If you have been diagnosed with urinary stone disease then you probably already know that stone attacks cause severe and distressing pain. This page aims to answer some of the questions you may have about your stone.
Is it serious?
Aside from being acutely painful, urinary stones can be serious if they cause obstruction of the urinary tract or are associated with urinary tract infection. In fact, urinary stones can often present a medical and surgical emergency, but they’re very treatable. As long as you are treated promptly by an experienced urologist, urinary stones are rarely life-threatening and are usually not a cause of ongoing concern with proper management.
Why do stones form?
The exact chemistry of stone formation is complex and not fully understood. Certain conditions increase the probability of stone formation: dehydration (by producing concentrated urine), conditions which interrupt the flow of urine from the kidneys or bladder, recurrent urinary tract infections, certain metabolic abnormalities and/or excess salt in the diet.
Endoscopic removal of a stone from the ureter.
What are the different kinds of stones and how are they different?
Calcium oxalate stones:
The great majority of urinary stones (95%) treated in Australia are composed of calcium oxalate. Because they contain calcium, like your bones, these stones are visible on plain X-rays. High calcium levels or hypercalcaemia may contribute to calcium oxalate stone formation. Hypercalcaemia has a number of treatable underlying causes – if you have high calcium, further investigations will be undertaken. Most calcium oxalate stones form in the absence of hypercalcaemia. Excess dietary salt may increase the risk of stone formation as it increases calcium in the urine and decreases the action of inhibitors of stone crystallisation.
Uric acid stones:
Around 5% of urinary stones are comprised of uric acid, produced as a by-product of purine metabolism. Purines are found in certain foods, including red wine, beer and red meat. If you suffer from uric acid stones, your doctor may recommend limiting your dietary intake of purine containing foods. Uric acid stones tend to form in acidic urine, so treatments to reduce the acidity (or alkalinise) your urine may also be recommended, usually this involves taking sodium bicarbonate in solution.
Cystine stones are rare, but may occur in people with high levels of cysteine (an amino acid) in the urine.
Struvite or infective stones:
Bacteria can reduce the acidity of the urine, predisposing to precipitation of stones formed from calcium, magnesium and phosphate. Women in particular are prone to infective stones.
All stones have the potential to cause obstruction in the urinary tract, so surgical treatments are necessary.
What kind of tests will I have when I am diagnosed?
You will have a CT scan and a plain X-ray, you may also have an ultrasound.
You will have a blood test to measure calcium and uric acid levels; if these are abnormal you may need follow up blood tests.