Online Health Chat with Jeffrey Donohoe, MD, and Raed Bou-Matar, MD

Wednesday, April 29, 2015


Description

Many people have heard of some adults having kidney stones. Yet, kidney stones can also form in children and cause the same type of severe pain and blood in the urine as it does in adults.

Solid particles and minerals resulting from highly concentrated urine can form into kidney stones. Stones that remain in the kidney, although often painless, can be the source of recurrent urinary tract infections. Most stones remain in the kidney, but up to one third may travel from the kidney through the ureter to the bladder. Although, no larger than a grain of sand, stones that become stuck in the ureter (the tube that connects the kidney to the bladder) may cause severe, colicky type pain and require medical or surgical intervention.


About the Speakers:

Jeffrey Donohoe, MD, is a board-certified pediatric urologist in the Glickman Urological & Kidney Institute at Cleveland Clinic. Dr. Donohoe's specialty interests include urinary obstruction, vesicoureteral reflux, undescended testicles, hydrocele, penile disorders and pediatric genitourinary tumors.

Dr. Donohoe earned his medical degree from the New York Medical College in 1997; he had previously completed his undergraduate studies at Queens College in 1992. He completed his residency at SUNY Downstate in Brooklyn, NY, and his fellowship at Vanderbilt University, Monroe Carell Children’s Hospital in Nashville, TN.

Raed Bou-Matar, MD, is a board-certified pediatric nephrologist at Cleveland Clinic Children’s. Dr. Bou-Matar’s specialty interests include nephrotic syndrome, glomerulonephritis, hypertension, cystic kidney diseases, and acid-based and electrolyte disorders.

Dr. Bou-Matar earned his medical degree from Beirut Arab University in 2003. He completed his residency at Miami Children's Hospital and his fellowship at Emory University Hospitals and School of Medicine in Atlanta, GA.


Let’s Chat About Kidney Stones in Children

Moderator: Welcome to our chat about Kidney Stones in Children with Cleveland Clinic pediatric urologist, Dr. Jeffrey Donohue, and pediatric nephrologist, Dr. Raed Bou-Matar. Thank you, Dr. Donohoe and Dr. Bou-Matar, for taking the time to be with us to share your expertise and answer our questions.

Let’s get started with our questions.


Online Health Chat with Jeffrey Donohoe, MD, & Raed Bou-Matar, MD

April 29, 2015

Description

Many people have heard of some adults having kidney stones. Yet, kidney stones can also form in children and cause the same type of severe pain and blood in the urine as it does in adults.

Solid particles and minerals resulting from highly concentrated urine can form into kidney stones. Stones that remain in the kidney, although often painless, can be the source of recurrent urinary tract infections. Most stones remain in the kidney, but up to one third may travel from the kidney through the ureter to the bladder. Although, no larger than a grain of sand, stones that become stuck in the ureter (the tube that connects the kidney to the bladder) may cause severe, colicky type pain and require medical or surgical intervention.


About the Speakers

Jeffrey Donohoe, MD, is a board-certified pediatric urologist in the Glickman Urological & Kidney Institute at Cleveland Clinic. Dr. Donohoe's specialty interests include urinary obstruction, vesicoureteral reflux, undescended testicles, hydrocele, penile disorders and pediatric genitourinary tumors.

Dr. Donohoe earned his medical degree from the New York Medical College in 1997; he had previously completed his undergraduate studies at Queens College in 1992. He completed his residency at SUNY Downstate in Brooklyn, NY, and his fellowship at Vanderbilt University, Monroe Carell Children’s Hospital in Nashville, TN.

Raed Bou-Matar, MD, is a board-certified pediatric nephrologist at Cleveland Clinic Children’s. Dr. Bou-Matar’s specialty interests include nephrotic syndrome, glomerulonephritis, hypertension, cystic kidney diseases, and acid-based and electrolyte disorders.

Dr. Bou-Matar earned his medical degree from Beirut Arab University in 2003. He completed his residency at Miami Children's Hospital and his fellowship at Emory University Hospitals and School of Medicine in Atlanta, GA.


Let’s Chat About Kidney Stones in Children

Moderator: Welcome to our chat about Kidney Stones in Childrenwith Cleveland Clinic pediatric urologist, Dr. Jeffrey Donohue, and pediatric nephrologist, Dr. Raed Bou-Matar. Thank you, Dr. Donohoe and Dr. Bou-Matar, for taking the time to be with us to share your expertise and answer our questions.

Let’s get started with our questions.


Stone Specifics

MaevesMom: What causes kidney stones in children?

Raed_Bou-Matar,_MD: The urinary tract is composed of two kidneys and ureters, a bladder and a urethra. A kidney stone usually forms when substances that are normally found in the urine, such as calcium, oxalate, cysteine or uric acid, are at high levels. However, in some children, stones can also form if these substances are at normal levels. Knowing what the stone is made of is important in deciding which treatment to use.
Certain factors can increase a child's risk of developing kidney stones. Approximately half of children with kidney stones have an underlying metabolic abnormality that increases the risk of stone formation.

  • History of kidney stones – Children who have had a kidney stone in the past have the highest risk of developing a stone in the future (up to 2/3). Preventive measures can decrease the risk of developing a stone in the future.
  • Not drinking enough – The amount of fluids a child drinks directly affects the amount of urine the body makes. Drinking a small amount of fluids means that the kidneys make a small amount of urine, which increases the concentration of stone-forming substances in the urine. Drinking more fluids can reduce the risk of recurrent stones.
  • Ketogenic diet – Diets that include a very small amount of carbohydrates, called ketogenic diets, can increase the risk of developing kidney stones. Ketogenic diets are sometimes used to treat seizure disorders.
  • Cystic fibrosis – Children with cystic fibrosis are at a higher risk of developing kidney stones.
  • Urinary tract abnormalities – Having congenital (from birth) abnormalities in the kidneys, ureters or bladder can increase the risk of developing a kidney stone.
  • Medicines – Some medicines increase the risk of forming crystals in the urine. These include furosemide (Lasix), acetazolamide (Diamox), and allopurinol (Aloprim, Zyloprim).
  • Inherited disorders – Several uncommon inherited disorders can increase a child's risk of developing kidney stones. Testing for these disorders might be recommended

Heidi: What is the difference between kidney stones in adults and those in children?

Raed_Bou-Matar,_MD: Kidney stones in adults are far more common, present usually with typical flank pain with or without other urinary symptoms and may not always warrant a metabolic evaluation. On the other hand, kidney stones in children may be silent (detected on an imaging study done for another indication) and always warrant an evaluation for metabolic causes. In approximately half of children with kidney stone(s), an underlying cause or metabolic risk factor is identified. Some of the metabolic abnormalities in children that cause stones may also cause renal failure in the long term, which again highlights the importance of a proper evaluation in all children with kidney stones.

Sarib: Can pediatric kidney stones be prevented?

Raed_Bou-Matar,_MD: The foremost recommended strategy to reduce the risk for recurrent kidney stones is to increase intake of water and other electrolyte-free fluids, targeting a minimum daily intake as follows: Infants – 750 mL or more (25 ounces or three cups); children younger than five years of age – 1000 mL or more (33 ounces or four cups); children between 5 and 10 years of age – 1500 mL or more (50 ounces or six cups); children older than 10 years of age – 2000 mL or more (66 ounces or eight cups).

Showboat: I've heard that kidney stones can happen because of problems with your parathyroid gland. What kind of treatment is done for this problem and what can be done to prevent stones when you have problems with your parathyroid gland?
 
Jeffrey_Donohoe,_MD: Usually, parathyroid gland problems relate to high calcium levels in the urine. There are different types of diseases of the parathyroid, and they are treated somewhat differently, and they also depend on kidney function and bone metabolism as well. One should ensure that they, indeed, have high urine calcium levels in the urine that are not diet related prior to having their parathyroid evaluated. A nephrologist can be helpful in determining this. Once it is confirmed, they are likely to have you evaluated by an endocrinologist who will work up the parathyroid gland. Occasionally, surgery of the parathyroid gland is performed.


Talking Treatments

Lynette: For children, what types of procedures are available to eradicate the stone?

Jeffrey_Donohoe,_MD: There are three modalities of treatment to eradicate kidney stones, and the size, the location and the composition of the stone will determine which is used. For instance, a larger and relatively softer stone in the kidney may benefit from shock wave lithotripsy, while a harder, smaller stone in the ureter would more likely benefit from ureteroscopy. All of the modalities require anesthesia. Shock wave lithotripsy requires no intervention other than shock waves generated outside the body being directed toward the stone using x-ray and ultrasound guidance. Ureteroscopy uses miniaturized instruments to directly visualize the stone. We gain access through the urethra (at the opening where the urine leaves the body) and advance the scope up the urinary tract until we find the stone. Under direct vision, we dissolve the stone with a laser. A third procedure called percutaneous nephrolithotomy is for much larger stones within the kidney and is more invasive.

Mr. Peanut: Why should I choose shock wave lithotripsy over other types of surgery?
 
Jeffrey_Donohoe,_MD: Shock wave lithotripsy (SWL) is great if the stone is in the upper aspect of the ureter or the kidney and is ~1cm in size or greater. It requires no instrumentation or incision. There are a few requirements for SWL: the stone should be easily visualized on x-ray. If it is hard to find on x-ray, then it will be unclear where to target the machine that generates the shocks to break up the stone. Also, it helps if the colon is cleaned out really well in children who have a tendency to be constipated. SWL is operator dependent, and some people prefer not to use it because they have better success in generating their patients "stone-free" with ureteroscopy.

Tippy_Rosewood: I've heard of laser stone surgery using rigid ureteroscopy. What is this and how it is more or less beneficial than traditional surgery?

Jeffrey_Donohoe,_MD: I assume that by saying "traditional surgery" you mean with an incision. We very rarely use an incision to treat urinary stones these days. With ureteroscopy, the instruments are excellent, as are the lenses. We have miniaturized instruments like lasers and stents for managing the stones in children. We gain access for the ureteroscope through the urethral opening. Ureteroscopy can be done with a rigid or flexible ureteroscope. Rigid scopes are for stones in the ureter, and flexible scopes for stones in the kidney. The rigid ureteroscope finds and visualizes the stone under direct vision, and the laser is used to generate enough power to break the stone into passable fragments. Larger fragments can be removed using a miniaturized, specialized basket.

Bogo: What is the purpose of a double J stent?
 
Jeffrey_Donohoe,_MD: A stent is used in an acute setting to bypass an obstructing stone and allow the kidney to drain. This is used in the setting of a patient with an obstructing stone and a fever. Stents are used after or in preparation of more definitive means of managing the stone. A stent can allow the ureter to passively dilate prior to definitive ureteroscopy and after the procedure to allow the ureter to heal over a scaffolding, so to speak.


Dietary Decisions

Kids4Now: How does diet affect kidney stones?

Raed_Bou-Matar,_MD: Dietary habits can have significant effects on the risk of kidney stone formation. For example, excessive intake of sodium (salt) in the diet can increase urinary calcium excretion predisposing to calcium stones. Eating too much or too little calcium can predispose to calcium stones as well. It is recommended that children receive the right amount of calcium from foods and drinks for their age (see below). Consuming too much calcium in foods and drinks is not recommended. However, the child should not stop eating foods and drinks with calcium because calcium is important in building strong bones. The "right" amount of calcium depends on the child's age: • 500 mg/day for children one to three years • 800 mg/day for children four to eight years • 1300 mg/day for children nine years and older. Potassium-rich foods (fresh fruits and vegetables) may also help reduce risk of kidney stones in preliminary research. There is some evidence from adult studies that excessive intake of caffeine, sweetened beverages and red meat may also increase the risk of developing kidney stones. In children with high oxalate in the urine, excessive intake of oxalate containing foods (turnip greens, rhubarb, strawberries, star fruit, sweet potatoes, wheat bran, tea, cocoa, pepper, chocolate, parsley, beets, spinach, dill, nuts and citrus juices) may also increase the risk of kidney stones. However, restriction of these food items is not recommended in all children and should be individualized.


Patient Particulars

DM: Our youngest son, born March 2005, has been diagnosed with uric acid stones. The first "accurately diagnosed" onset was in October 2014, which required the placement of x2 nephrostomy tubes and five procedures. (There was an obstructed stone in the left kidney.) It was a raw introduction to pain for our little fellow. His father carries a diagnosis of calcium stones. We've been told both kidneys are candy factories, and that medical management will be life-long. His current medications include potassium citrate 540 mg one twice a day and HCTZ 12.5 mg one daily. He is 58 pounds, 4'5". My questions: 1) What fluid and diet guidelines would you highlight to prevent recurrence? 2) Will he likely require life-long medications? He is an ideal patient for pediatric urologists and pediatric nephrologists in terms of how he handles very painful events, but he remains our dietary challenge. Like most little boys, his diet could be macaroni and cheese, pizza, eggs/bacon, cheese cubes and subs. We do our best to watch his sodium/potassium intake and try to avoid fast foods, but are challenged with prevention and hold our breath for the next event.
 
Raed_Bou-Matar,_MD: The foremost recommended strategy to reduce the risk for recurrent kidney stones is to increase intake of water and other electrolyte-free fluids targeting a watery appearing urine at all times and/or a minimum intake of:

- Infants – 750 mL or more (25 ounces or three cups)
- Children younger than five years of age – 1000 mL or more (33 ounces or four cups)
- Children between 5 and 10 years of age – 1500 mL or more (50 ounces or six cups)
- Children greater than 10 years of age – 2000 mL or more (66 ounces or eight cups)

Potassium citrate may also be helpful in his particular situation because it makes his urine more alkaline and, therefore, helps reduce the formation of kidney stones. Did your son also have other metabolic abnormalities on the 24-hour urine collection, such as high calcium or low citrate? The likelihood that he will need long-term medications depends primarily on the underlying cause. Periodic assessment with 24-hour urine collections (at least annually) for a metabolic stone profile is helpful to assess his risk and to adjust therapy accordingly.

Fran: My 16-year-old daughter had a 7mm kidney stone last summer. The kidney stone analysis indicated it was a calcium oxalate dihydrate. Would she benefit from the Oxalate-Controlled Diet on the Cleveland Clinic website? What are the causes of this type of kidney stone?

Raed_Bou-Matar,_MD: Calcium oxalate stones are by far the most common type of kidney stones in children. There are many causes of calcium oxalate stones. They include inherited metabolic abnormalities that increase oxalate in the urine, certain diets (such as the ketogenic diet), gastrointestinal disorder (chronic diarrhea or malabsorption) and intake of high doses of vitamin C. She would benefit from a low-oxalate diet if her urinary oxalate excretion is high, which in turn would be determined via a 24-hour urine collection. The general recommendations for this type of stone are as follows:

  • Drink more fluids.
  • Avoid vitamin C supplements.
  • Avoid foods that contain large amounts of oxalate, including beet and turnip greens, rhubarb, strawberries, star fruit, sweet potatoes, wheat bran, tea, cocoa, pepper, chocolate, parsley, beets, spinach, dill, nuts and citrus juices.
  • Avoid excessive salt in the diet and avoid caffeine.

DM: At this point in time, my son is asymptomatic. Should I be concerned about the frequency of ultrasounds to see what is taking place? His left kidney was obstructed with a stone that was uncooperative on cystoscopy; it was inflamed/embedded. We had no idea what was going on until he was in trouble.
 
Jeffrey_Donohoe,_MD: Ultrasound has not been proven to be harmful, and because of this and the fact that it is noninvasive, it is an excellent tool for screening patients and following patients with non-obstructing stones.

Fran: For my 16-year-old daughter with a kidney stone, her 24-hour urine test showed her phosphorus, chloride and urea nitrogen to be low. Are these values related to the cause of the kidney stone? If so, what can she do to increase the phosphorus, chloride and urea nitrogen?

Raed_Bou-Matar,_MD: If I understand your question correctly, you are referring to the phosphorus and chloride in the blood. Low phosphorus in the blood may be related to an inherited or acquired abnormality in how the kidney handles phosphorus excretion. It may also be related to abnormalities in certain hormones or vitamins (such as the parathyroid hormone or active blood vitamin D). Further details are needed. The underlying cause determines the treatment, which may include certain mineral supplements (including phosphorus, potassium or both).

DM: No high calcium, not sure about low citrate.

Raed_Bou-Matar,_MD: Treatment with thiazide diuretics (such as HCTZ) to lower urinary calcium excretion is generally considered when urinary calcium excretion is high. Similarly, treatment with citrate, an important stone-preventing constituent of normal urine, is generally helpful when urinary citrate excretion is low. For maximum benefit, these urinary substances should be monitored with repeat 24-hour urine collections to ensure that the treatment is effective and the values have normalized in the urine.


General Information

Robin: What is the incidence of kidney stone diagnosis in children? I think I heard that there is an increase in the number being diagnosed. Why would an increase occur?

Raed_Bou-Matar,_MD: In industrialized countries, the risk of kidney stones is estimated at approximately 0.5 percent, which is approximately 10 times lower than the risk of kidney stones in adults. A high-salt diet and the intake of sugary drinks and dark sodas have been associated with an increased risk. Even though the precise cause for the increase is not known, it is believed to be the result of shifting dietary trends over time.

Vincenzo: How do I find and choose a hospital to manage my child's kidney stones? What should I look for in a center?

Jeffrey_Donohoe,_MD: The center you choose should have a pediatric urologist and nephrologist or someone who has a significant amount of experience in treating children with kidney stones. Children have specific metabolic issues that can contribute to stone formation, and pediatric nephrologists are more familiar with this. Also, if surgical management becomes necessary then you want a pediatric urologist who has the proper-sized instruments to surgically treat the stones.

charlesRB: What kind of research is being done concerning kidney stones?

Jeffrey_Donohoe,_MD: Research studies are being done to better detect kidney stones; for instance, in order to predict their composition on CT scan. Also, we are always researching ways to improve the maneuverability and visibility afforded by the scopes we use. We are researching how certain metabolic states can lead to kidney stone formation and what we can do to prevent/reduce the frequency of recurrences.


Closing

Moderator: That is all the time we have for questions today. Thank you, Jeffrey Donohoe, MD and Raed Bou-Matar, MD, for taking time educate us about kidney stones in children.

On behalf of Cleveland Clinic, we want to thank you for attending our online health chat. We hope you found it to be helpful and informative.

Jeffrey_Donohoe,_MD: Thank you for your time and the opportunity to answer your questions. I hope this was helpful for all of you.

Raed_Bou-Matar,_MD: Thank you very much for your questions today.

DM: This is what physician excellence is about! Thank you.


For Appointments

To make an appointment with Jeffrey Donohoe, MD, or any of the other pediatric urology specialists in Cleveland Clinic’s Glickman Urological & Kidney Institute, please call 216.444.5600, toll-free at 800.223.2273 (extension 45600) or visit us at clevelandclinicchildrens.org/urology for more information. 

To make an appointment with Raed Bou-Matar, MD, or any of the other pediatric nephrology specialists in Cleveland Clinic’s Children’s, please call 216.444.5437, toll free at 800.223.2273 (extension 45437) or visit is online at clevelandclinicchildrens.org/nephrology for more information.


For More Information

Cleveland Clinic Health Information
Learn more about symptoms, causes, diagnostic tests and treatments for kidney stones in children.

Oxalate-Controlled diet
http://my.clevelandclinic.org/services/urology-kidney/treatments-procedures/kidney-stones-oxalate-controlled-diet

Kidney Stones in Children
http://kidney.niddk.nih.gov/KUDiseases/pubs/stoneschildren/

For additional health information, visit clevelandclinic.org/health.

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