Diffuse Alveolar Hemorrhage

Diffuse alveolar hemorrhage results from widespread damage to the pulmonary small vessels, leading to blood collecting within the alveoli. If enough alveoli are affected, gas exchange is disrupted. The specific pathophysiology and manifestations vary depending on cause. For example, isolated pauci-immune pulmonary capillaritis is a small-vessel vasculitis Overview of Vasculitis Vasculitis is inflammation of blood vessels, often with ischemia, necrosis, and organ inflammation. Vasculitis can affect any blood vessel—arteries, arterioles, veins, venules, or capillaries... read more limited to the lungs; its only manifestation is alveolar hemorrhage affecting people aged 18 to 35 years.

Many disorders can cause alveolar hemorrhage; they include

Symptoms and signs of milder diffuse alveolar hemorrhage are dyspnea, cough, and fever; however, many patients present with acute respiratory failure Acute Hypoxemic Respiratory Failure (AHRF, ARDS) Acute hypoxemic respiratory failure is defined as severe hypoxemia (PaO2 (See also Overview of Mechanical Ventilation.) Airspace filling in acute hypoxemic respiratory failure (AHRF) may result... read more , sometimes leading to death. Hemoptysis is common but may be absent in up to one third of patients. Most patients have anemia and ongoing bleeding, leading to a reduced hematocrit.

There are no specific physical examination findings.

Other manifestations depend on the underlying disorder (eg, diastolic murmur in patients with mitral stenosis).

Diagnosis is suggested by dyspnea, cough, and hemoptysis accompanied by chest x-ray findings of diffuse bilateral alveolar infiltrates and a suspicion of diffuse alveolar hemorrhage. Bronchoscopy Bronchoscopy Bronchoscopy is the introduction of an endoscope into the airways. Flexible fiberoptic bronchoscopy is used for virtually all diagnostic, and most therapeutic, indications. Flexible bronchoscopes... read more with bronchoalveolar lavage (BAL) is strongly recommended to confirm the diagnosis, particularly when manifestations are atypical or an airway source of hemorrhage has not been excluded. Specimens show blood with numerous erythrocytes and siderophages; lavage fluid typically remains hemorrhagic or becomes increasingly hemorrhagic after sequential sampling.

Patients can require mechanical ventilation Overview of Mechanical Ventilation Mechanical ventilation can be Noninvasive, involving various types of face masks Invasive, involving endotracheal intubation Selection and use of appropriate techniques require an understanding... read more and even die as a result of hemorrhage-associated respiratory failure. Recurrent alveolar hemorrhage causes pulmonary hemosiderosis and fibrosis, both of which develop when ferritin aggregates within alveoli and exerts toxic effects. COPD Chronic Obstructive Pulmonary Disease (COPD) Chronic obstructive pulmonary disease (COPD) is airflow limitation caused by an inflammatory response to inhaled toxins, often cigarette smoke. Alpha-1 antitrypsin deficiency and various occupational... read more (chronic obstructive pulmonary disease) occurs in some patients with recurrent diffuse alveolar hemorrhage secondary to microscopic polyarteritis.

Treatment involves correcting the cause.

Corticosteroids and possibly cyclophosphamide are used to treat vasculitides, connective tissue disorders, and Goodpasture syndrome Treatment Goodpasture syndrome, a subtype of pulmonary-renal syndrome, is an autoimmune syndrome consisting of alveolar hemorrhage and glomerulonephritis caused by circulating anti-glomerular basement... read more . Rituximab has been studied primarily in ANCA-associated vasculitis and has been shown to be noninferior to cyclophosphamide for induction treatment (1 Treatment references Diffuse alveolar hemorrhage is persistent or recurrent pulmonary hemorrhage. There are numerous causes, but autoimmune disorders are most common. Most patients present with dyspnea, cough, hemoptysis... read more ) and superior to azathioprine for remission treatment (2 Treatment references Diffuse alveolar hemorrhage is persistent or recurrent pulmonary hemorrhage. There are numerous causes, but autoimmune disorders are most common. Most patients present with dyspnea, cough, hemoptysis... read more ). Rituximab has also been used to treat alveolar hemorrhage related to systemic lupus erythematosus, Goodpasture syndrome, and antiphospholipid antibody syndrome.

Plasma exchange Plasma exchange Apheresis refers to the process of separating the cellular and soluble components of blood using a machine. Apheresis is often done on donors where whole blood is centrifuged to obtain individual... read more may be used to treat Goodpasture syndrome.

Several studies have reported successful use of recombinant activated human factor VII in treating severe unresponsive alveolar hemorrhage, but such therapy is controversial because of possible thrombotic complications.

Other possible management measures include supplemental oxygen, bronchodilators, reversal of any coagulopathy, and intubation with protective strategies as for acute respiratory distress syndrome Acute Hypoxemic Respiratory Failure (AHRF, ARDS) Acute hypoxemic respiratory failure is defined as severe hypoxemia (PaO2 (See also Overview of Mechanical Ventilation.) Airspace filling in acute hypoxemic respiratory failure (AHRF) may result... read more (ARDS) and mechanical ventilation Overview of Mechanical Ventilation Mechanical ventilation can be Noninvasive, involving various types of face masks Invasive, involving endotracheal intubation Selection and use of appropriate techniques require an understanding... read more .