|Year : 2016 | Volume
| Issue : 3 | Page : 186-189
Unusual presentation of a rare case of posterior urethral valves in a nine-year-old boy
Suleiman Lawal1, Philip O Ibinaiye1, Ahmad T Lawal2, Muhammad I Zaria1, Joseph B Igashi1
1 Department of Radiology, Ahmadu Bello University Teaching Hospital, Zaria, Nigeria
2 Department of Urology, Ahmadu Bello University Teaching Hospital, Zaria, Nigeria
|Date of Web Publication||17-Mar-2017|
Department of Radiology, Ahmadu Bello University Teaching Hospital, Zaria
Source of Support: None, Conflict of Interest: None
Posterior urethral valves are tissue leaflets fanning distally from the prostatic urethra to the external urinary sphincter. It is the most common obstructive uropathy leading to childhood renal failure. It constitutes a clinical spectrum ranging from severe forms to milder forms. When obstruction can be overcome by detrusor contraction, it may remain silent until later life
Keywords: Delay, obstructive uropathy, pediatrics, posterior urethral valve
|How to cite this article:|
Lawal S, Ibinaiye PO, Lawal AT, Zaria MI, Igashi JB. Unusual presentation of a rare case of posterior urethral valves in a nine-year-old boy. Arch Int Surg 2016;6:186-9
|How to cite this URL:|
Lawal S, Ibinaiye PO, Lawal AT, Zaria MI, Igashi JB. Unusual presentation of a rare case of posterior urethral valves in a nine-year-old boy. Arch Int Surg [serial online] 2016 [cited 2019 Nov 15];6:186-9. Available from: http://www.archintsurg.org/text.asp?2016/6/3/186/202371
| Introduction|| |
Posterior urethral valves (PUV) are tissue leaflets fanning distally from the prostatic urethra to the external urinary sphincter. It is the most common cause of urinary outflow obstruction in pediatric patients and the most common obstructive uropathy leading to childhood renal failure. This pathology constitutes a clinical spectrum ranging from severe forms, with important repercussions on the upper urinary tract and renal function, to milder forms. When obstruction can be overcome by detrusor contraction, it may remain silent until later life. Posterior urethral valve is found exclusively in males with an incidence of approximately 1 in 5000. In 1919, Young et al. first described PUV, and until the 1960s, it was reported to have an extremely poor prognosis. When PUV is diagnosed postnatally, the symptoms are often age-dependent. In general, boys with a greater degree of urinary tract obstruction present earlier. Infants who are not diagnosed prenatally may present with infection, hydronephrosis, ascites, and/or thick and distended bladder. In severe cases, renal failure, congestive heart failure, and respiratory distress may occur. Patients with mild obstruction may escape ultrasonographic detection and diagnosis may be delayed until adolescence.
This case is being reported because of the rarity of the type (Type 3) of PUV reported and the relative preservation of renal function in this patient, despite the fact that this type has been reported to have the worst prognosis.
| Case Report|| |
I.F. is a 9-year-old boy who presented with a chronic history of difficulty with micturition, dysuria, feeling of incomplete voiding, right loin pain, and recurrent fever, which was being managed in a peripheral clinic. Physical examination revealed a calm and well-preserved boy; he was mildly febrile (38.1°C), anicteric, not pale, and well hydrated. Genitourinary system examination revealed mild tenderness over the suprapubic region and the right renal angle.
A provisional clinical diagnosis of recurrent urinary tract infection complicating posterior urethral valves was made.
Complete blood count showed normal hemoglobin level (11.2 mg%) and high total leucocyte count (11300/μl), with neutrophils accounting for 66%. Biochemical examination revealed normal blood urea, creatinine, and serum electrolytes. Ultrasound revealed normal kidneys [Figure 1], and a distended echorich urinary bladder with borderline wall thickness [Figure 2]. Micturating cystourethrography (MCUG) showed a constant linear transverse filling defect in the posterior urethra with associated mild dilatation of the posterior urethra without vesicoureteric reflux [Figure 3]. Radiological diagnosis of posterior urethral valve (type III) was made.
|Figure 1: Ultrasound image of the kidneys showing normal size, parenchymal echoes, and pelvicalyceal system|
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|Figure 2: Ultrasound image showing distended urinary bladder with echorich urine and a borderline wall thickness|
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|Figure 3: FA coned view of the urinary bladder and posterior urethra showing a persistent transverse filling defect in the posterior urethra (arrow) with mild pre and post-stenotic dilatation is noted|
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Valvotomy was performed for the patient with the aid of a valvotome. The urinary stream was satisfactory after the procedure. The catheter was removed and the patient was discharged in satisfactory conditions with proper follow-up advice after 7 days of the operation.
| Discussion|| |
PUV are the most common cause of lower urinary tract obstruction in pediatric patients and the most common obstructive uropathy leading to childhood renal failure. It is a part of the spectrum of obstructive congenital anomalies of the urinary tract. The urethral valves are tissue leaflets fanning distally from the prostatic urethra to the external urethral sphincter in 95% of the cases, with a slit-like opening usually separating the leaflets. Valves are of unclear embryological origin and may cause varying degrees of obstruction. Approximately 30% of the patients experience chronic renal insufficiency or end-stage renal disease. There are three main types; type I is the most common, representing folds extending from the verumontanum to the membranous urethra; type II has leaflets radiating from the verumontanum to the bladder neck proximally; and type III presents as concentric diaphragms within the prostatic urethra. The index patient has the type III variant, which is like a diaphragm appearing as a transverse filling defect at the prostatic urethra, which shows mild dilatation of the posterior urethra in the micturating cystourethrogram [Figure 3].
The presentation of PUV is variable, ranging from severe in-utero bilateral hydronephrosis caused by vesicoureteric reflux, which occurs in 50% of the patients, and oligohydramnios  to the mild delayed presentation of voiding dysfunction. Nocturnal enuresis, urinary frequency, and recurrent urinary tract infection  may also be present in mild long standing cases, as was noted in this index case. The prostatic urethra normally dilates (the mechanism behind the post-stenotic dilatation of the urethra is because of the pressure jets of the urine hitting the wall as it emerges from the narrowed orifice) and the bladder muscle undergoes hypertrophy, however, in this patient only mild prostatic urethral dilatation was noted and no significant urinary bladder changes were seen apart from low level echoes and a borderline wall thickness of 3.3 mm in a grossly distended bladder [Figure 2]; this could be the result of capacious opening within the diaphragm of the urethral valve, resulting in a lesser urine pressure jet.
The incidence of late-presentation in boys with PUV may be significantly higher than originally thought. Hendren  suggested that these cases may not be rare but just infrequently identified as symptoms are often mild, and the fact that very young pediatric patient cannot express themselves except in serious painful situations where excessive crying is spontaneous. This patient's symptoms have been mild and recurrent as he evolved, and hence, the subtle nature of the symptoms is the reason it was not detected earlier. If the obstruction is severe and remains unrecognized during the neonatal period, infants may present later in life with failure to thrive due to uremia or sepsis caused by infection in the obstructed urinary tract.
Ultrasonography helps in the diagnosis of PUV, especially in the complications such as hydroureteronephrosis and diverticular formation, however, this patient had normal upper renal tract scan parameters, including the renal parenchymal echogenicity and pelvicalyceal system, although the urinary bladder showed significant residual urine volume rich in echoes and a borderline wall thickness, which was suggestive of infection. This is surprising given the subsequent MCUG finding of a congenital obstructing posterior urethral membrane (COPUM), which represents the rarest type of PUV seen in approximately 5% of cases (Type III) and is also documented to have the worst prognosis with varying extent of renal dysplasia.
Urethrocystoscopy was not done to confirm this because of nonavailability of pediatric endourologic facilities in our centre. This would have also given first-hand information on postobstructive bladder changes, confirming the presence of pop-off pressure mechanisms, such as bladder diverticulum, which helps in the preservation of renal function in these patients. The extent of renal dysplasia is the single most important predictor of the residual renal function in these patients. Other important predictors of renal function in these patients are the presence or absence of obstructive uropathy due to persistently high bladder pressures, which are often associated with significant structural changes in the lower urinary tract. These significant USS changes were not noted in our patient, which may be due to a more capacious opening in the COPUM in this patient.
Urethrocystoscopy is considered to be the gold standard in confirming the diagnosis and in treatment, helping in direct endoscopic visualization of the urethral valves and their subsequent ablation by the urologist, as well as achieving the primary goal of nephron preservation. Other procedures such as vesicostomy or ureterostomy can also be justified in patients too small for endoscopic instrumentation, those who are too ill, and in some particular cases to improve renal function prognosis. Our hospital has no facility for endoscopic valve ablation therapy, and hence the use of a locally designed, simple valvotome to avulse the PUV in the index patient. The low creatinine concentration in the first year of life is the most appropriate predictor of future renal function. Although PUV has been known to be rare in older children, adolescents and especially the adults, diagnosing PUV in these groups is difficult; in view of these, we must consider the possibility of PUV during evaluation of older patients presenting with obstructive symptoms, especially by the urologist, during cystourethroscopy.
Fibrous bladder neck contracture occurred in 76% of adults, as documented by Mahony et al., and its incidence has been correlated with patients' age. Some investigators have suggested that high prostatic pressure leads to sclerosing prostatitis and often to gradual fibrosis of the bladder neck. Bladder neck incision is recommended in the case of persistent obstruction after resection of PUVs or during PUV resection in the case of severe bladder neck contracture in adult patients.
| Conclusion|| |
PUV has a wide range of clinical presentations, and a proper history taking is essential to reach a correct diagnosis. Therefore, when investigating an older child presenting with recurrent urinary tract symptoms, PUV should be considered among the differentials.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]