Porth's Essentials of Pathophysiology, 4e

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Disorders of the Male Genitourinary System

C h a p t e r 3 9

disease are affected at some stage by priapism. 21 The rela- tive deoxygenation and stasis of cavernosal blood during erection is thought to increase sickling. Various medica- tions, such as erectile dysfunction drugs, antihypertensive drugs, anticoagulant drugs, antidepressant agents, alco- hol, and marijuana, can contribute to the development of priapism. Currently, intracavernous injection therapy for erectile dysfunction is one of the more common causes of priapism. The diagnosis of priapism usually is based on clini- cal findings. Color Doppler studies of penile blood flow, penile ultrasonography, and computed tomogra- phy (CT) scans may be used to determine intrapelvic pathology. Initial treatment measures include analgesics, sedation, and hydration. Urinary retention may neces- sitate catheterization. Local measures include ice packs and cold saline enemas, aspiration and irrigation of the corpus cavernosum with plain or heparinized saline, or instillation of α -adrenergic drugs. If less aggressive treatment does not produce detumescence, a temporary surgical shunt may be established between the corpus cavernosum and the corpus spongiosum. The prognosis for whether fibrosis or erectile failure will occur is determined by the severity and duration of blood stasis. Persistent stasis priapism is known to result in impaired erectile function and tissue fibrosis unless resolved within 24 to 48 hours of onset. 20 Neoplasms of the Penis Although relatively rare (<1% of male genital tumors) in developed countries of the world, cancer of the penis may account for 10% to 20% of all genital malignan- cies in areas such as Africa and South America. 22 When it is diagnosed early, penile cancer is highly curable. The greatest hindrance to early diagnosis is a delay in seek- ing medical attention. The cause of penile cancer is unknown. 16,22,23 Several risk factors have been proposed, including poor genital hygiene, human papillomavirus (HPV) infection, ultra- violet radiation exposure, increasing age, and immuno- deficiency states. Circumcision confers protection, and hence cancer of the penis is extremely rare in men cir- cumcised at birth. 14,15 It is thought that circumcision is associated with better genital hygiene, which, in turn, reduces exposure to carcinogens that may accumu- late in smegma and decreases the likelihood of poten- tially oncogenic strains of HPV. Ultraviolet radiation is thought to have a carcinogenic effect on the penis. 23 Men who were treated for psoriasis with ultraviolet A radiation (i.e., PUVA) have had a reported increased incidence of genital squamous cell carcinomas. Because of this observation, it is suggested that men should shield their genital area when using tanning salons. Immunodeficiency states (e.g., acquired immunode- ficiency syndrome [AIDS]) also may play a role in the pathogenesis of penile cancer. 16,23 Dermatologic lesions with precancerous potential include balanitis xerotica obliterans (discussed under penile inflammatory condi- tions) and giant condylomata acuminata. 22 Giant condy- lomata acuminata, or genital warts, are cauliflower-like

Fibrous plaque

Deep penile fascia

Tunica albuginea

Corpus cavernosum

A

Corpus spongiosum

Fibrous plaque

Corpus cavernosum

Corpus spongiosum

B FIGURE 39-7. Peyronie disease. (A) Penile cross-section showing plaque between the corpora. (B) Penile curvature.

During the 1st year or so after formation of the plaque, while the scar tissue is undergoing the process of remod- eling, penile distortion may increase, remain static, or resolve and disappear completely. In some cases, the scar tissue may progress to calcification and formation of bonelike tissue. Diagnosis is based on history and physical exami- nation. Ultrasonography may be used to diagnose the disorder. Although surgical intervention can be used to correct the disorder, it often is delayed because in many cases the disorder is self-limiting. Less invasive treat- ments include the administration of oral agents with antioxidant properties (e.g., vitamin E, colchicine); pentoxifylline, a drug that is thought to reduce blood viscosity, allowing it to flow more easily through par- tially obstructed areas; and intralesional treatments, including corticosteroids. Priapism Priapism is an involuntary, prolonged (>4 hours), abnormal and painful erection that continues beyond, or is unrelated to, sexual stimulation. 19,20 Priapism is a true urologic emergency because the prolonged erection can result in ischemia and fibrosis of the erectile tissue with significant risk of subsequent impotence. Priapism can occur at any age, in the newborn as well as other age groups. Sickle cell disease or neoplasms are the most common cause in boys between 5 and 10 years of age. 21 Priapism is caused by impaired blood flow in the cor- pora cavernosa of the penis. Priapism is classified as pri- mary (idiopathic) or secondary to a disease or drug effect. Secondary causes include hematologic conditions (e.g., leukemia, sickle cell disease, polycythemia), neurologic conditions (e.g., stroke, spinal cord injury), and renal failure. Between 6% and 42% of males with sickle cell