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February 2005, Volume 27, No. 2
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Update Articles
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Update on the management of common urological problems in childrenK K W Liu 廖鑑榮, M W Y Leung 梁偉業 HK Pract 2005;27: 53-60 Summary Paediatric urological problems constitute about one-third of the work load in a busy paediatric surgery unit. These disorders are initially seen by primary care/family physicians and subsequently referred to paediatric surgical specialists. This article gives an update on the current management of some common urological problems in children so as to assist colleagues in the front line in the initial disease recognition, treatment options, appropriate referral and the subsequent follow up. 摘要 小兒泌尿系統疾病約佔一個小兒外科部門工作量的三分一。此類疾病多經由基層家庭醫生診治後轉介。 本文敘述常見小兒泌尿科疾病的最新療法，從而在早期辨症、治療選擇、轉介和繼後跟進等各方面為前線醫生提供指導。 Introduction The understanding, diagnosis and management of various disorders of the genito-urinary system in children have improved greatly during the past several decades. New advances have brought revolutionary changes in management in some disorders. Front line family physicians are often consulted in many of these common paediatric urological problems. Delay in disease recognition and referral may lead to sub-optimal outcome. We shall concentrate on a few common urological disorders in children in this article. The prepuce Natural history of the prepuce The prepuce envelops the glans and may serve to protect it and the urinary meatus. The epithelial layers of the glans and prepuce remain fused for the first three to four years of life until natural separation occurs. (Table 1)1 The normal non-retractile prepuce is often termed "physiological phimosis". Before the prepuce fully separates from the glans, "ballooning" of the prepuce during micturition is a common phenomenon and is normal. This process of separation may be uneven and partial adhesions between the glans and prepuce may remain even up to adolescence. During the process of separation, the accumulation of desquamated epithelial cells may result in the formation of whitish pearls of smegma. Diseases of the prepuce Pathological phimosis This is a non-retractile, scarred prepuce and may be a result of trauma or lichen sclerosis et atrophicus, sometimes known as balanitis xerotica obliterans (BXO). Balanoposthitis Balanoposthitis is inflammation of the glans and the prepuce seen in about 4% of boys with non-retractile prepuce.2 Most cases are self resolving or respond to topical or systemic antibiotics. Balanitis xerotica obliterans It is a condition of unknown cause. The prepuce is severely scarred and may extend into the urethra. (Figure 1) Paraphimosis This occurs when the retracted prepuce becomes caught behind the glans leading to a tight constricting band just proximal to the glans. (Figure 2) There is increasing oedema of the prepuce and the glans giving rise to pain. In the acute phase, reduction of the prepuce under local or general anaesthesia should be performed. Urinary tract infectionThere are several studies showing that urinary tract infections are more common in uncircumcised infants suggesting the protective effect of circumcision through the reduction of the periurethral carriage of pathogenic organisms.3,4 However critical assessment has shown that around 100 prophylactic circumcisions would be needed to prevent one urinary tract infection and up to 1000 circumcisions have to be performed to avoid one renal scar.5 Medical indications for circumcision
Contraindications for circumcision
Circumcision Circumcision aims to remove sufficient prepuce to expose the glans while leaving enough skin to cover the penile shaft. There are various techniques including the use of clamps, plastibell, freehand method, guillotine and sleeve technique. Given the prevalence of circumcision, complications of the procedure though not that common, will have a significant effect on the clinical workload. Complications of circumcision include haemorrhage, infection, meatal stenosis, penile and urethral injury, incorrect amount of skin excision, etc. The common ones are infection and bleeding. A review of 420 consecutive circumcisions from our centre showed figures of 2% for bleeding and 5% for infection. Although routine circumcision is not prevalent these days, the procedure is still performed too often. Over 20,000 boys under 15 years of age are circumcised annually in the United Kingdom. In the United States, many boys are circumcised shortly after birth for cultural reasons or due to the preference of the parents. The neonatal circumcision rate is around 90%. In Hong Kong, there is no data on the rate of circumcision as there has not been a territory wide audit and many of these are being performed in private practice. In a study from Bristol, of all the children referred to a paediatric surgery centre, only one quarter required circumcision. It seems that a significant proportion of general practitioners have difficulty in discriminating between a true phimosis and a developmentally non-retractile prepuce. Other methods of treatment Preputioplasty Because of the complications associated with circumcision, another technique of producing a retractable prepuce has been designed. Preputioplasty is a prepuce preserving technique which widens the preputial orifice and produces a retractable prepuce.6 Topical corticosteroids Topical steroids have been advocated as an effective economical alternative to circumcision in patients with phimosis with an efficacy of around 80%.7 Hypospadias The male phallus increases in length during the first trimester. Urethral tubularisation occurs from proximal to distal under the influence of testosterone. Failure in this process of tubularisation results in a ventral urethral opening termed hypospadias. It is a relatively common anomaly with an incidence of about 1 in 300 male births. Recently there is evidence of increasing prevalence of hypospadias possibly related to the increasing amount of environmental oestrogens. Hypospadias is characterised by a ventral opening of the urinary meatus varying in position from the glans to the perineum, ventral curvature (chordee) of the penis and a dorsal hood of prepuce with a deficiency of skin on the ventral side. (Figure 3) Hypospadias can be named according to the position of the urethral opening ranging from perineal to glanular hypospadias. Diagnosis is often made in the first postnatal examination but minor degrees of anomaly may be missed. Severe forms of hypospadias may be associated with other genitourinary anomalies and investigations are warranted. All patients with hypospadias and undescended testes should be investigated to exclude ambiguous genitalia like congenital adrenal hyperplasia. Surgical reconstruction is usually performed in the second year of life. Many methods have been described and most cases can be corrected in one stage. The aim is to produce a straight penis on erection, a terminal urinary meatus and a good cosmetic result. Complications include poor cosmesis, meatal stenosis, meatal retraction, urethral diverticulum, residual chordee, stricture and fistulae. Buried penis Buried penis is a congenital anomaly in which the otherwise normal penis is partially or completely concealed within the subcutaneous tissue of the prepubic region. (Figure 4) There is significant variation in the severity and incidence of the condition. The anatomical factors accounting for buried penis include the followings:
Surgical treatment seems necessary as the condition tends to persist after puberty. The timing of surgery is controversial. Some advocate early intervention in view of the negative effects on the social and psychological development of the child. It seems logical to offer surgery until after the child has started to walk and has lost most of the prepubic pad of fat. In those with excessive obesity, weight reduction is recommended before embarking on surgery. The principles of surgical correction include:
Good cosmetic result can be achieved in most cases with minimal morbidity.8 Maldescent of the testes Maldescent of the testis is a common congenital urological anomaly. Its incidence is as high as 5% at full term falling to about 1% at one year old. Those that do not descend by the first three months after birth are unlikely to do so spontaneously.9 The incidence is higher in premature babies. Testicular descent occurs in two stages, the abdominal phase and the inguinoscrotal phase. Current evidence indicates that testicular descent requires the interaction of both hormonal and mechanical factors. Nomenclature A fully descended testis resides in the scrotum. An undescended testis cannot be manipulated into the bottom of the scrotum without undue force. Undescended testes that have become arrested in the line of normal descent can be described as incomplete descent in the following positions: intra-abdominal, emergent canalicular or superficial inguinal pouch. Those that are not in the line of normal descent are described as ectopic and can be found in various positions including pre-penile, femoral, perineal and crossed ectopia. Retractile testes are the ones that can be pushed into and stay in the scrotum when the child is examined in a warm and relaxed environment. Retractile testes are caused by marked cremasteric reflex which is strong during infancy and diminishes near puberty. They do not need surgical intervention. However they need to be followed up as some will develop into "ascending testes".10 Iatrogenic testicular ascent may occur after previous inguinal surgery.11 Diagnosis Maldescent of the testes is often detected at delivery or during postnatal follow up. Unilateral undescended testis can be seen in the outpatient clinic after three to four months of age. Those with bilateral undescended testes together with hypospadias should be treated with caution in case one may be dealing with a baby with ambiguous genitalia e.g. congenital adrenal hyperplasia. Palpation forms a most important part of the examination. Palpation should start with one hand moving from the lateral part of the inguinal canal towards the superficial ring milking the contents towards the scrotum. The other hand then examines the region between the superficial inguinal pouch and the scrotum for the presence of the testis. If the testis is impalpable along the line of normal descent, one should look for an ectopic testis. Various imaging studies and biochemical tests are usually of limited value in the management of unilateral impalpable testis. Laparoscopy is the investigation of choice. For patients with bilateral impalpable testes, a human chorionic gonadotropin stimulation test may detect functioning testicular tissue if it is positive.12 A negative test does not mean that there is no testis present. It may just be that the testis is abnormal or dysplastic and hence has no response to the stimulation. Laparoscopy is still required. Management The aim of treatment is to place the testis in the scrotum. Therapy for cryptorchidism is usually carried out at around one to two years of age to prevent histological deterioration. This may have some beneficial effect on fertility.13 Studies on semen analysis and fertility index showed that those with earlier operations and those with unilateral involvement have better outcomes. The other beneficial effect of orchidopexy is the earlier detection of malignant transformation. Individuals born with an undescended testis have approximately a 40-fold increased incidence of testicular malignancy over those born with scrotal testes, and the peak incidence is in the third and fourth decades. The incidence of malignant degeneration increases with the higher location of the undescended testis. The risk of malignant transformation is also present in the contra-lateral normally descended testis in cryptorchid patients.14 Currently there is no evidence to suggest that earlier surgery reduces the chance of malignant transformation.15 Hormonal manipulation of undescended testes using human chorionic gonadotropin and luteinizing releasing hormone have been used with a low percentage of success rate with nonrandomised trials reporting better results than randomised studies.16 For palpable undescended testes, a one stage open orchidopexy usually suffices. For impalpable testes, laparoscopy is the diagnostic test of choice. There are a few possibilities: Blind-ending vessels and vas deferens: (vanishing testis) Normal or attenuated vessels and vas deferens entering the internal inguinal ring. There are two possibilities. There may be a normal testis in the inguinal canal that has not been detected during physical examination or a small testicular remnant may be present. Orchidopexy is required for the former and excision of testicular remnant is necessary for the latter though this is controversial.17 A normal size testis within the peritoneal cavity. If the testis is just at the deep ring, orchidopexy can be performed using an open approach or laparoscopically.18 (Figure 5) If the testis is too far away from the internal inguinal ring, either a one stage microvascular auto-transplantation especially for patients with single functioning testis19 or a two stage Fowler-Stevens orchidopexy can be offered.20 The former consists of division of the testicular vessels and their anastomoses to the inferior epigastric vessels. The Fowler-Stevens staged orchidopexy involves division of the testicular vessels in the first stage. After about six months or so allowing the collateralisation of the testicular blood supply based on the cremasteric artery and the artery along the vas deferens, the testis is then brought down to the scrotum based on a pedicle of peritoneum that includes the vas and its enhanced blood supply. The two stages can be performed via an open approach or laparoscopically. Blind ending vas deferens only and blind ending vessels not identified. Testicular-epididymal disjunction may be present and requires further exploration.21 Acute scrotum An acute scrotum is a common urological emergency in infants and children. During a 5-year period from 1999 to 2004, a total of 221 children presented with acute scrotum to the Paediatric Surgical Centre in the Kowloon East and Kowloon Central Clusters. Epididymo-orchitis (40.5 %) was the most common diagnosis, followed by torsion of testicular appendages (35.9 %) and torsion of testis (14.5 %). The age of the child aids in the differential diagnosis. In newborns, the most likely cause is testicular torsion or trauma during delivery. Torsion of the testis in newborns involves a twist around the whole spermatic cord possibly related to the yet unfixed descended testis and hence is known as extravaginal torsion. Often it presents late, and the scrotum is red and contains a firm mass. Surgery may be required but the testis is often beyond salvage and has to be excised.22 Whether to fix the opposite testis is controversial but cases of bilateral neonatal torsion have been reported.23 In toddlers, the likely causes include epididymo-orchitis and idiopathic scrotal oedema. Other less likely causes are Henoch-Schlein purpura and acute leukaemia. Epididymo-orchitis are often caused by urinary tract infection. Most cases are diagnosed after surgical exploration. Investigation of the urinary tract is essential. Idiopathic scrotal oedema is characterised by the sudden onset of redness and swelling often involving both sides. The testes are non-tender. In adolescence, the likely causes are torsion of the testis, torsion of the testicular appendage, and epididymitis. Torsion of the testis is an important diagnosis to consider in pubertal and adolescent boys. It presents with sudden and severe testicular pain which may radiate to the groin. A horizontal or high riding testis may be found. Surgical exploration is essential if the diagnosis of torsion of the testis cannot be excluded. The testis is untwisted and if viable it should be fixed. As the anatomical anomaly of bell-clapper testis predisposing to torsion is often bilateral, the contra-lateral testis should also be fixed. The rate of testicular salvage depends on the time between onset and surgery.24 The testis is likely to be salvaged if it can be operated within the first six hours. Postoperative oligospermia may occur and may be related to the production of auto-antibodies as a result of ischaemia-reperfusion injury.25 Torsion of the testicular appendage is more likely to affect pubertal boys possibly due to the surge in gonadotropins causing enlargement of the appendage. The pain is less acute and severe. Tenderness is often confined to the upper pole of the testis and occasionally the twisted appendage may be seen (the blue dot sign). If the diagnosis is certain and the symptom is mild, conservative approach can be adopted. Any uncertainty should demand immediate surgical exploration. Epididymitis in adolescents may be related to sexually transmitted infection. Mumps orchitis may affect this age group and often follows an attack of parotitis. Testicular tumours usually teratomas may rarely bleed and present as acute scrotum. A careful history and ultrasound would establish the diagnosis. Antenatal hydronephrosis The use of routine antenatal ultrasound examination has identified a number of foetuses with abnormalities. In 1% of pregnancies, a structural foetal anomaly is detected. Genitourinary anomalies constitute about 20%. Renal pelvic dilatation or hydronephrosis is one of the most common abnormalities detected on prenatal ultrasound and accounts for approximately 50% of all renal lesions detected.26 The differential diagnosis includes the followings:
The chance of detecting a significant anomaly postnatally increases with the degree of antenatal hydronephrosis. Postnatal investigations should include a complete physical examination including the genitalia. Biochemical investigations including renal function tests are essential for those with bilateral diseases. The first postnatal ultrasound should be performed after the first few days. Prophylactic antibiotics are often prescribed. If hydronephrosis is not confirmed, the scan can be repeated in six weeks. If hydronephrosis is detected, a micturating cystourethrogram is performed to look for vesicoureteric reflux, bladder outlet obstruction and other possible bladder pathology. Static isotope renography provides information on functional renal tissue and is used to detect renal scar. Dynamic isotope renography provides relative renal function and possible evidence of obstruction. Pelvicureteric junction obstruction This is the commonest cause of hydronephrosis and about 50% of them resolve spontaneously. The aetiology of pelvicureteric junction obstruction (PUJO) includes an adynamic segment of ureter associated with high insertion on the renal pelvis, ureteric folds, fibro-epithelial polyps, aberrant vessels, horseshoe kidney, retrocaval ureter, etc. PUJO may present in infants with abdominal mass or urinary tract infection. Infection in an obstructed system may lead to pyonephrosis requiring emergency drainage. Older children may present with intermittent loin pain. Haematuria may occur especially after minor degree of trauma. Patients are followed up with serial ultrasound and dynamic isotope renography. Surgery is indicated in those patients with poor or reduction in renal function, marked and progressive hydronephrosis, recurrent abdominal pain and recurrent urinary tract infection. Dismembered pyeloplasty is the treatment of choice and can be performed via an open approach or laparoscopically. Vesicoureteric reflux Vesicoureteric reflux (VUR) is detected in about 10% of newborns with prenatal hydronephrosis. It tends to be of higher grade and usually affects male infants with underlying anomalies. If VUR presents later in life, it usually affects girls and is often detected following investigations for urinary tract infections. It is often related to a functional problem. There is a genetic predisposition to VUR and it is more likely to develop in families with siblings or parents with history of VUR. VUR predisposes to urinary tract infections and subsequent renal scars, hypertension and even renal failure.27 Micturating cystourethrography is essential for the diagnosis of VUR. It is divided into five grades according to the International Reflux Study Classification. Spontaneous resolution is common with low grades of VUR (5-year resolution rates approximately 80% for reflux grade I and II) but is greatly reduced with higher grades (5-year resolution rate 16% for reflux grades III-IV).28,29 Static isotope renogram is essential in the detection of renal scars. Management of VUR is often medical initially and consists of good toileting habits and prophylactic antibiotics. This is continued for four to five years and stopped even if VUR persists unless there are contraindications. Surgery is offered to those with recurrent breakthrough urinary tract infections despite prophylactic antibiotics, increasing renal scar and associated urinary tract anomalies. Surgery has traditionally been managed by ureteric reimplantation with over 95% success rate.30,31 Endoscopic subureteric injection of a bulking agent into the ureteric orifice (STING) has been in use for over 20 years using polytetrafluoroethylene (Teflon TM).32 Because of the risk of potential migration of the Teflon TM particles33, it has not been popularised. With the introduction of a new dextranomer/hyaluronic acid copolymer (Deflux TM) which is biodegradable and without evidence of migration, STING is becoming the procedure of choice for the management of VUR.34 The preliminary report of local experience of endoscopic correction of VUR using Deflux TM also reviewed satisfactory result.35 Vesicoureteric junction obstruction A small percentage of antenatal hydronephrosis is due to vesicoureteric junction obstruction (VUJO). This obstructed megaureter is caused by a stenotic or adynamic segment at the vesicoureteric junction. Apart from antenatal hydronephrosis, patients may present with pain or urinary tract infection. Investigations include ultrasound, micturating cystourethrogram and isotope renogram. Majority may resolve with conservative treatment. For those who fail to resolve, excision of the stenotic segment and ureteric reimplantation with remodeling may be required. Multicystic dysplastic kidney Multicystic dysplastic kidney (MCDK) consists of a variable number of non-communicating cysts of different sizes often associated with ureteric atresia. It often presents antenatally and a small number is found incidentally or rarely as abdominal mass. Diagnosis is by ultrasound showing the multicystic nature and absence of function in isotope renogram. It is important to check for associated anomaly in the urinary tract. There is a risk of hypertension and malignant change. The majority of MCDK will resolve. For those that fail to resolve, nephrectomy can be offered using an open or laparoscopic approach. (Figure 6) Conclusion Urological problems in children are common and constitute about one-third of the work load in a paediatric surgical unit. With the routine use of antenatal ultrasound, some even present before birth. As frontline clinicians, family physicians should have better knowledge of these problems. A few common disorders of the male genitalia, the testes, and urinary tract are discussed including the diagnosis, investigations and current advances in treatment. With earlier diagnosis, prompt referral and appropriate treatment, a satisfactory outcome can be achieved. Key messages
K K W Liu, MBBCh,BAO (NUI), FRACS, FRCSE, FHKAM (Surgery)
Consultant Paediatric Surgeon, M W Y Leung, MBBCh (CUHK), FRCSE, FHKAM (Surgery) Associate Consultant,Department of Surgery, United Christian Hospital. Correspondence to : Dr K K W Liu, Division of Paediatric Surgery, Department of Surgery, United Christian Hospital, Kwun Tong, Kowloon, Hong Kong.
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