Don't cast the first stone

Bladder and kidney stones are one of the common problems that may complicate bladder management, but unless you and your doctor are aware that they may present at any time in your life, they may go unnoticed and continue to cause problems for you.

This month’s article was sparked by questions I received from a patient who had developed bladder stones. The stones had not been detected and had not been treated and had caused him a lot of discomfort.

Patients who are immobilised and in wheelchairs, and more specifically patients with spinal cord injuries, tend to lose calcium from their bones. This not only results in weakening of the bone structure (known as osteoporosis, and perhaps another whole topic in itself), but causes an increase in the amount of calcium excreted from the blood and into the urine.

Kidney and bladder stones form when high concentrations of calcium (and sometimes magnesium and other mineral salts) crystallise around an initiating “nidus” or seed – which may be some bacteria from an infection or may be the balloon of an indwelling catheter.

Ordinarily the presence of a kidney or bladder stone would provoke severe pain in an able-bodied person, but in the presence of a spinal cord injury, this of course is not the case and the stones are therefore often missed.

People with spinal cord injury may experience:

Recurrent, unexplained bladder infections.
A generalised increase in spasticity.
A generalised increase in profuse sweating.
Blood in the urine without signs of bladder infection.
Vague unexplained and difficult to localise pain and discomfort.
Urine bypassing the catheter.

If any of these symptoms do develop you should consult your doctor who could then organise urological investigations or refer you to a urologist to have these done. Stones can usually be easily picked up by an ultrasound or by a contrast x-ray study called an intravenous pyelogram (IVP).

When present they can often be easily removed using some modern techniques where the stones are crushed or destroyed using ultrasound shock wave or laser – so-called “lithotripsy”. After this the fragments of the stone are either simply washed out of the bladder as “gravel”, or may be removed using a cystoscope (a fibre-optic instrument that the urologist passes through the urethra, into the bladder allowing him to see the inside of the bladder and with specialised instruments to perform a limited amount of surgery without actually having to cut into the bladder from outside. Rarely the stone may be so big or may be localised in a difficult-to-reach position. In these unfortunate situations it is necessary to perform formal, “open” surgery that is more invasive. In most cases it is possible to remove the stones without too many problems.

Prevention of stones

And of course we know that “prevention is better than cure”. While it is important that you recognise the symptoms of possible stones and seek help as early as possible if you think that you have these symptoms, it is more important to try and prevent the stones from occurring in the first place.

Preventing stones involves a couple of simple steps:

Make sure, in conjunction with your doctor, that you have taken all steps to prevent urinary tract infections and that you managed any infection aggressively and completely. If in doubt talk your doctor again about this.
It is useful to keep your urine slightly acid by using simple vitamin C or ascorbic acid because this discourages the formation of the calcium salt crystals that tend to form better in alkaline urine.
Ensure that you keep your urinary output above 1500-1800 millilitres per day if you are using intermittent self catheterisation, or above 3000 millilitres per day if you have an indwelling catheter. This results in a better washout effect, ensuring that there is no stagnancy around the catheter or in the bladder.
Change your silastic indwelling catheter at 4-6 week intervals (or your latex catheter every 1-2 weeks) because this prevents the build-up of so-called eggshell stones around the balloon. Watch out for grit in the tubing or in the catheter and report this to your doctor if it does occur.
Try to be as active as possible and to engage in therapeutic standing in a standing frame or chair as much as possible because this reduces the loss of bone calcium caused by immobilisation.
Avoid excessive calcium intake by way of large amounts of dairy products and calcium supplements. A normal, but not excessive intake is recommended.
Make sure that you do attend your doctor at least once a year for urological screening and investigation.

The simple take-home message is that these stones are common, but their presence may be hidden by your lack of sensation. Unless you are aware that they may exist, they can continue to make your life unpleasant and leave you feeling ill. Make sure that you do everything to prevent them, and if you think that they may be present get to your doctor early. He will be able to help you to find them and remove them if they are there.

Kidney and bladder stones form when high concentrations of calcium (and sometimes magnesium and other mineral salts) crystallise around an initiating “nidus” or seed. The photos below represent just a few of the types of stones that can be found in the kidneys and bladder: a) Calcium Oxalate Monohydrate b) Carbonate Apatite c) Cystine d) Silica e) Uric Acid f) a stone measuring 50 mm across.

Columnist Photos