When the stones in your urinary tract are formed due to urinary tract infections, they are called “infection stones”.

A urinary stone is a hard mass that forms in your urinary tract from minerals and salts in the urine. Urinary stones usually resemble small” pebbles ”and can cause severe pain if they are large enough. Urinary stones usually form when there is a decrease in your urine volume and/or an excess of stone-forming substances in the urine.

Urinary stones are an increasing clinical problem in both children and adults. 1 out of 10 individuals will experience urinary stones.

Know Your Urinary Tract

The main function of your urinary tract is to make and store urine, one of the body's liquid waste products.

Your urinary tract comprises of:

  • Kidneys: These small organs are located on the back of your body, just above the hips, that function as filters. Your kidneys remove waste and water from your blood. This waste becomes urine and is passed out through the urethra.
  • Ureters: These are two tubes that arise from each kidney that carry urine from the kidneys to your bladder.
  • Bladder: The bladder, also known as the urinary bladder, is a muscular sac-like container, that stores your urine before it leaves the body.  
  • Urethra: This thin, muscular tube carries the urine from your bladder to the outside of the body during urination.

How Are Urinary Tract Infections (UTIs) and Stones Related? 

A urinary tract infection (UTI) is an infection in any part of your urinary system. In most cases, infections happen in the lower urinary tract — the bladder and the urethra. A urinary tract infection can involve the bladder (condition is known as cystitis) or the kidneys (a condition known as pyelonephritis). 

Urinary tract stones usually form in the kidney and can increase in size by the time they reach the ureter or bladder. Urinary stone can be called a kidney stone, ureteral stone, or bladder stone depending on its location in the urinary tract. 

A urinary tract infection may occur when there is a blockage in the urinary tract and the bacteria get trapped in the pool of urine above the blockage. This blockage is by the urinary stones which cause the urine to back up in the tubes inside the kidney, leading to excessive pressure on the kidneys. 

The increased pressure causes the kidneys to swell (the condition is known as hydronephrosis) and eventually results in kidney damage.

Type of Stones That Cause UTI

Stones are made up of minerals and salts in your urine that forms crystals. Around 85% of the stones are composed of calcium and the remaining are made up of various substances like uric acid, cystine, or struvite. 

Out of these, only struvite stones cause urinary tract infections. Struvite stones are composed of magnesium, ammonia, and phosphate and are also known as infection stones as they are formed only in infected urine. 

Risk Factors For Developing Infection Stones

Infection stones can occur in people with:

  • Urinary tract obstruction

  • Neurogenic bladder (a condition in which you lose control of your bladder due to brain, spinal cord, or nerve problem)

  • Voiding dysfunction (a condition in which there is no/little coordination between your bladder muscles and urethra which can cause urgency, frequency, or incontinence)

  • Indwelling urinary catheters

  • Conditions like distal RTA (Renal tubular acidosis) and medullary sponge kidney. RTA is a condition in which your kidneys are not able to acidify the urine leading to increased levels of acid in the blood. This causes symptoms like fatigue, muscle weakness, and other kidney problems.Medullary sponge kidney is a condition seen at birth in which tiny fluid-filled sacs called cysts develop in the tubules of the kidney (medulla)  creating a sponge-like structure, hence the name.

Symptoms of Infection Stones

In some cases, if you have a urinary stone, you may notice symptoms similar to those of a urinary tract infection (UTI), such as:

  • More frequent urination or urge to urinate

  • Pain or discomfort during urination

  • Discolored urine

  • Foul-smelling urine

  • Blood in the urine

  • Fever

Diagnosis 

Your doctor will conduct a blood test, urinalysis, and urine culture to check for the presence of bacteria in your urine. If your doctor suspects a problem such as stones in your urinary tract, an X-ray, an ultrasound, a CT (Computer Tomography)  scan, or an MRI (Magnetic Resource Imaging) scan might be done to take a closer look. 

IVU (Intravenous urography) test can also be done. IVU uses X-rays and special dyes to check the problems with your kidneys, ureters, and bladder. 

Prevention and Treatment of Infection Stones 

Diet change is not effective at preventing struvite stones because they are caused by infections. You should drink extra fluids if you have a propensity to form stones as crystals are not likely to be formed in watery urine. 

Drinking certain fluids like lemonade, orange juice, cranberry juice, coffee, and tea may prevent the growth of struvite stones. Consult your doctor to ask how much fluid you should drink.

Your doctor may advise the following treatment:

  • Painkillers to relieve the symptoms: NSAIDs (Non-steroidal Anti inflammatory Drugs) are most commonly used to relieve pain.

  • Stone removal by surgery

  • Antibiotic treatment for UTI till the stones are removed

Post-surgery, your doctor may prescribe medications to prevent the regrowth of struvite stones.

Urinary stones are a common problem and require treatment. If you have symptoms like back and side pain, fever, and frequent urination,  do not neglect them! Consult your doctor for timely diagnosis and treatment. 


References:

1. Urologyhealth.org. 2021. Urinary Stones: Symptoms, Diagnosis & Treatment - Urology Care Foundation. [online] Available at: <https://www.urologyhealth.org/urology-a-z/k/urinary-stones> [Accessed 4 March 2021].

2. National Kidney Foundation. 2021. Urinary Tract Infections. [online] Available at: <https://www.kidney.org/atoz/content/uti> [Accessed 4 March 2021].

3. Miano, R., Germani, S. and Vespasiani, G., 2007. Stones and Urinary Tract Infections.     Urologia Internationalis, 79(1), pp.32-36.


Disclaimer: This article is written by Practo for informational and educational purposes only. The content presented on this page should not be considered as a substitute for medical expertise. Please "DO NOT SELF-MEDICATE" and seek professional help regarding any health conditions or concerns. Practo will not be responsible for any act or omission arising from the interpretation of the content present on this page.