A pulmonary arteriovenous fistula (PAVF) can occur in a number of situations.
Causes of a PAVF:
(1) hereditary hemorrhagic telangiectasia (HHT)
(2) other congenital malformation
(3) after penetrating trauma (knife or bullet, including delayed migration of retained fragments)
(4) metastatic carcinoma (thyroid, other)
(5) pulmonary schistosomiasis
(6) cirrhosis
(7) actinomycosis
(8) mitral stenosis
(9) Fanconi's syndrome
(10) Pneumocystis jirovecii pneumonia
(11) possibly pulmonary arterial hypertension
