Sudden testicular pain, with or without testicular swelling, is often referred to as “acute scrotal pain” and is more common in both children and adolescents. The attending physician may be a urologist, a pediatrician, or a general practitioner, an emergency physician, or a general surgeon. Among the causes of acute scrotal pain, testicular torsion is a clinical emergency that requires accurate and rapid diagnosis to prevent loss of testicular function. What are the common causes of acute scrotal pain The incidence of different causes varies in different studies. Testicular torsion, testicular epididymitis, and testicular adnexal torsion are the most common causes, together accounting for 85% of the morbidity. In 2012-2013, there were 2753 hospital admissions for testicular torsion in the UK, with the average age of these patients being 16 years. Testicular torsion usually occurs in neonates and late adolescence, but cases have been reported in all age groups. Testicular torsion is caused by the rotation of the spermatic cord along its longitudinal axis resulting in an obstruction of the blood supply to the testis and is usually spontaneous. Testicular torsion can be divided into two types: intrasphincteric and extrasphincteric. The intrasphincteric type is caused by the absence of the posterior aspect of the testis and the fixed portion of the testicular sheath, where the testis is free to rotate within the testicular sheath. This anatomical anomaly, also known as “pendulum anomaly”, has a male prevalence of about 12%; 40% of these patients are bilateral. In this type of anatomical anomaly, testicular torsion usually occurs in adolescence. In contrast, extrasynovial sheathing usually occurs during the fetal and neonatal periods. Testicular torsion occurs in utero or during the perinatal period, before the testis is secured to the scrotum by the testicular leash. Therefore, the spermatic cord and the sheath are torsioned simultaneously within or below the inguinal canal. 2., Epididymitis, epididymitis and orchitis Epididymitis is an inflammation of the epididymis and testes, the cause of which is usually an infection secondary to urinary reflux, urinary tract pathogens or sexually transmitted diseases. Inflammation limited to the epididymis is called epididymitis, and limited to the testes is called orchitis. The etiology of epididymitis in children is inconclusive, with definitive evidence of the cause found in only 25% of patients. In post-pubertal males with a history of unprotected sex, the cause is most often a sexually transmitted disease. In men of any age, urinary tract infections can cause acute epididymitis. Therefore, it is important to know the risk factors for urinary tract infection, such as (anatomical or functional) urethral abnormalities or recent invasive urinary tract operations (e.g. catheterization or cystoscopy). 3. torsion of the testicular appendage ( cyst of Morgagni) The cyst of Morgagni is a small embryonic remnant of the upper pole of the testis, also known as the testicular appendage. Torsion of the testicular attachment can be spontaneous. After torsion of the testicular attachment, ischemia of the cyst can lead to pain. Testicular adnexal torsion usually occurs in prepubertal males. What are the less common causes of acute scrotal pain 1. Acute idiopathic scrotal edema Acute idiopathic scrotal edema is a self-limiting edema of the scrotal skin with normal testes and epididymis. It is more common in children under 10 years of age and is usually unilateral in onset. The diagnosis is confirmed by ultrasound findings of scrotal skin thickening and normal testes. The cause of acute idiopathic scrotal edema is not known, and it cannot be excluded that it is caused by allergic reaction. 2.Testicular cancer Testicular cancer usually manifests as a painless lump with slow testicular growth or testicular hardening. Doctors should note that although testicular pain is not a typical manifestation of testicular cancer, it has been reported that up to 20% of testicular cancer patients have testicular pain, which may be caused by bleeding within the tumor. Also, nearly 10% of patients with inflammatory testicular cancer present similarly to epididymal orchitis, leading to misdiagnosis. Varicocele is an abnormal dilatation, lengthening and tortuosity of the veins in the scrotum due to venous reflux caused by testicular venous valve insufficiency. 15%-20% of adolescents develop varicocele, but it is rare in children under 10 years old. They are most common on the left side (78%-93%). Varicocele can cause pain, edema, and low fertility. 4. Testicular syringomyelia The sphincter of the spermatic cord does not close, causing fluid to flow into the abdominal cavity, resulting in testicular syringomyelia. 5, testicular injury Most testicular trauma has no specific medical history; the typical history is a violent blow to the testicle, a straddling injury or a penetrating injury, the latter presenting with traumatic entrance and exit. A complete clinical examination should be performed for any associated injury. The injury may result in an accumulation of blood in the scrotum – the testicle may rupture, the fibrous tissue covering the testicle (white membrane) may be torn, or a hematoma may develop. 6. Involvement pain An inguinal scrotal hernia may radiate to the scrotum and have a clinical presentation similar to scrotal disease. Typically, an incarcerated hernia will be edematous and markedly painful to palpation. There is also abdominal pain and vomiting if the contents of the hernia contain an obstructed small bowel. Appendicitis and inflammation of the renal flexure of the colon also present similarly to scrotal disease. A detailed history, physical examination, and imaging (if necessary) can identify scrotal edema and testicular torsion due to these disorders. What are the clinical features of acute scrotal pain Below we have two tables to understand the clinical features of acute scrotal pain. Table -1 summarizes the clinical features of testicular torsion, testicular adnexal torsion, and epididymal orchitis. Table-2 summarizes the important features of the medical history. Table 1. Clinical features of the three etiologies of acute scrotal pain Clinical features Testicular torsion Testicular adnexal torsion Epididymitis Age Neonatal and postpubertal male Prepubertal Postpubertal (sexually active) course Acute More acute More acute Pain most pronounced site Diffuse Upper pole Epididymal Epididymal reflex cannot be elicited Can be elicited Can be elicited Other findings Testicular swelling “blue spot sign” positive Epididymal fever hardening, pain relieved by raising testis ( Prehn’s sign), fever Table 2. Significant features in the history * Age * Duration of symptoms * Site of pain Testis Epididymis Upper pole of testis * Painful and frequent urination * Sexual history * Fever * Past history, such as urinary tract abnormalities, infection * History of recent catheterization or urinary tract manipulation 1. Age Age is an important factor in the differential diagnosis of acute scrotal pain (see Table-3). In the neonatal period, testicular torsion is the most common cause; whereas in prepubertal males, testicular adnexal torsion is the most common cause. According to a series of studies, testicular torsion is still the most common cause after puberty, accounting for approximately 90% of cases. Age helps in the differential diagnosis, but does not exclude these disorders. Table 3, Frequency of age group characteristics of acute scrotal pain (%) Age group testicular torsion testicular adnexal torsion epididymitis orchitis other 0~12344741513~2186905 2. Pain Testicular torsion is usually accompanied by sudden and severe pain in the affected testis, which may be accompanied by nausea and vomiting. Whereas epididymitis and testicular adnexal torsion can also produce pain, the pain is a slowly progressive process, usually over several days. A retrospective study showed no significant differences between testicular torsion, testicular adnexal torsion, and epididymitis in any way other than the course of the disease. Patients with testicular torsion will present to the hospital earlier than those with epididymitis and testicular adnexal torsion. Repeated severe testicular pain and self-remission suggest intermittent testicular torsion and remission. For children, more shy or embarrassed adolescents, clues from parents are very important. Trauma that causes only a mild red bell, especially if the symptoms of the trauma do not match the severity of the pain, should also be considered testicular torsion. Testicular torsion can occur in the fetal or neonatal period. Testicular torsion in the fetal period presents as a hard, painless lump in the scrotum at birth. In contrast, testicular torsion in the neonatal period presents with acute pain and swelling of the testicle. Examination of the scrotum at birth is normal, and the presence of these symptoms after birth suggests that neonatal testicular torsion has occurred. Varicocele in men is usually asymptomatic, but a sensation of scrotal swelling may occur. A painless mass that changes in size with increased intra-abdominal pressure (e.g., coughing) suggests testicular syringomyelia. An incarcerated hernia often presents as severe pain in the inguinal region or scrotal area. Vomiting, abdominal pain, and swelling may also occur if the hernia contents contain the small intestine. The pain of appendicitis is often fixed in the right lower abdomen. 3. Urinary tract symptoms Frequent urination, painful urination and odor of urine suggest urinary tract infection secondary to epididymitis orchitis. Inflammation of the urethra or overflowing of the penis suggests epididymitis due to sexually transmitted diseases. 4. Fever In a series of case reports, 16% of fevers were associated with epididymitis. In mumps virus-induced orchitis, the fever begins before unilateral or bilateral swelling of the parotid glands, and unilateral testicular swelling occurs 7-10 days later. 20-30% of patients with mumps virus infection develop orchitis. For sexually active men, the patient’s sexual history should be examined in detail. Sexual history is a sensitive topic and patients are reluctant to reveal their sexual life in front of colleagues or relatives, so they usually need to be questioned individually. 6. Past history A history of previous urological disorders is very important, as urinary tract abnormalities can suggest that patients are more likely to have urinary tract infections and epididymolysis. Urinary tract manipulations such as catheterization and cystoscopy are risk factors for urinary tract infections and epididymitis. How to assess the condition? The physician should observe the patient’s expression to assess the degree of discomfort, risk or signs of infection. This should be followed by a general abdominal examination, including a check for spinal angle pain – renal / renal colic may also cause scrotal involvement pain. Palpation is performed to check for bladder distention, inguinal hernia, and other changes that are not swelling or skin changes (e.g., cellulitis). Physical examination should be noted for bilateral scrotal symmetry, testicular size, position, degree of swelling and other skin changes (Table – 4). In patients with testicular torsion, the affected testicle is elevated (compared to the opposite side), swollen, and painful to palpation. The torsioned testicle is sometimes transverse in position. Table 4: Evaluation of the patient with acute scrotal pain * Check for testicular position, size and symmetry * Check for redness of the scrotal skin * Check for the presence of the “blue spot sign” * Check for the testicular reflex * Determine the most pronounced site of pain Testis Epididymis Upper pole of the testis * Check the groin and abdomen for hernias and appendicitis The testicular reflex is impaired in testicular torsion, but is normal in patients with testicular adnexal torsion and epididymitis. Reflexes are normal. This simple test has a sensitivity of 100% and a specificity of 66%. The ejaculatory reflex may not be elicited in neonates and in patients with neurophysiological disorders. Light stimulation (paddling or pinching) of the inner thigh may elicit the ejaculatory reflex (L1 and L2 spinal nerves), and changes in the scrotal contents should be observed. Because of the common innervation, there is normally a contraction of the levator muscle, leading to an elevation of the ipsilateral testis. In patients with epididymitis, lifting the testis relieves pain, but does not relieve pain in patients with testicular torsion (Prehn’s sign). However, this test is not reliable in children. If the pain is confined to the upper pole of the testis, it is suggestive of adnexal testicular torsion; if there is also a blue change in the scrotal skin of the upper pole of the testis (bluish sign), it is characteristic of adnexal testicular torsion. A Scandinavian study showed that only 10% of children presented with this symptom. In patients with acute epididymitis, palpation may reveal significant pain, swelling, hardening and increased skin temperature. Figure-1 illustrates the scrotal anatomy and the process of testicular torsion. Figure 1. Normal scrotal anatomy; intrasphincter type (only the spermatic cord is twisted within the sheath), “pendulum-like” deformity, testis is transverse due to immobilization; extrasphincter type, the spermatic cord and sheath are twisted together. What tests should be done? 1. Urology or general surgery emergency consultation Unless other conditions can be ruled out, torsion should be considered in all cases of acute scrotal pain. If torsion is suspected after a rapid clinical evaluation, immediate referral to emergency urologic surgery/surgery for scrotal exploration is indicated. Fasting and pain relief should be instituted prior to further evaluation. 2. Urinalysis Urinalysis is useful for urinary tract infections. The presence of nitrites and leukocytes on urinalysis and the patient’s complaints of painful urination support a urinary tract infection secondary to epididymitis orchitis. At the same time, a midstream urine specimen should be collected for microscopy, culture and drug sensitivity testing. It should be noted that normal urine test results cannot exclude epididymitis orchitis; similarly, abnormal urine test results cannot exclude testicular torsion. 3.Ultrasound For patients who cannot be diagnosed by clinical evaluation, emergency ultrasound can help in the diagnosis. The sensitivity of ultrasound in diagnosing testicular torsion is 63.6%-100%, and the specificity is 97%-100%. Ultrasound can reduce the number of scrotal explorations, but ultrasound findings are determined by operator experience and technique and are difficult to perform in adolescent boys. In addition, in early and intermittent torsion, ultrasound can show false-negative results leading to misdiagnosis. In fact, in a multicenter study of 208 boys with testicular torsion, 24% of patients had normal testicular blood flow. High-resolution ultrasound can show the torsioned spermatic cord directly with better results. Overall, emergency ultrasound findings performed by an experienced physician can be helpful in the diagnosis of acute scrotal pain. However, it should be emphasized that if testicular torsion is suspected, scrotal exploration should not be postponed because of ultrasound. 4. Special tests If sexually transmitted diseases are suspected of causing epididymitis, in addition to collecting mid-section urine for microscopy, culture and drug sensitivity testing, Gram stain of urethral smear is needed to check for urethritis (leukocytes), especially Gram-negative intracellular diplococci (gonococci). Microscopic examination to rule out UTIs can be done using the first morning urine. More specific tests include urethral swab cultures and PCR amplification for gonococci and Chlamydia trachomatis. How is it treated? 1. Testicular torsion Testicular torsion is the clinical diagnosis. If testicular torsion is suspected, the scrotum should be explored urgently. It can be done in the midline and both testes can be explored at the same time; or two small incisions can be made and explored separately. If torsion is found, the testicle should be repositioned and observed for 10 minutes with a wet dressing of warm saline gauze. If the testicle is still viable, it is immobilized with a three-point fixation. The contralateral testis, which has a 40% risk of torsion, should also be immobilized. If the testicle cannot be reperfused after repositioning, it must be removed during exploration. If testicular torsion has not occurred, testicular fixation is not recommended. Suturing may disrupt the blood-testis barrier and produce anti-sperm antibodies, leading to infertility. During the preoperative interview, the parents should be informed of some relevant and important points. Both testes need to be fixed at the same time. The sutures may penetrate the scrotal skin during suturing, causing pain and irritation. In some rare cases, the testes may shrink/atrophy after repositioning and fixation and may become infertile. If reperfusion fails, the testis should be removed if it is determined to be inactive. There is a clear correlation between the success of testicular salvage and the duration of symptoms. If the testicle is repositioned 0-4 hours after pain, the probability of successful salvage is as high as 95%; however, if it is 8-10 hours, the success rate drops to 45-60%; after that, the success rate is significantly lower. Infection and hematoma may also occur after surgical exploration. Epididymitis in adults is usually caused by sexually transmitted diseases, so anti-microbial treatment should cover the pathogens, especially Chlamydia trachomatis and gonococcus. Empirical treatment is given first, along with bacterial culture/nucleic acid amplification tests, and medication is adjusted based on laboratory results. Referral to genitourinary medicine is possible for a complete evaluation. If a urinary tract infection is suspected and leads to epididymitis, medication should be administered against the common pathogens (Gram-negative bacteria such as Escherichia coli and Gram-positive bacteria such as Enterococcus). Medication needs to be adjusted based on urine culture, urethral swab culture and nucleic acid amplification test results. Other recommendations include appropriate rest, scrotal support and pain relief (e.g., general anti-inflammatory medications). Sexual activity should be avoided in adults with epididymitis due to sexually transmitted diseases, and sexual partners should be examined and treated. Table 5. summarizes the empirical use of medications for epididymitis, as recommended by the Royal College of General Practitioners and the British Association for Sexual Health and HIV. Empirical treatment of epididymitis * Possible STI causing epididymitis Without gonococcus: Doxycycline 100 mg bid × 10-14 d or Ofloxacin 200 mg bid × 14 d Considering gonococcus: Ceftriaxone: 500 mg single intramuscular dose + doxycycline 100 mg bid × 14 d * Urinary tract infection causing epididymitis (to be adjusted according to mid-stage urine culture) Ciprofloxacin 200 mg bid × 14 d or ciprofloxacin 500 mg bid × 10 d Note: Attention should be paid to the use of ciprofloxacin by performing drug sensitivity test (bacterial culture, not nucleic acid amplification test) first; ciprofloxacin is not effective against Chlamydia trachomatis. The etiology of epididymitis and orchitis in prepubertal boys is mostly primary. Most urinalysis results are negative and no antibiotics are indicated (but treatment is usually initiated with antibiotics). The patient’s symptoms are self-limiting and supportive therapy is recommended. In advanced stages of epididymitis orchitis, redness, tenderness, and fluctuating sensation of the scrotal skin on pressure suggest abscess formation, and ultrasound can confirm the diagnosis. The abscess requires incision and drainage, and the testis may be removed due to necrosis. Patients with mumps orchitis have a history of fever and mumps prior to testicular swelling. Mumps orchitis is treated conservatively, but there is a risk of secondary bacterial infection requiring antibiotic treatment. In the UK, mumps is a disease that requires attention. It is important to prevent the spread of the disease, especially in adolescents and young adults who are not immune to it. 3. Testicular adnexal torsion If testicular adnexal torsion is diagnosed, it can be treated conservatively with painkillers. If the diagnosis cannot be confirmed, surgical exploration is required. If the testicular adnexal torsion is diagnosed during surgery, it can be ligated and removed. There is no need to remove the contralateral attachment.