Idiopathic pulmonary hemosiderosis (IPH) is a rare disease of unknown cause characterized by intermittent pulmonary hemorrhage. More than 200 cases have been reported internationally, with over 120 cases reported in China (as of 1994). After the destruction of red blood cells in the alveoli, globin is absorbed, and hemosiderin deposits in the lung tissue, causing a reaction. Recurrent bleeding may lead to secondary iron deficiency anemia.

bubble_chart Etiology

The exact cause is unknown. It is speculated to be related to several factors: abnormal development of pulmonary epithelial cells, mechanical instability of pulmonary interstitial capillaries leading to recurrent bleeding; immune dysfunction, such as pulmonary eosinophil infiltration in 1/8 of patients, increased mast cells and plasma cells, and positive cold agglutinin tests in some patients. Some patients may develop conditions resembling wind-dampness, polyarthritis, myocarditis, or Goodpasture syndrome.

Other mentioned causes include animal protein intake and exposure to toxic substances (e.g., organic pesticides).

bubble_chart Pathological Changes

The lung weight is increased, and diffuse brown pigmentation can be observed on the cut surface. Microscopic examination may reveal necrosis and hyperplasia of alveolar epithelium, local capillary dilation, and macrophages containing hemosiderin in the alveoli and interstitium. In the late stage [third stage], diffuse interstitial fibrosis may occur. Electron microscopy indicates widespread swelling of capillary endothelial cells, with protein deposits in the membrane. After washing and drying the lung tissue, the iron content remains 5 to 200 times higher than that of normal lungs and is proportional to the severity of the disease.

This disease is more common in children, mainly seen between the ages of 1 and 7, with 15% of cases occurring over the age of 15. The male-to-female ratio in adults is 2:1, and there is no obvious familial tendency. Symptoms depend on the degree of pulmonary hemorrhage. Grade I persistent chronic bleeding may present with dry cough, lack of strength, pale skin, weight loss, and even clubbing of fingers. During acute bleeding episodes, symptoms such as blood-streaked sputum, hemoptysis, low-grade fever, and chest pain may occur. In the late stage [third stage], manifestations such as dyspnea and even cardiac insufficiency may appear. During acute episodes and secondary infections, obvious moist rales may be heard. Stool occult blood tests are positive.

X-ray findings show multiple poorly defined patchy shadows in the middle and lower lung fields, which resolve within weeks after the cessation of pulmonary hemorrhage. In cases of persistent moderate bleeding, lung lesions may appear as foxtail millet-sized granular shadows.

bubble_chart Diagnosis

Repeated hemoptysis, blood-streaked sputum, ill-defined patchy shadows in the lungs, and secondary iron-deficiency anemia can lead to a preliminary diagnosis. The diagnosis is confirmed by finding hemosiderin-laden macrophages in sputum, bronchoalveolar lavage fluid, or lung biopsy, while excluding cardiac (congestive) causes.

bubble_chart Treatment Measures

During the acute phase, hormone therapy may be attempted, commonly using prednisone at 1–2 mg/(kg·d), with dosage reduction after 2–3 weeks, gradually tapering to a maintenance dose. Symptomatic management includes iron therapy for iron-deficiency anemia and antibiotic treatment for secondary infections.