Diffuse alveolar hemorrhage is an acute life threatening lung disorder. In our lungs there are tiny alveoli. They are air sacs having thin wall and are in direct contact with pulmonary capillaries. Exchange of respiratory gases, oxygen and carbon dioxide from the pulmonary capillaries takes place in these tiny air sacs. It becomes easy to understand what the condition diffuse alveolar hemorrhage is after having basic knowledge about lungs and alveoli.
As the name suggests, in diffuse alveolar hemorrhage, there is continuous or recurrent bleeding in the alveolar space. Several reasons have been blamed to cause diffuse alveolar hemorrhage, but among them auto immune disorders are common.Breathing difficulty, cough, blood in sputum, and new infiltration of alveoli are the main symptoms of diffuse alveolar hemorrhage.
Early recognition of disease is important for a better prognosis. Treatment consists of immunosuppressant drugs in case of auto immune disease and other supportive respiratory measures.
Causes Of Diffuse Alveolar Hemorrhage
Diffuse alveolar hemorrhage occurs when small blood vessels of the alveoli are damaged. Due to this, blood gets collected in the air sac (alveoli). With collection of blood in the alveoli, the space for exchange of gases becomes less. It is one of the reasons for breathing difficulty that occurs in alveolar hemorrhage.
Below are given common causes for diffuse alveolar hemorrhage.
- Autoimmune diseases. (Systemic lupus, Good pasture syndrome, antiphospholipid antibody syndrome).
- Lung infection such as Hanta virus infection, aspergillosis.
- Inhaling or absorption of certain pesticides and toxic substances can cause damage to the tiny blood vessels of the alveoli leading to hemorrhage. Example; isocyanates, cocaine, trimellitic anhydride etc.
- Reaction to certain drugs. Example; amiodarone, methotraxate, nitrofurantoin, infliximab etc.
- Mitral valve disease such as mitral stenosis.
- Blood coagulation diseases.
- Use of anticoagulant medicines.
- Organ transplantation.
- Idiopathic pulmonary siderosis.
Diffuse Alveolar Hemorrhage Symptoms
The symptoms may exemplify as manifestation of underlying auto immune disease such as systemic lupus erythematosus, systemic sclerosis, rheumatoid disease etc. It can also occur as an isolated pulmonary abnormality.
- Patient complains of gradual progression of breathing difficulty, especially on exertion. It is accompanied by persistent dry cough.
- Recurrent episode of fever is present.
- Blood in sputum is common, but in few patients it may be completely absent.
- Iron deficiency anemia if the underlying cause is idiopathic pulmonary hemosiderosis.
- Chest expansion is poor.
- A sudden acute hemorrhagic episode may cause acute respiratory failure and death.
- Physical examination may reveal skin rash, purpura, lesions in eye, enlargement of liver and spleen. All the signs are manifestation of underlying disease.
Diagnosis of diffuse alveolar hemorrhage is possible by history, medical examination as well as with X-ray chest, bronchoscopy, and certain blood tests.
Treatment For Diffuse Alveolar Hemorrhage
- Treatment of alveolar hemorrhage is centered upon treating the underlying condition, mostly the autoimmune disease. Use of corticosteroids and immunosuppressive drugs remain the standard treatment, especially if the condition is accompanied with pulmonary vasculitis, Goodpasture syndrome or rheumatic disorders.
- Other mode of treatment includes plasmapheresis, and intravenous immunoglobulin. It is useful in cases of vasculitis and connective tissue disorders.
- Other supportive treatment includes oxygen supplementation, use of bronchodilator, intubation and mechanical respiration in case of respiratory failure.
- Administration of human recombinant-activated factor V11 is found to be useful in controlling the bleeding in the air space.
- Treating mitral stenosis is useful in reducing the symptoms of diffuse alveolar hemorrhage.