This talk from pediatric nephrologist Sanober Sadiq, MBBS, offers a deeper understanding of hydronephrosis, a condition affecting 1 in 100 pregnancies and ranging from an essentially benign problem that resolves on its own to one requiring surgical or other interventions. Sadiq covers possible causes of a swollen, non-draining kidney; systems used to classify hydronephrosis severity and how the grade impacts treatment decisions; imaging modalities from routine prenatal ultrasounds to nuclear medicine scans; antibiotic use; and which cases to refer as well as how to know whether urology or nephrology is the best choice.
Hi, everyone. Um Thanks Maria for the introduction. Um I'm Sanoba Sadiq. I'm one of the pediatric nephrologist that works at U CS F I do my satellite clinic in Fremont and in Monterey. And then I have also my clinics in Mission Bay. Um The topic that I'm going to talk about today is assessment and treatment of hydronephrosis. And the reason for doing this talk is firstly, um I know you guys see a bulk of patients who have hydronephrosis and it's also sort of a gray area as to who to refer to is should it be nephrology or urology? And so I just wanted to provide some education on that. And so I'm going to get started uh with the objectives. So, the objectives of my talk are I'm going to spend a few minutes on um renal development as to how the kidney is formed. Um and then review the incidence etiology and relevant findings for hydronephrosis. Um then delve into the classification system for hydronephrosis and lastly talk about the management guidelines. So renal development, it starts in the first trimester. Um around ninth to 10th week of gestation. It consists of pronephros, mesonephros and then metanephros and the pronephros, mesonephros they form and then involuted. And it's actually the metanephros that develops into the functional final kidney. And this is how it looks like um that the metanephros, it forms into the ric bird and then the metanephrogenic blastema and in turn, it forms into the um uh the, the ureter, the pelvis. Um and then the major Calix, the minor Calix um the collecting tubules, which includes both the proximal um the distal collecting tubules and then the loop of handling. So, as I mentioned before, um the first glomeruli or the, the kidney filter forms at about 9 to 10 weeks of gestation and then the development continues, but then there is an exponential increase in nephrons um between 18 and 32 weeks of gestation. And then the nephron development completes between 32 to 36 weeks of gestation. So that, that's why anyone born before 36 weeks of gestation, we can we think about them as having low Nephron mass, which puts them in uh at risk for complications which include uh being at more risk for um acute kidney injury or um having developing hypertension um or other kidney complications. So, secondly, I'm going to talk about the incident and etiology and then relevant findings for hydronephrosis. So, what is hydronephrosis? Um It is the dilation of the renal collecting system and it is most commonly diagnosed on antenatal ultrasounds. And um it's sort of, it's getting more, more routinely diagnosed now because everyone gets antenatal ultrasounds done. Um It can be benign or, or, or I would say I call it as transient or it can be associated with significant congenital abnormalities of the kidney or the urinary tract. And the incidence is one in 100 pregnancies or 1 to 5% of all pregnancies. Um The causes for um hydronephrosis. So the most common one is transient hydronephrosis and the incident being 41 to 88%. Um The second common cause is the urethral pelvic junction obstruction. Uh The incidence being 10 to 30% vesicoureteral reflux being the third common cause with incidence being 10 to 20% urethrovesical junction obstruction. The incidence being 5 to 10%. Multicystic dysplastic kidney. The incidence being 4 to 6% posture Toral valves, um which is one of the more um uh concerning uh reasons for hydronephrosis. But uh the incidence is low being 1 to 2% or urethrocele ectopic ureter duplex system and the incidence being 5 to 7%. So, transient hydronephrosis, it's um it's basically, it's seen on the antenatal ultrasounds. Um and there is history of renal pelvis or callis dilation and it is mostly related to narrowing of the urethral pelvic junction or there are just natural kings or physiologic kings that occur or folds that occur early in development. And usually for these patients. It's um it's getting a postnatal ultrasound when they are greater than 48 hours of age and then assessing about the hydronephrosis. Um what, what is the, what is the staging of hydronephrosis? At that time? In my experience, usually transient hydrone nephro just takes about approximately 1 to 2 years to resolve. But it, it, it is, it is not associated with any kidney injury. It is not associated with any urine infections. And as it is transient, it resolves on its own and basically just requires um serial um ultrasound screening. The second common cause of the urethral pelvic junction obstruction. So this is there is pelvic cal aal dilation present, but there is no ureter dilation present. And this is like the key mark uh for, for UPJ obstruction and it is commonly unilateral. Um and this is uh if, if these findings are present and they are highly suggestive of um UPJ obstruction. Um In most cases, it does not require any management, any surgical management, but surgical intervention may be needed in 32 to 50% of these cases. Um And in cases where no surgical intervention is needed, it's mostly about, you know, medical management monitoring them um ensuring that, you know, just educating patients about um urine uh urine tract infection prevention. Um And so this is how it goes. Um the third common cause for hydronephrosis is vesicoureteral reflux. So this is, as the name says, it's basically retrograde passage of urine from the bladder into the upper urinary tract system. And the management of this um is basically, it's just monitoring, antibiotic, prophylaxis and surgical correction as needed based on the uh based on the um uh the, the grading of the uh vaso urethral reflux. So this is what the classification looks like. So there is um grade 125. and this is uh the gold standard for diagnosing vesicoureteral reflux is voiding cystourethrogram. So this is how the grading is done on BC UG or voiding cystourethrogram. So grade one is that uh is reflux that is limited to ureter. So there is um no dilation present. It's just reflux that is going into the ureter. Um Grade two, it's reflux into renal pelvis, but without pelvic lal dilation present and then grade three is mild dilation of the ureter. So now the ureters look a little thickened and then there is also pelvic aal system dilation present as well. And then grade four is blunting of the FACS but preserve papillary impressions which are towards the periphery. Um And then the ureter is dilated moderately and then it also looks more tortuous, it's not straight anymore. And then grade five is loss of furnaces and papillary impressions. So now the the papillary impressions are not visible as they were before. And then there is severe dilation of the pelvic glacial system. The ureter is also more tortuous and then it's more severely dilated. So this is what the grade five looks like. I'm going to share another um uh slide uh with just how it looks like on the waiting system. Urethra gram or BC UG. So starting from the far left and going to the right. Um So this one is grade one. and then um on the same picture on the same picture A um the one on the right, that's grade two, moving to picture B so one on the left is grade three. Um And then the one on the right is grade four and then picture c shows how dilated it is and it's grade five, the prognosis of vesicoureteral reflux. So, uh and this is like one of the questions that parents always pose if their kid has vasal reflux. So grade one and two, the spontaneous resolution chances are pretty good. They are greater than 80% for grade three. It is 50 to 80% and then it slowly goes down with the grade. So grade four, it's 35% with grade five. It's less than 15%. Um This study which is also known um So vital reflux, I believe is one of the most um most uh that it's one of the topics that has been studied um a lot. Um And so the river study was done uh and River stands for randomized intervention for vasal reflux. So this was a very large multi center trial um double blinded um study um that was done in 607 Children to assess the effectiveness of using antibiotic, which was tri Merin sulfamethoxazole. Um And comparing them with placebo um in kids who had bur over a two, be over a two year follow up period. Um And what they found is that Children who received um the antibiotic or the trimethoprim sulfur metox azole were less likely to have recurrent febrile or symptomatic UTIs. Um What they also found is that Children with grade three or four, vesicoureteral reflux were more likely to have febrile or symptomatic ut I than those with grade one or two, which makes sense based on how um how dilated the urinary tract system becomes in grade three or four versus how it was in grade one or two. And then the uh the patients who received the antibiotic um compared with placebo. Um This was a significant finding, it did not reduce the incidence of renal scarring um uh in patients who received the antibiotic versus those who received the placebo. They also found that among Children with recurrent E coli ut I, um Bactrim actually was increasing the risk of Bactrim resistance and it was closer to 63 versus um just um 19%. And then the assessment by VCUG done at two year follow up and about 400 patients demonstrated resolution of reflux in 51% of patients. Um There was improvement in 23% of patients. There was no change in 19% of patients and then worsening of reflux was seen in 7% of cases. So, moving on to the fourth common cause, which is the urethrovesical junction obstruction. It's different from the ureter pelvic, which is basically blockage that happens at uh uh at the ureter and the renal pelvis level. This in contrast is a blockage which happens at the ureter and the bladder junction. Um And so basically blockage where ureter meets the bladder. And so it is associated with dilated ureter. Um And um uh of course, um it's put it put patients at risk for um urine urinary tract infections, um how it is diagnosed. So, basically, um anyone who had um uh prenatal hydronephrosis present and then in older kids, uh they can present with flank pain, stones or urine, urine tract infections, as I mentioned. Um it's usually we start off the work up uh with the ultrasound and then moving on to VCUG and then thinking about nuclear imaging or scans in, in like ma three or um thinking about MRI. Um the reasons for this is it can occur during development, as we mentioned, as I mentioned before, um one of the congenital causes, but there are other causes too, which include scar tissue, um, infection, polyps, stones itself can cause urethrovesical junction obstruction, which of course, um uh can happen. Um And so anyone who also present with stones, um that's, that's one of the reasons for getting ultrasound. And also thinking about is you know, uh is this the reason um uh for um it can, as it can cause both stone formation and then it can also cause uh it's one of the stones is one of the reasons for UVJ obstruction. Um And then most patients who are born with U AJ UBJ, they resolve over time and do not need any surgical correction. Um They do need to be followed to train creatinine and then assess um uh what their level of continence is. Um I will keep this one short because this is multicystic dysplastic kidney. So, um it is basically presence of noncommunicating cyst of various sizes and um and there is no um evidence of identifiable renal Perma. So, this is essentially a nonfunctioning kidney. Um and um it can be one of the reasons for causing hydronephrosis and then post urethral valves. So, as I mentioned before, the incidence of that is 1 to 2%. But it's, it's one of the more um serious causes for hydronephrosis that requires very, very close monitoring. So this is associated with um prenatal hydronephrosis. Um there is dilated, thick wall bladder and or ureter um and then dilated posterior urethra and then there is decreased amniotic fluid. So, some of the findings that are seen on the antenatal ultrasounds and it is basically caused by the membrane remnant in prosthetic urethra in males. Um it can cause um of course, just with the uh membrane remnant, it can cause lower urinary tract obstruction and which uh which can cau which of course carries worse prognosis um due to pulmonary hyperplasia and renal damage itself from having the decreased amniotic fluid. And so, um the survival for this. So the 10 year survival O I is iii I mean, it's over 90% in patients who are diagnosed with it in first year of life. Um And the important prognostic factor is what was the creatinine? Where did the creatinine made in first year of life? That tells us the most about what, how does the prognosis looks like in the long term? The complications of course, are there is concern for lower urinary tract function. Um So they um may need um to do long term cathing. Um 20 to 65% of patients will develop CKD um which could be from just having urine infections too. And then 8 to 21% will progress to end stage kidney disease. Usually for these patients, it's uh just about um they are, they make urine, they are poly uric. Uh But it's just that they just with uh with their kidneys being formed under so much pressure antenna. Um they are just not functioning good. So what? But so some of the reasons or one of the reasons I would say that we think about starting them dialysis or thinking about transplant is just because their kidneys. Um the creatinine uh is not good. The B UN is very high. So their kidneys are not functioning well. Um They are still filtering, ok. But it's the clearance thing that is not good. And so that's why they ultimately, if they, if they were to, they may require dialysis or transplant for that reason. So now moving on to the classification system for hydronephrosis. Um so this is an area that has changed a lot over time. So firstly, um in 1993 there was a society of Fetal Urology Classification. Um and then um they modified it. And so in 2010 came the society of fetal urology, um anterior posterior diameter system. And then in 2014, there was a urinary tract dilation system that came up. So I'm going to start off with talking about um the sfu grade system, which is the society of Fetal Urology grade system, which was in 1993. So over here, they graded it um from 1 to 4. Um and they looked at the appearance of calluses pelvis and then the thinning of the parent chema. So they started off with grade one with renal sinus with just with urine and then grade two filled pelvises will fill pelvis with dilated major calluses. And then grade three was uniform dilation of major and minor calluses. And then grade four was parental thinning. They did modify this system. Um just because um they were um I I it was still leading to um uh it, it was still uh it was a little misleading and it was not um uh helping in diagnosing all the cases uh of hydronephrosis. So, they modified in 2010 for society for Fetal Urology, a PD system which was the interior posterior diameter system. And over here, they were looking at the diameter of the renal pelvis. And then based on that, assessing what the, what the grading of the hydronephrosis would be. And so over here, they graded aid based on mild, moderate and severe and then second trimester and third trimester and so mild was uh on the second trimester four to less than seven millimeter. Um in the third trimester, seven to less than nine millimeter, moderate seven to less than equal to 10 millimeter in second trimester. And then in third trimester, nine to less than equal to 15 millimeter and then severe was greater than 10 millimeter. Um And then third trimester greater than 15 millimeter. And so the degree of um hydronephrosis uh based on this um grading system, the mild was 56.7 to 88. So most of the cases moderate was 10.2 to 29%. Um And then severe was 1.5 to 13.4%. And then lastly came this system, which is the Society for Fetal Urology UTD system, which most of the centers use now um including U CS F. Um And over what happened with this one is just because it, it was a combination of everything. So it included the things from the 2010 A PD system, the anterior, posterior diameter of the renal pelvis. Um And then it also included the anatomical markers which are present in the 1993 sap grading system. Um And so for this one, it was um it was implemented after um after providers from different societies sat down and then discussed that, you know, this is how the system should be including everything, the anatomical markers and then also looking at the diameter. And so these were some of the, so these were the societies or a societies that sat down and made this grading system. And so this one basically includes the interior posterior renal pelvis diameter and then um the cecal dilation which is the central and peripheral, the parental thickness, the parental appearance, um the ureter bladder and then if there was any unexplained oligohydramnios. So this is how it looks like the anterior posterior renal pelvis diameter. So either uh measuring it from um uh uh a as they as they're measuring in picture one or uh measuring it in picture two and then galaxy central is this one and then better, better flow. And this is how the report looks like. Um And it's usually towards the bottom of the report, it says UTD classification and this is how the radiologist um now grade it, it's still not present in all the imaging centers. Um But most of the imaging centers use this grading system now as I mentioned before. So these are just as just some of the um radiological imaging pictures and it mentioned. So the interior posterior renal pelvis diameter in picture A um they are sorry. Uh my apologies, there are a lot of picture BS over here but um this is how the central cal caliceal dilation looks like and then how the peripheral calico dilation looks like over here. Um Here, um there can be a, a cyst can be seen and there is also perent gal thinning present and then bladder wall thickness. This is the bladder in picture C so um dividing this up to antenatal hydronephrosis, UDD system and then there is postnatal hydronephrosis, UDD system. So the antenatal um uh hydronephrosis UTD system. So it's basically divided into um when was the ultrasound done? So, 16 to 27 weeks. So, looking at the anterior posterior renal pelvis diameter four to less than seven millimeter or if it's greater than equal to 28 weeks, then uh the anterior posterior renal pelvis diameter being seven to less than 10 millimeter. And then looking at if there is any central or there is no calico dilation present. So then this is UTD a one and this is low risk. Now moving on to um the yellow yellow boxes over here. So 16 to 27 weeks with the anterior posterior renal pelvis diameter being greater than equal to seven millimeter and then greater than equal to 28 weeks. Uh The anterior posterior renal pelvis diameter being greater than equal to 10 millimeters over here, if there is peripheral callico dilation present or pereny thickness, abnormality, pereny appearance abnormality, ureters, abnormal bladder abnormal, or if there is any unexplained oligohydramnios, then that's concerning and they are classified into increased risk category which is UTD A 2 to 3. And I'm going to talk about the management of this in the management guideline section. Now, um this is the postnatal presentations. So for the UTD system and over here, they classify it as based on um uh based on a again, the uh basically, the first thing that they look at is that the ultrasound should be done and greater than 48 hours of age and then the anterior posterior renal pelvis diameter. So if it's 10 to less than 15 millimeter with uh with central calico dilation present, then this is classified as low risk ultrasound. Again, then at greater than 48 hours of age with anterior posterior renal pelvis diameter, greater than equal to 15 millimeter with peripheral calico dilation present and then the ureters are abnormal. So then this is classified as intermediate risk and then greater than 48 hour ultrasound. Um interior postural pelvis diameter, greater than equal to 15 millimeter with peripheral callico dilation present, peren chim thickness abnormality noted or pereny appearance abnormal or ureters, abnormal or bladder, abnormal. So then that is classified as high risk. So, um in the antenatal, there are two, they put it as low risk. A one and then a two or a three are high risk. Over here, there are three categories. So UTDP one, UTDP two and then UTDP three. So um how reliable is this classification system since this was the, since so much effort and thoughts were put into this. So, um there uh it has been shown to have high agreements between writer and then substantial agreement within writers using the UTD classification system. The most discrepancy uh was uh was noted for interpretation of central and peripheral callico dilation. Um uh There was a discrepancy noted within that area and then the only other thing with this one was especially the UTDP three. since um it just fails to demonstrate the severity of hydronephrosis. And so, um and I'm just going to go back. So, you know, it just has a lot of components into it. And so um it sometimes uh can uh lead uh mislead from prompt treatment. So, uh it sometimes it's hard to, it's uh it can be a little hard to know just from this grading system as to who needs surgical treatment and who can safely be followed non operatively. Um But again, this classification system so far has been shown to be the most reliable. And so that's why it's still being followed upon. And again, if there is any confusion that is noted on the ultrasound, then we usually move on to getting other imaging done um including a VCUG or um thinking about um nuclear imaging um to find it out. But again, this is still one of the best screening tools and one of the best screening grading system for hydronephrosis. Um And so, lastly, moving on to the management guidelines for this. Um So, um as I said for the antenatal hydronephrosis, so, um the antenatal hydronephrosis was a UTD a one. it's low risk and um I'm just going to move a little back and this is what it was. So, um anyone with central or no calcium dilation, they were low risk. And so, moving back again over here, um they uh it's usually recommended to get another uh uh ultrasound at greater than equal to 32 weeks of gestation. And then after birth, they should get two additional ultrasounds. So, one is greater than 48 hours to one month uh within that time frame. And then the second one is 1 to 6 months later. Um And then the UTD A 2 to 3 which was the increased risk category. Um The prenatal period. Um Initially, it should be done in 4 to 6 weeks uh from the last ultrasound and then after birth, um they should have an ultrasound at greater than 48 hours to one month of age and again, um it depends on how s how concerning the ultras. The antenatal ultrasound was looking because if there was bladder thickness present or if there was unexplained oligo hyd or unexplained oligohydramnios or if the parent kyma uh uh was looking abnormal, then they should get an ultrasound earlier than 48 hours. Uh because it may indicate some something more concerning including post eal valves and may need more urgent intervention. And for these cases, usually, um uh they do require specialist consultation including um which does include nephrology or urology. And um um uh we uh for these patients, uh we also meet with the family and let them know about if you know, for example, this looks like this could be posture, then this may be, this is how things would look like once your baby is born, um there is chance for chronic kidney disease, there is chance for um um end stage kidney disease and we talk about dialysis transplant. Um and all those things too. And usually for these patients to um it is recommended that once they are born, they are started on antibiotics until they get the ultrasound done and other imaging done. But just because they are um at more risk for um any sort of infections. And then uh this is the um uh the management uh for the postnatal um hydronephrosis. So, uh for the UTDP one. So for this one, it was um um Yeah. So for this one, it was um the anterior posterior renal pelvis diameter being 10 to less than 15 millimeter um with central caliceal dilation present. And so this was low risk and coming back to this slide um over here, they do recommend follow up ultrasound at 1 to 6 months. Um in our practice, I mean, if they are born, um uh it, we do recommend that just getting an ultrasound um uh right before discharge because that is usually like when they are written in 48 hours of age and it's just easy versus calling them back and getting the ultrasound done. But again, the ultrasound follow up ultrasound for low risk, it can be done be between that time frame of 1 to 6 months. It does not need to be done urgently while even when they are admitted, it just, it's just um easier and more convenient for parents to get it, get it done when their newborn is still in house. Uh And, and it can be, and a as long as it's done greater than 48 hours of age, um it is usually accurate and reliable. Um Again, the cug antibiotics and functional scan are mo most like mo are not recommended unless there is worsening of hydronephrosis or um there is concern for um urine infections, then it is recommended um and then for UTDP too. So that is the intermediate risk. So I'm just going to go back um and look into this um slide. So, uh again, for this one, the anterior posterior renal pelvis diameter is greater than equal to 15 millimeter. And for these patients, the peripheral calico dilation is present and then the ureters are abnormal. So that puts them at intermediate risk. So for these ones, the what the guidelines suggest is that they should get an ultrasound done 1 to 3 months. And for these ones, maybe we do ask to get an ultrasound or suggest getting an ultrasound done while they are in house as long as it's greater than 48 hours of age. Um And then again, depending on what the ultrasound shows, deciding on if they need a VCUG. Um Does this look like a vesicoureteral reflux or um, it requires more information, um, antibiotics? Um Again, it depends, um, usually if the follow up ultrasound, um I mean, if it shows P two, most of the time we think about starting them on antibiotics. But, um, again, it's sort of a gray area and it depends on what does the ultrasound shows. For example, if the ultrasound does show that the ureters are abnormal, then we think about starting them on antibiotics, um, until we get the VCUG and then decide on, um, and then the functional scan, I think it depends a lot on um also what the, what the uh what the VCUG shows. Um and how the patient is doing. Uh We also think about getting just a, just a chemistry panel on them just to see what their kidney function looks like. And then deciding on if they need a functional scan or not. Or for example, if the uh ultrasound is showing the dilation, the VCUG is not showing any concern for obstruction. Then we're thinking about like if the functional scan, if there may be like an upper level obstruction that's present and that may be seen by um a functional scan more easily. Um And then lastly, the UTDP three, which is high risk, which includes all the components. So, uh firstly, um the um ante the anterior postural pelvis diameter being greater than equal to 15 millimeters with peripheral calico dilation present with pereny thickness, abnormality, parental appearance being abnormal ureters being abnormal or bladder being abnormal. So, they are high risk categories. And for these ones, it's usually recommended to get an ultrasound. Um again, you know, as I mentioned before, it's usually if it's very concerning then getting an ultrasound, less than 48 hours of age is recommended. And then uh based on that design on when should be the next ultrasound. Um for these patients, most of the time they end up getting yes, they get, they get a VCUG and then it is recommended that they get started on antibiotics. And then the functional scan can be decided on later, especially if the VCUG is um not showing something or are, you know, ju just need more information on how the the the both the kidneys are functioning. Um So then it is um recommended too. So again, um uh we recommend that ultrasound should be done greater than 48 hours of birth because um hydronephrosis could may not be detected due to extracellular fluid shifts that are present in newborns. And so, waiting until then, except for um cases where there is bilateral hydronephrosis, um associated with urethral dilation or there is a dilated bladder um or with a hydronephrotic nephrotic solitary kidney. So all more concerning and serious findings than getting an ultrasound done sooner. Um And then again, ut I prophylaxis may not be beneficial and low and intermediate risk and they are mostly reserved for high risk. So including poster urethral valves, if there is bilateral UBJ obstruction or if patients have giant hyper nephrosis. So basically having like a an interior posterior renal pelvis diameter greater than 15 millimeters. So that's why um I think over here um the, the P one and the P three are clear. I think the P two is a little bit of a gray area where you know, it does require more thinking about does this patient need to be on antibiotics or not? Um And you know, does this patient need more imaging or not? And then choice of antibiotics are usually um um amoxicillin for less than three months of age. So that's what usually the newborns end up being on and then try Merin sulfur metox azole or nitro for to and for greater than three months. Um circumcision has been shown to prevent UTIs in infants with hydronephrosis and there was this very big study done which did show that circumcision was associated with a significantly reduced risk of ut I. But this is an area still that is being studied upon. Um and there still needs to be large trials done on this. And so it is suggested, but again, it's not, it's not something that is mentioned to be recommended to families like sometimes and that's what when we recommend to families, some families are just like, oh we, but we heard that um you know, I think the the families have already done their um research on this too. So sometimes they are a little hesitant and they do say, oh, but you know, it's, it's, it's a little bit of a gray area again, like um again, it can, of course it prevent UTIs but um it's still something that needs to be studied more upon. And then um yeah, and then deciding based on that. But um yeah, this is a study that was done in Australia did show that uh it, it was associated with a significantly reduced risk of UT A and then moving on to the imaging modalities. So the renal ultrasound, it's one of the most um most best or, or one of the best screening. Um uh techniques because it does not require sedation. Um It's very easy to get done. Um It's inexpensive, but again, it provides limited information. Um, the VCUG, it can identify bladder outlet obstruction. Um But within, with this, of course, um, a catheter has to be inserted into the bladder, which for, um, which I have seen in my practice. Um, some families or especially moms are a little bit more hesitant. Um, just because it can cause a lot of discomfort to insert a bladder into the, insert a catheter into the bladder of a baby. Um And there is the risk for radiation exposure, but uh that's why it's a step going, step wise um is useful. Um because uh once a renal ultrasound is not giving it, it shows something but it's not exactly providing us with all the information and then talking to families and um they do then agree on getting the VCUG. Um also sometimes um at U CS F the ultrasound and the VCUG can be done together too. So that's something else that um that is helpful and convenient um for uh families too. And then there are these imaging modalities which includes nuclear medicine scan. So the the two most common ones that we use um are the mag three scan and the D MS A scan. So the mag three scan is, is the agent of choice for functional kidney imaging. It helps in knowing like how much each kidney is helping uh is contributing to the kidney function. So it should be 5050. Um And if there is, I think greater than equal to 5 to 10 point difference, then it can be concerning that. One of the kidneys is functioning less than the other one. It is helpful in detecting obstruction and then it helps in evaluating um kidney transplant allografts um after um kidney transplant and then D MS A scan is um it's good for evaluating renal cortex. Um looking for scarring or um looking um uh scarring just from the uh from scarring from kidney injury or scarring from urine tract infections. And then the last one is the magnetic resonance uro urography. So, um a at least for U CS F I can say we usually don't do this that often. Um I'm even not sure that if we do it at all. Um uh we usually um uh go with the uh the nuclear medic medicine scans that I talked about. But um it has been shown to provide more superior anatomical and functional information. Um It's just that it is um it does require contrast and uh anyone who has chronic kidney disease or if their GFR is less than um is less than 30. Um then the, the, the contrast it's which is the gadolinium. Um it can put them at risk for getting nephrogenic systemic fibrosis, which is a skin condition. Um And again, this uh contrast agent um it used to happen more uh with the older contrast agent and with the newer contrast agent, they have not seen it. But again, the risk is still present. Um And again, it requires sedation too. So, um, uh there, there is swirling technique and swelling technique does work with the babies. But again, if it doesn't, then it does require sedation, which is again, uh, you know, uh it's just a big, big thing, um to think about too. So, um this is actually my last slide. So, um I, I think this is one of the areas where everyone is. Ok. Should we refer them to urology versus nephrology? Um Referral to both the subspecialty simultaneously, of course, can cause duplication of work for both the provider and the patient. And so, uh that's why uh um I think that's why avoiding to do that is um uh is, is helpful. Um um um uh to just not refer to both subspecialties. Um I think patients uh who have uh severe bilateral hydronephrosis or they have hydronephrosis that is associated with urethral or bladder dilation. So, anything concerning? So anyone with P three, or high risk they should be referred to urology because there is this increased chance that they would require some surgical intervention and it's good for them to establish um care with urology for that reason. Um Also patients who have uh who are symptomatic uh and having recurrent UTIs um or um developing resistance um to antibiotics that they are getting um after having multiple recurrent UTIs, um they should also be referred to urology because there is a good chance, especially with, even with kids who have vesicoureteral reflux, like even if it's grade three, but they are getting a lot of urine infections. Um and then they are requiring um uh AAA use of a lot of antibiotics and that puts them at increased risk for resistance. Then they should be referred to urology and that is what we do in our practice too. Um Anyone who have had like 2 to 3 infections, um they should be referred to urology because there is a good chance that they would require some sort of surgery to correct that vasal reflux. Um anyone of course, who has hydronephrotic solitary kidneys. So they only have one kidney and if that also has dilation, that's concerning and may need to be corrected rather than just being monitored or watched, they should also be referred to urology um for patients who are uh referred to nephrology. Um So anyone with UTDP one or P two or anyone who had hydronephrosis and it could be just transient hydronephrosis, they can be followed by nephrology. Um And the only reason for seeing them outpatient is um uh getting ultrasounds done. Um or if they need any other imaging studies or assessing what their kidney function looks like, uh what the creatinine is looking like. Um um And so someone who can watch those things and it can, it can easily be done by us. Um And I mean, even for us, so the nephrology group. So anyone who has, um for example, if I start seeing a patient who has UT DB one and then it sort of worsens or they start having urine tract infections, then uh I, I can easily just refer them to urology too. Um So this is how it can also go. Um, and, uh, from my experience, what I have seen is that anyone who has severe bilateral hydronephrosis, um, as you know, we get the antenatal ultrasounds done, it's usually, it's usually seen. And so from that point to the neurology does get involved. And so, um, uh, they are already familiar with the patients too. So, um, I think those are, those are the things, uh, those are some of the reasons for thinking about referring them to urology or versus nephrology. Um, and so, um, yeah, so this is how I would go about with this, um, uh, the referring process.
