Alveolar Hemorrhage

Abstract

Alveolar hemorrhage (AH) is a clinical syndrome with diverse etiologies both immune and nonimmune. The defining pathological feature of AH is the presence or absence of pulmonary capillaritis. The antineutrophil cytoplasmic antibody (ANCA) related vasculitis and systemic lupus erythematosus are the commonest causes of immune AH with pulmonary capillaritis, whereas Goodpasture's syndrome and idiopathic pulmonary hemosiderosis are common causes of immune AH without pulmonary capillaritis. The major nonimmune causes of AH are primarily drug induced, or due to hematological malignancy and disorders of coagulation. Clinical features of AH include: dyspnea, fever, hemotypsis, bilateral crackles and pallor. Hypoxemia and bilateral diffuse airspace disease on the chest radiograph with relative sparing of the bases and apices which most often clears within 48 hours after its onset further characterize this syndrome. The major clinical implications of this syndrome are its potential to cause respiratory failure in severe cases and its sequelae of pulmonary fibrosis with associated morbidity and disability. In addition, AH may be the initial manifestation of a systemic immune disorder which can be managed optimally if recognized early. The diagnosis of AH is confirmed by bronchoalveolar lavage by demonstrating a progressively bloody return on successive aliquots of instilled saline or hemosiderin laden macrophages in the bronchoalveolar lavage fluid. The open lung biopsy remains the gold standard for the diagnosis of AH but is reserved for inapparent cases in whom corticosteroids and immunosuppressive therapy may be life saving. Serologic testing and examination of the urine sediment are useful adjuncts to the diagnosis. The treatment of AH is primarily supportive while an attempt is made to determine its etiology and initiate specific therapy. Glucocorticoids and cyclophosphamide are the cornerstones of therapy in immune AH with adjunctive plasmapheresis in life-threatening cases.