Indian 3, Ptdlatr, 40 g G6, |g"19
CONGENITAL MALFORMATIONS OF THE URINARY TRACT IN PAEDIATRIC PRACTICE* W.K. BELOKAR
S#oagram Congenital malformations of the urinary tract b e c o m e imporltant when we realise that the kidneys' perform a vital homeostatic function. Autopsy studies have shoavn that more than 10 per cent of humans are born with some a n o m a l y of the urogenital tract. Anomalous development attains the highest incidence in the urogenital tract, being found in 30-40 per cent of m a l f o r m e d individuals, frequently in conjunction with other congenital defects. However, m a n y ol these do not give rise to symptoms till adult life. T h e most d r e a d e d complication is infection. I t is axiomatic that an anomalous organ is more prone to disease than a normal one. T h e majority of urinary tract anomalies are obstructive which produce urinary stasis infection or stone formation or even severe back pressure resulting in renal injury. Thus tF~e most d r e a d e d complication is progressive renal failure. I f we detect the m a l f o r m a t i o n early before *.he occurrence of complications, surgical repair m a y be helful. M a n y malformations are incompatible with life beyond a tew clays a n d hence are of academic importance. S o m e children m a y have a normal childhood, the presence of ~he anom a l y being discove'rd in adult life. A few are discovered in infancy and childhood. This is the most i m p o r t a n t group. It is easier to *From the Department of Surgery, Mahatma Gandhi Institute of Medical Sciences, Sevagram, 442101[ Wat;dha. Received Jaunary 20, 1078.
classify the T a b l e 1~.
anomalies anatomically (Fig. 1,
B~C!
'ING
URF.TE G
Fig. 1. Malformations of the urinary tract.
Pitfalls in diagnosing renal malformation as abdominal turnout. In order to understand this fully, knowledge of the embryology and physiological function is necessary. (a) Low placed kidneys in the pelvic region m a y suggest a wrong diagnosis of abdominal tumour through ~he palpation of functionally normal kidneys that have failed to migrate upward. These are often bilateral. (d) The normal foetal lobulation persisting into early childhood may mistakenly give a
IBELOKAR~CONC3ENITAL MALFORMATIONS OF THE URINARy TRACT
Table 1.
Urinary tract malformations
|
A) Kidney
r
B) Ureters
Absent Hypoplasia Hyporplazia Duplication Ectopia Holycystic Fused
Hypoplasia Duplication Dilated ar ectoptc Strictures Valves or kinks Aberrant blood vessels Megaureter
Bladder
D) Urethra
Absent Aypoplastic Trigonal hypertrophy Extrophy
Absent Hypoplastic Strictures
Ureterocele Patent urachus Neuro-muscular Bladder
Hypospadias a n d Epispadias Phimosis
false sense of a multilobulated tumour mass in the abdomen. (c) One kidney m a y undergo hyperplasia to such an extent as to be easily palpable. This is a norma! physiologically enlarged kidney due to failure of the other kidney. Attention should be directed to the .nonpalpable kidney rather than the palpable 'lump'. (d) A lump at the umbilicus may be a cystic collection o f urine from a patent urachus rather than an umbilical hernia, art umbilical cyst or abscess.
BilaWral renal ageneJis. This is rare and not compatible with life beyond a few days. Hence the significance of inquiring whether a neonate has
67
passed urine or not within the first 24 hours. No doubt the more common cause is failure to feed adequate quantity of fluids but absence of the kidneys as a rare cause may be borne in mind. Renal agenesls is often associated with Potter's facies--hyperteleorism, palpebral fissures, flattened nose, a prominent epicanthus, large ears and a receeding chin. It is seen mostly in males.
Unilateral renal agenesis This is a milder variant of the above two. The opposite kidney will hypertrophy sufficient enough to be compatible with normal life. However, woe to the surgeon wfio removes this " e n l a r g e d " kidney or tumour mass.
Bilateral renal hyboplasia This is a variant of the above, in which life may be compatible from a few months to a few years. Sometimes the pronounced renal dysfunction manifests itself as renal dwarfism, so called renal rickets or renal hypertension.
PolycyJtic kidneys. The condition rarely gives rise to any symptoms till adult life. Its incidence in childhood autopsies is less than 0.5 per cent. However, an unexplained haematuria or a persistent urinar,/ infection with hypertension should draw one's suspicion. An abdominal mass may or may not be palpable, depending on the size o f the kidney. T h e earlier the condition is discovered, the poorer is the prognosis. Intravenous pyelography reveals the characteristic picture of a normal pelvis with elongated, distorted calyces and islands, of dye in places. T w o forms of polycystic disease are recognised. In the first group (33%), it
68
VoL. 46, No. 373
INDIAN JOURNAl. OF PRDIA'IRICSS
appears in infancy, early life, or when the child is stillborn, and in the ;econd, the lesion appears after puberty or adulthood with enlarging renal m.-.:;ses and fMling renal function (67%). The ;nfantile form is said to fie geiaetie in origin, of the Mendeliao r~ce-%'i;'e type.
it may produce pressure on nerves, blood vessels or neighbouring organs and cause lower abdominal pain (pelvic neuralgia}, The palpation of such an nrgan may lead to the incorrect diagnosis of neoplasm o! cystic ovary, appendicea] or iliocaecal pathology.
Fusion of kidneys
Anomalies of pelvis and ureters
This can only be suspected in cases of unexplained renal failure. Its diagnosis is radiological. The two kidneys may be fused together in a variety of ways, fusion being at the upper poles, lower poles, median planes and other bizarre ways. T h e kidneys are often held in low ectopia by an early established, abnormally low vascular derivation from the inferior aortic or iliac vessel=. E v e n surgery has failed to help these patients. It is curious how kidney malformations are associated with abnormally shaped low placed ears.
A variety o f malformations are des. cribed, such as, duplication, complete o r partial absence, blind ending, small or narrow ureteric passage, valve llke flaps ill the lumen. These anomalies are important in that they produced obstructive uropathy. The duplicated ureters usually cross each other especially in the bladder region. T h e y are a surgical curiosity and call for ingenuity in repair, few of which are really successful.
Abberrara renal arteries Although m a n y forms are described, the most important is the artery that crosses over the pelvis or upper ureter to compress it and give rise to obstructive uropathy with hypertension. This is amenable to surgery, whereas other forms are less amenable. An auscultatory bruit over the kidney region is significant. Arteriography shows the exact anomaly.
Ectopic kidney The kidney may be ectopic on its own side (simple dystopia) or may be fused or unfused with its renal mate (crossed dystopia). During parturition the ectopic organ may cause dystopia or by renal impingement on the bladder, produce vesical disturbances. Often the organ is the site of surgical disease, especially infection and stone; also
Megaureters This is analogous to Hitschsprung's colon explained o n t h e basis of aganglionic parasympathetic nerve supply.
Ectapir ureter In the males the ureter may open into the posterior urethra, vas deferens, epididymis or seminal vesicle; however, in the female this opening is generally in the urethra or just adjacent to the external urethral meatus. Rarely, it opens into the cervix or uterine cavity. I n females it leads to constant urinary dribbling.
Bladder Ectopic vesica is a distressing malformation where the anterior wall of the bladder is exposed on the anterior abdominal wall with epispadias in the male and an absent vagina in the female. It is associated with non-fusion of the pubic bone. The
~s~LO~;'~--CONG~.NIT^L M^LFORMAT~ONSO~ THE URISARY TRXCT
69
diagnosis is obvious but surgical repair and m a n a g e m e n t is unsatisfactory. It occurs in one in 40,000 births,
with hypertrophy of the bladder wall there is likely to be somc hypertrophy" vf the trigone.
persistent urachus
Malformation ~ ur~thra
A persistent urachus is less obvious and escapes diagnosis until there is bladder distension when urine may flow up the urachus and show a cystic swelling at the umbilicus. I f there is intermittent bladder distension, there will be intermittent cystic swelling which m a y be mistaken for an umbilical hernia. I f the urine is opaque from phosphaturia or infection, this swelling m a y be mistaken for an abscess. In all such cases it is wise to investigate the cause of
Urethral malformations are some of the commoneo-t . . . . I: . . . . :.~ ~Art.:l.,, absent urethral passage, hypoplasticurethral lumen or a stricture m a y rarely be present, the more common malformations are hypospadias, epispadias and occluded external urethral rrleatus.
bladder distension,
ventral portion o f the foreskin absent. Such
,Bladderneck obstruction
abnormalities require treatment more for cosmetic and psychological reasons. The skillful surgeon utilises the foreskin to create a full length of urethra. It does not interfere with sexual activity. Sometimes, undescended testes are associated. The condition is
This is by far the most important of all ~arinary tract m a l f o r m a t i o n for it is seen in ,childhood and if diagnosed early is amenable to surgery. I t appears almost entirely in trays, This results from hypertrophic muscles involving all or part of the bladder neck. T h e r e is increased fibrous tissue, resuhing in inelasticity and decrease in the lumen o f the bladder outlet and chronic inflammatory changes. This results in chronic vesical distension due to difficuhy in micturit i o n a n d consequent hydroureters, hydronephrosis and urinary infection, In congenital valves o f the posterior urethras deep mucosal folds (paper thin) are located in the posterior urethra. T h e y are partial or complete diaphragms which show a wide range in location and confirmation. These cause practically complete
urinary obstruction. In such an obstruction the v e r u m o n t a n u m is usually anomalous, greatly enlarged and elongated, often three ~ofour times the normal size. Coincident
Hypospadias. This has the urethral opening just behind the lower surface of the glans. T h e glans itself is angulated and the
entirely in males. Epispadias is a much less common condition and often associated with bladder anomaly. Surgical repair gives good results. In both these conditions, the repair should be undertaken after the age of 4 years so as to give the surgeon more developed foreskin to work with. The external urethral meatus may be absent or occluded by a membrane. Sometimes these membranes are deep inside the the urethra" Except for the valve-like type, other membranes can be easily broken open. It is important to remove these obstructions to prevent obstructive uropathy.
Prepuce The prepuce is normally adherent to the glans in the newborn and early infancy
70
VOL. 4(3,NO. 373
INDIAN JOURNAL OF PEDYATRtCS
No a t t e m p t to retract it should be made. Further it should not lead one to think that phimosis is present. T h e adhesions disappear of their own. An extreme degree o f phimosis rasulting in obstruction to urinary outflow is more imaginary than real and unnecessary circumcisions are advised. A similar feature is seen in adhesions of the labia in females. This also requires no t r e a t m e n t as they
disappear of their own accord. Associated anomalies The associatiotl of uinary tract malformations with abnormal pinna, eventration of the diaphragm and absent abdominal muscles, are other well d o c u m e n t e d associations. Unfortunately, the defects o f the urinary tract are more often of a severe nature leading to a poor prognosis.
CONGENITAL MALFORMATIONS OF THE URINARY TRACT IN PAEDIATRIC PRACTICE* W.K. BELOKAR
S#oagram Congenital malformations of the urinary tract b e c o m e imporltant when we realise that the kidneys' perform a vital homeostatic function. Autopsy studies have shoavn that more than 10 per cent of humans are born with some a n o m a l y of the urogenital tract. Anomalous development attains the highest incidence in the urogenital tract, being found in 30-40 per cent of m a l f o r m e d individuals, frequently in conjunction with other congenital defects. However, m a n y ol these do not give rise to symptoms till adult life. T h e most d r e a d e d complication is infection. I t is axiomatic that an anomalous organ is more prone to disease than a normal one. T h e majority of urinary tract anomalies are obstructive which produce urinary stasis infection or stone formation or even severe back pressure resulting in renal injury. Thus tF~e most d r e a d e d complication is progressive renal failure. I f we detect the m a l f o r m a t i o n early before *.he occurrence of complications, surgical repair m a y be helful. M a n y malformations are incompatible with life beyond a tew clays a n d hence are of academic importance. S o m e children m a y have a normal childhood, the presence of ~he anom a l y being discove'rd in adult life. A few are discovered in infancy and childhood. This is the most i m p o r t a n t group. It is easier to *From the Department of Surgery, Mahatma Gandhi Institute of Medical Sciences, Sevagram, 442101[ Wat;dha. Received Jaunary 20, 1078.
classify the T a b l e 1~.
anomalies anatomically (Fig. 1,
B~C!
'ING
URF.TE G
Fig. 1. Malformations of the urinary tract.
Pitfalls in diagnosing renal malformation as abdominal turnout. In order to understand this fully, knowledge of the embryology and physiological function is necessary. (a) Low placed kidneys in the pelvic region m a y suggest a wrong diagnosis of abdominal tumour through ~he palpation of functionally normal kidneys that have failed to migrate upward. These are often bilateral. (d) The normal foetal lobulation persisting into early childhood may mistakenly give a
IBELOKAR~CONC3ENITAL MALFORMATIONS OF THE URINARy TRACT
Table 1.
Urinary tract malformations
|
A) Kidney
r
B) Ureters
Absent Hypoplasia Hyporplazia Duplication Ectopia Holycystic Fused
Hypoplasia Duplication Dilated ar ectoptc Strictures Valves or kinks Aberrant blood vessels Megaureter
Bladder
D) Urethra
Absent Aypoplastic Trigonal hypertrophy Extrophy
Absent Hypoplastic Strictures
Ureterocele Patent urachus Neuro-muscular Bladder
Hypospadias a n d Epispadias Phimosis
false sense of a multilobulated tumour mass in the abdomen. (c) One kidney m a y undergo hyperplasia to such an extent as to be easily palpable. This is a norma! physiologically enlarged kidney due to failure of the other kidney. Attention should be directed to the .nonpalpable kidney rather than the palpable 'lump'. (d) A lump at the umbilicus may be a cystic collection o f urine from a patent urachus rather than an umbilical hernia, art umbilical cyst or abscess.
BilaWral renal ageneJis. This is rare and not compatible with life beyond a few days. Hence the significance of inquiring whether a neonate has
67
passed urine or not within the first 24 hours. No doubt the more common cause is failure to feed adequate quantity of fluids but absence of the kidneys as a rare cause may be borne in mind. Renal agenesls is often associated with Potter's facies--hyperteleorism, palpebral fissures, flattened nose, a prominent epicanthus, large ears and a receeding chin. It is seen mostly in males.
Unilateral renal agenesis This is a milder variant of the above two. The opposite kidney will hypertrophy sufficient enough to be compatible with normal life. However, woe to the surgeon wfio removes this " e n l a r g e d " kidney or tumour mass.
Bilateral renal hyboplasia This is a variant of the above, in which life may be compatible from a few months to a few years. Sometimes the pronounced renal dysfunction manifests itself as renal dwarfism, so called renal rickets or renal hypertension.
PolycyJtic kidneys. The condition rarely gives rise to any symptoms till adult life. Its incidence in childhood autopsies is less than 0.5 per cent. However, an unexplained haematuria or a persistent urinar,/ infection with hypertension should draw one's suspicion. An abdominal mass may or may not be palpable, depending on the size o f the kidney. T h e earlier the condition is discovered, the poorer is the prognosis. Intravenous pyelography reveals the characteristic picture of a normal pelvis with elongated, distorted calyces and islands, of dye in places. T w o forms of polycystic disease are recognised. In the first group (33%), it
68
VoL. 46, No. 373
INDIAN JOURNAl. OF PRDIA'IRICSS
appears in infancy, early life, or when the child is stillborn, and in the ;econd, the lesion appears after puberty or adulthood with enlarging renal m.-.:;ses and fMling renal function (67%). The ;nfantile form is said to fie geiaetie in origin, of the Mendeliao r~ce-%'i;'e type.
it may produce pressure on nerves, blood vessels or neighbouring organs and cause lower abdominal pain (pelvic neuralgia}, The palpation of such an nrgan may lead to the incorrect diagnosis of neoplasm o! cystic ovary, appendicea] or iliocaecal pathology.
Fusion of kidneys
Anomalies of pelvis and ureters
This can only be suspected in cases of unexplained renal failure. Its diagnosis is radiological. The two kidneys may be fused together in a variety of ways, fusion being at the upper poles, lower poles, median planes and other bizarre ways. T h e kidneys are often held in low ectopia by an early established, abnormally low vascular derivation from the inferior aortic or iliac vessel=. E v e n surgery has failed to help these patients. It is curious how kidney malformations are associated with abnormally shaped low placed ears.
A variety o f malformations are des. cribed, such as, duplication, complete o r partial absence, blind ending, small or narrow ureteric passage, valve llke flaps ill the lumen. These anomalies are important in that they produced obstructive uropathy. The duplicated ureters usually cross each other especially in the bladder region. T h e y are a surgical curiosity and call for ingenuity in repair, few of which are really successful.
Abberrara renal arteries Although m a n y forms are described, the most important is the artery that crosses over the pelvis or upper ureter to compress it and give rise to obstructive uropathy with hypertension. This is amenable to surgery, whereas other forms are less amenable. An auscultatory bruit over the kidney region is significant. Arteriography shows the exact anomaly.
Ectopic kidney The kidney may be ectopic on its own side (simple dystopia) or may be fused or unfused with its renal mate (crossed dystopia). During parturition the ectopic organ may cause dystopia or by renal impingement on the bladder, produce vesical disturbances. Often the organ is the site of surgical disease, especially infection and stone; also
Megaureters This is analogous to Hitschsprung's colon explained o n t h e basis of aganglionic parasympathetic nerve supply.
Ectapir ureter In the males the ureter may open into the posterior urethra, vas deferens, epididymis or seminal vesicle; however, in the female this opening is generally in the urethra or just adjacent to the external urethral meatus. Rarely, it opens into the cervix or uterine cavity. I n females it leads to constant urinary dribbling.
Bladder Ectopic vesica is a distressing malformation where the anterior wall of the bladder is exposed on the anterior abdominal wall with epispadias in the male and an absent vagina in the female. It is associated with non-fusion of the pubic bone. The
~s~LO~;'~--CONG~.NIT^L M^LFORMAT~ONSO~ THE URISARY TRXCT
69
diagnosis is obvious but surgical repair and m a n a g e m e n t is unsatisfactory. It occurs in one in 40,000 births,
with hypertrophy of the bladder wall there is likely to be somc hypertrophy" vf the trigone.
persistent urachus
Malformation ~ ur~thra
A persistent urachus is less obvious and escapes diagnosis until there is bladder distension when urine may flow up the urachus and show a cystic swelling at the umbilicus. I f there is intermittent bladder distension, there will be intermittent cystic swelling which m a y be mistaken for an umbilical hernia. I f the urine is opaque from phosphaturia or infection, this swelling m a y be mistaken for an abscess. In all such cases it is wise to investigate the cause of
Urethral malformations are some of the commoneo-t . . . . I: . . . . :.~ ~Art.:l.,, absent urethral passage, hypoplasticurethral lumen or a stricture m a y rarely be present, the more common malformations are hypospadias, epispadias and occluded external urethral rrleatus.
bladder distension,
ventral portion o f the foreskin absent. Such
,Bladderneck obstruction
abnormalities require treatment more for cosmetic and psychological reasons. The skillful surgeon utilises the foreskin to create a full length of urethra. It does not interfere with sexual activity. Sometimes, undescended testes are associated. The condition is
This is by far the most important of all ~arinary tract m a l f o r m a t i o n for it is seen in ,childhood and if diagnosed early is amenable to surgery. I t appears almost entirely in trays, This results from hypertrophic muscles involving all or part of the bladder neck. T h e r e is increased fibrous tissue, resuhing in inelasticity and decrease in the lumen o f the bladder outlet and chronic inflammatory changes. This results in chronic vesical distension due to difficuhy in micturit i o n a n d consequent hydroureters, hydronephrosis and urinary infection, In congenital valves o f the posterior urethras deep mucosal folds (paper thin) are located in the posterior urethra. T h e y are partial or complete diaphragms which show a wide range in location and confirmation. These cause practically complete
urinary obstruction. In such an obstruction the v e r u m o n t a n u m is usually anomalous, greatly enlarged and elongated, often three ~ofour times the normal size. Coincident
Hypospadias. This has the urethral opening just behind the lower surface of the glans. T h e glans itself is angulated and the
entirely in males. Epispadias is a much less common condition and often associated with bladder anomaly. Surgical repair gives good results. In both these conditions, the repair should be undertaken after the age of 4 years so as to give the surgeon more developed foreskin to work with. The external urethral meatus may be absent or occluded by a membrane. Sometimes these membranes are deep inside the the urethra" Except for the valve-like type, other membranes can be easily broken open. It is important to remove these obstructions to prevent obstructive uropathy.
Prepuce The prepuce is normally adherent to the glans in the newborn and early infancy
70
VOL. 4(3,NO. 373
INDIAN JOURNAL OF PEDYATRtCS
No a t t e m p t to retract it should be made. Further it should not lead one to think that phimosis is present. T h e adhesions disappear of their own. An extreme degree o f phimosis rasulting in obstruction to urinary outflow is more imaginary than real and unnecessary circumcisions are advised. A similar feature is seen in adhesions of the labia in females. This also requires no t r e a t m e n t as they
disappear of their own accord. Associated anomalies The associatiotl of uinary tract malformations with abnormal pinna, eventration of the diaphragm and absent abdominal muscles, are other well d o c u m e n t e d associations. Unfortunately, the defects o f the urinary tract are more often of a severe nature leading to a poor prognosis.
