Chronic Eosinophilic Pneumonia

Patients with chronic eosinophilic pneumonia often present with fulminant illness characterized by a nonproductive cough of several months' duration, fever, progressive breathlessness, wheezing, and night sweats. The clinical presentation may suggest a community-acquired pneumonia. Asthma or another atopic disease (eg, atopic dermatitis, allergic rhinitis) accompanies or precedes the illness in > 50% of cases. Patients with recurrent symptoms may have weight loss due to ongoing chronic inflammation.

• Chest radiograph and high-resolution CT (HRCT)

• Complete blood count (CBC) with differential and other laboratory tests

• Pulmonary function tests

• Exclusion of autoimmune or infectious causes of pneumonia

• Bronchoscopy for bronchoalveolar lavage

Diagnosis of chronic eosinophilic pneumonia is suspected in patients with indolent onset of characteristic symptoms and typical radiographic appearance after excluding an infectious cause of the pneumonia.

Chest radiograph findings of bilateral peripheral or pleural-based opacities, most commonly in the middle and upper lung zones, are described as the photographic negative of pulmonary edema and are virtually pathognomonic (although present in < 25% of patients). A similar pattern can be present on HRCT, but the distribution of consolidation can vary and even include unilateral lesions.

Diagnosis also requires a complete blood count (CBC) with differential, erythrocyte sedimentation rate (ESR), IgE levels, sometimes iron studies, and exclusion of infectious causes by appropriate cultures. Peripheral blood eosinophilia (eosinophil counts > 500 cells/mcL [0.5 × 10⁹/L]), a high ESR and/or C-reactive protein (CRP) , iron deficiency anemia, and thrombocytosis are all frequently present. Unlike in acute eosinophilic pneumonia, peripheral eosinophilia is a characteristic finding in chronic eosinophilic pneumonia.

Pulmonary function tests may show an obstructive, restrictive, or mixed pattern. Diffusing capacity of the lung for carbon monoxide (DLCO) may also be reduced.

Bronchoalveolar lavage is usually done to confirm the diagnosis. Eosinophilia > 40% in bronchoalveolar lavage fluid is highly suggestive of chronic eosinophilic pneumonia.

• Systemic glucocorticoids

• Sometimes maintenance therapy with inhaled corticosteroids (also called glucocorticoids), oral glucocorticoids, or both

Patients with chronic eosinophilic pneumonia are uniformly responsive to IV or oral glucocorticoids; failure to respond suggests another diagnosis. Initial treatment is with an oral prednisone taper (Patients with chronic eosinophilic pneumonia are uniformly responsive to IV or oral glucocorticoids; failure to respond suggests another diagnosis. Initial treatment is with an oral prednisone taper (1). Clinical improvement is frequently striking and rapid, often occurring within 48 hours. Complete resolution of symptoms and radiographic abnormalities occurs within 14 days in most patients and by 1 month in almost all.

Symptoms and chest radiographs are both reliable and efficient guides to therapy. Although HRCT is more sensitive for the detection of imaging abnormalities, there is no benefit gained by repeating CT.

Peripheral eosinophil counts, ESR and/or CRP, and IgE levels can also be used to follow the clinical course during treatment. However, not all patients have abnormal laboratory test results.

Symptomatic or radiographic relapse occurs in many cases either after cessation of therapy or, less commonly, with tapering of the corticosteroid dose. Relapse can occur months to years after the initial episode. Thus, low-dose corticosteroid maintenance therapy may be required for long periods of time (years). Inhaled corticosteroids (also called glucocorticoids, eg, fluticasone or beclomethasone 500 to 750 mcg twice a day) may be effective, especially in reducing the maintenance dose of oral glucocorticoids. Symptomatic or radiographic relapse occurs in many cases either after cessation of therapy or, less commonly, with tapering of the corticosteroid dose. Relapse can occur months to years after the initial episode. Thus, low-dose corticosteroid maintenance therapy may be required for long periods of time (years). Inhaled corticosteroids (also called glucocorticoids, eg, fluticasone or beclomethasone 500 to 750 mcg twice a day) may be effective, especially in reducing the maintenance dose of oral glucocorticoids.

Relapses do not necessarily indicate greater morbidity, treatment failure, or ultimately, a worse prognosis. Patients usually continue to respond to glucocorticoids as during the initial episode. However, fixed airflow obstruction can persist,in some patients who recover, but the abnormalities are usually of borderline clinical significance and do not affect prognosis.

In patients with inadequately treated inflammation, irreversible fibrosis may occur, but the abnormalities are usually mild enough that this disorder is an extremely unusual cause of morbidity or death.