For a man to have an erection, a complex process takes
place within the body.
Penile erection is occurs via two different mechanisms.
The first, reflex erection, is achieved by directly touching
the penile shaft.
The second is the psychogenic erection, which is achieved
by erotic stimuli. Erections occur in response to touch,
smell, and visual stimuli that trigger pathways in the
brain. Information travels from the brain to the nerve
centres at the base of the spine, where primary nerve fibres
connect to the penis and regulate blood flow during erection
and afterward.
The former uses the peripheral nerves and the lower parts
of the spinal cord, whereas the latter uses the limbic
of the brain. Both mechanisms require an intact neural
system for a successful and complete erection.
Sexual Stimulation of penile shaft leads to the release
of chemicals from the nerve endings in the penis that trigger
a series of events that ultimately cause muscle relaxation
in the erection bodies of the penis and subsequently penile
erection. Venous drainage channels are compressed and close
off as the erection bodies enlarge.
As can be understood from the mechanisms of a normal erection
thus elucidated, impotence may develop due to hormonal
deficiency, disorders of the neural system, lack of adequate
penile blood supply or psychological problems. Restriction
of blood flow may be secondary to abnormalities in the
blood vessels due vascular disease.
Detumescence (a flaccid penis) results when muscle-relaxing
chemicals are no longer released. Ejaculation causes the
smooth muscle tissue of the erection bodies in the penis
to regain muscle tone, which allows the venous drainage
channels to open and the blood drains from the penis.
Causes
Erectile dysfunction can be caused by any number of physical
and psychological factors. In general, ED is divided into
organic (having to do with a bodily organ or organ system)
and psychogenic (mental) impotence, but most men with organic
causes have a psychological component as well.
A few causes of impotence may be iatrogenic (medically
caused). Various medications may be responsible. Luckily
impotence is usually reversible following ceasation of
such drugs.
Erection problems will usually produce a significant psychological
and emotional reaction in most men. This is often described
as "performance anxiety", a pattern of anxiety
and stress that can further interfere with normal sexual
function.
Almost any disease can affect erectile function by altering
the nervous, vascular, or hormonal systems. Various diseases
may produce changes in the smooth muscle tissue of the
penis or influence mood and behaviour.
Vascular diseases e.g. arteriosclerosis (fatty deposits
on the walls of arteries), peripheral vascular disease),
and high blood pressure account for nearly half of all
cases of ED in men older than 50 years.
Systemic diseases commonly associated with ED
Diabetes, kidney failure, liver cirrhosis, sickle cell
disease
Diseases of the nervous system associated with ED
Stroke, epilepsy, Alzheimer disease, Parkinson disease
Endocrine disorders associated with ED
Thyroid dysfunction, hypogonadism
Psychiatric conditions associated with ED
Depression, anxiety, fear of sexual failure
Penile conditions associated with ED
Peyronie's disease, priapism
Medications causing ED
Common medications associated with ED include antidepressants;
antipsychotics; antihypertensives; anti-ulcer drugs such
as cimetidine; hormonal medication such as goserelin, finestride,
dutasteride
Surgical procedures associated with ED
Surgical intervention for a number of different conditions
may remove anatomical structures necessary for erection,
damage nerves, or impair blood supply. Such include procedures
on the brain and spinal cord.; complete removal of the
prostate gland (radical prostatectomy) or transurethral
resection of the prostate or external beam radiotherapy
of the gland are common causes of impotence; both are treatments
for advanced prostate cancer; cystectomy (removal of the
bladder)
Social Excesses
These include alcohol abuse, excessive smoking and hallucinogens
such as marijuana and cocaine. Smoking is considered an
important risk factor as it is associated with poor circulation
and reduced blood flow in the penis.
Management
Making a diagnosis
Although this information focuses primarily on male, remember
that the partner plays an integral role. If successful
and effective management is to occur, any discussion of
treatment should include the couple.
Grades of Erection
Grade 1: penis is larger, but not hard
Grade 2: penis is hard, but not hard enough for penetration
Grade 3: penis is hard enough for penetrating but not
completely hard.
Grade 4: penis is completely hard and fully rigid
Patient History
Questions will be asked to get a thorough sexual, medical, and psychosocial
history as they help define the degree and nature of ED. A medical history
can disclose diseases that lead to ED, while a simple recounting of sexual
activity might distinguish among problems with sexual desire, erection, ejaculation,
or orgasm. A useful and simple way to distinguish between physiological and
psychological impotence is to determine whether the patient ever had an erection.
If never, the problem is likely to be physiological; if sometimes, it is
more likely to be psychological.
The quality and duration of the erection will be sought
to know if the erection is suitable for penetration, if
the erection can be maintained until the partner has achieved
orgasm, if ejaculation occurs, and if both partners have
satisfaction.
Sexual urge (libido)
You will be asked about your relationship with your partner.
Does your partner know you are seeking help for this problem?
If so, does your partner approve? Is this a major issue
between you? Is your partner willing to participate with
you in the treatment process? Do you have more than one
partner?
You will also be asked on the following
History of psychotraumatic experience,
History of medication in the past year, pelvic surgery,
History of tobacco use, alcohol and caffeine intake, as
well as any illicit drug use.
Patient Examination
A physical examination is necessary, attention to the
genitals and nervous, vascular, and urinary systems. Your
blood pressure will be checked. The physical examination
will confirm information you gave the doctor in your medical
history and may help reveal unsuspected disorders such
as diabetes, vascular disease, penile plaques (scar tissue
or firm lumps under the skin of the penis), testicular
abnormalities, low male hormone production, injury or disease
to the nerves of the penis and various prostate disorders.
Clinical tests such as the bulbocavernosus reflex test
are used to determine if there is sufficient nerve sensation
in the penis. The doctor squeezes the glans (head) of the
penis, which immediately causes the anus to contract if
nerve function is normal. The doctor measures the latency
between squeeze and contraction by observing the anal sphincter
or by feeling it with a gloved finger inserted into the
anus. Specific nerve tests are used in patients with suspected
nerve damage as a result of diabetes or nerve disease.
Laboratory Investigation routinely includes:
-Hormonal assay for testosterone (early morning), luteinizing
hormone, prolactin
-blood sugar
-urinalysis
Other investigation which maybe needed:
Ultrasound Scan: This test may be done on the lower abdomen,
pelvis, and testicles, or restricted to just the penis.
A duplex ultrasound is a diagnostic technique most useful
in evaluating possible penile arterial disorders
One of the most common tests used to evaluate penile function
is the direct injection of PGE1 into the penis (PGE1 is
a medication that increases blood flow into the penis and
normally produces erections.). Where there is no significant
structural abnormality with the penis, an erection should
occur within several minutes. The quality of the erection
is assessed. A successful, test also establishes penile
injections as one possible therapy.
The sensitivity of the
skin of the penis to detect vibrations (biothesiometry)
can be used as a simple office nerve function
screening test. This involves the use of a small vibrating
test probe placed on the right and left side of the penile
shaft as well as on the head of the penis. The strength
of the vibrations is increased until you can feel the probe
vibrating clearly. Although this test does not directly
measure the erectile nerves, it serves as a reasonable
screening for possible sensory loss and is simple to perform.
More formal nerve conduction studies are only performed
in selected cases.
Nocturnal penile tumescence testing (NPT) may be useful
in distinguishing mental from physical impotence. Inadequate
or no erections during sleep suggests an organic or physical
problem, while a normal result may indicate a high likelihood
of emotional, psychological, or mental causes.
TREATMENT
With the current therapeutic approaches available, virtually
any man who wishes to have erectile function can obtain
it, regardless of the underlying cause of his problem.
Treatment depends on the cause.
Options include sex counseling, medications, external
vacuum devices, hormonal therapy, penile injections, intraurethral
suppositories, penile prosthesis implants.
Lifestyle Changes
Adopting a few healthy lifestyle changes may be beneficial.
Ceasation of smoking, weight loss and increasing physical
activity may help regain sexual function.
Ceasation of medication that may have ED as a side effect
may be considered, however this must be done in consultation
with your doctor.
Psychotherapy
Psychologically based ED may be treated using techniques
that decrease the anxiety associated with intercourse.
Fore-play is advised as the partner can help by exercising
sexual gimmicks that gradually develop intimacy and stimulation.
Such techniques also can help relieve anxiety when ED from
physical causes is being treated.
Vacuum devices
These are specially designed vacuum devices that produce
erections. They work by using a manually generated vacuum
to draw blood into the penis, engorging and expanding it
to create the erection. The typical vacuum device consists
of three components; a plastic cylinder that is placed
over the penis, tension rings of various sizes, and a small
hand pump. Air is pumped out, causing a partial vacuum,
which creates the erection. Once an erection is obtained,
a tension ring, which acts like a tourniquet to keep the
blood in the penis and maintain an erection after the cylinder
is removed and during intercourse, is placed at the base
of the penis. An external vacuum pump will produce an engorged
penis with success approaching 90%, although it should
be removed after not more than 30 minutes.
Medication
PDE5 Inhibitors
The cyclic nucleotide phosphodiesterases constitute a
group of enzymes that catalyse the hydrolysis of the cyclic
nucleotides cAMP and cGMP. They work by blocking an enzyme
found mainly in the penis that breaks down a chemical produced
during stimulation that normally produces erections. PDE5
Inhibitors allows this chemical of arousal to survive longer
and improves erection function. That is also why sexual
stimulation is necessary for them to work
Examples include: sildenafil citrate (Viagra), vardenafil
citrate (Levitra), tadafil citrate (Cialis),
PDE5 Inhibitors do not improve erections in normal men,
only in those with difficulty in achieving or maintaining
erections sufficient for sexual intercourse due to a true
medical problem. They do not have any aphrodisiac property.
They require sexual stimulation to function, without which,
they won't have any effect.
Yohimbine
Tradomedical medication obtained from the bark
of a West African tree. Its effectiveness is compared to
that of
a placebo.
Hormonal replacement
Testosterone hormone replacement may be of benefit in
men with low sex drive and ED that have been found to have
low testosterone levels. Libido and an overall sense of
well-being are likely to improve when serum testosterone
levels are restored. However, its supplementation alone
is not particularly effective in treating erectile dysfunction.
Replacement testosterone is available as pills, depot injections,
patches, and a gel that is rubbed into the skin
Follow-up testosterone (hormone) levels, periodic blood
counts and prostate checks are necessary for all men on
long-term testosterone replacement therapy.
Injection therapy
If the structure of the penis is healthy, the use of injectable
drugs is almost always effective.
Alprostadil(Caverject), a synthetic PGE1, is the most
commonly used single drug for injections into the penis
as a treatment for ED. Others include papavarine, phentalomine.
Intraurethral therapy (Medicated Urethral System for Erections,
MUSE)
Alprostadil which has been formulated into a small suppository
that can be inserted into the urethra (the canal through
which urine and semen are excreted).A pre-filled applicator
is used to deliver the pellet about an inch deep into the
urethra. This is a useful alternative for men who do not
want to use self-injections or those in whom oral medications
have failed.
Implants
Inflatable implant
Rigid implant
Implanted devices, known as prostheses, can be used in
restoring erection in many men with ED.
Malleable implants usually consist of paired rods, which
are inserted surgically into the penis. The patient manually
adjusts the position of the penis and, therefore, the rods.
Adjustment does not affect the width or length of the penis.
Inflatable implants consist of paired cylinders, tubes
(which connect the cylinders to a fluid reservoir) and
a pump, which are all surgically implanted. The patient
inflates the cylinders which are surgically inserted inside
the penis, using pressurized fluid by pressing on the small
pump located under the skin in the scrotum. Unlike the
malleable implants they somewhat expand the length and
width of the penis. They also leave the penis in a more
natural state when not inflated.
Possible problems with implants include mechanical breakdown
and infection.
Surgery
If a vascular pathology is identified, it may be surgically
corrected. The aim is to reconstruct arteries to increase
flow of blood to the penis or to block off veins that allow
blood to leak from the penile tissues. The latter is rarely
done.
Surgery to repair arteries can reduce ED caused by obstructions
that block the flow of blood. The best candidates for such
surgery are young men with discrete blockage of an artery
because of an injury to the groin or fracture of the pelvis.
The procedure is almost never successful in older men with
multiple blockages from arteriosclerosis, etc.
SUMMARY
ED can in many cases be treated by drugs taken orally,
injected, or as penile suppositories. Treatments (with
the exception of testosterone supplementation, where effective)
work on a temporary basis: they enable an erection to be
attained and maintained long enough for intercourse, but
do not permanently improve the underlying condition.
These drugs increase the efficacy of substance NO, which
dilates the blood vessels of penis. When oral drugs or
suppositories fail, injections into the erectile tissue
of the penile shaft are extremely effective but occasionally
cause priapism. When pharmacological methods fail, a purpose-designed
external vacuum pump can be used to attain erection, with
a separate compression ring fitted to the penis to maintain
it.
More drastically, inflatable or rigid penile implants
may be fitted surgically. Implants are irreversible and
costly.
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