Being<unk> ,<unk>  by definition has an unknown cause. It is thought to be an immune-mediated disease. The lung bleeding causes accumulation of iron, which in itself causes additional lung damage. Meanwhile, there is insufficient iron for inclusion into the haemoglobin molecules inside red blood cells which carry oxygen to body tissues for cellular respiration.<unk>  can occur either as a primary lung disorder or as the sequela to other pulmonary, cardiovascular or immune system disorder. * PH1 involves PH with circulating anti-GBM antibodies. * PH2 involves PH with immune complex disease such as systemic lupus erythematosus, SLE. * PH3 involves no demonstrable immune system involvement. A distinct subset of patients with pulmonary<unk>  has hypersensitivity to cow's milk which result in formation of IgG antibodies against basement membrane. This is called Heiner syndrome. Mechanism of haemorrhage is similar to that observed in Goodpasture syndrome. Related or similar conditions There are many pulmonary problems that may seem to mimic<unk>  but do not necessarily include the deposits of iron into the lung. The deposition of iron in the lungs, occurring in the form of haemosiderin, is the defining characteristic of this illness. These other conditions may occur separately or together with<unk> . :*Pulmonary fibrosis :*Adult respiratory distress syndrome (ARDS) :*Immune complex disease :*intra-alveolar bleeding
Idiopathic pulmonary haemosiderosis
Melioidosis
Sarcoidosis
Extrapulmonary tuberculosis
Chronic pulmonary aspergillosis
Tuberculosis
Allergic bronchopulmonary aspergillosis
Amyloidosis