|Year : 2018 | Volume
| Issue : 2 | Page : 49-51
Challenge of congenital abnormalities of the kidney and urinary tract
Consultant Pediatric Nephrologist, Indraprastha Apollo Hospitals, New Delhi, India
|Date of Web Publication||27-Dec-2018|
R N Srivastava
Indraprastha Apollo Hospitals, New Delhi - 110 074
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Srivastava R N. Challenge of congenital abnormalities of the kidney and urinary tract. Asian J Pediatr Nephrol 2018;1:49-51
An increasing recognition of congenital abnormalities of the kidney and urinary tract (CAKUT) has led to challenges in their diagnostic evaluation and management. Antenatal ultrasonography is now widely available, and experts in fetal medicine can suspect and detect the presence of various anomalies. They, along with obstetricians and pediatric nephrologists, need to follow the events until delivery. Thereafter, the nephrologists along with urologists and imaging specialists jointly take over the management. CAKUT may be responsible for 34%–59% of chronic kidney disease (CKD).
| Prevalence of Congenital Abnormalities of the Kidney and Urinary Tract|| |
CAKUT comprise a variety of disorders. Antenatal suspicion of abnormalities and their subsequent confirmation has, to some extent, defined their incidence. CAKUT are present in 1%–3% of live births and cause neonatal death in 1 of 2000 births. Some isolated conditions are relatively common; those that are a component of a syndrome are rare. The former include anomalies such as pelviureteric junction obstruction, posterior urethral valve, ureterovesical junction obstruction, polycystic kidney disease, and anomalies of structure and location. CAKUT occurring as part of a syndrome are occasionally serious, but more often other syndromic abnormalities (as in Down syndrome and Turner syndrome) predominate.
As the majority of renal diseases are being satisfactorily managed, the clinical workload of CAKUT has increased at most tertiary centers. The incidence of postinfectious acute glomerulonephritis has decreased in most countries, and a large proportion of children with idiopathic nephrotic syndrome can be adequately treated until permanent remission. Acute kidney injury can be prevented or properly managed until recovery. Children with CAKUT present increasing workload at referral centers. The diagnostic evaluation of CAKUT involves imaging expertise and various modalities that entail considerable time and expenses. Urgent surgical procedures are required for obstructive lesions. Bilateral, severe abnormalities may lead to early CKD, which needs appropriate management with attention to growth and development. Eventually, renal replacement therapy is necessary, which presents serious difficulties in countries with low resources. Infants and children with CKD requiring renal replacement therapy constitute ~5% of all end-stage renal failure, but require greater time and resources for their management.,
| Etiology of Congenital Abnormalities of the Kidney and Urinary Tract|| |
The development of kidney and urinary tract is complex involving precise nephrourogenic programming and timely expression of multiple genes. Crucial developmental events such as obliteration of ureteric duct and its subsequent recanalization occur between 14 and 22 weeks of intrauterine life. Failure of development of ureteric bud results in renal agenesis and that of its recanalization causes obstruction. Factors adversely affecting renal embryogenesis are not well understood.
A large number of genetic abnormalities have been reported in various isolated CAKUT and in those associated with syndromes. Only few of these have distinct relationships, e.g., in polycystic kidney disease., They help in genetic counseling, but seldom influence the treatment and outcome.
| Patterns of Congenital Abnormalities of the Kidney and Urinary Tract|| |
Abnormalities of kidney include those of number, size, ascent, rotation, duplication, ectopia, fusion, combinations of these, and cystic disorders. These can be unilateral or bilateral. Common anomalies include pelviureteric junction and ureterovesical junction obstruction, vesicoureteric reflux, megaureter, ureterocele, and posterior urethral valves. Their severity varies considerably. While patients with posterior urethral valves require prompt surgical intervention, others require careful evaluation and continued observation. Several anomalies are asymptomatic and incidentally detected while being investigated for a urinary tract infection or an unrelated complaint.
| Diagnostic Evaluation|| |
Important developments have taken place in prenatal imaging including fetal magnetic resonance imaging and Doppler analysis. Proteomics of urine and amniotic fluid have been studied to determine prognostic biomarkers of prenatal renal injury. High resolution ultrasonography identifies various structural abnormalities with clarity, and serial estimation of the amniotic fluid index helps the obstetrician to decide about conducting preterm delivery. Ultrasonography, magnetic resonance imaging, and nuclear imaging are crucial in diagnosis and subsequent observation. Noninvasive urodynamic studies including uroflow and postvoid residual measurement are often sufficient to evaluate the function of lower urinary tract. Invasive urodynamic examination is required in complex situations. These studies have led to better understanding of abnormal bladder function and detrusor sphincter dyssynergia. Combinations of hyper- or hypoactivity of detrusor and urethral sphincter have been observed in spinal dysraphism that result in obstruction or incontinence.
| Management|| |
Pediatric urology centers are few in developing countries, which restrict optimal management of CAKUT. Obstructive and bilateral abnormalities need to be treated expeditiously and adequately. Patients with posterior urethral valves require prompt intervention. The treatment of pelviureteric junction obstruction is standardized with a period of observation in most cases. Obstructive megaureter can be treated with endoscopic balloon dilatation and double-J stenting. Laparoscopic and robotic methods are being used at few centers and further refinements and training of operators would make them more widely available. Adequate bowel care is essential for satisfactory management of neuropathic bladder and detrusor sphincter dyssynergia. Early use of clean intermittent catheterization and adequate bowel management are crucial. Anticholinergic agents (oxybutynin) and intravesical administration of botulinum toxin are effective in managing detrusor overactivity.
Over the past several years, attempts have been made to carry out fetal intervention in lower urinary tract obstruction. Serial vesicocentesis are performed and urine examined to look at markers of decreasing renal function. Vesicoamniotic drainage can relieve back pressure and progressive renal damage. The procedure, however, carries serious hazards and is presently considered an investigative modality.
Chronic kidney disease
In a majority of cases, severe bilateral abnormalities lead to CKD, eventually requiring renal replacement therapy. Obstruction due to posterior urethral valves, even when treated within the first few days, may still lead to CKD. Intrauterine obstruction leads to various degrees of renal dysgenesis, which cannot be reversed. During the first 2 years, renal function may decline gradually and the infant may appear relatively well. The management of CKD in infants and early childhood is one of the greatest challenges to the pediatric nephrologist. It is stressful to the family and the treating medical team and presents difficult ethical dilemmas. Multidisciplinary, intensive management is necessary to optimize growth. The dietitian has a crucial role to ensure adequate intake of various nutrients, vitamins, and minerals. Clear explanation and interaction with the parents are necessary. Standard medical treatment for CKD, including necessary vaccinations, is carried out. Anemia, bone mineral disease, hypertension, and associated infections are appropriately treated.
Renal replacement therapy
Despite optimal management, most patients ultimately require dialysis and renal transplantation. Chronic ambulatory peritoneal dialysis and hemodialysis provide temporary options. Renal transplantation in infants and young children presents serious difficulties. The outcome and potential for long-term survival should be discussed with family. Few centers can undertake real transplantation in small children. Moreover, socioeconomic conditions and donor issues often preclude renal transplantation.,
| the Challenge|| |
Most CAKUT cannot be prevented. Although the causality of maternal diabetes, infections, and multiple drugs has not been clarified, these can be addressed. Medications should be used with utmost caution. CAKUT should be promptly detected and expertly managed. Necessary, multidisciplinary expertise should be established at leading referral centers. Pediatric nephrologists need to have some expertise of medical urology and closely interact with their surgical counterparts. The challenge is greatest with the management of CKD and providing renal replacement therapy for young children. Constraints in treatment should be understood and clearly explained to the family and their decisions concerning long-term care respected.
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