Pathologies of the Male Reproductive Tract

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Pathologies of the Male Reproductive Tract


Aarush Sajjad, Muhammad A. Akhtar, and Yasmin Sajjad


Introduction


The functional male reproductive tract involves complex processes that includes androgen homeostasis, spermatogenesis, sperm transport and storage, and normal erectile and ejaculatory ability. The control of these functions involves the hypothalamic–pituitary–gonadal axis, central and peripheral nervous systems, and genitalia.


The external male reproductive organs comprise the scrotum, testis, and penis. The testes are responsible for the production of testosterone and spermatozoa. Testosterone and dihydrotestosterone are responsible for the development of male sexual characteristics, which includes the distribution of pubic hair, maturation and enlargement of the penis, and deepening of the voice (by larynx enlargement). During ejaculation, the sperm are transported through the reproductive ducts that include the epididymis, vas deferens, ejaculatory duct, and urethra.


The epididymis is a collection of coiled microscopic tubes that together are almost 6 metres long. Sperm are transported to the epididymis where they remain and mature, gaining functional properties essential for motility. One epididymis lies against each testis. The other ducts include the vas deferens, ejaculatory duct, and urethra. The vas deferens is a firm tube that transports sperm from the epididymis. One such duct travels from each epididymis to the back of the prostate and joins with one of the two seminal vesicles and secretions from bulbourethral glands. These are called the accessory sex glands of the male reproductive system. The reproductive glands produce secretions that become part of semen, which is ejaculated from the urethra; this single duct passes through the penis (Chapter 2 covers the male reproductive anatomy in more detail).


This chapter will discuss only the disorders of the male reproductive tract.


Disorders of the Testes and Epididymis


Cryptorchidism


Testes are not always in the scrotum at birth as they form in the abdomen from the gonadal ridge or indifferent gonad that develops around 3–5 weeks of gestation. At 6 weeks’ gestation, primordial germ cell migration occurs leading to testes development. This process is stimulated by the SRY gene (sex‐determining region on Y chromosome); this gene is the testis‐determining factor.


The testes descend prenatally from their initial intra‐abdominal location on the urogenital ridge into the low‐temperature environment of the scrotum via a complex multistage mechanism (Hutson et al. 1997). Prenatal ultrasonography shows no testicular descent before 28 weeks’ gestation, other than transabdominal movement to the internal inguinal ring. Transinguinal migration, thought to be under hormonal control, occurs at 28–40 weeks’ gestation, usually resulting in a scrotal testis by the end of a full term of gestation.


Undescended testis, or ‘cryptorchidism’, is a very common anomaly in male infants and preadolescent boys (Figure 13.1), with about one in 20 boys undergoing treatment by the time they reach puberty (Hutson 2013). The incidence of cryptorchidism shows large geographic variation, and in several countries increasing trends have been reported affecting 2–9% of male newborns (Toppari et al. 2010). It could be complete or incomplete failure of intra‐abdominal testes to descend into the scrotal sac and is unilateral in most cases.

Illustration of a prepubescent male’s lower body displaying the sex organ infected with cryptorchidism, the right undescended testis forms a swelling in the inguinal canal.

Figure 13.1 Cryptorchidism. The right undescended testis forms a swelling in the inguinal canal in a prepubescent male.


Source: https://commons.wikimedia.org.


Factors that predispose or might increase the risk of undescended testes in a newborn include low birth weight and premature birth (Chung and Brock 2011). Exposure to oestrogen in utero and prenatal diethylstilbestrol (DES) exposure was associated with an almost twofold risk of cryptorchidism, and a stronger association was observed for exposures starting before the eleventh week of pregnancy (Palmer et al. 2009; Virtanen and Adamsson 2012).


Other factors include family history of undescended testes (Elert et al. 2003), or other problems of genital development, including conditions of the fetus that can restrict growth, such as Down syndrome or an abdominal wall defect (Koivusalo et al. 1998), as well as the mother’s exposure to some pesticides (Carbone et al. 2006). These factors may contribute towards failure of the testes to descend into the scrotum at birth.


The mode of treatment for undescended testes has been debated for many years. Recently, a group of specialists in various related disciplines from the Nordic countries summarized the available information from literature, debated the advantages and disadvantages of different treatment modalities, and framed a consensus on the management of undescended testes (Ritzen et al. 2007; Ritzen 2008).


In most cases, the testis will descend without treatment during the child’s first year. If this does not occur, treatment may include hormone injections (B‐HCG or testosterone) or surgery (orchidopexy) to bring the testis into the scrotum. Orchidopexy is the main treatment for this condition.


Early surgery may prevent damage to the testes that can cause infertility (Ritzen et al. 2007). An undescended testis that is found later in life may need to be removed. Males with undescended testes are 40 times more likely to develop testicular cancer than males without undescended testes (Farrer et al. 1985). Ten percent of testicular cancer cases involve patients with undescended testes (Abratt et al. 1992). There is an increased risk of developing a germ cell tumour, especially seminoma and embryonal carcinoma, in undescended testes. Recent studies have shown that prepubertal orchidopexy reduces this risk (Walsh et al. 2007; Tuazon et al. 2008).


Although successful scrotal repositioning of the testis may reduce the risk, it does not prevent the potential long‐term issues of infertility and testis cancer, and appropriate counselling and follow‐up of the patient are essential (Kolon et al. 2014).


Testicular Torsion


As discussed previously, the testes develop from condensations of tissue within the urogenital ridge at approximately 6 weeks of gestation. With longitudinal growth of the embryo, and through complex multistage mechanisms under endocrine and paracrine signals, the testes ultimately descend into the scrotum by the third trimester of pregnancy (Hutson et al. 1997). The testes migrate through the inguinal canal and as the testes leave the abdomen it carries the peritoneal lining with it, creating the processus vaginalis. Although the testis is located in the scrotum, it gets its blood supply from an artery that originates in the abdomen, called the spermatic artery. The spermatic arteries and pampiniform venous plexus enter the inguinal canal proximal to the testes, and together with the vas deferens, form the spermatic cord (Barteczko and Jacob 2000). Distally, the testis is attached to the scrotum by the gubernaculum.


It is not clear why testicular torsion happens. Testicular torsion can occur due to testicular injury or congenitally loose attachment of the testis to the scrotum. It often occurs several hours after vigorous activity – a minor injury to the testes can even occur in sleep. Cases of testicular torsion have been documented during periods of cold weather, with an increase in winter (Korkes et al. 2012; Gomes Dde et al. 2015).


It is understood that testicular torsion occurs when the testis rotates, twisting the spermatic cord and its contents (Figure 13.2). It is a surgical emergency, with an annual incidence of 3.8 per 100 000 males younger than 18 years (Zhao et al. 2011). This twisting cuts off the blood supply to the testis, causing the sudden onset of severe pain and swelling.

Diagram of a normal testis with parts labeled spermatic cord, scrotum, spididymis, and testis (left) and a testis having a torsion of spermatic cord with a line marking the ischaemic testis (right).

Figure 13.2 Testicular torsion. During testicular torsion a testis rotates, twisting the spermatic cord that supplies blood to the testis. The resultant reduced blood flow causes sudden and often severe pain and swelling.


Reproduced with permission of Keith Carroll.


There is typically a 4–8 h window before significant ischaemic damage occurs, manifested by morphological changes in testicular histopathology and deleterious effects on spermatogenesis (Bartsch et al. 1980). The viability of the testis in cases of torsion is difficult to predict; hence, emergency surgical treatment is indicated despite many patients presenting beyond the 4–8 h time frame (Davenport 1996). If treated quickly, the testis can usually be salvaged. When testicular torsion is not treated for several hours, blocked blood flow can cause permanent damage to the testis. Hence, removal of the testis, called orchidectomy, is performed if the affected testis appears grossly necrotic or nonviable. Torsion accounts for approximately 10–15% of acute scrotal disease in children, resulting in an orchidectomy rate of 42% in boys undergoing surgery for testicular torsion (Barbosa et al. 2013; Liang et al. 2013). Orchidectomy rates vary widely in the literature, typically ranging from 39 to 71% in most series (Jefferson et al. 1997; Kaye et al. 2008; Yang Jr et al. 2011). Therefore, prompt restoration of blood flow to the ischaemic testis is critical in cases of testicular torsion (Thomas et al. 1984; Romeo et al. 2010)


If surgery is performed in time and the affected testis is deemed viable, orchidopexy (resolving the torsion) with permanent suture should be performed to permanently fix the testis within the scrotum (Taskinen et al. 2008). It is also recommended that contralateral orchidopexy should be performed regardless of the viability of the affected testis (Bolin et al. 2006). In some cases, damage or loss of a testis affects a male’s ability to father children.


Testicular Atrophy


Testicular atrophy is the shrinkage of the testes. There are many causes but it is commonly due to injury to the testes, use of recreational drugs, anabolic steroids and testosterone, cryptorchidism, end stage of inflammatory orchitis, progressive atherosclerotic narrowing of the blood supply in old age, hypopituitarism, generalized malnutrition or cachexia, obstruction to outflow of semen, irradiation, and prolonged administration of hormones. Testicular atrophy can lead to hypogonadism, resulting in reduced testosterone production and poor spermatogenesis, the consequences of which are azoospermia and infertility (Møller et al. 1996).


Testicular Tumours


Testicular tumours are rare (1% of all tumours in men). Each year in the UK around 2300 men are diagnosed with testicular cancer, according to Cancer Research UK. It presents with a painless swelling in the testes with a dull ache or feeling of heaviness in the scrotum.


Risk factors for testicular tumours are:



  • Age: common in young and middle‐aged men. Men aged 30–34 are more likely to develop testicular cancer and risk reduces after age 49 years.
  • Ethnicity: more prevalent in Whites (five times higher) compared with other ethnicities.
  • Undescended testes.
  • Smoking.
  • Subfertility: subfertile men are three times more likely to develop testicular cancer.
  • Human immunodeficiency virus.
  • Height: taller men (>190 cm tall) are two to three times more likely to develop testicular cancer. The taller you are, the higher the risk. In shorter men (<170 cm) the risk of testicular cancer is reduced by 20%.
  • Family history of testicular cancer.

Types of testicular tumours are:



  • Germ cell tumours: most common (95% of all cases). Two subtypes, seminoma and nonseminoma, both account for half of all germ cell tumours. They respond well to chemotherapy.
  • Leydig cell tumours (1–3% of all cases).
  • Sertoli cell tumours (1% of all cases).
  • Lymphomas – Hodgkin or non‐Hodgkin (4% of all cases).

If a testicular tumour is suspected, it can be investigated either by examination or testicular ultrasound. Refer for an urgent (within 2 weeks) outpatient appointment with a urologist. Measure the tumour markers alpha‐fetoprotein (AFP) and human chorionic gonadotrophin (hCG) (NICE 2010; Albers et al. 2015).


Treatment for germ cell tumours is orchidectomy, chemotherapy, radiotherapy, and/or lymph node dissection. Prognosis is excellent following treatment, particularly if the tumour is detected at an early stage. Following treatment, 5‐year survival is nearly 100% for nonmetastatic germ cell tumours (Ehrlich et al. 2015). For metastatic disease, 5‐year survival is, on average, 85%, but varies from 48 to 92% depending on the stage and type of tumour (NICE 2010; Albers et al. 2015).


Epididymo‐Orchitis


Epididymitis refers to inflammation of the epididymis, and may be associated with inflammation extending to the testis itself, in which case the term epididymo‐orchitis is used (Tracy et al. 2008). This should be distinguished from isolated orchitis, which is by comparison much less common. Epididymo‐orchitis most often presents with acute onset of pain and swelling of the scrotum, which can be a result of bacterial infection, However, this can also be due to noninfectious causes, particularly in children.


In sexually active men under the age of 35 years it is usually caused by a sexually transmitted infection, such as chlamydia or gonorrhoea ascending from the urethra (Zdrodowska‐Stefanow et al. 2000). This will be discussed in more detail in Chapter 14.


In older men over the age of 35 years it is usually caused by nonsexually transmitted uropathogens spreading from the urinary tract (Trojian et al. 2009). The majority of cases are bacterial in origin arising from the bladder, prostate, or urethra, which can reflux via ejaculatory ducts into the epididymis. The inflammatory response usually starts in the tail of the epididymis due to the its greatest blood supply before spreading to the body, head, and testis (Mukherjee and Sinclair 2010).


Risk factors include bacterial prostatitis, urinary tract infection, underlying congenital abnormalities (in children), urinary stasis as a result of bladder outlet obstruction, and invasive procedures such as instrumentation/catheterization (Nickel 2007).


Mumps orchitis is a complication of the childhood viral disease. Although less common, incidences of mumps orchitis is increasing, as a result of the decline in vaccinations (Lane and Hines 2006; Phillip et al. 2006). Mumps affect around 20–30% of infected postpubertal males as a result of haematogenous spread, usually 4–11 days after the onset of parotitis (Philip et al. 2006). This viral infection can spread to the epididymis, with bilateral orchitis occurring in 10–30% of cases. Severe infection may result in testicular atrophy and infertility (if mumps orchialgia is bilateral). To reduce the risk of secondary bacterial infection, antibiotic therapy should be given (even with an obvious clinical diagnosis of mumps orchitis) (Lane and Hines 2006).


Less common causes include an operation to the prostrate or urethra. Tuberculous epididymo‐orchitis is also considered in patients from high prevalence countries or with a previous history of tuberculosis and particularly in patients with immunodeficiency (Viswaroop et al. 2005). It is usually as a result of disseminated infection and commonly associated with renal TB but can be an isolated finding (Ferrie and Rundle 1983; Viswaroop et al. 2005).


Unilateral and bilateral epididymo‐orchitis has also been reported as an adverse effect of amiodarone treatment and will resolve once treatment is ceased (Gasparich et al. 1985). Other rare infective causes include Brucella and fungi such as Candida (Hagely 2003).


Epididymo‐orchitis presents characteristically with unilateral scrotal pain and swelling of relatively acute onset. Torsion of the testis is the most important differential diagnosis (Giesler and Krieger 2008). Other symptoms may include pyrexia accompanied by chills, and a sore swelling of the epididymis with hot, reddish scrotal skin. Occasionally, there may be pain in the stomach accompanied by a sick feeling and vomiting.


In sexually transmitted epididymo‐orchitis there may be symptoms of urethritis or a urethral discharge; however, the urethritis is often asymptomatic (Hawkins et al. 1986; Mulcahy et al. 1987; Hoosen et al. 1993).


Appropriate rest, analgesia, and scrotal support are recommended. Nonsteroidal anti‐inflammatory drugs may be helpful (Walker and Challacombe 2013). Patients should be advised to abstain from sexual intercourse until they and their partner(s) have completed treatment and follow‐up in those with confirmed or suspected sexually transmitted epididymo‐orchitis (Centre for Disease Control Prevention 2006).


Empirical therapy should be given to all patients with epididymo‐orchitis before culture results are available. The antibiotic regimen chosen is determined in light of the immediate tests (urethral or urinalysis) as well as age, sexual history, any recent instrumentation or catheterization, and any known urinary tract abnormalities in the patient.


Antibiotics used for sexually transmitted pathogens may need to be varied according to local knowledge of antibiotic sensitivities. Most commonly a ceftriaxone 500 mg single intramuscular injection is given along with doxycycline 100 mg by mouth twice daily for 10–14 days or ciprofloxacin 500 mg twice daily with a stat dose of azithromycin 1 g (Berger et al. 1979; Hoosen et al. 1993).


Epididymal Cysts


An epididymal cyst is a fluid‐filled sac within the epididymis. It is always benign. It can present unilaterally or bilaterally either as single or multiple cysts. It is not associated with any medical conditions or infections. Most epididymal cysts do not require treatment; very rarely, large epididymal cysts require surgical removal. Aspiration of a cyst is not recommended.


Disorders of the Scrotum


Scrotal disorders include inguinal hernias extending to the scrotum, varicocele, hydrocele, scrotal squamous cell carcinoma, cryptorchidism, testicular torsion, and testicular tumours. Some have been described earlier in the chapter.


Inguinal Hernia


Inguinal hernia is protrusion of abdominal contents through the inguinal canal. It presents with a lump in the groin, which can reduce in size with minimal pressure or by lying down. The lump can cause discomfort, which sometimes increases with physical activity. Inguinal hernias are at risk of irreducibility or incarceration, which may result in strangulation and obstruction. However, the risk of strangulation is very low in comparison to femoral hernia (Jenkins and O’Dwyer 2008).


Inguinal hernias can be direct or indirect. Indirect inguinal hernias are more common. Direct inguinal hernia arises from protrusion of abdominal contents through a weakness of the posterior wall of the inguinal canal medial to the inferior epigastric vessels. Indirect inguinal hernias occur due to failure of embryonic closure of the deep (internal) inguinal ring after testicular descent. It is present lateral and superior to the course of the inferior epigastric vessels protruding through the deep inguinal ring into the inguinal canal.


Suspect strangulation if a patient presents with an acutely painful, firm, tender, irreducible inguinal hernia. The risk of strangulation for all inguinal hernias is estimated to be 0.3–3.0% per year (Simons et al. 2009). Suspect obstruction if a patient presents with nausea, vomiting, constipation, absence of flatus, abdominal pain, and distension. In these cases, urgent surgical intervention is required by general surgeons (NICE 2010).


If an inguinal hernia extends into the scrotum, it is almost always indirect (Douglas et al. 2009). It is recommended that any inguinal hernia extending into the scrotum should be repaired (NICE 2010) as the risk of strangulation is 10 times higher for indirect hernias compared with direct inguinal hernias (Simons et al. 2009).


Hydrocele


A hydrocele is defined as presence of a fluid‐filled sack along the spermatic cord between the tunica vaginalis and testes within the scrotum (Figure 13.3) (Albino et al. 2010). It can be unilateral or bilateral. The cause can be congenital or acquired. It presents with a painless swollen scrotum (Cimador et al. 2010). A referral to a paediatric surgeon is required if this is present in infancy and young age for any congenital hydrocele. Most hydroceles will resolve spontaneously by the age of two and aspiration is not recommended (NICE 2010). Laparoscopic surgery is offered for treatment of hydrocele in children if needed (Clarke 2010).

Diagram of the male sex organ depicting hydrocele as the presence of a fluid‐filled sack along the spermatic cord between tunica vaginalis and testes within the scrotum.
Close-up view of a scrotum with a large swelling being measured by a ruler.

Figure 13.3 Hydrocele. (a) Hydrocele depicted as presence of a fluid‐filled sack along the spermatic cord between tunica vaginalis and testes within the scrotum. (b) Presented at a large scrotal swelling.


Source: (a) Michael Carroll; (b) https://commons.wikimedia.org).


Acquired hydroceles may be due to testicular torsion, epididymo‐orchitis, testicular cancer, varicocele, inguinal hernia, trauma, or continuous peritoneal ambulatory dialysis, renal or heart failure. Diagnosis is made on examination with transillumination and testicular ultrasound. Approximately 10% of testicular cancers presents with a reactive hydrocele (Albino et al. 2010). Manage according to the cause and if required refer to a urologist. Aspiration of hydrocele is not recommended (NICE 2010).


Varicocele


Varicocele is an enlargement of the scrotal veins due to an abnormally dilated pampiniform venous plexus. It is present in 15% of the normal male population, and present in approximately 40% of infertile males (Nagler et al. 1997

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Apr 3, 2020 | Posted by in EMBRYOLOGY | Comments Off on Pathologies of the Male Reproductive Tract

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