Offer Pharmaceutical Guidance to Parents as the Frequency of Kidney Stones in Children Climbs
Kidney stones aren’t usually associated with children, but that’s changing as the number of pediatric cases continue to rise. Even worse, children don’t get minor cases just because they’re little—stones in kids are the same size and as agonizingly painful as those in adults. The stones also come back at rates similar to, if not higher than, recurrence in adults.
Prevention is the key. In fact, experts in urology recommend aggressive preventive measures. Pharmacists can step in and help by screening children taking medications known to promote kidney stones and by counseling parents to diligently implement dietary changes that prevent stone development.
Kidney Stone Incidence Increasing in Children
For decades, the incidence of kidney stones in children hovered at 1 to 2 percent of the incidence in adults—now it’s around 10 percent.1 Kidney stones are currently responsible for 1 in every 685 pediatric hospitalizations, with more than half of those cases being children younger than 13 years.2 Adolescent cases of stones rose from 18 to 57 per 100,000 between 1999 and 2008.
Here are a few other facts to round out the clinical picture of kidney stones in children:
- Children can develop stones at any age, from newborn to teenager.
- 40 to 50 percent of children with kidney stones have metabolic abnormalities
- 30 percent of all pediatric urolithiasis cases are associated with anatomic abnormalities.
- Most stones in children are calcium-based — 40 to 65 percent are calcium oxalate; 14 to 30 percent are calcium phosphate.
Two groups have a higher prevalence than others: adolescent girls and children with seizure disorders. When girls reach puberty, higher levels of estrogen may increase their risk of developing stones. Anti-seizure medications such as topiramate and zonisamide, as well as the high-protein ketogenic diet used to control seizures, can potentiate stone formation.
Metabolic Abnormalities and Kidney Stone Recurrence in Children
Children often have the same symptoms as adults—abdominal pain, flank pain, and vomiting—but it’s vital for parents to understand that younger children often don’t have typical symptoms. Vague symptoms like irritability, less localized pain, hematuria, or a urinary tract infection are more common in children, especially if they’re younger than 5 years. In infants, symptoms often resemble colic pain.
Once the acute crisis is over and the stones either pass or are removed, children continue to face challenges. One of the biggest is a life-long risk of stone recurrence. It’s estimated that half of all children will have a recurrence within three years.3 Unfortunately, the risk is 5-times higher in those with an underlying metabolic disorder, such as:4
The most common metabolic problem, hypercalciuria, is diagnosed in 30 to 50 percent of children with stones. This adds another long-term risk that must be monitored—low bone density. Patients with idiopathic hypercalciuria usually have a strong family history of kidney stones, but hypercalciuria is associated with a variety of clinical disorders that must be ruled out, including:
- Hypervitaminosis D
- Juvenile idiopathic arthritis
- Corticosteroid excess
- Adrenal insufficiency
- Williams syndrome
Pharmacist Guidance to Promote Prevention
Patients often don’t know they have a problem to thwart until after kidney stones develop for the first time. However, pharmacists can help prevent stones by warning parents whose children take medications known to promote kidney stones. They may be able to take simple steps, like increasing their child’s water consumption, to avoid stone formation while on these pharmaceuticals:5
- Calcium-containing drugs
- Loop diuretics
- Magnesium-containing drugs
The best way to prevent kidney stones is through dietary changes, but the first step is making sure parents truly understand why it’s important and what’s at stake for their child. For example:
- Pharmaceuticals – If dietary changes aren’t implemented or they fail, children may need to take prescription medications to prevent stones, such as diuretics, alkalizing agents, thiol-containing agents or allopurinol.
- Comorbidities – Stones are associated with diabetes and hypertension, although cause-and-effect hasn’t been determined.6
- Increased risks from stone recurrences – These risks include kidney infection and renal damage
The recommended dietary changes sound simple on the surface but they’re complex and must be determined by the physician because they vary depending on age, each child’s health, the type of stone and substances excreted in urine. But it’s still important for pharmacists to know the most common dietary advice in order to answer patients’ questions and give some guidance. The key recommendations from the American Urological Association (AUA) follow:
- Ensure adequate fluid intake – All children who have stones should drink enough to achieve a urine volume of at least 2.5 liters daily. Of course, parents aren’t going to measure urine output, so advise them to be sure their kids drink 8 to 10 cups of fluids daily—understanding that fluid requirements vary for each person. Water is preferred, otherwise they should choose beverages that increase urinary pH and citrate excretion, such as orange juice. Be aware that sugar-sweetened sodas and punch may increase the risk of stones.7
- Maintain low-salt and normal calcium intake – Children with calcium stones should limit sodium and consume normal calcium. As with all nutrients, intake recommendations vary according to age, so parents should consult their physician or at least check dietary reference intakes established by the Institute of Medicine.8 It’s interesting to note that a low-calcium diet increases the risk of stones if it’s not implemented together with other dietary changes.
- Limit oxalates – Children with calcium oxalate stones and high urinary oxalate output will need to limit oxalate-rich foods while consuming normal calcium. This means limiting or avoiding nuts, chocolate, spinach, soy beans, beets, sweet potatoes, wheat bran and black raspberries, to name only a few of the items on the list of oxalate-containing foods.9
- Limit non-dairy proteins – This is important for children with calcium, uric acid and cystine stones, but again, specific intake amounts must be established by the physician.
- Avoid vitamin C supplements – Children with calcium oxalate stones should steer clear of vitamin C supplements.
- Increase potassium-rich foods – Fruits and vegetables contain citrate, which protects against stones.
Pharmacist Outreach Helps Ensure Compliance
As pharmacists reach out, they can help manage side effects of medications, ask about compliance with the regimen, and try to determine what roadblocks parents face if they’re not following the treatment plan. You should also ask if they’ve kept appointments with doctors, as children with stones need regular assessments and tests to verify the regimen is working. Finally, when you counsel parents, encourage them to teach their children about which foods to avoid or to increase in their diet—their understanding and cooperation is the best way to prevent future stone formation.
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- “Calcium Kidney Stones: Pathogenesis, Evaluation, and Treatment Options,” June 2011, https://www.uspharmacist.com/article/calcium-kidney-stones-pathogenesis-evaluation-and-treatment-options ↩
- “Pediatric Urolithiasis,” Feb 2016, http://emedicine.medscape.com/article/983884-overview ↩
- “Kidney Stone Recurrence in Children,” accessed October 2016, http://www.chop.edu/pages/kidney-stone-recurrence-children ↩
- “Urolithiasis in Children,” August 2012, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3426770/ ↩
- “The Role of Pharmacists in the Management of Acute Kidney Stones,” August 2013, https://www.uspharmacist.com/article/the-role-of-pharmacists-in-the-management-of-acute-kidney-stones-42381 ↩
- “Medical Management of Kidney Stones: AUA Guideline,” August 2014, https://www.auanet.org/education/guidelines/management-kidney-stones.cfm ↩
- “Soda and Other Beverages and the Risk of Kidney Stones,” July 2013, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3731916/ ↩
- “Dietary Reference Intakes (DRIs): Recommended Dietary Allowances and Adequate Intakes for Vitamins and Minerals,” accessed October 2016, https://fnic.nal.usda.gov/sites/fnic.nal.usda.gov/files/uploads/RDA_AI_vitamins_elements.pdf ↩
- “Oxalate Content of Foods,” July 2005, http://www.childrensdayton.org/cms/resource_library/nephrology_files/5f5dec8807c77c52/lithiasis__oxalate_and_diet.pdf ↩