Guido Filler

Before I answer, we have to be clear that you mean a kidney infection and not a bladder infection. Kidney infections typically come with a fever because about 25% of the circulating blood is in the kidneys. A urinary tract infection with fever is typically in the kidneys and is called a pyelonephritis. Many of kidney infections are caused by bacteria and need antibiotics. Your doctor will get a urine sample for a urinalysis and for a urine culture to determine what is the best antibiotic. Your doctor may also choose to get some blood tests to make sure that your kidney function is not compromised and to get a blood culture and some tests to make sure that the infection has not gone into your blood. The urine culture takes 24-48 hours. In the meantime, your doctor needs to treat the infection without knowing what bacteria caused it. This will be based on epidemiological data and your past medical history. If you have a chronic bladder problem like with spina bifida and had multiple infections before, it may have to be a very strong antibiotic to be given intravenously because the bacteria may be resistant to the commonly used antibiotics. The prescription may change once the culture and the sensitivities are available. You will need a doctors prescription for this. There are no natural remedies that eradicate the bacteria from your kidneys. Also, the longer it is untreated, the higher the risk for scaring and losing a lot of your kidney filters, which cannot be made new after 34-36 weeks of gestation. Occasionally, the infection can be by other organisms such as yeasts, especially when long-term antibiotics were used. Very rarely, some atypical pathogens such as tuberculosis can cause a kidney infection. The treatment would be specific to the pathogen and the sensitivities of the pathogen. Hope this helps. Don't consider alternative medicine for a true pyelonephritis. Guido Filler, MD, PhD, FRCPC Professor of Paediatrics, Medicine, and Pathology&Laboratory Medicine Western University Children's Hospital, London Health Sciences Centre

I am currently on my annual leave. I will have limited access to the internet and the reply may have to wait until after my return.

Kidney biopsies are prone to bleeding because 25% of the cardiac output goes to the kidneys. They are really well perfused. While a small bleed cannot be avoided, it is of utmost importance to make the procedure as safe as possible. Before the biopsy, blood tests will be performed to guarantee that there is no increased risk of bleeding. The time at the hospital after a kidney biopsy varies by institution and methodology. I can only comment on the procedure for children and adolescents. In our institution, we perform kidney biopsies as a one-day stay procedure. Two of the paediatric nephrologists had extensive training in the procedure. We use a real-time ultrasound-guided approach, which allows us to go to the lower pole of the left kidney and get 2-3 passes at the lowest part of the kidney, which reduces bleeding. We do the procedure under full anaesthesia and in the case of infants, with intubation, to allow for a controlled stop of breathing for a few seconds when performing the biopsy. This approach leads to minimal bleeding. Patients then recover and remain prone for 4 hours. A repeat renal ultrasound assesses for additional bleeding after that time, since most of the bleeds occur within the first few hours. Usually, there is no worsening. Typically, patients are discharged after they had a meal after the ultrasound. Patients who live more than 2 hours away are asked to remain close to the hospital at the Ronald McDonald House so that they can be reassessed in case of any problem.
In other institutions, the procedure may be different, depending on local resources, the technique used, and the risk profile of the patient. Each institution has to decide what is safest for the patient. It may also vary on the acuity of the reason for a kidney biopsy. An acute kidney injury leading to rapid deterioration of kidney function may require a kidney biopsy and obviously, you would be an inpatient in that case. Hope this helps.

Dear Concerned Mother,

This obviously must be very disturbing for you. Hypertension (also known as high blood pressure) used to be a disease of older folks in their fourties and up and often this is associated with life style. However, there are some genetic dispositions and there are some important issues such as coarctation of the aorta or a renal artery stenosis and many other issues that may cause high blood pressure at a young age.

The first order of the day is to verify that your child does not have white coat hypertension. White coat hypertension is a condition where your office blood pressure is elevated, but in fact, you do not have high blood pressure. This test involves a small programmable monitor attached to a proper size cuff which measures the blood pressure in the outpatient setting at school and at home over 24 hours. Measurements are done every 15 minutes during the day and every 30 minutes at night. This test is the gold standard for the diagnosis of hypertension. If the blood pressure load (values above the 95th percentile for the daytime and the sleep time) is over 40%, then you diagnose hypertension. If your doctor performed ambulatory blood pressure monitoring and this confirmed high blood pressure, then the diagnosis is probably real. If not, I would strongly recommend that you are referred to either a pediatric cardiologist or a pediatric nephrologist for assessment. There is no need to treat white coat hypertension. Your cardiologist or nephrologist may also examine the back of the eye of your child to look for changes due to long-standing high blood pressure and may ask for an ultrasound of the heart to look for thickening of the heart muscle. If any of these are abnormal, the high blood pressure may have been there for some time.

There are many reasons for high blood pressure. Whereas in overweight older folks this is most commonly "essential" hypertension, children have a long list of reasons, which have to be evaluated by a trained specialist. Most often, this is a pediatric nephrologist.

The most common reason today is obesity. There is a clear relationship between the blood pressure and the body mass index, which is a measure of the body composition. Treatment of obesity may help to ameliorate the high blood pressure, but this is not easy.

Another reason is salt (chemical name: sodium chloride). In the 1970s, children ate as little as 700 mg of sodium per day and today it is as high as 3700 mg per day. Nobody needs more than 2000 mg of sodium per day, which is one flush tablespoon of salt. Eating less than that is very difficult because 80% of the salt comes from processed food. The only way to get to a decent amount of salt per day is to cook everything from scratch with little or no salt. Eating out and purchasing prepared processed food makes it impossible to eat less than 2000 mg of sodium per day. Cheese, cold cuts and even bread (because we eat so much of it) are a major source of salt intake. The food industry adds a lot of salt to food to improve the shelf life.

Yet another reason is high fructose corn syrup, which is in all pop and sodas and also in many prepared foods. High fructose corn syrup is made from corn syrup, which is treated with an enzyme that converts glucose to fructose to make a consistent very sweet syrup that used to be cheaper than sugar. Fructose is a sugar with 5 C-atoms, whereas glucose has 6. Fructose can be converted to glucose (the sugar that feeds our brains) in the body, but only when fasting or when the glycogen stores in the liver are empty. Nobody fasts any more, and therefore the fructose goes into the beta oxidation and is immediately stored as fat. Moreover, fructose consumption raises the level of uric acid in the blood. This is bad as it can raise the blood pressure. I now check uric acid levels in every child with high blood pressure and often find it elevated. A doctor from Birmingham, AB, treated children with high uric acid levels and high blood pressure with a medication that lowers uric acid levels and normalized the blood pressure. There is no need to consume high fructose corn syrup (also called HFCS 55 and HFCS 44). HFCS 55 isi in all sodas, even though sugar is cheaper nowadays than HFCS 55. My advice is to read food labels and to avoid any food that contains high fructose corn syrup.

There are many other reasons. Some of these are weird and wonderful, for instance, some folks cannot tolerate black licorice. I would recommend that a specialist such as a pediatric nephrologist is consulted to work this up. Certain conditions such as coarctation of the aorta (a narrowing of the main blood vessel coming from the heart) or a narrowing in the arteries of the kidney can be treated and the high blood pressure problem can be cured.

I am hoping that your boy just has white coat hypertension, but please have this checked out thoroughly. High blood pressure is a silent killer. If left undiagnosed and untreated, this can lead to serious consequences including heart attacks, strokes, dementia and a short life expectancy.

Kind regards,

Guido Filler, MD, PhD, FRCPC

Dear concerned brother,


Kidney filter units are only made until 4 weeks before birth in babies that are born at term. Like other branching organs such as the pancreas and the lungs, kidney filter units cannot be made after that. Not everyone has 600,000 filter units in each kidney at birth. Genetic factors and factors of the environment such as famine and possibly obesity may result in a lower number of filters. A blockage of the kidneys can also lead to a reduced number of filter units. During life, we slowly lose kidney filter units. This may be one of the reasons why (wo)man cannot live more than 120 years. A famine during the 2nd or 3rd trimester of the pregnancy such as the Dutch famine 1944/1945 can lead to a smaller number of filters and an increased risk of high blood pressure, heart attacks and strokes in the offspring, as shown by Barker.

If we have a lower number of filters, we generally live less long. However, life style plays a huge role. For instance, in Norway, where most kidney transplants are done from living donors, the life expectancy of the kidney donors is actually longer than that of the general population because the healthiest people are selected as donors and there is a very healthy life style in Norway. Avoiding overweight or obesity, a sedentary life style and healthy diet that consists mostly of vegetables are known to slow the loss of kidney filter units. Moreover, there are medications such as angiotensin converting enzyme inhibitors and angiotensin II receptor antagonists that can help to slow the decline of the remaining kidney filter units by blocking the kidney filter units from overworking. Strict blood pressure control also helps. A nephrologist can help guide such therapies.

From your question it sounds as if you are an older brother who is worried about your younger sibling having only one kidney. If that kidney is completely healthy, your brother can be fine, although his blood pressure and protein in the urine should be monitored. It appears that the legacy of losing a kidney in early life is worse than when donating a kidney as an adult, however, the statistics are based on no intervention. If that other kidney is also stressed, then the answer to your question is that one should be concerned. Nonetheless, you can control lifestyle and diet and you can take your brother to a pediatric nephrologist who can guide you about the most appropriate interventions.

Hope this helps,

Guido Filler, MD, PhD, FRCPC

I am sorry to hear this, as passing kidney stones is considered extremely painful. You need to go to the nearest emergency room. They will do an ultrasound, possibly also an x-ray and/or a CT scan. The diagnosis of kidney stones requires imaging. Whether or not the stone can pass by itself depends on its size. In the emergency room, they can give certain medications that may help to pass the stone. Certainly, effective pain control should be considered. If your child has a fever or only one kidney or decreased kidney function, the child may have to be admitted. The urine should be strained so that the stone can be analyzed. In a small proportion of cases, the stone cannot pass spontaneously and procedures are required to help. There are several options depending on where the stone is and how big it is. Often, a pediatric urologist and a pediatric interventional radiologist may be involved. You will also likely get a referral to a pediatric nephrologist. The role of the nephrologist is to determine if anything in the urine composition can be modified to reduce the risk of more stones. Unfortunately, 50% of patients have another stone within a year. Kidney stones are a chronic disease with a risk of developing chronic kidney disease. We are noticing a dramatic increase of kidney stones in children and adolescents, especially adolescents. This disease used to be a disease of elderly men but much of the increase of the incidence of kidney stones in the pediatric realm is seen in adolescent girls. The incidence seems to be doubling every 5-10 years, depending on your region. We often don't find any genetic cause. We used to see calcium wasting as the most frequent reason, but now insufficient urinary citrate has become the most frequent reason, together with a poor diet that is high in salt, animal protein, and very low in vegetables. That diet leads to a high acid load and low urinary pH. The high salt intake leads to calcium wasting, and the lack of citrate leads to calcium in the urine that can precipitate (make crystals) with other salts. We often treat with potassium citrate supplements or with lemon juice which is a natural source of citrate. We ask the patients to drink lots of water to dilute the urine, and we sometimes give them medication. With good management, new stones can be avoided in most patients. But for now, please seek immediate medical attention.

Guido Filler, MD, PhD, FRCPC

Dear worried family,

The diagnosis of kidney disease may be quite challenging. One may lose up to 80% of kidney function with only very minimal symptoms. The need to drink and pee at night and large water intake may be the only symptoms for years. Fatigue is actually a late symptom. I would seek the attention of your GP or pediatrician. A blood test and a urine test should be done. The most helpful tests in urine would a urinalysis and a microalbumin/creatinine ratio. Especially if protein was found in the urine, this would be concerning and needs to be studied further. For the blood tests, extended electrolytes including a bicarbonate, calcium, magnesium and phosphate level, urea, creatinine and full blood count should be considered. Again, abnormal findings warrant further workup and possibly a referral to a pediatric nephrologist. Unfortunately, you did not specify what exactly the symptoms are, but urinary crystals or kidney stones are also to be considered, and a kidney ultrasound would be helpful.

Kind regards,

Guido Filler, MD, PhD, FRCPC

A burning sensation in the penis during voiding urine can be a sign of a urinary tract infection and should definitely be ruled out. A urinary dipstick will help, especially if there are nitrates and white blood cells in the urine. If there is blood, then it is not necessarily a urinary tract infection. A urine culture would confirm a urinary tract infection.

It would be a bit unusual though for a 13-year old to have all of a sudden urinary tract infections. There may be other causes.

Men may experience painful urination due to prostatitis. This condition is the inflammation of the prostate gland. It’s a primary cause of urinary burning, stinging, and discomfort. This would be unlikely at this age. Excessive masturbation can also cause such symptoms.

You may also experience pain when urinating if you have a sexually transmitted infection (STI). Some STIs that may cause painful urination include genital herpes, gonorrhea, and chlamydia. It’s important to be screened for these infections, especially because they don't always have symptoms.

Certain sexual practices will put you at a higher risk for sexually transmitted infections (STIs), such as having sex without a condom, or sex with multiple partners. Anyone who is sexually active should get tested for STIs. Unfortunately our youth is getting younger and younger with sexual experiences.

I have a different suspicion though. Owing to our high salt intake, we are seeing so many adolescents now with kidney stones or urinary crystals. To make matters worse, children and adolescents eat a high salt, high protein and no vegetable diet. The high salt load requires that the kidneys excrete more salt as the salt level in the blood must remain constant. Delivery of a lot sodium in the urine leads to calcium wasting, which unfortunately can easily form crystals and stones. I would be curious if the symptoms occur at the end of the void. The high protein diet and the lack of vegetables leads to a high acid load which worsens the likelihood to make crystals in the urine. Urinary calcium can precipitate with weak acids when the urine pH is low. Ask for the urine pH when you have your son tested. Ideally, it should be 7.0-7.5, but we see so many children now with a urine pH of 5.0. There is unfortunately a direct linear relationship between urinary sodium and urinary calcium excretion. Lastly, the lack of vegetables (we should eat 5-7 servings of vegetables per day) leads to a lack of citrate. If there is not enough urinary citrate to envelop the calcium, urinary crystals can develop. We are now seeing this more often than a high urinary calcium/creatinine ratio. If the diet of your son is like that of most, you can try giving him 2 table spoons full of lemon juice three times daily. Lemon juice is an excellent source of citrate.

Also, ask for the specific gravity in the urine. So many of our youth are not drinking the recommended 2 litres of water per day. Instead, they drink sugary beverages which contain high fructose corn starch syrup, mostly HFCS 55. The reason is that this is 99% of the sweetness of sugar but used to be much cheaper. Unfortunately, this is not good. As our youth never fasts, and the liver glycogen storages are usually full, this goes right into the beta oxidation and into fat cells. Through a complicated mechanism, this leads to high uric acid, the stuff that can give you gout. To much uric acid in the urine can the be caused by those sugary drinks, which again may give rise to the formation of crystals. This should also be evaluated.

Hope this helps!

Unfortunately, high blood pressure is no longer a disease of older people. Owing to lifestyle choices and high salt intake, the age of onset of the most common form of high blood pressure, also known as primary hypertension, is decreasing. We witness an unprecedented increase among children and adolescents.
First and foremost, and before worrying about causes and treatment, it should be shown that your daughter truly has high blood pressure. We are aware of a condition called white coat hypertension, which just means that your blood pressure may be high when you see a doctor. This is no true hypertension but rather a response to the sometimes anxiety provoking situation in a doctor's office and does not need any treatment. The diagnosis of white coat hypertension is made by 24-hour ambulatory blood pressure monitoring (ABPM). Unfortunately, this test is not widely available and a referral to a paediatric nephrologist may be necessary. Moreover, at least in most provinces of Canada, the government does not reimburse ABPM and sometimes physicians charge about $80 per test. This is unfortunate, however, it is really important to identify this condition as white coat hypertension can only be identified with this test and unnecessary treatment can be avoided.
The test is done through a device that measures the blood pressure every 15 minutes during the awake time and every 30 minutes during sleep and records this information which can later be downloaded into a computer. Based on gender and height specific reference intervals, the nephrologist or cardiologist interpreting the test can determine how much of the blood pressure is over the wake and sleep limits. The proportion of blood pressure over the limit is called blood pressure load. If more than 40% of the measurements are over the limits, there probably is hypertension. An ultrasound of the heart and an eye exam should follow to look for end-organ damage. If there is thickening of the left chamber of the heart or hypertension changes in the background of the eyes, the high blood pressure has likely existed for months. In those cases, treatment is indicated as high blood pressure is a silent killer which may lead to heart attacks and strokes and shorter life expectancy.
High blood pressure can occur at all ages, even in newborn, but it is rare in children compared to adults over the age of 40. In adults, most of the hypertension is lifestyle associated, especially due to the sugary drinks and high salt intake as well as obesity. In children and adolescents, a full workup is required. There are many different reasons and the workup may involve a cardiologist and a nephrologist. Narrowing in the aortic arch is one possible reason, or narrowing in the blood vessels of the kidney. It would be beyond the scope of this website to list all reasons, but some are weird and wonderful such as high blood pressure caused by black liquorice. In very few individuals with certain genetic conditions, consumption of liquorice can lead to dangerously high blood pressure and dangerously low potassium levels. (hypokalemia). However, all these rare conditions are not increasing, whereas the lifestyle associated high blood pressure now is seen more and more often in adolescents and even in younger children. Your cardiologist or nephrologist will choose lifestyle intervention and appropriate medications depending on the cause of the hypertension. Sometimes dietary changes, weight loss and exercise may suffice. It also depends on the severity of the elevated blood pressure or the stage of hypertension. I trust that your paediatrician has made the appropriate referrals to work up the high blood pressure of your daughter.

Kidney stones are extremely painful. Some say it is more painful than child birth when they pass. As such, it would have to be general anaesthesia.

Kind regards,

Guido Filler, MD, PhD, FRCPC

Dear parent,

I am sorry to hear about your friend's son. You must be rather frustrated to find out about chronic kidney disease (CKD) late in the course of a disease. Of course, this really limits opportunities to slow progression of CKD. Unfortunately, this is not at all uncommon. It depends a bit about the underlying reason for CKD. You may lose more than 80% of kidney function before symptoms may become obvious. This is especially true for some slowly progressive disorders such as nephronophthisis, where sometimes the only symptom may be increased thirst and the need to pee at night a couple of times. The changes are very slow and the body may compensate for a long time. It is different if the disease that leads to CKD produces a lot of symptoms, but cases of renal dysplasia, oligomeganephronia, nephronophthisis and other diseases may progress so slowly and silently that some patients present when it is all too late.

Kind regards,

Guido Filler, MD, PhD, FRCPC

There is not a simple and straight forward answer to your question. More details would be helpful. First and foremost: Dialysis is only a bridging therapy. Every child with end-stage chronic kidney disease should have a functioning kidney transplant. We sometimes are able to transplant the children without the need for dialysis, but this may be impossible in the case you are referring to.

In your note, it states that the child has congenital nephrotic syndrome. These children typically require the surgical removal of both kidneys prior to transplantation and several weeks of dialysis. The reason is that due to the losses of protein in the urine the entire blood proteins are deranged and this is associated with a high risk for clotting the transplant. It may take 1-2 months before the protein levels in the blood are restored.

There is a choice between two types of dialysis: hemodialysis and peritoneal dialysis. The former is typically done in centre and requires frequent visits to the hospital. You need to have access to clean the blood, for instance, through a central venous line, or an arteriovenous fistula. Peritoneal dialysis in children can be done at home. As most children have a very fast transport of solutes through the lining of the abdomen, they can typically dialyze with a machine overnight for perhaps 8-10 hours using physiological solutions such as Physioneal. This treatment is not painful, does not require accessing the blood system, and allows to go to school. Peritoneal dialysis is the preferred form of dialysis in children, but not every child can do it and it is demanding on the parents.

Best regards,

Guido Filler, MD, PhD, FRCPC

Dear Concerned Parent:

I understand that you are worried. A decrease in urine output is the most visible sign of acute kidney injury (AKI) in all age groups, particularly younger children. Oliguria occurs when the urine output in an infant is less than 0.5 mL/kg per hour for 24 hours or is less than 500 mL/1.73 m2 per day in older children. Anuria is defined as absence of any urine output.

However, the first thing is to determine whether it is real. Sometimes children hold their urine. It has happened several times that a parent brought the child to the emergency room for decreased urine output, and then the child had a large void while in the emergency room. The most common reason for decreased urine output is dehydration. Dehydration takes place when your body loses more fluid than you drink. The most common cause of water loss from the body is excessive sweating. There are numerous other reasons why you can dehydrated. These include fever (which increases insensible losses), diarrhea, vomiting, a stomach flu, food poisoning, and rarer conditions. There are a number of other conditions that can cause an AKI. These can only be identified with additional tests.

If you are really worried, I would recommend that you consult a physician.

Kind regards,

Guido Filler, MD, PhD, FRCPC

Dear Concerned Parent,

Kidney transplantation is the therapy of choice for end-stage chronic kidney disease (also known as end-stage renal failure). A successful renal transplant offers the best metabolic control, the lowest long-term cardiovascular risk, the best longevity, and a better quality of life despite the need for life-long immunosuppression. It is also the cheapest treatment, even though this should not be a factor.
After transplantation, the child will go from the operating room to the paediatric critical care unit for a couple of days. Physicians may push the fluids to maintain high urine output, which improves the monitoring of the kidney function after transplantation. The team will frequently assess the electrolytes and other factors in the blood to make sure that the transplant will work well. You son will have to take antirejection drugs, which may be highly variable from person to person, and may need a lot of adjustments. There will also be repeated imaging of the transplant. Another potential problem is related to viral illnesses that the donor may have had and your son may not yet have acquired, such as cytomegalovirus and the virus that causes mononucleosis (also known as mono). Prophylaxis against pneumocystis pneumonia infection is also needed, possibly life long. It may be necessary to give prophylactic medications. Rarely the transplant may be slow with picking up function, and the patient may have to continue on dialysis for a while.
Once the patient is more stable, he will return to a regular ward and should be discharged soon thereafter. It is not unusual to have high blood pressure after the transplantation. There may be 3 antirejection medications (typically tacrolimus, mycophenolate mofetil and corticosteroids), infection prophylaxis, blood pressure medications and others. It is not uncommon that a magnesium supplement is needed as tacrolimus can induce magnesium wasting. This usually gets better.
After the discharge home, you will have to come to the hospital frequently to check kidney function and medication levels. Due to a lot of drug interactions especially with tacrolimus, this is of high importance. You may be asked to avoid any grapefruit juice. In some cases, there may also be urinary tract infections. All of this is done to prevent acute rejection of the transplant and to minimize infectious complications.
Over time, the frequency of these visits will drop as the issues diminish. In the long run, it may only be necessary to be seen every 3 months. It will be of the highest importance that the antirejection medications are being taken with absolute adherence to the recommendations as rejection of the transplant still remains a major problem. When your son becomes an adolescent, there will be additional challenges with adherence. It may be very wise to educate him about his new condition as much as possible and to develop habits and routines that help to avoid any non-adherence. Non-adherence may lead to donor-specific antibodies and premature graft loss. Your nephrologist may also treat similar issues as with the chronic kidney disease, for instance the blood pressure, or vitamin D therapy, growth hormone therapy if there is insufficient growth despite of good graft function, etc. . These factors are just as important after the transplant as before.
You may notice a big growth spurt in the first year. You may also notice substantial improvements in the school performance, and in the development. Poor kidney function unfortunately affects school performance and cognitive development. It may take a while before some of the toxins of chronic kidney disease are getting out of the body.
Unfortunately, a transplant is not a cure, and there will be underdosing of nephrons which leads to slow deterioration of graft function. If everything goes well, the transplant may work for 15 or 20 years or longer. Ideally, a second transplant is pursued before the patient needs to go back on dialysis. Antirejection medications, especially tacrolimus, may have to be continued even after graft failure to prevent sensitization, which might make retransplantation very difficult. However, with retransplantation, a very respectable life expectancy can be achieved. Most important is the adherence to the antirejection drugs, which have to be finetuned by your nephrologist to avoid too much of too little of it. Therefore, transplantation is a therapy, not a cure. We are fortunate to have this treatment.

The most important thing for an ultrasound of the kidneys and the urinary tract is a full bladder. I therefore recommend to drink a lot of water. There is sometimes confusion because of issues with gas in the bowel and visibility of the kidneys from the side. Indeed, gas reflects the ultrasound waves and makes it more difficult to see especially the lower urinary tract. Sometimes, the radiology centre therefore asks that the patient be fasting, however, this is in contradiction to the need for a full bladder. It is fine to drink water for a kidney ultrasound. I would recommend to avoid foods like beans, lentils, asparagus, broccoli, brussel sprouts, cabbage, and other vegetables as well as foods containing fructose, a natural sugar found in artichokes, onions, pears, wheat, and some soft drinks. Also, avoid lactose, the natural sugar found in milk and milk products. Avoid these foods that make you gassy for the entire day before the scan.
Ultrasound does not hurt. Most kids are quite curious to see into their own belly and do not need anything special. Based on your question, I suspect that your son may have some difficulties or may be anxious. You should explain that some gel needs to be put on his tummy and his back so that there is no air between the ultrasound transducer and the skin. A good radiology centre that does ultrasound in children regularly will have the gel heated so that it does not feel cold. Explain to him that this gel is harmless. Explain that this procedure will not hurt and that he can look inside his tummy. He will likely also have to be prone to see the kidneys from the back. If he does not want to watch his own organs on the screen, you may want to bring a game on a mobile device for distraction. He will have to lie still and cooperate, otherwise it will be very difficult to perform the procedure. Make sure that you bring a bottle of water and let him drink while you are driving to the appointment. Try to avoid that he pees before the appointment. Hope this helps,

Guido Filler, MD, PhD, FRCPC

Dear Concerned Parent:

I understand that you are worried. A decrease in urine output is the most visible sign of acute kidney injury (AKI) in all age groups, particularly younger children. Oliguria occurs when the urine output in an infant is less than 0.5 mL/kg per hour for 24 hours or is less than 500 mL/1.73 m2 per day in older children. Anuria is defined as absence of any urine output.

However, the first thing is to determine whether it is real. Sometimes children hold their urine. It has happened several times that a parent brought the child to the emergency room for decreased urine output, and then the child had a large void while in the emergency room. The most common reason for decreased urine output is dehydration. Dehydration takes place when your body loses more fluid than you drink. The most common cause of water loss from the body is excessive sweating. There are numerous other reasons why you can dehydrated. These include fever (which increases insensible losses), diarrhea, vomiting, a stomach flu, food poisoning, and rarer conditions. There are a number of other conditions that can cause an AKI. These can only be identified with additional tests.

If you are really worried, I would recommend that you consult a physician.

Kind regards,

Guido Filler, MD, PhD, FRCPC

Sorry to hear about your son's chronic kidney disease. Renal transplantation is the therapy of choice for end-stage chronic kidney disease. Pre-emptive transplantation would be preferable. If no kidney is available, there is peritoneal dialysis and haemodialysis available for children in most countries. The treatment should be considered a bridging therapy until a transplant becomes available. Peritoneal dialysis may provide more gentle, continuous treatment, but parents have to perform this treatment at home, and there is a risk for infections (peritonitis and exit-site infections). For this, a peritoneal dialysis catheter should be surgically placed into the abdominal cavity, preferably as a swan-neck catheter with two cuffs. For haemodialysis, vascular access is required. Home haemodialysis is not widely available, but provides excellent clearance if done daily, for instance, as slow overnight treatment. In centre haemodialysis is often restricted to thrice weekly and demanding, because all the fluid has to be removed in a short time period. You need to speak with your local paediatric nephrologist to discuss the options. Survival for many years on both dialysis options have been reported in children and adolescents. If no dialysis or transplantation is offered and the chronic kidney disease becomes end-stage, chances for survival are guarded.

Your son should be referred to a paediatric urologist for the management of the stones and to a paediatric urologist for the workup for treatable causes. Owing to the poor diet and high salt intake, 56% of patients in the paediatric age group now have kidney stones because there is not enough citrate for a given amount of calcium in the urine. The second most common reason is hypercalciuria. Often this is caused by eating too much salt, which leads to calcium wasting. There are rare other causes such as hyperoxaluria and cystinuria or hypomagnesuria that can cause kidney stones and may need very specific treatment. Your paediatric nephrologist can counsel you. For sure, you should start immediately with a high water intake to dilute the urine, and reduce the salt intake to less than 1500 mg per day. This is not easy as 75% or more of the salt in the diet of our children and adolescents comes from processed food. Home cooked meals from scratch are preferable. Read the sodium label. More than 97% of Americans eat more than 1500 mg of salt per day. The salt intake of children and adolescents has increased 10-fold over the past 25 years. There also is insufficient intake of vegetables, which provide the vitally important citrate and potassium. Another source of citrate is lemon juice concentrate. You can encourage the intake of lemon juice, there are even studies with lemonade in the adult literature. Citrate and potassium, apart from high water intake, are the two main minerals that reduce new stone formation. However, while smaller stones may pass, larger stones may require the assistance of paediatric urologists to remove the stone. For sure, pain and blood urine should prompt a visit to the emergency room. Passing stones may be the most painful event known to man. The paediatric urology team has multiple methods to deal with large stones, including lithotrypsy, percutaneous lithotomy, and others. Your paediatric urologist will guide you to the most effective and least traumatic option.

There are many hereditary kidney conditions that run in families. The most common condition would be autosomal dominant polycystic kidney disease. This is characterized by cyst formation in both kidneys which slowly lead to kidney failure, typically in the 4th to 6th decade of life. This is inherited with a 50% chance from generation to generation and could be diagnosed in your 7-year old son with a kidney ultrasound. It would be helpful to make the diagnosis early because there are now treatments available that may slow progression of chronic kidney disease, including treatment of high blood pressure and tolvaptan. Polycystin I and II gene mutations have been associated with this disorder.
There are other hereditary kidney diseases to consider, for instance, Alport syndrome. This disorder is variable and different genes are implied, which can be tested through a tertiary paediatric nephrology centre. Sometimes patients have hearing loss as well, and occasionally the cornea of the eye may be involved. While there is no specific treatment for this disorder, early treatment may be helpful to slow progression of renal disease.
Certain anomalies of the kidneys and urinary tract may also be hereditary. You will likely have undergone antenatal ultrasounds, and if they were normal, there is probably no concern about this.
There are a number of other conditions that are also genetic, and it would be too long to list them all. Your local paediatric nephrologist can counsel you. Many can be diagnosed early. However, knowledge about the kidney problems in your family will be extremely helpful. By far the most common reason for kidney failure is diabetes mellitus which is poorly controlled. If that is the reason for your family history, and your son does not have diabetes mellitus, then there is nothing to worry about.

Water retention in the legs (or other parts of the body) is called edema. It is not very common. Many conditions are associated with edema, which means that there are many causes, too. Here are some ways that conditions could cause edema:

Liver disease:

A healthy liver helps to regulate the level of fluid in the body. If the liver is damaged, it may not be able to do this, leading to fluid build-up. Often, this is in the abdomen though, not in the legs. Your pediatrician probably checked the albumin level and liver enzymes. Liver disease in toddlers should be treated by a pediatric gastroenterologist/hepatologist.

Kidney disease:

The kidneys may not be able to eliminate enough fluid from your child’s body. Another possible reason is a low albumin level in the blood because the kidneys are oozing albumin and other plasma proteins. In children of this age, one must test whether there is protein or albumin in the urine and the level of total protein and albumin in the blood. Your child could have nephrotic syndrome. Any kidney disease should be treated by a pediatric nephrologist.

Heart disease:

Edema related to heart disease can be associated with:

* congestive heart failure
* cardiomyopathy
* congenital heart defect

Since your child’s body depends on her heart to pump blood to her organs, poor cardiac function can cause edema in several ways:

* If your child’s heart, for whatever reason, isn’t pumping blood efficiently, blood can build up in the parts of her body furthest from the heart, such as the legs, ankles, and feet.
* This puts increased pressure on the tiny blood vessels called capillaries, which may begin to leak blood into the surrounding tissues, causing swelling.
* Because of the poor heart function, the kidneys sense less blood fluid available and begin to conserve water and sodium.
* Also, without sufficient blood supply, the kidneys have a harder time doing their job of ridding the body of excess fluid.
* Eventually, this excess fluid builds up in the lungs.

What are the other symptoms of edema?

Aside from the actual swelling, you or your child may notice your child:

* feeling tired after minimal physical exertion, like climbing stairs
* gaining weight
* having trouble breathing
* with a cough that gets worse at night or when she is lying down. This may be a sign of acute pulmonary edema, or excessive fluid in the lungs, which requires emergency treatment.

There are also some other reasons which are very rare. Your pediatrician will screen for liver, kidney, and heart disease and make appropriate referrals to subspecialists. The cause of the edema must be identified and treated.

Kind regards,

Guido Filler, MD, PhD, FRCPC