Priapism

Priapism (πριαπισμός) is a potentially harmful and painful medical condition in which the erect penis does not return to its flaccid state, despite the absence of both physical and psychological stimulation, within four hours. Priapism is considered a medical emergency, which should receive proper treatment by a qualified medical practitioner. A similar diificulty can occur with the clitorishe condition is known as clitorism

The name comes from the Greek god Priapus, who was noted for his disproportionately large and permanent erection.

Causes
The causative mechanisms are poorly understood but involve complex neurological and vascular factors. Priapism may be associated with haematological disorders, especially sickle-cell disease, and other conditions such as leukemia, thalassemia, and Fabry's disease, and neurologic disorders such as spinal cord lesions and spinal cord trauma (priapism has been reported in hanging victims; see death erection). Recent breakthroughs in research of the disease have pointed to a raised level of the biochemical adenosine being the cause of the condition. This seems to cause blood vessels to dilate and has the potential to influence blood flow into the penis.

Sickle cell disease often presents special treatment obstacles. Hyperbaric oxygen therapy has also been used with success in some patients.

Priapism can also be caused by reactions to medications. The most common medications that cause priapism are intra-cavernous injections for treatment of erectile dysfunction (papaverine, alprostadil). Other groups reported are antihypertensives, antipsychotics (e.g., chlorpromazine, clozapine), antidepressants (most notably trazodone), anticoagulants, cantharides (Spanish Fly) and recreational drugs (alcohol and cocaine). Phosphodiesterase type-5 (PDE5) inhibitors such as sildenafil citrate ("Viagra"), tadalafil ("Cialis"), and vardenafil ("Levitra"), have very rarely been implicated. PDE-5 inhibitors have even been evaluated as preventive treatment for recurrent priapism. Priapism has also been linked to achalasia. Priapism is also known to occur from bites of the Brazilian wandering spider.

Complications
Potential complications include ischemia, clotting of the blood retained in the penis (thrombosis), and damage to the blood vessels of the penis which may result in an impaired erectile function or impotence. In serious cases, the ischemia may result in gangrene, which could necessitate penis removal.

Treatment
Medical advice should be sought immediately for cases of erection beyond four hours. Generally, this is done at an emergency department. The therapy at this stage is to aspirate blood from the corpus cavernosum under local anaesthetic. If this is still insufficient, then intracavernosal injections of phenylephrine are administered. This should only be performed by a trained urologist, with the patient under constant hemodynamic monitoring, as phenylephrine can cause severe hypertension, bradycardia, tachycardia, and arrhythmia.

If aspiration fails and tumescence recurs, surgical shunts are next attempted. These attempt to reverse the priapic state by shunting blood from the rigid corpora cavernosa into the corpus spongiosum (which contains the glans and the urethra). Distal shunts are the first step, followed by more proximal shunts.

Distal shunts, such as the Winter's, involve puncturing the glans (the distal part of the penis) into one of the cavernosa, where the old, stagnant blood is held. This causes the blood to leave the penis and return to the circulation. This procedure can be performed by a urologist at the bedside. Winter's shunts are often the first invasive technique used, especially in hematologic induced priapism, as it is relatively simple and repeatable over time.

Proximal shunts, such as the Quackel's, are more involved and entail operative dissection in the perineum to where the corpora meet the spongiosum, making an incision in both, and suturing both openings together.

Female priapism
Priapism in females (continued, painful erection of the clitoris) is also known as clitorism.