I was doing a well-check on a six year-old boy, and he couldn’t be any healthier. His growth and development was excellent and his blood pressure and vital signs were normal.

 

As we were finishing the exam, my nurse handed me the results of his urinalysis. It was normal except for a “large amount of blood” detected on the urine sample. His urine was clear and yellow which meant that he had “microscopic hematuria” meaning that the blood couldn’t be seen by the naked eye. I gave mom a container and asked her to drop off a first morning urine so I could double check the urine. Sure enough, the next morning his urine showed the same thing. The urine was clear yellow with no evidence of infection, protein, or glucose, but large blood was detected once again. I sent this urine to the lab for a urine culture to rule out a urinary tract infection (it was negative), and to measure the calcium and creatinine in the urine. The calcium/creatinine ratio (urine calcium level divided by the urine creatinine level) was in fact elevated at 0.42. The normal should be below 0.2 so this confirmed the diagnosis of hypercalciuria. I was intrigued as I had a similar patient just a few weeks earlier.

 

Hypercalciuria refers to increased levels of calcium in the urine.

 

It is fairly common in children occurring in 3-6% of all children usually between the ages of 4 and 8 years. In children, it may be asymptomatic, or it may cause frank blood in the urine, voiding dysfunction, flank pain, abdominal pain, recurrent urinary attract infections or kidney stones.
 

Hypercalciuria may be idiopathic, meaning there is no known cause, or it may be genetic with a strong family history of kidney stones.

 

Risk factors include not drinking enough fluids, a diet high in sodium and protein, excessive Vitamin D intake or medications such as steroids or Lasix. It is well documented that excessive salt in the diet is linked to increased calcium in the urine. This is also the case with excessive protein in the diet. A very concentrated urine also leads to excessive calcium in the urine. Dietary potassium which is found in fruits and vegetables is beneficial in minimizing urinary calcium. It is important to note that hypercalciuria is NOT caused by too much calcium in the diet.

 

After making the diagnosis of hypercalciuria, I did a kidney ultrasound to make sure there were two normal kidneys with no evidence of kidney stones.

 

That was the case. I then referred him to a pediatric kidney specialist for further management. The first step in managing pediatric hypercalciuria is dietary. The goal is to insure adequate fluid intake to make sure the urine is not too concentrated. It is also important to establish a diet that is low in sodium and high in potassium as these affect the amount of calcium in the urine. Protein also affects the amount of calcium in the urine, but a growing child needs the right amount of protein to insure normal growth. A child with hypercalciuria is actually losing calcium in the urine and this is may be coming from the bones so it is critical that they are getting the appropriate amount of calcium in their diet. Most pediatric kidney specialists will work with a nutritionist to guide the parents in formulating a diet for their child that will meet all of the nutritional requirements, will be practical and above all will be palatable to the child.
 

If the dietary changes do not resolve the hypercalciuria, then the kidney specialist may need to add a medication known as a diuretic which increases the urine output and regulates the sodium, potassium and calcium.

 

I did send my patient to the nephrologist who agreed with the diagnosis and work up and had his parents meet with the nutritionist. They found this meeting to be most informative and helpful. They realized that they didn’t have to make drastic changes in the diet and they told me that the entire family would benefit from these changes and would be eating much healthier as a result. I will periodically check my patients urine and follow him closely.