What is Peyronie's disease and what causes it?
Peyronie's disease is a benign (noncancerous) condition of the penis that tends to affect middle age males. The incidence is 4.3 per 100,000 men aged 20 to 29 years and increases to 66 per 100,000 men aged 50 to 59 years. Approximately two thirds of affected men are between the ages of 40 and 60 years. The exact cause of Peyronie's disease is not known. The disease is characterized by the formation of plaques in the tunica albuginea of the penis. These plaques may be felt on penile examination and at times can feel as hard as bone. The plaques are like scar tissue and affect the function of the tunica in that area. Because the plaque is not elastic and stretchy like the rest of the tunica, it pulls the penis to the side of the plaque during an erection and may also cause "wasting" (an indentation in the penis) at the site of the plaque. There may also be pain associated with an erection. Lastly, because the plaque does not behave like normal tunica, it may also cause erectile troubles. The plaque may occur anywhere along the penile shaft but is more commonly identified on the top (dorsal) surface of the penis. More than one plaque may be palpable. The hallmarks of Peyronie's disease are a palpable plaque (a hard spot along the shaft of the penis that one can feel when examining the penis), penile curvature, and a painful erection.
The disease typically has a slow onset, and most men cannot identify a precipitating factor. Several theories exist as to the cause of Peyronie's disease; the most commonly accepted theory is that minor trauma during intercourse leads to minor tears in the tunica or rupture of small blood vessels. Bleeding and abnormal healing occurs after this injury and produces the plaque. In some men, there is a family history of Peyronie's disease, and 16% to 20% of men with Peyronie's have a disease called Dupuytren's contractures. Dupuytren's contractures is an inherited condition that causes contractures in the hands that pull the affected fingers inward. An increased incidence of arterial disease (30%) and diabetes with its associated small arterial disease (2.7% - 12%) has also been noted in men with Peyronie's disease.
The natural history of Peyronie's disease is variable. The disease is thought to have two phases: the acute phase, which usually lasts up to 18 months and is associated with pain, penile curvature, and plaque formation, and a more chronic phase, in which there is minimal or no pain, a palpable plaque, and residual penile curvature. Over time, the disease may progress in about 42% of men, improve in 13%, and remain the same in about 45%. In many cases, the disease produces few symptoms, the curvature does not prevent sexual performance, and there is no pain or associated erectile dysfunction. In such cases, reassurance that there is nothing bad going on is often all that is necessary.
How does one evaluate Peyronie's disease?
As with any initial presentation, the evaluation of Peyronie's disease starts with a history of symptoms: duration and presence of pain; current erectile status and erectile status before the onset of the Peyronie's disease; whether symptoms are stable, progressing, or regressing; and degree of penile curvature and its effect on sexual function. The physician will ask about a history of prior penile trauma or manipulation.
Because the penile abnormality has a classic presentation and most men are able to accurately describe the symptoms, little investigation is needed initially. After the history is elicited, an examination will be performed. Examination of the hands will be performed to look for Dupuytren's contractures. Examination of the penis includes assessment of penile length and girth and palpation for penile plaques. In most cases, the physician will ask the man to bring in either a Polaroid photograph or digital picture of his erect penis to demonstrate the degree and the location of the curvature. If the patient is unable to obtain a photograph, the physician may induce an erection in the office by injecting a chemical that causes an erection in order to allow the physician to locate the area of curvature and to assess the degree of curvature. If the man has erectile dysfunction in addition to the penile curvature, further studies are needed to assess the cause of the erectile dysfunction.
Erectile dysfunction is found in about 19% of men with Peyronie's disease. The erectile dysfunction in Peyronies disease may be the result of:
- performance anxiety;
- the penile deformity preventing intercourse;
- a flail penis, whereby extensive Peyronies disease causes scarring in a segment of the penis that therefore does not become rigid, while the remainder is able to become rigid;
- an impaired erection, which may be related to concomitant arterial disease (36%) or veno-occlusive disease (59%)
The use of penile Doppler ultrasonography with injection of a dilating agent, such as alprostadil or triple P is helpful in determining the cause of the erectile dysfunction.