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PRIAPISM
“Priapus Weighing his Phallus” Fresco, 1st
century AD Pompeii.
This is the ancient Roman god of male fertility,
Priapus. It is from a wall mural found in the
House of the Vettii, in Pompeii.
Because of the eruption of Vesuvius in 79 AD we
know far more about Roman life at the end of the
first century AD, than for any other ancient
culture.
Ancient Pompeii was full of erotic symbols,
inscriptions, and even household items. The
ancient Roman culture of the time was much
more sexually permissive than is the case today.
When serious excavation of Pompeii began in
the 18th century a clash of cultures was the
result. In1819, King Francis I of Naples visited
the site with his wife and daughter and was so
embarrassed by the erotic artwork that he
decided to have it locked away in a secret
cabinet, accessible only to “people of mature
age and respected morals.”
A fresco on a wall that showed the ancient god of male fertility, Priapus, with his
extremely enlarged “phallus”, was covered over again with plaster. It was only
rediscovered again in 1998. Apart from a brief period in the “liberated” 1960s most of
this art remained hidden from the general public until the year 2000. Even today minors
are not allowed entry to the once secret cabinet without a guardian or written
permission.
The medical condition of “Priapism” was named in reference to the ancient Roman god
PRIAPISM
Introduction
Priapism is a painful, pathologic erection in which both corpora cavernosa are engorged
with stagnant (but unclotted) blood. The glans and corpus spongiosum are usually soft
and not involved.1
It is an involuntary prolonged erection unrelated to sexual stimulation and unrelieved by
ejaculation.
Duration longer than 4 hours is consistent with priapism.
This condition is a true urologic emergency, and early intervention allows the best
chance of functional recovery.
Pathophysiology
Transverse Section of the Penis, (Lecture notes on Urology 4th Ed).
Erection is the result of smooth muscle relaxation and increased arterial flow into the
corpora cavernosa, causing engorgement and rigidity. Engorgement of the corpora
cavernosa causes compression of the venous outflow tracts (ie, subtunical venules),
resulting in blood trapping within the corpora cavernosa.
Nitric oxide (NO) is the major neurotransmitter controlling erection; the endothelium that
lines the corpora cavernosa secretes NO.
These events occur in both normal and pathologic erections.
The pathophysiology of priapism involves failure of detumescence and is the result of
excessive arterial inflow (ie, high flow) or, more commonly, the failure of venous
outflow (ie, low flow).
Priapism may be defined as either a low-flow (ischemic) or a high-flow (nonischemic).
Treatments for these 2 types are different.
Low-flow Priapism
This is by far the most common type. There is a failure of the detumescence mechanism
due predominantly to a failure of outflow with respect to inflow.
Prolonged low-flow priapism leads to a painful ischemic state, which can cause fibrosis
of the corporal smooth muscle and cavernosal artery thrombosis.
High-flow Priapism
This type is uncommon. It is due uncontrolled arterial inflow from a fistula between the
cavernosal artery and the corpus cavernosum.
It is generally a result of blunt or penetrating injury to the penis or perineum.
Complications
1.
Erectile dysfunction due to fibrosis.
2.
Impotence.
3.
Rarely ischemic gangrene.
4.
Occasionally urinary retention.
Complications depend on the duration of symptoms, the patient's age, and the underlying
pathology. The time to treatment is the single most important factor affecting outcome.
Ishemia of the tissues generally begins to occur after 6 hours.
Causes
Another proposed classification is reversible and non reversible. 1 This is useful in terms
of predicting outcome and likely treatment that will be required.
Reversible causes:
1.
Iatrogenic injection of vasoactive substances used to treat impotence.
2.
Leukemic infiltration.
3.
Sickle cell disease.
Non Reversible causes:
1.
Idiopathic.
2.
Drugs, most commonly major tranquilizers with significant alpha blocking
activity such as chlorpromazine and haloperidol
3.
Local trauma
4.
High spinal cord injury.
The non reversible causes are more resistant to medical treatment and will more often
require surgical intervention. Regardless of etiology, however, medical treatment should
always be tried in the first instance.
Investigations
Usually none are required unless there is a specific indication.
1.
Blood tests:
●
FBE if a blood malignancy is suspected.
●
ABGs have been advocated (to differentiate a high flow, non ischemic
versus a low flow, ischemic (pH < 7.1) cause) However, in practice there
is a wide spectrum of ischemia which is also dependent on the duration of
symptoms and the utility of this test is questionable.
2.
Urine drug screen may be considered if a drug cause is being sought.
3.
Doppler ultrasound is useful in cases of trauma to document and locate fistula.
Management
Oral pseudoephidrine 60 mgs may be tried initially.
Otherwise management involves aspiration of stagnant blood and saline irrigation.
1.
Use local anesthesia to infiltrate the skin where aspiration is to occur.
●
Insert an 18G needle at either the 10 or 2 o’clock position on the dorsal
surface of the middle third of the penis. It need only be on one side due to
the excellent communication between the corpora.
●
2.
Stagnant blood is then aspirated into a 20ml syringe until bright red flow
occurs or the priapism resolves. Up to 100 mls may be aspirated. Some
irrigation with normal saline may be needed to unblock the needle.
If aspiration is unsuccessful, then a trial of intracavernosal alpha-adrenergic
therapy should be tried.
These agents should be used with caution in patients with hypertension or
cardiovascular disease.
The 2 most common agents used are adrenaline and metaraminol.
3.
●
Metaraminol 0.5 mg can be injected via a butterfly needle. This can be
repeated at 5 minute intervals to a maximum dose of 5 mg, whilst
carefully monitoring the blood pressure at 5 minute intervals.
●
Alternatively adrenaline may be used. Use the 1:10,000 preparation and
give 1 ml (100 ugms) at 5 minute intervals for 2-3 doses, again monitoring
blood pressure. Patients receiving adrenaline should also have an ECG
monitor.
If pharmacological treatment is unsuccessful then urgent consultation should take
place with the Urologist on call as failed medical treatment will require a surgical
shunt procedure
●
Priapism secondary to traumatic fistulas will require radiographic
embolisation or surgical intervention.
●
Surgical interventions should be within 24 hours.
It is important to emphasize that the priapsim and not the treatment is the cause of
the impotence as there is a high incidence of medico-legal activity over priapism,
especially where impotence is involved.
References:
1.
Schneider RE: Male Genital Problems in Emergency medicine a comprehensive
study guide: 4th Ed Tintinalli et al 1996 p.532
2.
eMedicine Website
3.
Garrett P Priapism: Emergency Medicine vol 7 no 3 September 1995, p. 145-149
Dr J Hayes
Reviewed 14 March 2003