72. Pulmonary Arteriovenous Fistula
Definition
Pulmonary arteriovenous fistula (PAVF) is an abnormal communication between the pulmonary arteries and vein. It is typically a congenital anomaly, but may also develop as the result of a number of acquired conditions/diseases. The end result of this communication is a right-to-left shunt.
Conditions Associated with Pulmonary Arteriovenous Fistula Formation
• Actinomycosis
• Fanconi syndrome (see p. 132)
• Hepatic cirrhosis
• Metastatic thyroid carcinoma
• Mitral stenosis
• Schistosomiasis
• Trauma
Incidence
The exact frequency has not been documented because PAVFs have not been carefully studied. In adults PAVF seems to occur more frequently in females than in males by almost a 2:1 ratio; among newborns, males are more frequently affected.
Etiology
The exact cause of PAVF has not been demonstrated. One theory suggests that a defect resulting in dilation of thin capillary sacs occurs in the terminal arterial loop. A different theory suggests the cause may be an incomplete resorption of the vascular septa separating the arterial and venous plexus that would usually anastomose during fetal development. Still another theory points to development of small PAVFs resulting from failure of capillary development during fetal growth.
Signs and Symptoms
• Anemia
• Chest pain
• Congestive heart failure
• Cough
• Cyanosis
• Diplopia
• Dizziness
• Dysarthria
• Dyspnea
• Epistaxis
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