Priapism

Priapism is persistent erection of the penis
It is uncommon but early diagnosis and treatment is essential
Delayed presentation or treatment results in corporal anoxia and loss of erectile function

Pathophysiology

Two types of priapism exist
- High-flow
- Low-flow
Low-flow priapism is more common
Due to venous stasis and ischaemia
Aetiological factors include
- Intracavernosal injection
- Pelvic malignancy
- Blood disorders - sickle-cell disease, leukaemia
- Trauma - spinal cord injury
- Prolonged sexual activity
- Urogenital tract inflammation
- Drugs
High-flow priapism is uncommon
Due to the development of an arteriocavernosal fistula
Can follow blunt or penetrating penile or perineal trauma
Anatomically it involves the corpora cavernosa only

Clinical features

History and clinical features will allow differentiation of low-flow and high-flow priapism
Low-flow priapism presents with painful persistent erection
Penile shaft is firm and glans penis is usually soft
High-flow priapism is often painless
There is invariably a clear history of trauma

Management

Aspiration of the corpora will distinguish the two types
- In high-flow priapism the blood is arterial
- In low-flow priapism the blood is dark and viscous and is similar to venous
Intracorporeal blood blood gas analysis can be useful to distinguish the two types
Early treatment is essential, preferably within 12 hours of onset
Low-flow priapism requires urgent aspiration and instillation of a vasoconstrictor
Aspiration alone is successful in 30% cases
Phenylephrine is the vasoconstrictor of choice
This should be followed by a drainage procedure into
- The glans penis (Modified Winter / Ebbehoj shunt)
- The corpora spongiosum (Quackel's procedure)
- The long saphenous vein (Grayhack procedure)
Detumescence can be achieved in 50-70% of patients
Maintenance of erectile function is present in about 40%
High-flow priapism requires closure of the arteriocavernosal fistula
Can often be performed by an interventional radiologist

Bibliography

Cherian J, Rao A R, Thwaini A et al. Medical and surgical management of priapism. Postgrad Med J 2006; 82: 89-94

Gorich J, Ermis C, Kramer S C et al. Interventional treatment of traumatic priapism. J Endovasc Ther 2002; 9: 614-617.

Kalsi J S, Arya M, Minhas S, Ralph D J. Priapism: a medical emergency. Hosp Med 2002; 63: 224-225.

Keoghane S R, Sullivan M E, Miller M A. The aetiology, pathogenesis and management of priapism. BJU Int 2002; 90: 149-154.

Montague D K, Jarow J, Broderick G A et al. American Urological Association guidelines on the management of priapism. J Urol 2003; 170: 1318-1325.