Clinical Practice Guidelines for the Management of
Erectile Dysfunction
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Clinical Practice Guidelines for the Management of
Erectile Dysfunction
An "evidence-supported" Canadian consensus document
Contributors
+ Michael A. Adams, MD, Moderator
+ Brewer Auld, MD
+ Gerald Brock, MD
+ Francois Benard, MD
+ Rosemary Basson, MD
+ Serge Carrier, MD
+ Michael Chetner, MD
+ John Collins, MD
+ Michael Condra, MD
+ Ms. Janet Fenemore
+ Jerzy Gajewski, MD
+ Jeremy P.W. Heaton, MD
+ Sender Herschorn, MD
+ Mrs. Brenda Johnston
+ Alvaro Morales, MD
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CONTENTS
1. Nomenclature
2. Physiology of Erection
3. Office Diagnosis
4. Patient goal-directed therapy
5. The non-invasive pharmacologic treatment of erectile
dysfunction
6. Intracavernous injection (ICI) therapy
7. Treatment with vacuum devices
8. Penile prosthetics
9. Vascular surgery
10. Nursing aspects
11. Acknowledgments
12. Additional information
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PREAMBLE
This document summarizes the current state of knowledge of
erectile
dysfunction (ED) and defines some principles of diagnosis and
treatment.
The original material was submitted by a panel of Canadian
experts drawn
from across the country. This material was put together and a
composite
document discussed in Ottawa in June 1995.
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NOMENCLATURE
Erectile Dysfunction is preferred to the common form
"impotence", as
directed by the N.I.H. Consensus Conference on Impotence,
1992.(1) ED is
defined as the persistent inability to gain or maintain a
penile erection
sufficient for sexual intercourse. ED is a defined problem
and should be
distinguished from premature ejaculation, other orgasmic
dysfunction, and
Peyronie s disease.
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PHYSIOLOGY OF ERECTION
The basic essential elements of a normal erection with an
appropriate
stimulus will remain unchallenged:
1. An adequate nervous system.
2. Adequate arterial inflow.
3. A functioning veno-occlusive mechanism.
4. Functional penile anatomy.
5. An adequate hormonal environment.
6. Mind focussed on the sexual stimulus, freedom from
distractions, and
from fear of an unrewarding outcome.
The understanding of the physiological basis for erectile
function is
under
continuous revision. Much is known about the function of
penile smooth
muscle,(2) the role of neurotransmitters,(3) the anatomical
and
structural
elements,(4) and the basis of central nervous system
control.(5) Much
will
change and be refined over the next half-decade. See Appendix
for more
details.
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OFFICE DIAGNOSIS
Office evaluation is initially directed to characterizing the
exact
nature
of the sexual problem and developing a rapport that will be
the
foundation
of successful management. Patient comfort and cooperation are
reinforced
by
the examiner's facility in discussing sexual problems, using
easily-understood terminology.
Male erectile dysfunction, changes in sexual desire, and
orgasmic
disturbances are frequently believed to be synonymous by both
patients
and
referring persons. Each of these areas should be carefully
explored and
distinguished as a separate entity.
History
+ Sexual History (Appendix B contains an acceptable but
non-validated
form of history.(6)
+ Partner and relationship issues;
+ Other medical problems: diseases, prior surgery, and
medications.
Physical Exam
+ General health
+ The genitalia should be routinely examined, including the
testes for
size and consistency and the penis for deformities, scars, or
plaques.
+ Secondary sexual characteristics;
+ Digital rectal exam (DRE).
+ More detailed examination of the relevant region or system
when
indicated.
Psychological Assessment
Especially important when there is situational variation in
erectile
ability (for details, see Appendix A).
+ Intrapersonal problems (e.g., performance anxiety);
+ Interpersonal problems (e.g., marital);
+ Coexistent psychiatric disease;
+ History of addiction;
+ History of abuse or violence.
Laboratory There are no mandatory laboratory tests.
Serum testosterone (morning value) determination is useful.
Serum prolactin when libido is depressed.
Full endocrinologic assessment is indicated in cases of
secondary
hypogonadism.
Karyotyping, if there is a basis for suspicion.
RBS or, preferably, glycosylated hemoglobin is indicated in
diabetics.
Supplementary formal investigations
+ Nocturnal penile tumescence (NPT);
+ Dynamic infusion cavernosometry and cavernosography (DICC);
+ Dynamic Doppler ultrasound studies;
+ Selective arteriography (only if arterial surgery or PCTA
is
contemplated);
+ Biothesiometry.
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PATIENT GOAL-DIRECTED THERAPY
The therapy for ED has a somewhat different basis, when
compared with the
treatment of many other diseases. It is not life-threatening,
and
although
commonly physical in origin, it can have significant
psychological impact
on both partners and has a potential for a widespread effect
in many
socioeconomic domains. Sexual activity, by its nature, is
intermittent
and
generally involves a partner whose support is vital to the
success of the
therapy. The patient and partner must be sufficiently
motivated to get
involved in a form of therapy. For couples to be satisfied
with
treatment,
it is imperative that both partners have a thorough
understanding of the
problem and realistic expectations of the possible solutions
(See
Appendix
A).
* Goal-directed therapy - an algorithm
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THE NON-INVASIVE PHARMACOLOGIC TREATMENT OF ERECTILE
DYSFUNCTION
The treatment of erectile dysfunction should be tailored to
the patient's
specific needs and expectations, i.e.,
"goal-directed". Non-invasive
therapy includes the careful elimination of erectolytic
agents (drugs
that
prevent erection). Currently, no medication fulfils the
criteria of the
"ideal" agent for the treatment of ED, which would
be:
1. effective;
2. useful "on demand";
3. free of side effects;
4. easy to administer;
5. affordable.
The agent should be specific for the etiology of the
dysfunction.
Unfortunately, the only ones in this category are hormonal
supplementation
agents.
Hormonal
Testosterone Specifically indicated for the treatment of
hypogonadic
states. Its use is restricted for patients with biochemical
evidence of
hypotestosteronemia. There are injectable, oral, and
transdermal
preparations.
a. Injectable esters: 200 to 300 mg I.M. every two to three
weeks. Safe
but
has a "roller-coaster" effect.
b. Oral: the undecanoate is readily absorbed by the gut and
is free of
liver toxicity; 120 to 160 mg daily. Methylated forms carry
significant
liver toxicity.
c. Transdermal (currently not available in Canada): One or
two patches
with
daily application to the shaved scrotum or skin.
Neuropharmacologic
Useful as a first-line treatment for a limited trial period.
1. Yohimbine. An alpha-2 adrenoceptor antagonist, with
limited
effectiveness. Useful on a trial basis during the evaluation
process.
Currently used orally at 10 mg (or near equivalent) t.i.d.
2. Phentolamine. Also an adrenoceptor antagonist. Most
commonly used for
intracavernosal injection. Difficult to obtain for buccal
administration,
20 to 40 mg "on demand".
3. Trazodone. A serotoninergic agonist with some adrenoceptor
antagonistic
properties. Uses at oral doses 50 to 150 mg at bedtime or 50
mg t.i.d.
Early evidence suggests a synergism with yohimbine.
Peripheral vasodilators
1. Nitroglycerin paste. Applied to the penile shaft, produces
modest
increases in tumescence but not usable rigidity.
2. L-arginine. In limited trials, has been reported to be
effective. It
is
readily available.
3. Minoxidil. Initial enthusiasm has vanished with results of
controlled
studies.
4. Prostaglandin E1. Recent reports suggest it may be
effective by
intra-urethral application. Not yet commercially available.
There are a number of other compounds under investigation.
However,
results
of limited trials must be taken with much caution. It should
be
remembered
that it is unlikely that systemic administration of drugs
would prove to
be
effective in the presence of major alterations of penile
physiology.
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INTRACAVERNOUS INJECTION (ICI) THERAPY
A program of ICI should be implemented as an integral part of
a
goal-directed assessment of sexual and erectile dysfunction,
with
suitable
education and follow-up. The prescribing physician should
therefore have
special competence in the use of potent vasoactive agents on
an ad hoc
basis.
Indications
+ Patient choice;
+ Failure of less invasive therapy.
Contraindications
+ Proven problem with allergic response to the medications
proposed;
+ Patients in whom significant systemic changes in blood
pressure
would
have grave consequences;
+ Patients with an inability to inject themselves (or be
injected by
a
partner) safely.
Relative Contraindications
+ Sickle-cell disease;
+ Patients at risk for subacute bacterial endocarditis;
+ History of idiopathic priapism;
+ Poor compliance, e.g., drug dependency.
Agents
Single agent:
* PGE1: a rapidly metabolized vasoactive prostaglandin; PGE1
is the
only agent with FDA approval for ICI.
Combination (based on one or more of the following agents):
+ Phentolamine: an alpha adrenoceptor blocker;
+ Papaverine;
+ PGE1;
+ Triple therapy (PGE1, papaverine, phentolamine).
The mixture required for this should comply with good
standards of
pharmacy
preparation, and the shelf-life of the mixture should be
defined. Use of
a
single agent from a single-dose vial may be considered
optimal from the
quality control standpoint.
Doses and titration
+
+ Determined by the precise mixtures;
+ Between 0.2 and 1 mL for the initial injection;
+ Doses depend entirely on the actual combinations;
+ Suggested starting dose for PGE1 is 2.5 micrograms;
+ Increments of 2.5 micrograms until achievement of a
satisfactory
response;
+ Benefits of doses exceeding 20 micrograms are small and the
risk of
systemic effects increases.(7)
The starting dose of any preparation should be reduced for
those
suspected
of having a primary neurogenic cause. The suggested starting
dose is one
half of the usual starting dose for any local mixture, and
1.25
micrograms
for PGE1 alone.
Potential side effects
+ Priapism: increases with the amounts of compound injected.
Phentolamine is associated with an increased rate of priapism
(see
Appendix for treatment);
+ Pain on injection;
+ Penile fibrosis (<1%);
+ Systemic pressure changes which should not occur with
appropriate,
regular use, but may from time to time be associated with
intracavernosal injection;
+ Bruising is uncommon. Injection may be used in people on
concurrent
anticoagulant therapy;
+ Appropriate use of intracavernosal injection may improve
spontaneous
erectile function. Suggested frequency of use of
intracavernosal
therapy is up to three times per week.
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TREATMENT WITH VACUUM DEVICES
High-quality vacuum devices have relatively few adverse
effects and are
effective alternatives to more invasive and complex
treatments.
Constriction rings used with the vacuum devices can sometimes
be used
alone, in order to maintain erections in men where premature
detumescence
is the major complaint. These vacuum devices can also be used
in
conjunction with intracorporeal injections to produce and
maintain
functional erections.
VED erections 1. Tumescence occurs only distal to the
constriction band
and
may cause some pivoting of the phallus.
2. The skin temperature of the penis decreases an average of
one degree
Celsius for each 30 minutes the constriction ring is in
place, due to
decreased arterial blood flow [3].
3. The vacuum causes some engorgement of extracorporeal
penile tissue,
resulting in a larger-than-normal circumference erection [4].
Adverse effects
1. Some initial minor pain or discomfort is not uncommon, but
it usually
dissipates with ongoing use.(8)
2. Ecchymosis or petechiae of the penile skin occurs in 12 to
25% of
patients, but is self-limiting and resolves without
intervention.
3. The sensation of climax is unaffected, but antegrade
ejaculation is
often impeded due to occlusion of the urethra by the
constriction
band.(9)
4. The device is relatively contra-indicated in men on
anticoagulants or
with blood dyscrasias.
Efficacy
These devices produce erections sufficient for intercourse in
73 to 100%
of
men who use them.(10) Individualized patient education and
instruction on
the proper use of vacuum devices, coupled with help in
overcoming the few
potential difficulties encountered in using them, improve
patient
satisfaction with this technique of treating erectile
impotence.
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PENILE PROSTHETICS
Since the late 1970s, prosthetic penile implantation has been
a very
successful means of treating organic erectile dysfunction.
Penile
prostheses are mechanical devices that produce a firm penis.
They may not
necessarily reproduce the patient's former erections in size
or rigidity.
Indications
1. Patients who are refractory to other forms of treatment;
2. Patient preference, with concurrence of physician.
Types 1. Malleable rod;
2. Self-contained inflatable;
3. Two-piece inflatable;
4. Three-piece inflatable.
Device selection There is no single prosthesis that is the
best for every
patient. The following factors should be considered in
selecting a
device:
patient age, medical status, penile and scrotal size, manual
dexterity,
personality, social activity, and economic status.
+ Malleable rod: lowest possibility of mechanical failure;
good
choice
for older patients and patients with significant medical
problems;
possible problem of concealment.
+ Three-piece inflatable: most complete flaccidity on
deflation; on
inflation, potential to increase in length as well as girth,
giving
perhaps a more natural erection; more extensive operative
procedure.(11)
+ One-piece inflatable: inflation and deflation appearance
very
similar; little advantage over malleable type, for patients
with
short
penis; selected indicators where other prostheses
contraindicated.
+ Two-piece inflatable: potential to give benefits of
three-piece
inflatable type, with less extensive surgery.(12)
Complications
Rates of mechanical complications are quite acceptable.
Meticulous
attention to technical detail before, during, and after
surgery is
important in maintaining surgical complications at their
current low
rates.(13) An awareness of the susceptibility of certain
groups (revision
surgery, diabetics, spinal cord-injured patients) to
infection is vital
to
proper patient selection and preparation for surgery.
Outcome Overall patient and partner satisfaction is high with
all types
of
prostheses.(14) Important factors that lead to these good
results are
proper patient selection and appropriate counselling to
create realistic
expectations for outcome.
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VASCULAR SURGERY
Vascular deficiency causing ED may be arterial, venous, or
both. Many
operations have been devised to restore arterial inflow and
decrease
venous
outflow, but the published studies have all been
retrospective and are
based frequently on differing inclusion criteria, workups,
and outcome
measures. The successful results reported in expert hands,
however,
justify
the ongoing evaluation of these surgical techniques. Vascular
surgery
should, therefore, probably be restricted to centers with
expertise.
Venous Surgery Corporeal veno-occlusive dysfunction or venous
insufficiency
may be primary or secondary and the result of smooth muscle
dysfunction,
abnormal perforating veins, collagen degeneration intunica,
or incomplete
smooth muscle relaxation.
+ Diagnosis
+ Dynamic infusion cavernosometry and cavernosography after
ICI;
+ Cavernosography may demonstrate leakage into dorsal,
cavernous, or
crural veins. Opacification of the glans is considered
physiological;
+ Duplex ultrasonography may also be performed, to rule out
arterial
insufficiency.
+ Therapy (VED with or without ICI may be effective)
+ "Venous leak" surgery: considered experimental by
many authorities.
+ Transluminal venous embolization and sclerosis.
+ Results
+ Cure rates of 10 to 50%;
+ Tend to decline with length of follow-up;
+ Complications seen are penile edema, hematoma,
hypoesthesia, and
shortening. The incidence of complications ranges from 0 to
46%.
Arterial Surgery
Cavernosal artery insufficiency is most commonly the result
of
atherosclerosis. The condition results in lowered rigidity of
the erect
penis and prolonged time to maximum erection. It may be a
sole cause of
or
contributing factor to the erectile dysfunction.
Another recently described and seemingly common cause is
blunt perineal
trauma.
+ Diagnosis
+ Sudden onset of weak erections after blunt perineal trauma;
+ ICI is the most commonly used screening test;
+ Duplex ultrasonography after ICI;
+ DICC may be performed to determine concomitant venous
insufficiency;
+ Internal pudendal super selective arteriography with ICI.
+ Treatment (ICI, VED, and penile implants are non-specific
but
effective)
+ Revascularization: usually reserved for post-pelvic or
perineal
trauma;
+ The results are uncertain, because of unstandardized
diagnostic
tests
and unobjective and uncontrolled postoperative follow-up
methods
used
for reporting.
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NURSING ASPECTS
A nurse coordinator, in cooperation with the physician and
team, can
improve the quality of intervention and create a
comprehensive supporting
program for:
a. Patient education;
b. Counselling;
c. Support for patient and partner;
d. Diagnostic testing;
e. Treatment.
Experience has shown that few patients present clear-cut
single-factor
cases of ED. The final diagnosis is not uncommonly different
from the
first
impression, as there are often complex psychosocial and
medical issues
involved that only emerge as confidence builds. A
well-trained and
knowledgeable nurse can supplement historical information and
coordinate
the couple's management.
November 13, 1996
19:55 +0000
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