Chapter 85: Male Genitourinary Problems

• Acute scrotal pain is usually caused by testicular torsion, epididymitis, or torsion of the appendix testis.

• Epididymitis is often caused by viral infections; however, bacterial urinary tract infections must be evaluated for in young children and sexually transmitted disease in adolescents.

• Persistent scrotal swelling and a “bag of worms” appearance indicates possible obstruction from tumor.

• Priapism can be divided into two mechanisms: low-flow or ischemic as in sickle cell vaso-occlusion and high-flow or engorgement.

Acute scrotal pain and swelling in children have many causes; however, in most cases the emergency physician (EP) can determine the etiology by the history and physical examination and by considering the age of the patient. Scrotal swelling may be painful or painless (Table 85-1). The most common diagnoses for an acute scrotum are testicular torsion, torsion of the appendix testis or epididymis, and epididymitis. In all cases, the possibility of a surgical emergency must be considered and the evaluation and management must proceed accordingly. Color Doppler ultrasound is the examination of choice for imaging scrotal pathology.

Testicular Torsion

Testicular torsion has a bimodal incidence, with the first peak in the neonatal period and a second in adolescence.^1,2 Torsion of the testes is a urologic emergency and results in a significant amount of legal action against EPs for missed diagnosis. The EP must suspect this diagnosis in any child with complaint of scrotal pain or signs of scrotal swelling on physical examination.

The classic description of the anatomic abnormality associated with torsion is the “bell-clapper” deformity that is often bilateral and causes the testes to have a horizontal lie within the scrotal sac (Fig. 85-1). The abnormal testicular attachments to the tunica vaginalis allow the testis to twist along with the spermatic cord and the testicular artery; the vascular supply is compromised and the testis will necrose. After 4 to 6 hours of continuous pain, the salvage rate is 96%, but drops to 20% after 12 hours of pain, and below 10% at 24 hours.¹ Torsion may be intermittentand therefore the duration of symptoms may not necessarily predict the viability of the testis.

Testicular torsion usually presents with sudden onset of unilateral scrotal or testicular pain, commonly associated with vomiting and flank or abdominal pain. There may be a history of scrotal trauma or recent diagnosis of epididymitis. Episodic pain suggests intermittent torsion, and bilateral torsion (concurrent or asynchronous) can occur. An undescended testis is 10 times more likely to torse than when fully descended, and presents with lower quadrant pain and a nonpalpable testicle. Karmazyn et al., showed that pain for less than 6 hours, absent/decreased cremasteric reflex, and presence of nausea/vomiting were highly suggestive of a diagnosis of testicular torsion. If none of these were present, none of the children had testicular torsion but if all three were present 87% of the children had torsion.³ No single sign or symptom can predict testicular torsion 100% of the time; however, a combination of signs and symptoms may assist the EP in determining the risk. Beni-Israel et al., demonstrated in 17 boys with testicular torsion that all of the children had at least one of the following risk factors: pain duration less than 24 hours, nausea and/or vomiting, high position of the testis, or abnormal cremasteric reflex. Although the odds for having testicular torsion in the absence of a normal cremasteric reflex was high (OR 27.8, 95% CI 7.5–100), the presence of the reflex did not rule out torsion.⁴

Physical examination often reveals a swollen, erythematous, and exquisitely tender hemiscrotum (Fig. 85-2). Classically, the testicle is high riding and lying horizontally within the scrotum.¹ The examination becomes more difficult with time as edema, erythema, and a reactive hydrocele may develop.¹ Tenderness of the affected testis is diffuse, and the cremasteric reflex is most often absent. Elevating the testis will cause further pain (Prehn's sign) instead of the relief that can be seen in epididymitis; however, this cannot reliably include or exclude torsion.^5,6

Diagnostic Evaluation

Prompt urologic consultation should not be delayed to obtain confirmatory tests when torsion is suspected. Urinalysis often is normal, but may show pyuria or bacteriuria suggesting alternative diagnoses such as urinary tract infection (UTI), epididymitis, or orchitis. It is important to recognize that these findings do not rule out torsion. Other studies such as complete blood count and chemistries may be requested preoperatively but rarely help the diagnosis. High-resolution ultrasound with color-flow Doppler rapidly provides information about testicular blood flow. Moreover, anatomic structure and relationships are displayed with ultrasound, and ultrasound findings may be predictive of testicular viability.⁷ Sensitivity of ultrasound for torsion is 90% and specificity above 98% in experienced hands.⁶ Radionuclide imaging was the traditional test of choice, but is no more accurate than ultrasound and is now rarely performed.² Further diagnostic evaluation (such as MRI) is reserved for patients in whom the diagnosis is in question after a negative ultrasound test and classic signs of testicular torsion. Urology consultation should be obtained immediately in patients with classic signs and symptoms, despite results of imaging studies.

Management

Rapid urologic consultation should be obtained early on all patients with suspected torsion, and prompt surgical exploration is indicated. The torsed testicle is untwisted and removed if nonviable, and bilateral orchiopexy is performed. Manual detorsion of the torsed testes may be attempted in the ED if urology is unavailable or will be delayed. Patients are sedated, and the testicle is detorsed by turning the testicle outward toward the thigh, like “opening a book” (Fig. 85-3). If this does not provide sudden relief, then detorsion in the opposite direction may be attempted.⁶

Torsion of the Appendix Testis

Testicular appendices are common and may occur on the testicle (known as hydatid of Morgagni, most likely to torse), the spermatic cord, or the epididymis. Torsion of the appendix testis occurs most frequently in prepubertal boys, and is often difficult to distinguish from torsion of the spermatic cord.^6,8

Clinical presentation of torsion of the appendix testis is usually less severe than in testicular torsion (Table 85-2). Systemic symptoms such as nausea and vomiting are uncommon, and the physical examination may reveal diffuse testicular enlargement and pain or only a focal tenderness in the upper pole of the testis. A “blue-dot” sign is occasionally noted when the necrotic appendage casts a blue hue under the scrotal skin (Fig. 85-4).

Diagnostic Evaluation and Management

Color Doppler ultrasonography (US) occasionally is diagnostic, but usually is normal or reveals increased flow to the testicle.⁶

Bed rest, urologic follow-up, and analgesia are recommended for torsion of the appendix testis. The condition is self-limited and complications are rare. Surgical intervention is indicated when testicular torsion cannot be reliably excluded.

Epididymitis

Epididymitis occurs in approximately one-third of children who present to the ED with acute scrotal pain and is the most common misdiagnosis for testicular torsion. It is more common in adolescents than young children and is rare in infants.

In adolescents, epididymitis is often caused by sexually transmitted diseases such as Neisseria gonorrhea and Chlamydia trachomatis. In children younger than 6 years, urinary tract anomalies may be present and pathogens causing UTIs (such as Escherichia coli) are rare. Bacterial infections represent a small minority of cases overall, and epididymitis may be viral or occur after other infections (such as upper respiratory infections), or possibly as a chemical inflammation caused by reflux of sterile urine into the ejaculatory ducts.⁹

History should include the time course of the symptoms; any history of trauma; sexual activity; and urinary symptoms (dysuria, hematuria, etc.). The primary symptom is dull unilateral scrotal pain with swelling, often increasing over several days.⁶ Fever, vomiting, and urinary symptoms may be present, and with time the pain may become diffuse and radiate to the lower abdomen. Symptoms in young children may be vague, and infants may present with an incidental finding of scrotal swelling.

Physical examination reveals an erythematous, warm, swollen epididymis, testicle, and scrotum. Tenderness is localized to the superior aspect of the testicle, and the testicle itself should be nontender and have a normal lie. Patients usually have a normal cremasteric reflex and Prehn's sign (relief upon elevation of the scrotum) may be present. However, these signs are not reliable in distinguishing epididymitis from testicular torsion.

Diagnostic Evaluation and Management

Epididymitis is often difficult to distinguish from testicular torsion, and urologic consultation should be obtained when the cause of scrotal pain is unclear. Urinalysis may show signs of UTI and a complete blood cell count may reveal an elevated white blood cell count with left shift; however, these tests are normal in many cases of epididymitis. Color Doppler US should be performed and will reveal normal or increased flow to the affected testis in epididymitis, although there may be a higher rate of indeterminate studies in infants and young children.

Once the diagnosis of epididymitis is made, a urine culture is indicated in all cases, and testing for N. gonorrhea, Chlamydia, and other sexually transmitted infections is appropriate in adolescents.⁹ Viral infections are common and diagnosed presumptively.⁶ After treatment, imaging may be appropriate in selected cases to screen for urinary tract anomalies or renal stones causing obstruction.

Admission to the hospital for IV antibiotics is indicated for children younger than 1 month with associated UTI, and should be considered in older infants and children younger than 2 years with severe signs and symptoms.¹⁰ Inpatient antibiotic therapy should include ampicillin and an aminoglycoside or cefotaxime (Table 85-3). Infants 3 months and younger should have a urinalysis and culture sent and treated presumptively for bacterial infection until cultures are negative. Most will be viral infections, but with high rates of negative urinalyses in presence of bacterial infection, it is prudent to treat this high-risk group. Older infants, children and adolescents with a negative urinalysis, can usually be treated as outpatients with analgesics, bed rest, and scrotal elevation/support. Given the low rate of bacterial infection in prepubescent males, empiric antibiotics are not indicated and culture results should direct treatment.⁹ For the sexually active adolescent, antibiotic treatment should include ceftriaxone and doxycycline (Table 85-3). Prompt urologic consultation and subsequent follow-up is recommended for all patients.

Scrotal and Testicular Trauma

Trauma to the scrotum can occur by many mechanisms, including child abuse. Most often, the mechanism is blunt trauma such as a direct blow, a straddle injury, or a motor vehicle crash. The resulting injury is a scrotal hematoma and, rarely, testicular rupture. The scrotum may be ecchymotic or tense with blood, and the testis may be difficult to palpate or ill defined. Prompt evaluation of the integrity of the testis by US is essential, and urologic consultation is sought immediately for cases of testicular rupture. Testicular rupture is classically managed by surgical exploration and repair, although testicular salvage rates are poor and nonoperative management may be reasonable for selected cases.¹¹ Scrotal hematomas and testicular contusions are treated with bed rest, scrotal support, ice packs, and analgesics.

Testicular Tumors

Testicular tumors are rare in childhood, and the majority of neoplasms are benign.¹² Types of testicular tumors include teratomas, embryonal carcinomas, yolk sac, choriocarcinomas, Leydig cell, and Sertoli cell. Lymphoma and leukemia can metastasize to the testis and present as a testicular mass. An undescended testis is up to a 50 times more likely to contain a tumor, especially when located intra-abdominally.

Testicular tumors often present with a feeling of fullness, tugging, or increased weight to the scrotum. Patients or their caregivers may feel a mass. On physical examination, the mass is firm, and does not transilluminate. Tumors are generally painless, but bleeding into the tumor can cause sudden pain in the testicle or referred to the abdomen or flank. Examination should also evaluate for lymphadenopathy, an abdominal mass, hepatosplenomegaly, a petechial rash, and gynecomastia.

Diagnostic Evaluation and Management

Ultrasonography is used to confirm the presence and location of a mass, and may differentiate between benign and malignant tumors.¹ Urinalysis should be performed, as well as a complete blood cell count and test for alpha-fetoprotein levels. Human chorionic gonadotropin is often produced by germ cell tumors, and may be detected in the urine or serum.

Urologic consultation and prompt biopsy or removal of the mass is necessary to establish tumor type and subsequent treatment options for patients. Most neoplasms are benign and can be treated with testicle-sparing surgery, and most malignancies are expected to have a good outcome.¹²

Inguinal Hernia

An inguinal hernia occurs when peritoneal or pelvic contents herniate through a patent processus vaginalis into the scrotal sac. Indirect hernias are usually right-sided, and are up to 10 times more likely in males than in females.^2,13 Approximately 2% of children have an inguinal hernia and the incidence increases with prematurity.^2,13,14 Indirect inguinal hernia repair is the most common pediatric surgical procedure.

Inguinal hernias are diagnosed most often in the first year of life, and present as an asymptomatic and intermittent bulge into the scrotal sac when the infant cries or coughs. Older children may note a pulling feeling or heaviness in the groin, or a bulge, which increases with intra-abdominal pressure. Symptoms such as fever, abdominal pain, poor feeding, or vomiting should raise suspicion for incarceration. Examination signs of incarceration include a firm, tender, and nonreducible mass in the inguinal area or scrotum. Incarcerated hernias can rapidly progress to strangulation, with ensuing peritonitis and shock.¹⁴ Approximately 10% of inguinal hernias incarcerate and most incarcerations occur in children younger than 1 year, particularly within the first 2 months.^13,14

Diagnostic Evaluation and Management

Inguinal hernias can usually be diagnosed by history and physical examination (Fig. 85-5). Transillumination of the scrotum should distinguish a hydrocele from an incarcerated inguinal hernia and from solid masses such as a swollen lymph node or a tumor. Undescended or retracted testes may mimic inguinal hernias, and both testicles should be palpated during the examination.¹³ Ultrasound may be helpful in unclear cases and it is the modality of choice in distinguishing a hernia from other inguinal masses such as an abscess, tumor, or hydrocele.^13,14 Abdominal radiographs are usually not helpful, except to establish the presence of an intestinal obstruction.

Incarcerated hernias can be reduced up to 95% of the time using a combination of firm finger pressure on the internal inguinal ring, analgesics or sedation, ice pack to the area, and placement of patients in the Trendelenburg position. Patients with an easily reduced hernia can be discharged to home with close follow-up with a surgeon, although exact timing and method for definitive repair remains controversial.¹⁵ Patients with hernias that are difficult to reduce should be admitted for observation and delayed surgical repair. Patients with hernias that remain incarcerated or with signs of peritonitis or bowel perforation must have an immediate surgical consultation and should receive fluid resuscitation and antibiotics in the ED.

Henoch–Schönlein Purpura

Henoch–Schönlein purpura (HSP) is a systemic vasculitis that is most common in children younger than 7 years. Up to one-third of patients may have genitourinary complaints, including hematuria, scrotal pain, swelling, erythema, or a purpuric rash on the scrotum.⁶ In some cases, it may be difficult to distinguish HSP from testicular torsion, and the EP should consult a urologist and obtain color Doppler US. If the diagnostic evaluation is negative and the patient has other features of HSP, surgical exploration may not be necessary.

Hydrocele

A hydrocele is formed from a patent processus vaginalis, and may communicate with the peritoneal cavity and can be associated with an indirect inguinal hernia. Fluid is noted adjacent to the testis and may result in a swollen and bluish-appearing scrotum. Transillumination reveals that the mass is fluid filled, but it may be difficult to distinguish hydrocele from indirect inguinal hernia. If the hydrocele presents as a painful swelling, then the physician must consider intraperitoneal pathology, such as a ruptured appendix, or testicular torsion. A nonpainful hydrocele may be observed for spontaneous resolution, and if the hydrocele persists past the first year of life, the patent processus vaginalis is surgically repaired.¹⁶

Varicocele

Varicoceles usually present in the adolescent male as painless scrotal swelling. Incompetent valves in the testicular veins and the pampiniform plexus of the spermatic cord result in venous dilatation and a scrotum that looks and feels like a “bag of worms.” Varicoceles occur in approximately 15% of the population and 85% are left-sided.² They are usually benign in nature, but could represent obstruction of the renal vein or inferior vena cava from a tumor, especially when right-sided. Patients should be examined in the standing position, which often exaggerates the physical findings of scrotal enlargement and “bag of worms” appearance. Patients in whom the scrotal swelling persists in the supine position should be evaluated for venous obstruction by renal ultrasound, or angiography. Surgical repair may be necessary for cases of testicular atrophy, lesions causing proximal obstruction, or patients with significant pain. There is an association between adolescent varicoceles and adult infertility, but there is insufficient evidence that surgical repair is preventative and treatment remains controversial.^17–20

Other Causes of Scrotal Pain or Swelling

Other causes of scrotal swelling with and without pain include scrotal cellulitis, idiopathic scrotal edema, and lymphadenitis. Idiopathic scrotal edema is more common in prepubertal boys and characterized by thickening and erythema of the scrotum not involving the testes. It is not always painful and may be pruritic. Minor trauma, inlcuding insect bites, localized irritation, or contact dermatitis results in idiopathic scrotal edema. Treatment usually consists of antihistamines or topical steroids, and antibiotics if cellulitis is a concern.⁶ Orchitis is an uncommon cause of scrotal pain and swelling; it is often viral mediated and is associated with mumps.

Fournier's Gangrene

Fournier's gangrene is an infectious necrotizing fasciitis of the perineum, and is rare in children.²¹ It may initially present as cellulitis, balanoposthitis, or scrotal pain and swelling, and patients may appear relatively nontoxic despite significant infection. Staphylococcal and streptococcal organisms are the most common organisms to be cultured, but management should include broad-spectrum antibiotics to cover anaerobic and aerobic, gram-positive and -negative organisms. Prompt surgical consultation and operative incision and drainage of infected tissue with excision of necrotic tissue are paramount. Generally, the prognosis in children is better than it is in adults.

The differential diagnosis for males who present to the ED with a swollen, erythematous penis includes phimosis, paraphimosis, balanitis, posthitis, hair tourniquet syndrome, and insect bite.¹

Phimosis

Phimosis occurs when the distal prepuce is unable to be retracted over the glans penis. This is a normal finding in infants and the prepuce will become retractable in 90% of children by the age of 6 years. Local irritation or infection (balanoposthitis) can cause an abnormal constriction of the prepuce, preventing its ability to retract normally.

Phimosis may be noted on routine physical examination or may be reported by parents. Pain and swelling can occur with associated infections of the glans. Urinary stream in some cases may be diverted to one side or children may have hematuria. Physical examination reveals a constricted distal prepuce that is unable to be retracted over the glans penis, and patients may have concomitant balanitis or balanoposthitis.

Diagnostic Evaluation and Management

The diagnosis is established clinically; however, examination for UTI may be warranted. If patients demonstrate signs of urinary tract obstruction, then renal function studies and renal US should be obtained.

As most cases are not pathologic, reassurance and an explanation of this condition to parents are often the best management. Steroid creams such as triamcinolone and betamethasone may be indicated when the phimosis is not anatomic but pathologic, but recurrence rates are high despite short-term effectiveness.²² Patients with recurrent balanoposthitis, UTI, or obstruction should be referred to a urologist for circumcision.

Paraphimosis

Paraphimosis is a condition in which the foreskin of the uncircumcised male is retracted over the glans and becomes trapped and unable to move back into its normal position (Fig. 85-6). Its constriction proximal to the coronal sulcus causes venous congestion of the glans that further prevents reduction, and ischemic injury to the glans may ensue.

Patients have pain and swelling of the distal penis and prepuce. The diagnosis is made by examination, and there should be a close inspection for possible hair tourniquets and penile foreign bodies.

Management

Paraphimosis is managed by manually reducing the prepuce over the head of the glans. Successful reduction is unlikely without adequate anesthesia, and sedation may be required. One effective technique is a penile block, which is placed by injecting lidocaine 1% without epinephrine around the base of the penis. Ice packs can then be placed around the distal penis for 10 minutes, after which manual reduction should be attempted (Fig. 85-7). The physician's index fingers are placed on the leading edge of the edematous foreskin, and the thumbs are placed on the glans. Gentle, constant pressure is directed inward with the thumbs as the prepuce is pushed back over the glans. Several techniques to decrease the edema prior to manual reduction have been described, including: compression of the glans and distal penis with a small elastic bandage; fenestration of the foreskin with a 26-gauge needle (the Perth–Dundee method); and application of osmotic agents such as honey or hypertonic saline.²³ If reduction of the prepuce is successful and the child is able to urinate spontaneously, then he can be discharged with urologic follow-up. If the prepuce cannot be reduced, then emergent urologic consultation is needed for surgical division of the phimotic ring. This may require general anesthesia, but subsequent circumcision is not necessary in most cases.²³

Balanitis and Balanoposthitis

Balanitis (infection of the glans) and balanoposthitis (infection of the glans and foreskin) are more common in the uncircumcised male but may also be found in circumcised children (Fig. 85-8). It frequently presents during the preschool-aged years and rarely before toilet training.

The etiology is often related to inadequate hygiene, chemical irritation from soaps or bubble baths, or persistent manual manipulation.¹ An infectious etiology follows from entrapment of organisms under the foreskin; these include gram-negative and -positive bacterial organisms (especially group A-hemolytic streptococcus), and Candidal species in infants. In adolescents, sexually transmitted diseases must be considered. Chronic balanitis or phimosis may result in balanitis xerotica obliterans, a sclerotic disease of the prepuce.

Signs and symptoms include swelling, erythema, penile discharge, dysuria, bleeding, and, rarely, ulceration of the glans. Phimosis can occur but is uncommon. A careful examination of the base of the penis should be performed to exclude a hair tourniquet.

Diagnostic Evaluation and Management

Balanitis is diagnosed clinically. In selected cases, the clinician may wish to obtain a urinalysis and send cultures of the penile discharge.

Most patients can be managed with local care: Sitz baths, gentle cleaning of the foreskin, and topical antibiotic ointment. Application of 0.5% hydrocortisone cream may be helpful.¹ Oral antibiotics, such as cephalexin, may be reserved for the more severe cases, especially when a streptococcal etiology is suggested by the presence of purulent discharge, fiery-red erythema, or moist exudate.¹ Patients with recurrent candida balanitis should be screened for diabetes.

Urethral discharge should prompt for cultures for sexually transmitted disease in adolescents. Patients should be followed closely to assure that symptoms have resolved, and recurrent cases may be referred to a urologist for elective circumcision.

Priapism

Priapism is a prolonged (over 4 hours), painful erection unrelated to sexual stimulation. It is relatively uncommon in childhood except in patients with sickle cell disease. In this group, priapism occurs in up to 10% of patients. Priapism is rare in the neonatal period and polycythemia and trauma should be considered as possible etiologies.

Pathophysiology of priapism can be divided into two mechanisms:

1. Low-flow or ischemic: there is little or no cavernous blood flow, and the penis is painful and tender to palpation; this may be encountered in sickle cell disease and polycythemia.

2. High-flow or engorgement: the penis is typically not fully rigid or painful; preceding trauma is the most common etiology.^24,25

Either mechanism results in engorgement of the corpora cavernosum with a flaccid corpora spongiosum and glans. If unrelieved, this engorgement leads to increased stasis of cavernous blood, deoxygenation and acidosis, thrombosis, and eventually impotence. Numerous factors that may precipitate priapism in patients with sickle cell anemia include infection, trauma, acidosis, hypoxia, sexual intercourse, and masturbation. Other etiologies of priapism include trauma (such as a straddle injury), drugs of abuse and medications (antihypertensives and vasoactive agents, anticoagulants, psychoactives, and alprostadil), leukemia, Kawasaki's disease, and polycythemia. Phosphodiesterase-5 inhibitors commonly used for erectile dysfunction (such as sildenafil and tadalafil) have also been associated with priapism.²⁴

Patients often have delayed presentation, possibly a result of embarrassment. History should include any prior episodes of priapism and its treatment, duration and degree of pain, and placement of urethral and penile foreign bodies. Physical examination will reveal an erect penis, which is firm on the dorsal surface (corpora cavernosum) and soft on the ventral surface (corpora spongiosum) and glans. The bladder should be palpated for signs of urinary retention, which can be relieved with a urinary catheter.

Diagnostic Evaluation and Management

Priapism is diagnosed by physical examination. Selected patients may benefit from a complete blood count, looking for evidence of leukemia or anemia, and a sickle cell preparation and hemoglobin electrophoresis. Renal function studies are indicated if there has been significant urinary retention. If patients have suffered perineal trauma, a retrograde cystourethrogram may be indicated, and color Doppler US may differentiate between a low-flow and a high-flow state if the mechanism is unclear.

Treatment is based on the presumed etiology. Aggressive supportive care with oxygen, hydration, and analgesics, is appropriate for all patients and may be sufficient to alleviate the priapism in patients with sickle cell disease. If not, an exchange transfusion in consultation with a hematologist is considered. Patients with leukemia should receive hydration and analgesics and appropriate treatment for their cancer. Urologic consultation is recommended in all cases, but the timing of surgical management of priapism is controversial. Although some clinicians prefer to attempt medical management initially, the American Urological Association recommends that surgical treatment be initiated concurrent with systemic treatment for ischemic priapism.²⁴ Invasive therapy begins with therapeutic aspiration with or without irrigation, followed by intracavernous injection of a sympathomimetic vasoconstrictor such as phenylephrine. If unsuccessful, surgical shunting of blood from the cavernosum to the spongiosum or the glans may be performed.²⁴ Parenteral vasodilators, including hydralazine or terbutaline (0.25–0.5 mg IV every 4 hours), have been used to treat priapism with varying success. Management of high-flow priapism is directed at the specific underlying etiology, and may require consultation with interventional radiology as well as urology.^24,26

Special thanks to John W. Williams for his contributions to the previous edition of this chapter.