth, which is shallow initially but can become extremely erosive and sometimes neoplastic. Mildly irritating to the cat. Called also indolent ulcer, rodent ulcer. See also feline eosinophilic granuloma complex (above).

Bilateral eosinophilic ulcer. By permission from Kummel BA, Color Atlas of Small Animal Dermatology, Mosby, 1989

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eosinophilic pneumonia

Clinical medicine A nonspecific term for disease processes in which the lung parenchyma is inflamed and diffusely infiltrated with eosinophils and histiocytes, ± PMNs, lymphocytes, plasma cells, mast cells Etiology Ancylostoma duodenale, Ascaris lumbricoides, Dirofilaria immitis, Fasciola hepatis, Necator americanus, Strongyloides stercoralis, Toxocara canis, Trichinella spiralis, Wuchereria malayi, drugs;¹⁄₃ are idiopathic Clinical From mild and transient–Löffler syndrome with fever, cough, and wheezing to severe and progressive–chronic EP with weight loss, dyspnea; an acute form is accompanied by respiratory failure and recuperation Clinical forms Loeffler syndrome, tropical eosinophilia, drug-induced pulmonary eosinophilia, EP associated with asthma Lab Eosinophils in BAL, peripheral blood Management Treat cause if known–eg, stop offending drug, kill offensive parasite, default to corticosteroids if idiopathic