High flow priapism due to an arterial-lacunar fistula complicating initial veno-occlusive priapism.

High flow or arterial priapism is rare, caused by unregulated arterial blood flow from a lacerated cavernous artery or branch entering directly into lacunar spaces, bypassing the protective, high resistance helicine arterioles and resulting in an arterial-lacunar fistula (ALF) and usually occurs following direct blunt or penetrating perineal trauma. Clinical features include delayed onset of a constant, painless, nontender erection of incomplete rigidity with potential for full rigidity with sexual stimulation. Colour duplex Doppler ultrasonography (CDU) is reliable in the diagnosis of arterial priapism. Treatment by arterial ligation, super-selective embolisation with autologous clot, gelatin sponge or microcoil, duplex guided compression, systemic or intracavernous administration of a variety of alpha-adrenergic agents or methylene blue, mechanical compression/ice packs or expectant management has been reported.