Diseases of the Male Reproductive System

Published on 19/03/2015 by admin

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Diseases of the Male Reproductive System

The male reproductive system develops in close relation with the urinary tract, and the two are usually thought of as the urogenital system. After formation of the metanephric duct and the induction of nephrons, a distal part of the meso-nephric (Wolffian) duct becomes integrated into the lateral walls of the urogenital sinus with separation into ureters and male ejaculatory channels. The testes develop from the gonadal ridge, and their seminiferous tubules combine with the secretory channels formed by the Wolffian duct. The prostate develops from epithelial invaginations in the distal urethra. Therefore, congenital diseases of the genital system may also be associated with disorders of the urinary tract. A summary of the many infectious and inflammatory diseases of the male reproductive system is shown in Table 7-1.

TABLE 7-1

INFECTIOUS AND INFLAMMATORY DISEASES OF THE MALE REPRODUCTIVE SYSTEM

Diseases of the Glans Penis and Prepuce (Balanitis, Balanoposthitis)
Simple balanitis (infants, older men) Congenital or acquired phimosis, secondary bacterial infection
Balanoposthitis (adults) Adhesions, phimosis secondary to obstruction (edema, cancer, elephantiasis), trauma, chemical irritation, sexually transmitted infections
Erosive balanitis Phimosis, anaerobic organisms (spirochetes, vibrios)
Gangrenous balanitis Phimosis, anaerobic organisms (spirochetes, vibrios)
Vesicular or ulcerative balanitis Herpes progenitalis due to herpes simplex virus (HSV) type 2, histoplasmosis, keratosis blenorrhagia, pemphigus, scabies
Atrophic (leukoplakic) balanoposthitis Dysplasia of epithelium
Venereal warts (Condylomata accuminata) Human papilloma viruses (HPV), especially types 6, 11, 42, and 44
Diseases of the Uretha
Acute and subacute urethritis Neisseria gonorrhoeae (gonorrheal urethritis), Trichomonas vaginalis, Chlamydia trachonatis serotypes D-K, other infections
Diseases of the Penis, Scrotum, and Inginual Lymph Nodes
Chancre of glans, penile body, scrotum Syphillis due to Treponema pallidum
Ulcerative lesions with lymphadenopathy Chancroid (Haemophilis ducreyi), lymphogranuloma venereum (Chlamydia trachomatis serotypes L1, L2, L3), Granuloma inguinale (Calymmatobacterium granulomatis)
Elephantiasis Wuchereria bancrofti (filaria), nonfilarial elephantitis (lymphedema)
Diseases of the Prostate
Acute prostatitis Neisseria gonorrhoeae, staphylococci (instrumentation), nonspecific
Prostatic abscesses Complication of urethritis and prostatitis, systemic infections
Chronic prostatitis Insidious onset or extension of actue prostatitis, various pyogenic bacteria, tuberculosis (Mycobacterium tuberculosis)
Diseases of the Scrotum
Tinea cruris (jock itch) Superficial fungal infection (Epidermophyton and Trichophyton groups)
Erythrasma Nocardia minutissima
Dermatitis venenata and other contact dermatoses Chemical irritants, drug eruption (Dermatitis medicamentosa)
Eczema (chronic) Allergic reactions, atopic dermatitis
Intertrigo Erythema due to chemical irritation with secondary infection with cocci and fungi
Scabies Mite infestation (Sarcoptes scabiei)
Pediculosis pubis (phthiriasis) Crab louse infestation (Phthirius pubis)
Furuncle (abscess) of the scrotum Pyogenic bacteria, esp. Staphylococcus aureus
Erysipelas of the scrotum Pyogenic bacteria, esp. Streptococcus pyogenes
Gangrene of the scrotum Mechanical, chemical or thermal injuries with secondary infection, idiopathic gangrene (Fournier’s gangrene)
Diseases of the Testis
Orchitis, epididymitis, epididymoorchitis Multiple organisms, spread from local or systemic infections
Acute pyogenic orchitis, abscess of the testis Pyrogenic bacteria
Mumps orchitis Mumps virus
Epididymitis Specific (gonorrheal, syphilitic, etc.), nonspecific, traumatic
Granulomatous orchitis Syphlitic orchitis, syphilitic gumma, tuberculosis (M. tuberculosis)

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Diseases of the Penis and the Urethra

A variety of disorders may result in urinary or sexual dysfunction: structural and functional anomalies, including malformations; urethral stenosis and phimosis; fibromatosis (Peyronie disease); and priapism. In addition, the penis is a frequent site of inflammatory diseases, including sexually transmitted diseases (STDs) and some benign and malignant tumors. STDs and related infections, such as papilloma virus and candidiasis, have recently received considerable attention because of their rising incidence, association with HIV infection, and copathogenetic effects in the development of certain cancers. Squamous cell carcinoma (SCC) of the penis represents only 0.5% of all cancers in men in the United States but is significantly more frequent in some parts of Africa and Asia. Most penile SCCs are confined to the penis and can be cured by amputation. Delayed diagnosis or the presence of occult metastases at initial presentation, however, worsens the prognosis.

Diseases of the Prostate Gland and the Seminal Tracts

Prostatitis occurs fairly frequently in men older than 50 years and is usually nonbacterial. In all ages, bacterial prostatitis usually follows urinary tract infection, but hematogenous forms may occur. Among the more common causative organisms are Escherichia coli, Chlamydia species, Mycoplasma, and Trichomonas vaginalis.

Benign prostatic hyperplasia (BPH) is common in older men, affecting more than 50% at the age of 60 years and more than 75% at the age of 80 years. The etiology of BPH is unknown, but recent studies suggest a relation with disturbed 5-dihydrotestosterone synthesis. Clinical features result from compression of the prostatic urethra with resultant obstruction of urine outflow, muscular hypertrophy of the bladder, and retrograde back pressure, ultimately causing hydroureter and hydronephrosis.

Cancer of the prostate (adenocarcinoma, ACP) is among the most frequent malignant tumors in men, causing approximately 30,000 deaths per year in the United States. One of 10 American men has clinically apparent prostate cancer during his life. The etiology of ACP is unknown. Hormonal imbalances (estrone to testosterone ratio) and exogenous carcinogens may play important roles in the pathogenesis. ACP constitutes 98% of prostatic neoplasias. Because the clinical features of ACP are similar to those of BPH, with which it often coexists, only 10% of patients with ACP present at an early stage. Demonstration of prostate-specific antigen (PSA) in serum and/or biopsy specimens may be helpful in the primary diagnosis and follow-up. The treatment and prognosis of ACP are stage dependent.

Testicular Disorders

Testicular tumors are divided into 2 major classes: germ cell tumors and gonadal stromal tumors (sex cord tumors). More than 90% of testicular tumors are germ cell tumors, most frequently seminoma, embryonal carcinoma, and teratoma. Seminoma accounts for approximately one half of all germ cell tumors. The so-called classic type, occurring at the ages of 25–55 years, is radiosensitive and, after treatment of solitary tumors, is associated with 5-year survival greater than 90%. Embryonal carcinoma, which occurs at younger ages (20–35 years), is the second most common germ cell tumor. It is histologically more pleomorphic and may include human chorionic gonadotropin- (β-HCG) or α-fetoprotein–producing cells (transition to choriocarcinoma or teratoma). These tumors tend to respond well to chemotherapy; in localized cases, 5-year survival may exceed 95%. Sex cord tumors include Sertoli cell tumor and Leydig cell tumor.

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Figure 7-1 Functional Gonadal Relations
The 3 gonadotrophic hormones of the pituitary adenohypophysis are (1) follicle-stimulating hormone (FSH); (2) luteinizing hormone (LH) of the female, known as interstitial cell–stimulating hormone (ICSH) in the male; and (3) luteotropin (prolactin, LTH). These pituitary hormones determine the development of the male and female gonads. The germinal epithelia of the testes and ovaries are responsible for the production of sperm and ova, respectively. Various stromal cells of the gonads are responsible for the production of the androgen and estrogen hormones, which act on the organs of the reproductive tract, the secondary sex organs, and other parts of the body. There is a feedback loop for interdependent regulation of the production of the gonadal and pituitary hormones.

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Figure 7-2 Hermaphroditism
True hermaphroditism, defined as the presence of both testicular and ovarian tissue in the same patient, is rare. The chromosomal karyotype usually is euploid, with either a 46, XX or a 46, XY pattern, but may be aneuploid (45X/XY). Complex alterations in sex chromosomal gene expression lead to abnormal development of the gonads, including the formation of 1 or 2 ovotestes, an ovary on one side and a testis on the other, or a combination of these arrangements. The internal and external genitalia and secondary sexual characteristics correlate with the composition of the gonadal structures. Male pseudohermaphrodites have gonads with the histologic features of testes and varying degrees of feminine characteristics. Female pseudohermaphrodites have ovaries, but their external genitalia appear male. Male and female pseudohermaphroditism both generally result from a spectrum of neoplastic and nonneoplastic endocrine disorders.

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Figure 7-3 Congenital Anomalies: Congenital Valves, Epispadia, and Hypospadia
Certain congenital anomalies of the urinary bladder and urethra are clinically important. Congenital valves of the posterior urethra are thin folds of mucosa that develop in the prostatic urethra and extend from the verumontanum to the sides of the urethra. Obstruction to urine flow leads to bladder hypertrophy and dilatation, bilateral hydronephrosis, and, ultimately, fatal renal failure. Epispadia

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