Priapism (prolonged erection)

• What is Priapism
• Statistics on Priapism
• Risk Factors for Priapism
• Progression of Priapism
• Symptoms of Priapism
• Clinical Examination of Priapism
• How is Priapism Diagnosed?
• Prognosis of Priapism
• How is Priapism Treated?
• Priapism References

What is Priapism

Priapism refers to the medical condition in which the patient experiences a persistent and painful erection that is present for longer than 6 hours, which is not induced by stimulation nor sexual desire. It usually only affects the corpus cavernosa of the penis. There are two types of priapism:

1. Low-flow priapism – Most common form of disease, arising from the slow passage of blood through the vascular chambers of the penis. This is primarily caused by increased viscosity of blood in the penis. This type of priapism is a rugical emergency for the penis may be damaged with prolonged low-flow priapism.

2. High-flow priapism – Less common, this form of disease occurs most commonly with trauma (penile, perineal or pelvic.) This form of priapism does not pose a threat to the future heath of the penis.

Statistics on Priapism

This condition is exceedingly rare when the entire population is considered. The incidence in patient’s being treated for erectile dysfunction, however, varies between 0.5 and 6%. This is because the most common cause of priapism is the use of agents to treat erectile dysfunction.

The condition may occcur in any age group, but most common occcurs at 19-21 years of age in those with sickle cell disease induced priapism.

Risk Factors for Priapism

The most common cause of priapism are drus used in the treatment of erectile dysfunction or impotence. Those drugs which are directly injected into the penis place the patient at most risk of this condition. About 25% of cases are associated with co-existing medical conditions such as:
1. Advanced cancer,
2. Leukaemia and
3. Sickle cell anaemia and other haemoglobin disorders
4. Treatment for erectile dysfunction (particularly penile injections)
5. Use of anti-coagulant and some psychiatric medications
6. Fabry’s disease

Other cases may be related to recent trauma, but the majority of patients have not predisposing factors, occurring spontaneously.

Progression of Priapism

Low flow priapism begins with the development of a painful persistent erection, with stimulation or sexual desire. The penis will remain erect and at sigificant risk of permanent damage, unless the patient seeks medical aid to restore normal blood flow to the penis. With adequate therapy, the patient will retain his erectile function. If therapy remains inadequate or is provided too late, the patient may suffer permanent damage and long-term impotence.

How is Priapism Diagnosed?

The cause of disease must be rapidly identified and treated in the case of low-flow priapism. General investigations should include urine samples for the detection fo infection and blood in the urine from trauma, and a variety of blood tests to search for an underlying cause of the priapism.

Prognosis of Priapism

The prognosis of low-flow priapism depends largely on the time taken to restore normal blood flow to the penis. If treatment is initiated early and is successful, the patient will retain normal erectile function and appearance. If treatment is delayed or unsuccessful, the patient may suffer irreversible penile damage and loss of erectile function.

The prognosis of high-flow priapism is generally good, for the blood supply to the penis is not compromised, only deranged. The penis is not at risk of major damage, and thus many physicians prefer to treat this condition is a “wait-and-see” manner, with the condition settling by itself in many cases.

How is Priapism Treated?

Low-flow priapism
a. Supportive measures – Analgesia such as morphine and anxiolytics such as diazepam to reduce patient anxiety.
b. Conservative measures – Exercise, ice and ejaculation have proven effective in some cases of this condition and should be tried before surgery.
c. Medical techniques – Antiandrogens, digoxin and alpha-blockers have been advocated in the treatment of priapism.
d. Surgical techniques – The surgical procedures used for this condition all aim to create an anastomosis between the corpus cavernosum and another vascular chamber of the penis. Initially, a connection is attempted between the glans and the cavernsum in the Winter and Ebbehoj procedures. If this fails (which occurs in 1/3) a more permanent connection between the corpus cavernosum and corpus spongiosum is fashioned. This is technique is more effective than the former, but the occurrence of iatrogenic impotence is far greater.
e. Sickle cell patients – This group of patients may require a specific regime of therapy to treatment their sickle cell disease, including oxygenation, hydration,
alkalinization, analgesia and exchange transfusion.

High-flow priapism
a. Interventional radiology – The use of specialised techniques may hasten the resolution of this condition, which does not pose significant threat to erectile function or appearance. These procedures aim to dissolve any clot that induces anomalous blood flow through the penis, causing high-flow priapism.
b. Surgical intervention – If the condition does not resolve with conventional therapy, surgery is the only other option available. Those blood vessels responsible for the condition are located by ultrasound and removed in surgery.
c. Expectant approach – As the condition poses little threat to erectile function or appearance, the patient may only be observed, as the condition may resolve on its own accord.

Priapism References

[1] Keoghane SR, Sullivan ME, Miller MA. The aetiology, pathogenesis and management of priapism. BJU International 90: 149-154.
[2] Way LW. Surgical Diagnosis and Treatment 10th Edition. Appleton-Lange, USA 1994.