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Abstract
The case of an elderly man with priapism as his only symptom is presented. The importance of clinical signs and simple investigations to make a diagnosis of aortocaval fistula associated with abdominal aortic aneurysm are discussed.
- aortic aneurysm
- aortocaval fistula
- priapism
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An 83 year old man was referred to the urology team as an emergency with a prolonged, non-painful erection of about 12 hours duration. On examination an engorged, non-tender penis including the glans was discovered. Corporal cavernosal aspiration was undertaken and blood gas analysis was performed. These results were consistent with normal systemic venous blood. On further inquiry it was discovered that an abdominal aortic aneurysm had been diagnosed some years ago after a laparotomy for a self inflicted knife injury to the abdomen during an episode of severe depression. Abdominal examination revealed a large pulsatile mass consistent with an abdominal aortic aneurysm. Distal pulses were present and there was general venous engorgement of the superficial veins. Cardiovascular function remained stable and a urinary catheter was passed that revealed frank haematuria. Renal function was impaired with a rise in serum creatinine activity. A CT scan was performed to ascertain whether there was rupture of the aneurysm. This revealed a 14 cm aneurysm, which had not ruptured, but instead an aortocaval fistula existed. At this stage after discussion with the patient it was decided to perform an emergency operation to close the fistula and repair the aneurysm.
DISCUSSION
The associations between arterial aneurysms and priapism have been previously reported and include aortocaval fistulas1 and traumatic A-V malformations and aneurysms.2 There have also been cases of priapism after rupture of intracranial aneurysms.3
Priapism is a rare condition particularly in this age group. In addition the presence of an erect corpus spongiosum as demonstrated by engorgement of the glans is also rare. Incidence in the older age group is particularly attributable to treatments for erectile dysfunction. However the incidence of priapism is much lower with oral drugs when compared with intracorporeal agents. Blood gas analysis from the penis permits differentiation from the common form, so called veno-occlusive or low flow priapism, in which the oxygen content would be far lower than normal and lead to ischaemic changes.
The development of priapism in this man was therefore suspicious as he had not had an erection for many years and was not receiving any treatment for this condition. It is important as there are several factors that taken together allow a high index of suspicion to exist to make a diagnosis of aortocaval fistula. These include the presence of a known aneurysm, which had not been electively repaired and thus allowed to reach a large size. The corpus spongiosum was involved in the priapism and blood gas analysis revealed non-ischaemic blood in addition to the prolonged erection with no associated pain thus indicating high flow priapism. The final important sign is that of frank haematuria attributable to venous engorgement that was also indicated by distended leg veins when lying down. An early emergency vascular opinion is necessary to ensure appropriate treatment is provided if these signs exist.