Penile Complaints

PRIAPISM

Priapism is an abnormally prolonged penile erection (>6 hours) that does not result from sexual desire. It generally involves only the corpora cavernosa and not the spongiosum. It is often associated with pain and difficulty urinating. It can occur at any age and may last for several days to several weeks if left untreated.

Etiology

Priapism can be classified into two distinct types: low-flow (ischemic) veno-occlusive and high-flow (nonischemic) arterial priapism. Low-flow ischemic priapism is secondary to failure of the detumescence mechanism and obstruction of the venous drainage of the corpora cavernosa. Ischemic priapism is associated with acidotic cavernosal blood gases. High-flow priapism is generally the result of trauma that causes laceration or rupture of the cavernous artery within the corpora cavernosa.

Many cases are classified as primary or idiopathic because the etiology is unknown. Other major causes of priapism include drug and alcohol abuse, erectile dysfunction drug therapy, sickle cell disease, neoplastic diseases, and trauma. Drugs that affect the neurovascular or central nervous system can potentially cause priapism. These include psychotropics (e.g., chlorpromazine and trazodone), antihypertensives (especially hydralazine, guanethidine, and prazosin), and alcohol. Anticoagulants (e.g., heparin) have also been associated with cases of priapism. Pharmacologic injection therapy to treat erectile dysfunction, such as intracavernous injection of papaverine or prostaglandin E₁, has become the most common cause of priapism.

Sickle cell disease and trait are common etiologies in boys and account for about 10% to 20% of cases overall. Attacks often occur during sleep with sludging of red cells in the corpora cavernosa after a normal physiologic nocturnal erection. It is referred to as stuttering priapism because of its intermittent recurrent pattern.

Neoplastic diseases can obstruct corporal outflow. Leukemias are the most common cause of priapism in boys.

Trauma can result in priapism secondary to hematoma formation and compression of venous drainage or injury to the cavernous artery and high-flow priapism.

Diagnosis

The diagnosis of priapism is straightforward. Patients present with a persistent erection (>4 hours) without sexual desire. Pain and fever may be present along with difficulty voiding. On physical examination the corpora cavernosa are fully rigid in low-flow veno-occlusive ischemic priapism and partial to fully rigid in high-flow priapism. The glans penis is generally flaccid. Ischemic priapism is often the result of the use of pharmacologic agents. Patients will often delay seeking attention because of embarrassment. Recognition of any underlying etiology such as neoplasm or sickle cell disease is important because it may affect the plan of treatment. A sickle cell preparation for hemoglobin S should be performed on all black patients with priapism. A complete blood count should be obtained to rule out leukemia. A thorough drug history is essential. Intracavernosal injection therapy complications will be evident from the history. Cavernosal blood gases and color duplex Doppler ultrasound scanning can be helpful in differentiating ischemic and nonischemic priapism. Patients with prolonged ischemic priapism will have no blood flow in the cavernous arteries, whereas patients with high-flow nonischemic priapism will have normal to high blood flow on ultrasound.

Management

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