Manifestations of Schistosomiasis in the Lung Vary Dependent on the Stage of Disease
Early Acute Schistosomiasis: transient, multiple small pulmonary nodules with peripheral eosinophilia
Chronic Schistosomiasis: embolization of ova in small arteries of the lung results in granuloma formation, occlusion and remodeling of pulmonary arteries, and further pulmonary hypertension mediared by portopulmonary hypertension
Post-Treatment of Schistosomiasis: eosinophilic pneumonitis (lung shift, verminous pneumonia, reactionary Loffler-like pneumonitis) due to antigen release following treatment
Manifestations of Schistosomiasis in the Lung Vary Dependent on the Stage of Disease
Early Acute Schistosomiasis: transient, multiple small pulmonary nodules with peripheral eosinophilia
Chronic Schistosomiasis: embolization of ova in small arteries of the lung results in granuloma formation, occlusion and remodeling of pulmonary arteries, and further pulmonary hypertension mediared by portopulmonary hypertension
Post-Treatment of Schistosomiasis: eosinophilic pneumonitis (lung shift, verminous pneumonia, reactionary Loffler-like pneumonitis) due to antigen release following treatment
Strongyloides Stercoralis: simple pulmonary eosinophilia (Loffler syndrome) may occur when larvae migrate through the lungs after acute infection
Chronic Cough with Sputum Eosinophilia (About 40%)
Normal Lung Function with Absence of Bronchial Hyperreactivity: although it may evolve over time into either fixed airflow obstruction without asthma or into true asthma
Absence of Eosinophilic Pneumonia
Gastric Cancer with Tumor-Related Production of GM-CSF and IL-5 (see Gastric Cancer)
Pulmonary Pathologic Lesions are Nodules (with Bronchiolocentric Stellate Shape) with Langerhans Cells and Variable Numbers of Eosinophils, Plasma Cells, and Lymphocytes
Eosinophils are Usually Present in the Initial, Active Stage of the Disease: they contribute to the eosinophilic granuloma
Eosinophils are Numerous in 25% of Cases: usually located at the periphery of the lesions
Eosinophils are Rare or Absent at the Chronic Stage of the Disease
Acute Lung Transplant Rejection (Acute Cellular Lung Transplant Rejection) (see Acute Lung Transplant Rejection): peripheral eosinophilia may occur with/without pulmonary infiltrates (as acute rejection may be detected by surveillance bronchoscopy with transbronchial biopsy prior to the development of pulmonary infiltrates)
May Be Present in the Disorders Noted Above to a Variable Extent
Definition of Peripheral Eosinophilia: absolute eosinophil count >500 eosinophils/μL
Definition of Peripheral Hypereosinophilia: absolute eosinophil count >1500 eosinophils/μL on two examinations at least 1 mo apart and/or tissue hypereosinophilia
Effect of Corticosteroids on Peripheral Eosinophilia: course of corticosteroids typically results in a decrease in peripheral eosinophilia
Although Pathologic Examination of the Lung is the Gold Standard for Diagnosing Eosinophilic Pneumonia, BAL is a Widely-Accepted Noninvasive Surrogate of Lung Biopsy for Diagnosis in Patients with High-Resolution Features of Eosinophilic Pneumonia
However, No Study Has Definitely Established a Correlation Between the Presence of BAL Eosinophilia and the Finding of Eosinophilic Pneumonia on Lung Pathology
BAL Eosinophil Percentage in Various Disease States
Normal: BAL eosinophil <1%
BAL Eosinophilia 3-40% (and Especially Between 3-9%): may be found in various disorders
BAL Eosinophilia >40%: found predominantly in patients with chronic eosinophilic pneumonia
BAL Eosinophil Percentage Proposed Cut-Off Values
Diagnosis of Idiopathic Acute Eosinophilic Pneumonia: BAL Eosinophilia >25%
Diagnosis of Idiopathic Chronic Eosinophilic Pneumonia: BAL Eosinophilia >40%
Transbronchial Biopsy (TBB)
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Video-Assisted Thoracoscopic Surgery (VATS) with Lung Biopsy
May Be Required in Unusual Cases
References
Eosinophilia and pneumonitis in chronic brucellosis: a report of two cases. Ann Intern Med. 1942;16:995-1001
Acute eosinophilic pneumonia as a reversible cause of noninfectious respiratory failure. N Engl J Med. 1989;321:569-574 [MEDLINE]
Cryptococcal pneumonia simulating chronic eosinophilic pneumonia. South Med J. 1995;88:845-846 [MEDLINE]