Cystinuria is an inherited metabolic disorder characterized by the abnormal movement (transport) in the intestines and kidneys, of certain organic chemical compounds (amino acids). These include cystine, lysine, arginine, and ornithine. Excessive amounts of undissolved cystine in the urine (cystinuria) cause the formation of stones (calculi) in the kidney, bladder, and/or ureter.
One of the peculiar things about cystinuria is that the amount of cystine excreted by the kidneys is not always related to the number and size of the stones formed. Some people with very high cystine levels form very few, if any stones. Others with comparatively low cystine levels are prolific stone formers.
Diagnostic tests for cystinuria include a 24 hour urine collection to determine the levels of cystine in the urine and a one off urine sample to detect higher than normal levels of cystine in the urine.
In recent years advances in genetic research have led to more information on the different types of cystinuria. There is more detail about cystinuria types included in the excellent article by Chandra Shekhar Biyani and Jon Cartledge. Regardless of which type you have most people with cystinuria can look forward to a lifetime of kidney stones. There are various ways of lowering the formation of stones, however as yet there is no cure.
Other problems, apart from kidney stones, people may encounter are:
- Knowing they have an incurable disease, which can remain silent and is like living with a time bomb
- Knowing the disease has no respect for personal circumstances and can present at the most inconvenient time.
- Knowing that at any time they can experience severe pain without warning when a stone is on the move.
- Knowing there will be times when they will require hospitalization for treatments, sometimes long term.
Other symptoms not generally associated with stone disease but which are commonly talked about are low grade chronic pain, tiredness, depression, unquenchable thirst, irritability, mood swings and generally being a pain in the neck to friends and families.
This can lead to a certain amount of depression and hopelessness. This can be overcome with the support of other people with cystinuria and a very supportive and loving family.
However, conversely, many others find that when they are well, they have less to complain about than other people and tend to enjoy life more when the disease gives them a break. They tend to have a higher pain threshold for other illnesses and a lower sick rate for minor ailments than the general population.
The most inconvenience some have is that they know the location of every toilet in their home town and are accused of drinking too much! Others find that they spend the majority of their time and money in a continual round of consultants, x-ray departments and treatments. Cystinuria is no respecter of wealth or convenience.