Erectile dysfunction:Overview

“Man survives earthquakes, experiences the horrors of illness, and all of the tortures of the soul. But the most tormenting tragedy of all time is, and will be, the tragedy of the bedroom.”

Tolstoy



ED is the inability to achieve and maintain an erection adequate for intercourse to the mutual satisfaction of the man and his partner.
Prevalence:
The Massachusetts Male Aging Study - 52% of men between the ages of 40 and 70. (1987-1997).Erectile dysfunction is classified as minimal, moderate, or complete. Of the 52% of men who suffer from erectile dysfunction 17% have minimal ED, 25% have moderate ED, and 10% have complete ED.
The worldwide incidence of erectile dysfunction estimated at over 152 million men, with a forecast of 322 million men by the year 2025. This may be because of change in life style-increasing population suffering from metabolic syndrome(syndrome with increased cholesterol,hypertension,cardiac disease,hyperuricemia and diabetes),smoking and substance abuse.It may also be because of increasing stress and change in interpersonal relationships.

Pathophysiology:
 The cGMP: The main mediator of penile erection causes smooth muscle relaxation and blood flows into the cavernous sinuses and the penis becomes erect.
 At the same time, the veins in the penis are squeezed almost completely shut due to this pressure. Since the veins are shut, blood can not drain from the penis, and it remains erect.
 Once the arousal has subsided, the cGMP is broken down and the penis again becomes flaccid.
 The main chemical responsible:phosphodiesterase-5 (PDE-5)sildenafil,Tadalafil are PDE-5 inhibitors :preventing the breakdown of cGMP, thus keeping blood in the penis to maintain the erection.







Causes
 Since an erection requires a precise sequence of events, ED can occur when any of the events is disrupted. The sequence includes nerve impulses in the brain, spinal column, and area around the penis, and response in muscles, fibrous tissues, veins, and arteries in and near the corpora cavernosa.

Damage to nerves, arteries, smooth muscles, and fibrous tissues, often as a result of disease, is the most common cause of ED. Erectile dysfunction is usually caused by one or more of the following pathologies::
 arterial vascular pathology: heart disease and vascular problems also raise the risk of erectile dysfunction.




 neurologic pathology
 Endocrine causes : Between 35 and 50 percent of men with diabetes experience ED. Also aging males can have dropping levels of testosterone which may lead to decreased libido,erectile dysfunction(Androgen Deficiency of Aging Male).Men with increased levels of prolactin will also experience erectile dysfunction because of decreased libido.
 Psychogenic causes Experts believe that psychological factors such as stress, anxiety(Performace anxiety), guilt(Previous sexual experiences), depression, low self-esteem, and fear of sexual failure cause 10 to 20 percent of ED cases.
 Post-Surgical: (especially radical prostate and bladder surgery for cancer) can injure nerves and arteries near the penis, causing ED.
 Local Pathology: Penile curvatures- Peyronies disease, corporal fibrosis-post trauma, surgery, post-priapism may also lead to impotence.
 Medications/substance abuse: many common medicines/drugs/substances-blood pressure drugs, antihistamines, antidepressants, tranquilizers, appetite suppressants,alcohol,tobacco and cimetidine (used for Acid Peptic Disease)-can produce ED




Evaluation:
 Somewhat subjective
 Doctor diagnosis
 Validated questionnaires like IIEF (International Index of Erectile Function)

Diagnosis
Patient History
Medical and sexual histories 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,Painful sex,.dysfunction either difficulty in initiation or maintainance of erection, ejaculatory problems like-retrograde ejaculation or anejaculation, or problems with orgasm- anorgasmia.
• Physical Examination
A physical examination can give clues to systemic problems. For example, if the penis is not sensitive to touching, Focal neurogical problems can pinpoint to neurological disorders.

• Abnormal secondary sex characteristics(defective androigenisation), such as hair pattern or breast enlargement, can point to hormonal problems, which would mean that the endocrine system is involved.
• The patient may have circulatory disturbances in the form of decreased pulsations in the ankle/popliteal region.
• Local pathologies: Penile curvatures, tender penile plaques will reveal local pathological cause for erectile dysfunction.

Practical Tips:
Psychogenic causes:
1. Younger patient (<40)
2. Preservation of morning erections and nocturnal erections
3. Achieve erection with masturbation
4. May be partner-specific(May achieve erection with specific person-quoad)
5. Often sudden onset(Related to sudden outburst of stress in life)
Organic ED:
1. Gradual deterioration over the period of months or years
2. Decrease in morning erections and nocturnal erections
3. No erections with masturbation
4. No loss of libido
5. Presence of co-morbid conditions like long standing hypertension,hyperlipidemia or diabetes.

•
Laboratory Tests

Several laboratory tests can help diagnose ED. Tests for systemic diseases include blood counts, urinalysis, lipid profile, and measurements of creatinine and liver enzymes. Measuring the amount of free and total testosterone, thyroid function or prolactin in the blood can yield information about problems with the endocrine system and is indicated especially in patients with decreased sexual desire.
Serum PSA is usually indicated in men over 50 years as if these men require testosterone replacement or supplementation they would need careful follow-up with Digital Rectal Examination and Serum PSA to rule out co-existing prostatic carcinoma which may flare up with the administration of testosterone.

Other Tests
Nocturnal Penile Tumuscence Tests:
Monitoring erections that occur during sleep (nocturnal penile tumescence) can help rule out certain psychological causes of ED. Healthy men have involuntary erections during sleep. If nocturnal erections do not occur, then ED is likely to have a physical rather than psychological cause.
In 1985, the RigiScan was introduced; it was the first device to provide automated, portable NPTR recording. The device combines the monitoring of radial rigidity, tumescence, number, and duration of erectile events with the convenience of a portable system that can be used at home. It consists of a recording unit that can collect data for three separate nights for a maximum of 10 hours each night. The mechanics consist of two loops: one is placed at the base of the penis and the other at the coronal sulcus. By constricting the loops, the device records penile tumescence (circumference) and radial rigidity at the penile base and tip. Measurement (initialization) is first done in the office for 15 to 20 minutes with the patient awake to establish an individual baseline. At home, penile rigidity is registered every 3 minutes by constriction of the loops, applying a radial compression.Radial rigidity above 70% represents a nonbuckling erection, and a rigidity of less than 40% represents a flaccid penis. The number of erections considered normal is three to six per 8-hour session, lasting an average of 10 to 15 minutes each
Cilurzo and colleagues (1992) recommend the following as normal NPTR criteria: four to five erectile episodes per night; mean duration longer than 30 minutes; an increase in circumference of more than 3 cm at the base and more than 2 cm at the tip; and maximal rigidity above 70% at both base and tip
The main advantages of NPT testing are its relative freedom from psychologic influences and its ability to detect sleep-related abnormalities. The documented presence of a full erection indicates that the neurovascular axis is functionally intact and that the cause of the ED is most likely psychogenic. Heaton and Morales (1997) have suggested indications for NPTR as follows: (1) suspected sleep disorder; (2) obscure cause of ED; (3) nonresponse to therapy; (4) planned surgical treatment; (5) legally sensitive case; (6) measurement of drug effects in placebo-controlled drug trials; and (7) suspected psychogenic cause.
• Colour Doppler examination:
When vascular evaluation is indicated, intracavernous injection with color duplex Doppler ultrasound is the most informative diagnostic test. This may be all that is needed to define and determine severity. Color duplex ultrasound should be used before other tests are considered because it is the least invasive technology for evaluating vascular ED, distinguishing high-from low-flow priapism, and assessing Peyronie's plaque. Recently, the combination of oral sildenafil citrate with visual erotic stimulation has been shown to be an effective noninvasive pharmacologic induction method for penile blood flow evaluation rather than giving intracavernosal injection(which many patients find repulsive at first instance) PSV less than 25 cm/s after intracavernous injection and sexual stimulation has a 100% sensitivity and 95% specificity in selecting patients with abnormal penile arteriography, because it reflects severe cavernous arterial insufficiency. A PSV consistently greater than 35 cm/s is associated with normal arteriography and defines normal cavernous arterial inflow.
• Penile arteriography:
Arteriography is most useful in providing anatomic information. The inferior epigastric vessels also need to be studied because they are most commonly used for penile revascularization. Because of the high cost and invasive nature of the study, only a small percentage of patients with complex ED are appropriate candidates- ED secondary to a traumatic arterial disruption or in a patient with a history of perineal compression injury. In these highly selected cases, a detailed “road map” of the arterial anatomy is essential to planning surgical reconstruction.
• Dynamic Infusion Cavernosography and Cavernosometry:
This is a complex test done in special circumstances like young men who might be candidates for penile vascular operations, specifically those with a history of pelvic trauma.
•Psychosocial Examination
A psychosocial examination, using an interview and a questionnaire, reveals psychological factors. A man's sexual partner may also be interviewed to determine expectations and perceptions during sexual intercourse.
Treatment
General Conservative measures:

Most physicians suggest that treatments proceed from least to most invasive. For some men, making a few healthy lifestyle changes may solve the problem. Quitting smoking, losing excess weight, and increasing physical activity may help some men regain sexual function. Avoiding drugs with harmful side effects is considered next. For example, drugs for high blood pressure like thiazides can be changed and alternative medications can be given.





Psychotherapy

Experts often treat psychologically based ED using techniques that decrease the anxiety associated with intercourse. The patient's partner can help with the techniques, which include gradual development of intimacy and stimulation.Master and Johnsons therapy involving couples can solve problems with performance anxiety /premature ejaculation
Drug Therapy
Drugs for treating ED can be taken orally, injected directly into the penis, or inserted into the urethra at the tip of the penis. In March 1998, the Food and Drug Administration (FDA) approved Viagra, the first pill to treat ED. Since that time, vardenafil hydrochloride (Levitra) and tadalafil (Cialis) have also been approved. Additional oral medicines are being tested for safety and effectiveness. Viagra, Levitra, and Cialis all belong to a class of drugs called phosphodiesterase (PDE) inhibitors. Taken an hour before sexual activity, these drugs work by enhancing the effects of nitric oxide, a chemical that relaxes smooth muscles in the penis during sexual stimulation and allows increased blood flow.

While oral medicines improve the response to sexual stimulation, they do not trigger an automatic erection as injections do. The recommended dose for Viagra is 50 mg, and the physician may adjust this dose to 100 mg or 25 mg, depending on the patient. The recommended dose for either Levitra or Cialis is 10 mg, and the physician may adjust this dose to 20 mg if 10 mg is insufficient. A lower dose of 5 mg is available for patients who take other medicines or have conditions that may decrease the body's ability to use the drug. Levitra is also available in a 2.5 mg dose.

None of these PDE inhibitors should be used more than once a day. Men who take nitrate-based drugs such as nitroglycerin for heart problems should not use either drug because the combination can cause a sudden drop in blood pressure. Also patients have severe cardiac diseases like recent Myocardial Infarction, reduced stress tolerance should avoid PDE-5 inhibitors.

Many men achieve stronger erections by injecting drugs into the penis, causing it to become engorged with blood. Drugs such as papaverine hydrochloride, phentolamine, and alprostadil (marketed as Caverject) widen blood vessels. These drugs may create unwanted side effects, however, including pain (36%) persistent erection (4%) and scarring. It gives a success rate of 70-90 % but these injections have a drop-out rate of 25-60% because of mainly pain or sometimes development of corporal fibrosis. A system for inserting a pellet of alprostadil into the urethra is marketed as Muse. The system uses a prefilled applicator to deliver the pellet about an inch deep into the urethra. An erection will begin within 8 to 10 minutes and may last 30 to 60 minutes. The most common side effects are aching in the penis, testicles, and area between the penis and rectum; warmth or burning sensation in the urethra; redness from increased blood flow to the penis; and minor urethral bleeding or spotting.




Vacuum Devices

Mechanical vacuum devices cause erection by creating a partial vacuum, which draws blood into the penis, engorging and expanding it. The devices have three components: a plastic cylinder, into which the penis is placed; a pump, which draws air out of the cylinder; and an elastic band, which is placed around the base of the penis to maintain the erection after the cylinder is removed and during intercourse by preventing blood from flowing back into the body The satisfaction rate varies from 35-80% but the problems with the Vacuum Erection devices are – cold penis, loosely hanging penis ,sometimes it can lead to bruises especially patient using it roughly and on aspirin or clopidogrel.



Surgery
Surgery usually has one of three goals:
•to implant a device that can cause the penis to become erect (Penile Implant surgery)
•to reconstruct arteries to increase flow of blood to the penis (Penile revascularization surgery for patient with focal arterial stenosis-post-trauma)
•to ligate veins that allow blood to leak from the penile tissues (penile venous leak-particularly detected on Doppler showing persistence end-diastolic velocity more than 5 cm/sec)

Implanted devices, known as prostheses, can restore erection in many men with ED. Possible problems with implants include mechanical breakdown and infection, although mechanical problems have diminished in recent years because of introduction of Viagra but there are a group of patients who fail with medications and refuse or fail with Vacuum Erection Device. Inflatable implants consist of paired cylinders, which are surgically inserted inside the penis and can be expanded using pressurized fluid Tubes connect the cylinders to a fluid reservoir and a pump, which are also surgically implanted. The patient inflates the cylinders by pressing on the small pump, located under the skin in the scrotum. Inflatable implants can expand the length and width of the penis. They also leave the penis in a more natural state when not inflated.



Advantages with the penile impants are:
 Good rigidity
 Freedom from medications
 Outpatient/24HR surgery
 Resume sexual activity 4-6 weeks
 No loss of ability to ejaculate or achieve orgasm








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 perineum or fracture of the pelvis.

Surgery to veins that allow blood to leave the penis usually involves an opposite procedure-intentional blockage. Blocking off veins (ligation) can reduce the leakage of blood that diminishes the rigidity of the penis during erection. However the results are not long lasting so the venous ligation surgery have diminished