I. Overview Pediatric inguinal scrotal emergencies refer to a group of surgical diseases in pediatrics with acute pain and swelling of the groin and scrotum as the main clinical manifestations. In pediatrics, the most common is incarcerated inguinal hernia (incarcerated hernia), followed by torsion of the testicular accessory and testicular torsion. The incidence of acute epididymitis and orchitis is much lower than in adults, with acute simple orchitis being a common complication of mumps. Acute syringomyelia has not received the attention it deserves in the early years. Acute inguinal lymphadenitis may be secondary to acute suppurative infection of the vulva or lower extremities. Individual scrotal surface swelling fails to have a clear etiology and is tentatively referred to as idiopathic scrotal edema. Other scrotal swelling due to spermatic vein thrombosis, acute varicocele, acute necrosis of scrotal fat, scrotal trauma hematoma or blood accumulation, testicular tumor, leukemia scrotal infiltration and scrotal abscess. Second, the etiology, pathology and clinical manifestations 1.incarcerated hernia: refers to the abdominal organs into the hernia sac, due to the narrowing of the outer ring, can not be reset by itself and stay in the hernia sac, followed by blood circulation disorders, is a common complication of pediatric inguinal hernia. If the intestinal tube hernia can not be timely and appropriate treatment, often resulting in strangulated intestinal obstruction, intestinal necrosis and cause serious consequences. Hernia incarceration can cause local pain, pain and reflex cause abdominal wall muscle spasm and aggravate incarceration. Blood circulation disorders from venous return obstruction, bruising, edema development to intestinal necrosis. Once intussusception occurs, a painful mass appears in the groin or scrotum, the child cries and is restless, accompanied by vomiting, if not detected in time to deal with the symptoms of intestinal obstruction aggravated, abdominal distension is obvious. Vomiting of intestinal contents, blood in the stool, suggesting that there has been intestinal strangulation, and eventually develop into intestinal perforation, peritonitis. 2. Testicular torsion: Testicular torsion is not rare, and it can occur at any age, but it is more common in adolescence and neonatal period, and it is more common on the left side and less common bilaterally. As a result of torsion, the obstruction of blood supply can lead to testicular ischemic necrosis. Testicular necrosis has been reported to occur 2 hours after symptom onset, but it is generally accepted that disruption of the testicular blood supply for 6 hours produces irreversible loss of spermatogenesis, and the testis is not viable for more than 24 hours. Prenatal testicular torsional necrosis is often the cause of testicular agenesis. There are two types of testicular torsion depending on the site of torsion: (1) Extrasphincteric torsion or spermatic cord torsion. The torsion is more than 360°. The site of torsion is outside the testicular sheath in the spermatic cord. Intrasphincteric torsion is testicular torsion. Under normal circumstances, the sphincter only wraps part of the testis, if the anatomical abnormality, the testis is completely wrapped by the sphincter, the dorsal side of the testis is not tightly adherent to the meatus, so that the testis in addition to the upper end of the spermatic cord end connection, the rest of the sphincter in the sphincter lumen is free, easy to torsion, and the torsion site often occurs in the epididymis above the end of the spermatic cord and the spermatic cord end connection part. Sometimes the epididymis is separated from the upper part of the testis, which is only membranously connected to each other, which is also a common site for testicular torsion. Special types of testicular torsion: 1) Neonatal testicular torsion: a lump in the scrotum at birth may be testicular torsion. Neonatal testicular torsion is located outside the sheath, i.e., total spermatic cord torsion. Perinatal extrasphincteric testicular torsion may be due to laxity or absence of attachment of the testicular sheath to the scrotum. In most newborns, the process of testicular torsion occurs intrauterine, so the scrotal skin may be edematous, discolored, and the mass may be hard, painless, and opaque. (ii) Cryptorchid testicular torsion: Cryptorchid testes have a higher chance of torsion than intracystic testes, and their clinical presentation is different from that of normal testicular torsion. Painful lumps are mostly in the inguinal area, such as intra-abdominal cryptorchid testis pain manifested in the lower abdomen, such as right intra-abdominal cryptorchid testis, symptoms and signs are quite similar to acute appendicitis. 3. Testicular adnexal torsion: mostly seen in older children, with the same symptoms as testicular torsion, but to a lesser extent, and some of them have the history of trauma or strenuous exercise. Early physical examination can be seen locally as blue dot sign, which is the symptom of necrosis of subcutaneous testicular adnexa, and nodes with obvious tenderness can be found without testicular tenderness. In prolonged cases, it is difficult to distinguish from testicular torsion because of the spread of tenderness and swelling. In pediatric scrotal emergencies, testicular adnexal torsion accounts for the first place, followed by testicular torsion, and the distinction between the two is sometimes difficult, so there is no need to spend too much time on differential diagnosis, and if necessary, active surgical exploration should be carried out. 4. Acute syringomyelia: pus accumulation in the syringomyelia capsule infection, the source of bacteria may be: ① hematogenous dissemination. ② secondary to purulent infection in the testicular adnexa or other adnexa. ③ Intra-abdominal infection flowing in through the unclosed sheath. Neonatal meconium peritonitis, appendicitis, pelvic inflammatory disease, strangulated bowel obstruction, etc., can lead to scrotal inflammation, and there are also reports of peritonitis leading to scrotal infection in children with traffic syringomyelia. All of the above types of syringomyelia infections or accumulation of pus are due to the presence of intra-abdominal inflammatory lesions. However, there are children diagnosed with acute syringomyelia infection and pus accumulation who have neither intra-abdominal lesions nor testicular or epididymal lesions, and the pathology confirms that the syringomyelia is thickened, congested, infiltrated with leukocytes, and other inflammatory and necrotic changes, which is clinically called idiopathic acute syringomyelia. 5. Acute orchitis and epididymitis: testicular and epididymitis rarely occurs in preschool children, and the incidence rate increases with age. Can be divided into: ① non-specific: the infection comes from systemic infection hematogenous dissemination, trauma or external bacteria brought in (catheter retention time is too long) and congenital anatomical anomalies caused by the urethra, spermatic reflux (urethral stenosis, posterior urethral valve, etc.). ② specific infection: gonococcus, tuberculosis, etc., the onset of the disease is more acute, scrotal redness and swelling mainly on the affected side, in severe cases, the entire scrotum and perineum infiltrative redness and swelling, the pain is progressive, and occasionally there is frequent urination, urinary urgency, urinary difficulty and other urinary tract irritation symptoms. Simple orchitis can be seen as a complication of mumps. 6. Acute spermatic vein thrombosis: clinical manifestations are pain in the groin, swelling of spermatic cord with scrotal edema, normal testicle and hard epididymis on palpation. Surgical exploration reveals obvious edema of the spermatic cord without testicular torsion, testicular accessory torsion and sphincteritis. If the disease is suspected, selective phlebography is performed, and atresia of the spermatic vein and filling defects can be seen, so as to make a definite diagnosis. 7. Acute necrosis of scrotal fat: There have been reports in the literature of cases of scrotal fat limited necrosis resulting in obvious swelling and pain in the scrotum. 8. Idiopathic scrotal edema: the scrotum is obviously swollen, but redness and warmth are not significant, and surgical exploration fails to find obvious lesions of the spermatic cord or the sphincter sac. If the scrotum is incised, the edema can be drained and the scrotal edema can subside rapidly. 9. Acute inguinal lymphadenitis: children with acute infection manifestations, local redness and swelling is more diffuse, neither intestinal obstruction symptoms, testicles are not swollen and painful, sometimes accompanied by vulvar infection foci. Third, diagnosis and differential diagnosis inguinal and scrotal emergencies are localized painful lumps as a common clinical manifestation, inguinal or scrotal mass tenderness is obvious, diagnosis and differential diagnosis are as follows: 1. incarcerated hernia: in addition to inguinal or scrotal mass, such as herniation of intestinal tubes, gastrointestinal symptoms such as nausea, vomiting is more prominent. At first, the mesentery is stimulated to produce the neurological reflex of vomiting, and later for the clinical symptoms of intestinal obstruction. If the disease is long, there may be abdominal distension, intestinal pattern, and hyperactive bowel sounds. If there is blood in the stool, it suggests that there has been intestinal strangulation. In more early cases, where intestinal obstruction has not yet developed, attention should be paid to examining the relationship of the mass to the testis, and if a normal testis is palpable beneath the painful mass, testicular torsion or testicular adnexal torsion can be excluded. Localized radiographs of the mass can confirm the diagnosis of an incarcerated hernia if an inflated bowel curvature is seen, or even a fluid plane. A case easily confused with an incarcerated hernia is syringomyelia. When the child cries, the inguinal swelling is often discovered incidentally and mistakenly thought to be concomitant with crying, making it difficult to differentiate from the history. When the syringomyelia rapidly increases in size and is associated with infection, or when repeated maneuvers result in redness and tenderness of the skin, it is more difficult to differentiate from an incarcerated hernia. In such cases, anal examination should be performed. In children with incarcerated hernia, the finger of anal diagnosis can touch the intestinal tube from the abdominal cavity through the inner ring into the inguinal canal, and the examination should be compared with the healthy side. Anal examination in conjunction with abdominal palpation is valuable in identifying incarcerated hernias and other disorders in infants and children. The inguinal hernia of girls is often the contents of the ovary and fallopian tube, can also be incarcerated, due to the lack of intestinal obstruction symptoms and easy to be ignored. 2. Testicular torsion: the painful mass of testicular torsion is located in the scrotum or inguinal area, and the testicle can be found earlier in the clinic from the normal oblique position to a transverse position, which is slightly higher than the opposite side of the testicle in the scrotum. Torsion of the cryptorchid testis is significantly more likely to occur than torsion of a normally positioned testis in the scrotum. Torsion of the cryptorchid testis occurs when a painful mass is located in the inguinal region, similar to an incarcerated hernia, and should be considered if the child has had a cryptorchid testis and suddenly develops a painful mass in the inguinal region. The diagnosis is clear on examination if the scrotum on the affected side is found to be empty and the testicle is not reached. Individuals with intra-abdominal cryptorchid testicular torsion do not have painful lumps in the groin or scrotum, but complain of pain in the lower abdomen, and there is pressure and muscle tension in the lower abdomen, which can be misdiagnosed as acute appendicitis if it occurs on the right side. However, if no testicle is found in the scrotum of the affected side, cryptorchid torsion should be considered. 3. Testicular adnexal torsion: the painful mass of testicular adnexal torsion is located in the scrotum, and the base of the scrotum may be lower than the opposite side. If a tender nodule can be found between the upper pole of the testis and the epididymis, it is a torsion of the testicular adnexa. However, children are usually diagnosed late, and the clinical symptoms are not typical. 4. Acute syringomyelia: Acute syringomyelia is often characterized by symptoms of infection and low body temperature. The scrotum is red, swollen and diffuse, and the local signs of late incarcerated hernia are quite similar, but the intestinal hernia into the incarcerated hernia late intestinal obstruction is obvious, while the syringomyelia does not have obvious gastrointestinal symptoms. Sphincteritis can be divided into spermatic cord syringomyelia and testicular syringomyelia. If the testis is detected in addition to the painful mass, torsion of the testis or testicular adnexa is very unlikely, and spermatic cord syringomyelia is considered.5. Acute epididymitisAcute epididymitis is characterized by tenderness and pain in the epididymal mass. For late diagnosis and difficult to identify, multiple routine urinalysis is valuable for diagnosis if there are positive findings. In recent years, the use of ultrasound Doppler and isotope scanning has been helpful in the differentiation of inguinal and scrotal emergencies. For inguinal and scrotal emergencies, puncture of the painful mass should be avoided as much as possible. For inguinal and scrotal emergencies, it is not necessary to spend too much time on differential diagnosis, and an attitude of active surgical exploration should be adopted when the diagnosis is difficult. 1. incarcerated hernia: incarcerated hernia, hernia sac tissue edema, fragile and not easy to separate, and because of the thin hernia sac of children, edema is more likely to tear, resulting in easy recurrence after surgery. Therefore, if the incarcerated time is within 12 hours, the child’s general and local conditions are good, should be the first manipulation, to be hernia reset 2-3 days later, the local edema subsides, and then surgical treatment. Note: ①Suspect that there has been intestinal strangulation can not be tried manipulation. ② Do not squeeze the hernia block violently, so as not to damage the contents of the hernia. Once the intestinal tube rupture, but also into the abdominal cavity is the formation of diffuse peritonitis. ③ some cases of incarcerated hernia although not long, there is no intestinal strangulation manifestation, but due to the hernia ring tight compression of the intestinal wall, delayed rupture can be formed, so 24 hours after the reset of the child’s abdomen and the general condition should be closely observed. Indications of incarcerated hernia surgery: ① incarcerated time more than 12 to 24 hours. ② Hernia incarcerated with blood in the stool or poor general condition. The girl’s incarcerated hernia, because of its hernia content is often the ovary or fallopian tube, can not be manipulated to reset. Neonatal incarcerated hernia often can not be clear onset time and high necrosis rate of intestines and testes. ⑤ Manipulation reset is unsuccessful. If the incarcerated hernia has a long course, in addition to intestinal strangulation, testicular infarction or distant atrophy may also occur, if the testicular necrosis is found in the operation, it should be resected. 2. Testicular torsion: testis has very poor tolerance to ischemia, so it should be actively explored by surgery. Although some testicular torsion is fixed after repositioning, semen production may still be abnormal in the future, and testicular atrophy may occur on the affected side of the biopsy. Retaining the necrotic or atrophic testis may cause the so-called sympathetic testicular pathology, even if the spermatozoa on the opposite side of the body is low, and the semen analysis of those who have removed the torsion side of the testis is normal, so it can be seen that retaining the testis involved is not beneficial. 3. Testicular adnexa torsion: testicular adnexa is a residual structure of embryonic development, which does not have physiological function and has no serious consequences after torsion and necrosis. Some people advocate non-surgical treatment, but testicular adnexal torsion is sometimes difficult to distinguish from testicular torsion, so it should be actively explored, and after necrosis of testicular adnexa, waiting for its dissolution and absorption, its clinical symptoms can last for a long time. Testicular adnexal torsion and necrosis cause inflammatory reaction in the sheath lumen, which increases the pressure in the lumen, causing obstruction of epididymal blood supply, secondary inflammation in the epididymis, leading to obstruction of the epididymal ducts, and ultimately affecting the epididymal function, and after surgical excision of the necrotic adnexa, the clinical symptoms will be relieved or disappeared immediately. 4. Acute syringomyelia: after surgical incision and drainage, clinical symptoms will be relieved and improved rapidly. 5. Acute epididymitis: it can be treated conservatively with appropriate antibiotics, bed rest, elevation of the scrotum, early localized cold compresses, and sedatives if necessary. For specific infection, according to the condition of the treatment, generally by antibiotic treatment 7 to 10 days symptoms and pain disappear, 4 weeks after the epididymis can return to normal size and texture, there are few complications. Indications for surgical treatment: ① acute epididymitis and testicular torsion difficult to identify. ② Acute epididymitis that cannot be controlled by drugs. If the swelling of epididymis is obvious and the peritoneum is too tight to compress the epididymis and cause pain, surgical incision of the peritoneum of the epididymis can be used to decompress the epididymis, which can not only reduce the pain but also shorten the course of the disease. 6. Spermatic vein thrombosis and idiopathic scrotal edema: relatively rare, although surgery has no obvious benefit, early exploration can avoid misdiagnosis of incarcerated hernia and testicular torsion. 7. Inguinal lymphadenitis: effective antibiotic treatment can be used after exclusion of incarcerated hernia and testicular torsion. If the above two conditions cannot be excluded, especially in neonates, the observation time should not be too long, and surgical exploration should be carried out under effective antibiotic treatment. In conclusion, inguinal and scrotal emergencies have relatively similar clinical manifestations, and sometimes differential diagnosis is difficult, and if not handled in time, it can be life-threatening or loss of some organ functions. Therefore, for inguinal and scrotal emergencies, a positive attitude should be taken and early surgical exploration should be performed if necessary.