Introduction
An ‘acute scrotum’ is defined as any episode of acute onset of scrotal swelling and pain. It is equivalent to an acute abdomen in general surgery. As the scrotum is a tight space, many structures can be damaged. Patients must be seen immediately to find and treat the cause.
There are many medical conditions that can lead to an acute scrotum. It is listed below.
Ischaemia
• Testicular torsion
• Testicular infarction due to other vascular insult (cord injury, thrombosis, sickle cell)
Trauma
• Testicular rupture
• Intratesticular haematoma, testicular contusion
• Haematocele
Infections
• Acute epididymitis/ orchitis/ epididymo-orchitis
• Insect bites
• Abscess
• Gangrene (Fournier’s gangrene)
Inflammatory conditions
• Henoch- Schonlein Purpura of scrotal wall
Hernia
• Incarcerated, strangulated inguinal hernia
Acute on chronic events
• Spermatocoele, rupture or haemorrhage
• Hydrocele, rupture, haemorrhage or infection
• Testicular tumour rupture, haemorrhage, infarction or infection
• Varicocele
Table 1: Differential diagnosis of acute scrotum. Source: https://www.urology.wisc.edu/system/assets/617/module_1_acute_scrotum.pdf?1268758320
The anatomy of the scrotum is presented before moving onto common causes of acute scrotum to help understand which structures are affected in each condition.
Anatomy
Figure 1: Anatomy of Scrotum Source: http://teachmeanatomy.info/pelvis/the-male-reproductive-system/scrotum/
Figure 2: Structure of testis and epididymis. Source: http://teachmeanatomy.info/pelvis/the-male-reproductive-system/testes-epididymis/
The scrotum is located between the penis and scrotum. Under the skin, the dartos muscle covers the major structures and helps regulate the temperature of the scrotum. There are three major structures: the testis, epididymis and spermatic cord.
The testes sit in the scrotum with the epididymis on the posterolateral aspect of each testicle. The left testicle is commonly lower than the right. They are suspended from the abdomen by the spermatic cord. The spermatic cord contains the testicular arteries and veins, innervation from the testicular plexus and lymphatic drainage. The testes are covered by tunica vaginalis and tunica albuginea. The testes are glands that produce sperm and testosterone. There are three parts to the epididymis: the head, body and tail. The epididymis functions to store and transport sperm from the testes.
Torsion
Testicular torsion is when the testicle twists upon itself, causing occlusion of blood flow and lymphatic drainage. Ischaemia and oedema then occurs.
It commonly presents in children or adolescents with sudden onset of severe testicular pain and gradual scrotal swelling. There are usually no preceding events such as trauma. On physical examination, the testes are very tender with a high, horizontal lie. There is also loss of the cremasteric reflex on the affected side. If there is a delay in presentation, the scrotum will be swollen and anatomical landmarks are lost.
In older men, torsion is less common and is therefore sometimes missed. If imaging is available and the clinical picture not classical, then scrotal ultrasound can be done to assess blood flow of the affected testis. This investigation may also help exclude other causes of scrotal pain such as trauma, epididymitis or hernia.
Time is essence in testicular torsion. With blood flow occluded, the testis undergoes ischaemia and may be unsalvageable beyond 6 hours (figure 3). Surgical exploration and detorsion are the best management. In recurrent torsions or when one testis is unsalvageable, orchidopexy can be done on the other side to prevent future torsion.
Figure 3: Dead Testis. Source: http://emedicine.medscape.com/article/2036003-treatment
Infection
It is important to diagnose infection in the scrotum because management is entirely non-surgical (Anon., Module 1: The Acute Scrotum, 2009). Other than scrotal pain and swelling, infections produce urological symptoms such as dysuria, haematuria or discharge.
The source of infection defers from age to age. In men under 35 years old, the source of the infection is most often sexually transmitted with pathogens like Chlamydia trachomatis and Neisseria gonorrhoeae (Emma Street, 2010). In men above 35 years of age, the pathogen is more commonly non-sexually transmitted enteric gram negative bacteria (Emma Street, 2010). They may have risk factors such as benign prostatic hypertrophy, urinary tract infections (UTIs) or recent instrumentation.
In the suspicion of an infectious cause, there are extra features in the history that needs to be explored such as any venereal exposure, UTIs or medications. Investigations will include taking a urethral smear and examination under microscopy and mid-stream urine microscopy and culture.
All patients should receive empirical treatment before culture results are available (Emma Street, 2010). The antibiotic regimen is then determined by the clinical case and the results of the urethral smear/ urinalysis.
Hernia
A hernia is a sack of peritoneum that extends through the internal ring, antero-medial to the spermatic cord, through which omentum or bowel can transverse (Anon., Hernias, n.d.). An indirect hernia does not herniate through the bowel wall; instead, it herniates through a congenital defect into the scrotum (Anon., Hernias, n.d.).
Pain and swelling are present in both scrotal and inguinal areas. Patients complain of a bulge when they stand up or other activities such as coughing or straining. The mass may or may not be pushed back into the abdomen. Bowel can be entrapped or incarcerated for long periods of time without strangulation. However, if blood flow is compromised, the bowel becomes strangulated and is an emergency. There is a high risk of incarceration and strangulation of the hernia the larger the defect and extension into the scrotum (Anon., Hernias, n.d.).
An incarcerated hernia may sometimes be pushed back with the patient sedated. If that does not work or strangulation is confirmed, surgery should be undertaken. Open surgery or laparoscopic surgery is done based on the surgeon’s experience and preference. If bowel is viable, repair should be reinforced with mesh. If there is dead bowel, open surgery is undertaken and dead bowel removed, along with non-mesh repair of the hernia (BMJ, 2016).
Summary
There are many scrotal pathologies that can cause pain and swelling of the scrotum. Some of the common causes of acute scrotum are highlighted above. However, other less common causes should still be considered. A careful history and examination should be able to differentiate between causes. Scrotal imaging is an adjunct and should not be always relied on. Some conditions are very time critical and require surgical exploration as treatment.
Bibliography
- Anon. (2009, 05 29). Module 1: The Acute Scrotum. Retrieved from Urology: https://www.urology.wisc.edu/system/assets/617/module_1_acute_scrotum.pdf?1268758320
- Anon. (n.d.). Hernias. Retrieved from University of Connecticut Health Center: http://fitsweb.uchc.edu/student/selectives/Luzietti/hernia_anatomy.htm
- BMJ. (2016, 08 31). Inguinal Hernia. Retrieved from BMJ: http://bestpractice.bmj.com/best-practice/monograph/723/treatment/step-by-step.html
- Emma Street, A. J. (2010). 2010 United Kingdom national guideline for the management of epididyno-orchitis. Retrieved from British Association for Sexual Health and HIV: https://www.bashh.org/documents/3546.pdf
- Jones, O. (2017, 01 31). The Scrotum. Retrieved from TeachMeAnatomy: http://teachmeanatomy.info/pelvis/the-male-reproductive-system/scrotum/
- Jones, O. (2017, 01 29). The testes and epididymis. Retrieved from TeachMeAnatomy: http://teachmeanatomy.info/pelvis/the-male-reproductive-system/testes-epididymis/
- Sarr, M. (2014, 06). Inguinal Hernia. Retrieved from National Institute of Diabetes and Digestive and Kidney Diseases: https://www.niddk.nih.gov/health-information/digestive-diseases/inguinal-hernia