What should I do if I think I have kidney stones?
If you have pain in your loin, especially if you also have other urinary symptoms or features suggesting an infection in your urine, you should contact your GP for further advice. Whilst kidney stones may cause pain in the loin with radiation down into your groin, there are many other causes for such pain. These include problems with your back and spine as well as a number of other non-urological conditions. The only way to find the cause of your symptoms is to have further investigations with your GP.
What are the facts about kidney stones?
- Kidney stones are found in 2-3% of people and 0.5% of people present each year with an acute episode of pain due to stones. These rates have been rising steadily since the start of the 20th century
- Men are more commonly affected than women. After the age of 50 when the sex distribution becomes equal
- At the age of 70, you have a lifetime risk of 1 in 8 for forming a stone
- Stones are responsible for more than 12,000 hospital admissions each year
- Stone formation is governed by both intrinsic (heredity, age & sex) and extrinsic factors (geography, climate, water intake & diet)
- Poor fluid intake combined with a low-roughage, high protein diet containing a lot of refined sugar increases the risk of forming stones
- There is an association with the “metabolic syndrome” (Syndrome X)
- Recurrence rates for stones are high (20% at 5 years, 35% at 10 years & 70% at 20 years)
What should I expect when I visit my GP?
1. A full history
Your GP will take a full clinical history, including asking about your diet, time spent in a hot dry climate, your fluid intake and whether there is a family history of stones.
2. A physical examination
A full physical examination, including assessment of your abdomen, will normally be performed and your blood pressure will be taken as part of the assessment.
3. Additional tests
The usual tests performed are:
a. General blood tests
The actual tests performed will be left to your GP’s discretion. It is normal to measure kidney function, liver function, blood sugar, uric acid, bone function (calcium levels) and to check the blood cells for anaemia or other problems
b. Urine tests
Your urine will normally be tested for blood (90% of patients with a stone have a trace of blood in the urine) and the pH (acidity) measured. A specimen may be sent to the laboratory to screen for infections and to measure a specific chemical called cystine. 24-hour urine output collections will also be arranged for more detailed chemical analysis If:
- you are less than 30 years old
- have a family history of stones
- have had stones within the previous 5 year
c. Other specific test
The best way to diagnose stones is to have a CT scan. Your GP may be able to arrange this for you. If not, he/she will arrange referral to a urology unit where the scan can be arranged. Almost all stones show up on a CT scan.
What could have caused my kidney stones?
The main reasons for forming stones are:
- Anatomical (structural) abnormalities (inherited or acquired)
- Excess stone-forming substances in the urine
- Lack of stone inhibitors in the urine
- Chronic Infection in the urine (mostly in post-menopausal women)
- Idiopathic (i.e. no reason identified in 5-10%)
In most patients, more than one of the groups above is involved in stone formation. Where no cause is identified, the stones are usually made of calcium oxalate. Recurrence of these stones is common. What treatments are available for this problem?
You will normally be given specific advice about changes to your diet and fluid intake which will reduce the risk of further stone formation. There is some evidence that stone inhibitor levels (especially citrate) can be increased by drinking fresh lemon juice in water. This reduces the levels of stone-forming chemicals in your urine. You should not restrict your calcium intake. Installing a water softener is not helpful in preventing further stones. Avoid grapefruit juice (pictured) and vitamin C supplements which can increase the risk of forming stones. Medical treatment Thiazide diuretics and other drugs may be used to reduce the calcium levels in your urine. It may be possible to dissolve certain less common types of stone using drugs but this is only appropriate for
- cystine stones (penicillamine therapy)
- uric acid stones (urinary alkalinisation)
If you have a stone caused by infection, you will be prescribed antibiotics before stone treatment and you may be asked to continue them after surgery. You may be given further advice about specific medical treatment once your stone has been analysed chemically.
Small, symptomless stones in the kidney can be monitored by regular checks with an X-ray. Stones of a similar size in the ureter (less than 5mm diameter) may pass by themselves but active treatment will normally be recommended if the stone shows no sign of passage after 2-3 weeks. If you are found to have a stone in the ureter, you may be prescribed a muscle-relaxant drug (usually an alpha-blocker, normally used to relieve prostate symptoms). This can help to speed stone passage by specifically relaxing the muscle of the ureter. Drugs which relieve muscle spasm (e.g.Buscopan, Probanthine) are still used but have little effect on symptoms and do not speed stone passage.
This is the most common treatment recommended for stones in the kidneys and for stones less than 1cm diameter in the upper ureter (the drainage tube between kidney & bladder). 90% of stones will clear with one treatment but some patients may need re-treatment or even surgical intervention. If your stone has not responded to two successive treatments with ESWL, it is unlikely to fragment with further treatments. Other removal methods will then be considered. ESWL cannot be performed safely in
- pregnant women
- patients on heparin, Warfarin or other blood-thinning agents (e.g. dipyridamole, clopidogrel)
- patients whose weight exceeds 300lb.
The main reasons for recommending surgical treatment are:
- a stone which is too large to pass spontaneously (greater than 5mm diameter)
- a stone which is causing obstruction to urine drainage
- a stone which is causing (or has been caused by) infection
- a stone which has formed as a result of an anatomical (structural) problem which also needs correction at the same time as stone treatment
- failure of simple painkillers to control symptoms
Percutaneous (keyhole) surgery
This is used for large stones in the kidney (e.g. “staghorn” stones) or large stones in the upper ureter, either as a primary measure or if ESWL has failed.
Smaller stones in the kidney can be extracted or fragmented with a laser, using a flexible telescope passed through your bladder. You may have a temporary stent inserted after this procedure.
Stones in the ureter can be extracted or fragmented with a laser, using a rigid telescope passed through your bladder. You may have a temporary stent inserted after this procedure. Courtesy Endourology Patras
Insertion of a ureteric stent
In the emergency situation, when a stone is blocking the ureter completely, it may be necessary to insert a stent under general anaesthetic to relieve the blockage so that definitive treatment can be performed at a later stage. Courtesy Nigel Bullock
If there is a blockage with severe infection due to a stone in the ureter, a drainage tube may be inserted into your kidney under local anaesthetic to relieve the problem. This will be followed, at a later date, by definitive treatment of the stone. Credit http://www.baus.org.uk/patients/symptoms/index
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