Priapism is a persistent and long lasting erection seen in the absence of sexual stimulation. It can typically last for hours and cannot be relieved by ejaculation. This painful condition can occur in males of all ages, even infants. If left untreated, priapism can lead to erectile dysfunction or necrosis of penile tissue. Treating the condition as early as possible, provides the best chance of a full recovery.
During an erection, signals from nerve cells and relaxation of muscle fibers in the penis cause blood to flow into the penis. The blood then gets trapped there, increasing pressure and making the penis erect. An orgasm leads to contraction of muscle fibers and arteries in the penile tissue, leading to decreased blood flow. The pressure in the penis eventually drops, blood flows out and the penis becomes flaccid.
Priapism results when blood in the penis gets trapped and cannot flow out. There are two forms of priapism, low flow or ischemic and high flow or non-ischemic priapism.
Low flow priapism: This is the more common form of priapism and occurs when blood is unable to leave the penis. In most cases, it is not entirely known what causes this condition and it is therefore considered to be of idiopathic etiology. Certain medical conditions and pharmacologic medications have been associated with low flow priapism:
- Sickle cell anemia: It has been found that almost half the patients with sickle cell anemia go on to develop low flow priapism.
- Other conditions associated with hypercoagulability (abnormal blood coagulation resulting in increased risk of blood clots) such as thalassemia, fat embolism and vasculitis may lead to priapism.
- Certain cancers such as prostate cancer, leukemia, bladder cancer, melanomas and renal carcinoma obstruct blood flow leading to low flow priapism
- Some medications can lead to priapism. These include anticoagulants like heparin, psychotropic like SSRIs, antihypertensive drugs such as calcium channel blockers and diuretics and hormones such as testosterone and gonadotropin releasing hormone.
- Illegal drugs such as cocaine and marijuana may also affect penile blood flow.
High flow priapism: is relatively rare and occurs when too much blood flows into the penis. This may happen due to a ruptured artery caused by trauma to the genitourinal area. Therefore common causes of high flow priapism involve those that cause injury to the penis or perineal area such as straddle injuries or intracavernous injections resulting in injuries to the arteries.
Other rare causes of priapism include black widow spider bites, carbon monoxide poisoning, amyloidosis, spinal cord injury and malaria.
Conditions that affect blood circulation in men, such as sickle cell disease, increase the risk of priapism. Overdosing on erectile dysfunction drugs, illicit drug use, alcohol abuse and strenuous sexual activity are some of the risk factors.
Signs and symptoms of low-flow priapism include:
- Rigid and persistent erection, sometimes lasting for more than four hours
- Stuttering priapism: This is seen when the erection comes and goes for several hours at a time.
- While the shaft stays rigid, the tip of the penis is soft
- This condition is usually accompanied by pain and tenderness in the penis.
Signs and symptoms of high flow priapism include:
- Injury to the penis or perineum
- An erection lasting for at least four hours
- The shaft of the penis is erect but not rigid
- It is usually not painful when compared to low flow priapism
Males suffering from priapism should seek medical care immediately as prolonging diagnosis increases the chances of permanent damage to the penile tissue. A doctor will require the patient’s full medical history as well as information about symptoms experienced. A physical exam is usually done to determine the cause of the condition, especially if trauma is suspected. Blood tests may also be done to determine if the patient has blood disorders such as sickle cell anemia. Imaging studies such as ultrasonography and pelvic angiographies may be done to detect fistulas caused by injury or trauma.
Treatment for priapism depends on the cause of the condition. In case of low flow priapism, the following treatment options are available:
- Intracavernous injection: vasoconstrictive medications are injected into the penis to narrow the veins, reduce blood flow and ease swelling. These drugs include alpha agonists such as terbutaline and phenylephrine.
- A surgical shunt may be inserted to divert the blood flow and return blood circulation to normal levels.
- In some cases, under local anesthetic, the penis may be punctured with a needle and the blood allowed to drain. This is done to return pressure back to normal.
Treatment for high flow priapism involves first detecting the underlying fistula caused by injury. Ruptured arteries or fistulas may then be surgically ligated or the fistula closure can be done by arterial embolization.
Prognosis for priapism is therefore good, when treatment is provided immediately. However if left untreated, it may result in long term damage and sometimes even impotency.