Priapism

Priapism (Greek πριαπισμός, the erection) is a painful and potentially harmful medical condition in which the erect penis (erection) does not return to its flaccid state (despite the absence of both physical and psychological stimulation) within four hours.

Priapism is a medical emergency and needs proper treatment by a qualified medical practitioner.

Contents

1 Causes
2 Complications
3 Treatment
4 Miscellaneous
5 See also
6 References

Causes

The causative mechanisms are poorly understood but involve complex neurological and vascular factors. Priapism may be associated with prolonged sexual activity, leukaemia, Fabry's disease, haematological disorders (such as sickle-cell disease), cerebrospinal disease (such as syphilis), genital infection, some spinal injuries, or inflammation (Beers & Berkow, 1999). Priapism can be caused by drugs such as certain antidepressants, antihypertensives, anticoagulants and corticosteroids. It can also be a withdrawal symptom of drugs such as heroin. Priapism is often present in spinal injuries or trauma to the spinal cord. This is partly because much of the spinal cord's efferent signals to the genitals are inhibitory: once these are removed the penis is disinhibited and will become erect. Of note is the fact that in copulating praying mantises the act by the female of eating the head of the male causes disinhibition of the mating end of the male and more effective copulation. It is also said a hanged man will get an erection and may ejaculate. This is, however, not caused by disinhibition of the penis, but rather due to blood rushing to the bodily extremities upon hanging.

One of the more significant classes of drugs which may precipitate priapism are the phosphodiesterase type-5 (PDE5) inhibitors such as sildenafil (popularly Viagra), tadalafil and vardenafil. Injected erectile-dysfunction therapies such as alprostadil are also significant. The antidepressant/sedative trazodone has also been associated with priapism.

Complications

Potential complications include ischaemia, 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 condition may result in gangrene, which may necessitate penis removal.

Treatment

Fresco of Priapus, House of the Vettii, Pompeii.

Medical advice should be sought immediately for cases of priapism. If the erection has been present for two hours the recommended therapy is pseudoephedrine 120 mg orally. If this has not subsided by four hours, a further 120 mg of pseudoephedrine is recommended. (Therapeutic Guidelines, 2001)

If the erection has been present for six hours, it is essential to contact a medical practitioner. The therapy at this stage is to aspirate blood from the corpus cavernosum under local anaesthetic. If this is still insufficient, then aspiration is conducted with injections of adrenaline as an adjuvant. (Therapeutic Guidelines, 2001)

If aspiration fails and tumescence re-occurs, 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.

Miscellaneous

The name comes from the god Priapus, referring to that god's most notable attribute: ironically and pertinently one version of the Priapus myth has Priapus punished by the gods for attempting to rape a goddess by being given a huge but useless set of wooden genitals. The female counterpart of this condition is known as clitorism.

References

Beers MH, Berkow R (Eds.) (1999). The Merck Manual of Diagnosis and Therapy (17 ed.). Whitehouse Station: Merck Research Laboratories. ISBN 0-911910-10-7
Therapeutic Guidelines Limited (2001). Therapeutic Guidelines: Endocrinology (2 ed.). North Melbourne: Therapeutic Guidelines Limited. ISSN 1327-9505
Priapism Primer: [Priapism]