Diffuse pulmonary hemorrhage

Diffuse pulmonary hemorrhage (DPH) is a subtype of pulmonary hemorrhage where bleeding into the lung is diffuse (cf. focal pulmonary hemorrhage). If the bleeding is into the alveolar spaces, it can be further subclassified as diffuse alveolar hemorrhage (DAH).

Epidemiology

Associations

• pulmonary vasculitides: especially small vessel vasculitides: alveolar hemorrhage secondary to extensive parenchymal small-vessel vasculitis is typically more diffuse and initially causes more widespread lobular ground-glass opacification with gravity-dependent density gradients through to air-space consolidation, often with interspersed areas of ground-glass opacity; these include
  • granulomatosis with polyangiitis ²
  • other connective tissue disorders
    • systemic lupus erythematosus (SLE) ^4,6
• post bone marrow transplantation ³
• all-trans-retinoic acid (ATRA) syndrome ¹¹
• Goodpasture syndrome ¹⁰
• pulmonary hemosiderosis: idiopathic pulmonary hemosiderosis ⁷
• coagulative disorders: often require another precipitating source such as an infection to cause DPH ⁷
• pulmonary hemorrhage complicating multifocal infection
• widespread metastatic lung disease: has been described as a very rare cause of DPH ⁵

Clinical presentation

While the exact presentation can vary is has been classically associated with dyspnea in the setting of hemoptysis +/- iron deficiency anemia ⁷.

Radiographic features

Plain radiograph

Whilst chest radiographic appearances are non-specific, there may be evidence of bilateral air-space consolidation with relative apical sparing ⁷.

CT/HRCT

May show areas of widespread ground glass opacification +/- crazy paving pattern ⁸ +/- areas of consolidation. In the subacute phase HRCT may show fine diffuse nodular densities ^9-10. In later stage there may also be evidence of interlobular septal thickening due to intralymphatic accumulation of hemosiderin.

Differential diagnosis

For plain radiograph and CT, in the acute phase of diffuse pulmonary hemorrhage appearances, consider:

• multiple localized pulmonary hemorrhages from diffuse aspiration of blood ⁷
• pulmonary edema ¹
• diffuse pulmonary infection / diffuse pneumonia ¹

For HRCT appearances in the subacute phase (i.e. fine nodules) consider:

• hypersensitivity pneumonitis ⁹