Acute scrotal pain
The scrotum is the bag-like structure which contains the male reproductive organs, the testes, and adjacent structures. The nerve supply to the scrotum is usually from the ilio-inguinal nerve and the genital branch of the genito-femoral nerve, as well as sympathetic supply brought with the testis into the scrotum, originating in the deep neural plexuses in the renal and aortic area. The testes are richly innervated, and thus even minor trauma can be followed by severe pain in the testes, which is often felt as a more generalised systemic appreciation of deep-rooted pain.
Acute scrotal pain can be the presenting symptom of a wide range of surgical and non-surgical conditions as diverse as organ-threatening testicular torsion and more rarely conditions as life-threatening as a ruptured aortic aneurysm. The diagnosis can usually be made via a careful history and examination with judicious use of investigations.
The management of the various conditions varies greatly and rapid speed of intervention is often the key to a good outcome. The diagnosis is strongly suggested by many factors in the presentation, especially age of the patient, the onset of the pain and presence of associated symptoms.
The most serious and common causes are outlined below.
Testicular torsion is a surgical emergency and the salvage of the testicle is dependant on the time between onset of symptoms and surgical intervention.
It is caused by the testis rotating on the axis of the spermatic cord. This can lead to complete occlusion of the testicular artery with interruption of testicular blood flow causing testicular ischaemia and necrosis. In the case of the less significant torsion, the testicular vein can become occluded causing an increase in intratesticular venous pressure and subsequent cessation of local supply of oxygen-rich arterial blood to the testis.
Torsion occurs in two main age groups and for different anatomical reasons. In the neonatal type the torsion occurs before the posterior aspect of the testicle has had time to fuse to the inner layers of the scrotal wall. In these cases this can occur before or after birth and consists of an extra-vaginal torsion (the whole cord and its investing layers twist). It is notoriously hard to diagnose due to the lack of localisation of symptoms in a baby and therefore has a low rate of testicular salvage, around one third of acute presentations. In many the diagnosis is missed and the testicle atrophies either in the scrotum or along the line of testicular descent.
The other main type of testicular torsion is intravaginal caused by an abnormally high investment of spermatic cord by the tunica vaginalis. This anatomical variant is frequently bilateral and allows testicle to lie transversely, the so called ‘bell clapper’ testicle. Torsion of this type can occur at any age but is most common during adolescence perhaps due to differential growth rates between the testicle and adjacent structures. The prevalence has been estimated to be 1 in 4000 males less than 25 yrs old and in males presenting with an acute scrotum this is the diagnosis in 16.0–39.5%.
Presentation is typically with a sudden onset of severe scrotal pain often associated with other symptoms particularly nausea and vomiting due to the common innervation of the testicle and the gastrointestinal tract by fibres from the coeliac ganglion. The presentation is usually rapid due to the severity of the symptoms and may be preceded by milder self-limiting episodes due to spontaneous detorsion.
Atypical presentations however do occur and has been reported in the context of trauma. Urinalysis can also be positive, leading to a misdiagnosis of epididymo-orchitis so a high index of suspicion should be applied.
On examination the boy is usually in severe pain and may refuse examination. If examination is possible the testicle is tense, tender and is usually high in the scrotum (‘high-riding’). If early in the course of the condition the twist in the spermatic cord may be felt as a tight ‘knot’ as the cord exits the external inguinal ring. The pain may persist on elevation of the scrotum, whereas the pain of epididymo-orchitis often resolves on elevation of the scrotum.
Various imaging modalities have been used to reduce the need for surgical exploration. Colour Doppler ultrasound can show decreased or absent blood flow in many cases of testicular torsion but is not sensitive enough to be relied on to avoid exploration in someone with a strong history. There have also been reports of normal blood flow on Doppler ultrasound in cases of proven testicular torsion. A detorted testicle and epididymis can also be hyperaemic and thus a false diagnosis of epididymo-orchitis can be made.
Radio-nucleotide scintigraphy can also be used to evaluate testicular blood flow and whilst more accurate than sonography it suffers from lack of rapid and widespread availability. Both imaging modalities should be reserved for ambiguous cases and should not delay the transfer of the patient to theatre.
Magnetic resonance imaging has been used in an experimental setting and may become a clinical imaging modality in the future.
Management of suspected testicular torsion consists of surgical detorsion and fixation (orchidopexy) of both testicles due to the chance of contralateral torsion in the future. Under general anaesthesia, the scrotum is explored via a midline incision through the median raphe. The affected testis is delivered from the scrotum and the cord is detorted and the testis is wrapped in warm swabs. The opposite testis is also delivered and fixed in place to the muscular wall of the scrotum, often with non-absorbable sutures, although the use of absorbable sutures is probably to be advised in the paediatric population.
If the testicle is necrotic on detorsion it should be removed. The rate of testicular loss is dependent on the time from onset of pain. Long-term follow-up has shown that up to 67% suffer testicular atrophy and infertility after prolonged torsion whilst others have reported that semen quality and fertility should remain within normal limits if detorsion is performed promptly prior to irreversible damage to the germinal epithelium.
If there is a delay in availability of theatre, manual detorsion has been recommended. The torsion usually occurs by the anterior surface of the testicle rotating medially, the method of detorsion has therefore been described as ‘opening a book’ after adequate analgesia. Of concern however is a series which reported finding at least some degree of torsion in 28% of those who had undergone successful detorsion, and therefore theatre should not be delayed after this manoeuvre.
Other modalities of treatment that have been used in an attempt to increase salvage rates include hyper-baric oxygen and (in animal studies) scrotal cooling with icepacks post-operatively.
Initial studies showing that the contralateral testicle can be affected by ‘sympathetic atrophy’, possibly due to an immunological insult, by the torsion of its neighbour appear to be unfounded.
Torsion of appendages
Appendages of the structures within the scrotum represent remnants of embryological structures which have undergone regression during development. They have been described in various sites on both the testicle and epididymis but the most important clinical appendage is found at the superior pole of testicle, a remnant of the mesonephric duct called the hydatid of Morgagni. It is involved in 92% of appendage torsions. The other appendage that accounts for most (7%) of the other appendage torsions is found on the head (superior) of the epididymis with other appendages, making up a minority.
The mean age of presentation is 9–10 which is younger than for testicular torsion and the presentation is often with milder pain and fewer associated symptoms compared to testicular torsion. The patient often will present later in the course of the condition and classically has a small tender ‘blue dot’ on scrotal examination; this is particularly obvious in children due to their thin scrotal skin. The cremasteric reflex is usually still present and the torted appendage is often able to be identified on ultrasound examination or radionucleotide scintigraphy (68% after 5 hours).
Management of this condition is usually conservative, if the diagnosis can be made with certainty preoperatively, with rest, analgesia and scrotal support. Surgical excision can be reserved for those whose pain is slow to settle.
This is an inflammatory condition usually infective in nature and thus has a more gradual onset of symptoms. Infective processes usually tracking down from the genito-urinary tract can infect the epididymis and the testis itself. This leads to swelling and severe testicular pain, as the testis swells within the taut tunica albuginea. There may be a history of dysuria and urethral discharge due to urethritis, and systemic symptoms and signs such as fever are common. A history of previous surgery, urinary tract infections and a full sexual history should be obtained as appropriate.
The patient presents with swelling of the hemiscrotum, often of gradual onset, and erythema of the overlying scrotal skin. The testis is swollen and tender, and the epididymis is engorged, swollen and tender. This sign is extremely important in the differentiation between epididymo-orchitis and testicular torsion. The patient will often also experience an acute leucocytosis, and pyrexia.
Treatment is with antibiotics, which may have to be administered intravenously, non-steroidal antiinflammatories and scrotal support. Urinalysis with culture and sensitivity and blood cultures are also important.
Epididymo-orchitis can occur at any age although the organisms involved vary depending on the aetiology.
Infantile epididymitis has a high incidence of associated urogenital abnormalities, particularly in those with coliform organism isolated from their urine and thus these children require full urological evaluation after treatment of the infection. In children presenting with an acute scrotum, the diagnosis of infection is made in 20–30%. In older children there is a lower association with these structural abnormalities and a lower rate of positive urine cultures. Dysfunctional voiding has been proposed as an aetiological factor in these older children.
In sexually active adolescents and adults the organisms involved are commonly Chlamydia trachomatis and Neisseria gonorrhoeae although penetrative anal intercourse can lead to coliform infection. Older men with epididymo-orchitis will often have coliform infections owing to bladder outlet obstruction, instrumentation, surgery and catherisation.
More exotic organisms such as Brucella, Candida and tuberculosis are occasionally involved in the immuno-compromised and those who have been exposed during overseas travel.
The testis can survive extremely great forces before being damaged. The testicle can be injured by direct trauma, assaults, sporting injuries and less commonly road traffic accidents and other major trauma.
The scrotum is usually very swollen, with significant ecchymosis if presenting after a period of time. The testis itself is often impalpable as result of the extensive swelling and the common occurrence of a haematocoele. If the testis itself is palpable, and the tunica albuginea is intact, with little to no significant haematocoele, then the patient may be managed conservatively. However, if there is any evidence of the tunica albuginea being breached or if there is significant haematocoele present, surgical exploration is mandatory if the patient's overall condition allows it.
The ruptured testis is exposed and the devascularised portion is excised. The tunica is then closed and the scrotum closed in layers. The aim of testicular exploration in this trauma situation is to preserve as much testicular tissue as possible to allow for testosterone production and spermatogenesis which may be important if the other testis is compromised in any way at this time or in the future.
Testicular cancers can cause acute pian if there is haemorrhage or infarction in the neoplasm. The presence or history of an abnormal swelling in conjunction with acute pain should alert the examining physician to this. Ultrasound can be used to further evaluate this.
A hydrocoele is a collection of fluid between the tunica albuginea and the testis itself. If rapidly forming, it can cause pain in the scrotum. The most effective way of dealing with this situation is to surgically repair the hydrocoele. In the paediatric patients, it often involves the presence of a patent processes vaginalis, which must be repaired. It is unusual to get acute pain from a hydrocoele.
A varicocoele is a dilatation of the veins of the pampiniform plexus around the testis. This is almost always on the left hand side, the swelling feels like a ‘bag of worms’ surrounding the testis. This can lead to a dragging sensation, and, if thrombosed, can cause acute pain. Repair is surgical or radiological, and should be considered in patients with large varicocoeles, with asymmetric or small testes, if discovered during the pubertal years or with subfertility, as varicocoeles are associated with reduced production of viable spermatozoa. Again, this situation does not commonly cause acute pain.
Epididymal cysts or spermatocoeles can both enlarge quickly or have haemorrhage into them which can cause acute pain. These can be surgically excised at a later date if deemed appropriate.
Incarcerated or strangulated inguinal hernias can often be found having travelled into the scrotum. The inability to palpate above a scrotal mass is a significant sign of a hernia. A history of a pre-existing hernia or the presence of bowel sounds in the scrotal lump aids in the diagnosis. This distinction can be difficult in the paediatric age group.
Pain can be referred from extra-scrotal sites and organs, and can be confused with scrotal pathology. A clear history and examination usually differentiates the cause. For example, the pain from ureteric colic often radiates down to the ipsilateral hemiscrotum and testis, but is of a different nature from most scrotal pains. This is especially common if the stone is low down in the course of the ureter, for example at the vesico-ureteric junction. Pain from a ruptured abdominal aortic aneurysm has been misdiagnosed as scrotal pain, and this diagnosis should be entertained in the older patient.