Priapism is a rare condition. The frequency is around 1.5 in 100,000 men. In principle, priapism can occur at any age. However, there are two peaks in disease:

Priapism is named after the Greek god Priapus, the god of fertility. Priapism is defined as an erection of the penis that lasts longer than 2 hours without sexual arousal. Priapism is therefore also called permanent erection. There are two forms of priapism between which a distinction is made: there is the low-flow type and there is the high-flow type of priapism. It is an acute urological emergency that requires immediate treatment to prevent permanent damage to the erectile tissue.


Priapism is a rare condition. The frequency is around 1.5 in 100,000 men. In principle, priapism can occur at any age. However, there are two peaks in disease:

  1. Summit: This occurs between the ages of 5 and 15. The priapism is then mostly associated with homozygous sickle cell anemia.
  2. Summit: It occurs between the ages of 20 and 50. The priapism is then mostly related to SKAT therapy.

Differentiation from normal erection

The normal erection of the penis comes about through an increased influx and inhibited outflow of the blood into the erectile tissue. The cause of the stiffening is sexual imagination or mechanical irritation of the penis. Priapism, on the other hand, is defined as an erection of the penis without sexual or mechanical stimuli.
In addition, with a normal erection, different regions are affected by the changed blood supply. In priapism, only the two cavernous bodies swell, while the glans remains flaccid. This allows the man to urinate, which is not possible with a normal erection. Priapism is very painful for those affected. Therefore, priapism cannot be reduced by sexual intercourse. If an attempt is possible, there will be no ejaculation, still to relax the penis.

Causes of Priapism

Priapism can be caused by different causes. Causally, priapism can be divided into a primary and a secondary priapism.

Primary priapism

In 30% to 50% of priapism cases, the cause cannot be clarified. These cases are known as primary or idiopathic priapism. In 2008, however, American scientists discovered an interesting connection in mice. They lacked a certain enzyme to break down adenosine, which is responsible for the expansion of the blood vessels. However, more research is needed to translate this link to humans.

Secondary priapism

The causes for the secondary form of priapism are manifold.

Medicines and drugs (20%)

Some psychotropic and other drugs in overdose can cause priapism. Antidepressants, pain relievers, anti-epileptic drugs, and antihypertensive drugs can also lead to priapism.
Alcohol, cocaine, or marijuana abuse can also be a cause.

Blood disorders (around 20%)

Sickle cell anemia, which is less common in our latitudes, can lead to priapism. Other blood disorders such as thalassemia, hemophilia, or thrombocytemia can also be a cause.

Tumor-related priapism

Metastases can compress the veins and affect blood circulation. Cancer types that favor priapism are leukemia, kidney cell or prostate cancer.


Blunt trauma can injure the arteries. An erection can aggravate the injuries and thus promote the influx of arterial blood. If too much blood flows in, the arteries can no longer carry the blood away and priapism occurs.

Metabolic diseases

Possible diseases are diabetes mellitus or gout. They can also be the cause of priapism.

Neurological causes

Certain nervous system damage can also be a cause of priapism. Such damage can be caused by paraplegia or a herniated disc.


The nerve toxin alpha-latrotoxin from the black widow or other related spiders can trigger priapism.

SKAT therapy

In SKAT therapy (also known as auto-injection therapy), the body’s own messenger substance alprostadil is injected into the flaccid penis to cause an erection. Alprostadil slackens the muscles of the arteries, which is why more blood can flow into the erectile tissue. This can also be a cause of priapism.

Forms of priapism

There are two forms of priapism: the low-flow type and the high-flow type.

Low flow type or ischemic priapism

Most cases (around 90%) of priapism are of the low-flow type. It is always spoken of when there is a form of reduced outflow of venous blood from the erectile tissue. The low-flow type of priapism is very dangerous because it can lead to an undersupply of the muscles. If the oxygen supply is interrupted or reduced for too long, this can lead to hypoxic damage (for example, fibrous changes). Therefore, low-flow priapism must be treated immediately. About 30-50% of those affected experience erectile dysfunction after low-flow priapism . The sooner treatment begins, the greater the chances of a full recovery.

Recurrent priapism

A sub-form of low-flow priapism is recurrent priapism. This is a repetitive, fleeting occurrence (several times a day). This form occurs more frequently in patients with haematological diseases (e.g. sickle cell anemia). This form is treated like the low flow type. In some cases, self-injection is used.

High flow type or non-ischemic priapism

The high-flow type of priapism is rather rare and only occurs in about 5% of cases. It is caused by an influx of arterial blood that exceeds the capacity of the veins. The high-flow type is usually not particularly painful and the full hardness of the erection is not achieved. It is less dangerous than the low-flow type of priapism.


Priapism is a urological emergency and must be treated immediately to avoid consequential damage. The most common first approach is to withdraw the blood from the erectile tissue. It should be noted that an untreated high-flow type can change into a low-flow type over time and thus cause erectile dysfunction.

General measures

It starts with the anamnesis and various examinations to determine the patient’s condition. In addition, a venous access is usually established and the patient is sedated if necessary. The circulatory parameters should be monitored continuously. The cooling of the penis is used as a decongestant.

Measures for high-flow priapism

Often only one observation is made, as priapism spontaneously regresses in around two thirds of cases. But it is rarely intervened. This type occurs most frequently after a blunt direct trauma (straddle trauma) and is already possible in childhood.

Actions for low-flow priapism

Since the low-flow type is an emergency, drugs are given, which are mostly α-adrenergic substances. In the case of special forms, antiandrogens and LHRH antagonists are also given.
If drug treatment does not promise any improvement, surgical measures are used.

Surgical intervention

During a surgical procedure, certain blood vessels are connected to one another (shunt method). The success rate of the shunt procedure is quite high: it is around 75%.

Prospect of treatment

The high-flow type is very treatable and there is most likely no permanent damage.
In 50% of the cases of the low-flow type, the ability to erect is retained. In the other cases, erectile dysfunction occurs as a result of an already existing fibrosis of the erectile tissue or an injury during the shunt procedure.

What to do about priapism

Priapism is a urological emergency and must be treated by a doctor. The sooner treatment begins, the greater the chances of a full recovery. While cooling the penis can provide temporary relief from the swelling, a visit to a doctor is still necessary. This should be done as soon as possible, so an ambulance should be called in an emergency to prevent permanent damage.

Scroll to Top