Idiopathic pulmonary hemosiderosis (IPH) is a relatively rare chronic lung disease, mostly in children and adolescents, and is characterized by recurrent alveolar hemorrhage. The typical triad is recurrent respiratory tract infections (such as hemoptysis, cough, and dyspnea), iron deficiency anemia, and diffuse pulmonary infiltration on imaging.
Pathogenesis
The pathogenesis has not been fully elucidated, and may be related to autoimmunity, genes, allergies, environment, and infection.
Clinical manifestations
IPH can be divided into acute IPH, subacute IPH, and chronic IPH.
Acute IPH
Moderate to severe anemia deteriorates quickly or relapses in a short period, or severe respiratory symptoms and signs such as massive hemoptysis, cough, tachypnea, dyspnea, hypoxemia, respiratory failure, and acute right heart failure may occur.
Subacute IPH
long-term or recurrent mild to moderate anemia, or moderate respiratory symptoms and signs such as recurrent or chronic cough, recurrent hemoptysis, and tachypnea are present.
Chronic IPH
Due to little hemorrhage in the lungs, there are no obvious symptoms or signs or only mild microcytic hypochromic anemia.
Other extrapulmonary symptoms include fever, pallor, fatigue, hepatomegaly, cyanosis, and clubbed fingers.
Laboratory and auxiliary examinations
Routine blood test often reveals moderate anemia, mostly microcytic hypochromic anemia, decreased serum iron and transferrin saturation, and increased total iron binding capacity. White blood cells and platelets are usually normal.
If there are little hemorrhage, the chest x-ray may be normal, and CT may show ground-glass opacity.
Chest x-ray and CT in the acute or subacute IPH may show active hemorrhage manifestations of focal or diffuse pulmonary infiltration, such as patchy opacity, ground-glass opacity, consolidation, and bronchial inflation, sometimes accompanied by pleural effusion.
With the protracted course, interstitial changes occur and are manifested by diffuse or focal reticular, granular, nodular opacities; cystic lesions; and pleural thickening. In the terminal stage of the disease, basal and subpleural pulmonary fibrosis and honeycomb changes can be seen.
Diagnosis
The diagnosis is mainly based on recurrent hemoptysis; poorly marginated, diffuse, spotty opacities in the lungs; and secondary iron deficiency anemia.
Routine BAL examination confirms the presence of alveolar hemorrhage and can detect occult hemorrhage. The presence of free erythrocytes or alveolar macrophages containing phagocytosed erythrocytes in BALF indicates recent alveolar hemorrhage, and the presence of many hemosiderin-containing macrophages indicates long-term alveolar hemorrhage. Autoantibodies such as anti-GBM, anti-ANCA, anti-ANA, and anti-RF antibodies should also be routinely tested to exclude diffuse alveolar hemorrhage caused by other reasons.
Treatment
In general, the clinical manifestations of IPH are relatively mild, particularly in adults, and 25% of patients can be relieved spontaneously. However, diffuse alveolar hemorrhage can lead to death. Supportive treatment is preferred. Glucocorticoids in combination with azathioprine or cyclophosphamide are beneficial for the prognosis of acute exacerbation and prevention of recurrent hemorrhage.