Kidney stones

Dear Alice,

I think I am passing Kidney Stones. I have a lot of left sided pain, that are a lot like labor pains (in their timing/frequency). I have been to the hospital twice, they have ruled out UTI or anything else. They sent me home with a strainer, told me to strain my urine, and bring any hard objects to my physician. But, I have having trouble identifying them. WHAT DO KIDNEY STONES LOOK LIKE, AND HOW BIG ARE THEY??

—Pebbles or avalanche?

Dear Pebbles or avalanche,

It's unlikely that you will have to sift through an avalanche of hard objects in your urine to find the kidney stones, although they can vary greatly in size. Smaller kidney stones can be the size of the head of a pin and are usually passed with relative ease. The largest stones, sized similarly to an apricot, can become stuck in the ureter (tube that carries urine from the kidneys to the bladder) or lodged in the junction between the kidney and ureter and require surgical removal under general anesthesia. Stones in the lower ureter usually can be crushed and removed with specialized tools and ureteroscope, a viewing machine that is maneuvered up the urethra and across the bladder. Another method of removal uses soundwaves to break stones down into a passable size.

It's estimated that approximately ten percent of people experience kidney stones in their life, but for a variety of reasons. Factors such as genetics, diet, and water intake can greatly influence whether someone experiences kidney stones. For some, drinking more water can reduce the likelihood of kidney stones forming; when the level of water is too low in the urine, the concentration of minerals that can turn into kidney stones is too high. At a certain saturation point, the minerals can crystallize and form a stone. This, however, also depends on the type of kidney stone.

The four groups of kidney stones include:

  • Calcium stones: Calcium oxalate is the more-common calcium-based kidney stone and may form when there is an excess oxalate in the diet (found in certain fruits, nuts, vegetables, and chocolate). Less-common calcium phosphate kidney stones are often tied to certain medications or metabolic conditions.
  • Struvite stones: Bacteria in the urinary tract that causes infection (UTIs) produce concentrations of ammonia high enough for crystallization to occur. As a result, this type of kidney stone can grow quickly and with minimal notice.
  • Uric acid stones: Form for a number of reasons including genetic predisposition, fluid imbalance, a high-protein diet, diabetes, or certain metabolic conditions.  
  • Cystine stones: People living with cystinuria have a genetic condition where they excrete too much of the amino acid cystine. At higher concentrations, cystine can crystallize to form stones in the kidneys, liver, and bladder.

List adapted from Mayo Clinic.

In terms of the symptoms associated with kidney stones, you've already described feeling pain in your side. Feeling pain in the side, back, and below the ribs is a common symptom of kidney stones. Pain may also be felt in other areas of the abdomen and groin as the kidney stones move. Other symptoms may affect the color or scent of urine, along with the feeling of how frequently you urinate. 

If you arrive home after a seeing a health care provider and realize that you have additional questions, never hesitate to call back your provider to ask. If you find that your urine is blocked or feeling additional pain, you may wish to return to them for additional testing to make sure they are kidney stones, and if they are, that they're small enough to pass through your body. 

Wishing you (and your stones) an easy passage! 

Last updated Feb 10, 2023
Originally published Apr 18, 1995

Submit a new comment


This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.

The answer you entered for the CAPTCHA was not correct.