Crystals in the urine can be a normal finding that occur due to eating habits, decreased water habits and changes to body temperature. High levels, however, may be a result of a health condition, like kidney stones, gout or a UTI.
Crystals found in the urine are made-up of built-up substances that are present in the body, like medications or organic compounds, like phosphate, calcium and magnesium. These substances form crystals for various reasons, like changes to body temperature, UTIs, changes to urinary pH, or if these substances start to accumulate in high concentrations.
Crystals can be detected in the urine through a urine test, particularly with the R&M (routine & microscopy) test. The R&M will also evaluate other markers, like urine pH and the presence of bacteria.
The presence of crystals in the urine usually do not cause symptoms, as they can be an expected or normal finding. However, high levels of crystals can cause symptoms like:
- Changes to urin ecolor
- Difficulty urinating
- Abdominal pain
If you experience these symptoms, you should see your family doctor or nephrologist for further testing, so that a diagnosis can be confirmed.
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A urine test can detect the presence of crystals and even identify the type of crystals noted. Normally, the lab report will report whether there are few, moderate, or several crystals, which will help to guide a diagnosis.
The main causes for the formation of crystals in the urine are:
- Dehydration: Decreased water intake can lead to an increased concentration in substances that can form into crystals. Dehydration can trigger the build-up of salts, leading to the formation of crystals.
- Medications: Some medications can lead to the build-up and formation of crystals, like casts of sulphonamide or ampicillin crystals, for example.
- UTI: The presence of bacteria in the urinary tract and lead to the formation of crystals due to changes in pH. pH fluctuations can facilitate the build-up of some compounds, like triple phosphate crystals that are generally found with genitourinary infections.
- High protein diet: Eating protein in excess can overload the kidneys, which can lead to higher concentrations of certain substances (e.g. ingested protein and uric acid) and the formation of crystals.
- Gout: Gout is a painful inflammatory disease caused by increase uric acid in the blood. Uric acid can also be noted in the urine as crystals.
- Kidney stones: Kidney stones can occur for many reasons and are often detected due to presenting symptoms and with a urine test. The urine test will usually show many oxalate crystals.
Crystals in the urine can also occur as a result of metabolic malfunctioning or of liver disease. Therefore, once crystals are present in the urine, the doctor should order additional testing to confirm the underlying cause, which will help to guide treatment.
Types of crystals
The type of crystals that form is determined by urine pH. The most common types of crystals are:
- Calcium oxalate crystals: These have an envelope shape and are usually present in urine that is acidic or neutral in pH. Low levels can be a normal finding, and may be related to kidney stones or decreased water intake. This type of crystal can be found in high levels with diabetes, liver disease, severe kidney disease or in vitamin C-rich diets.
- Uric acid crystals: These are usually noted in acidic urine and are caused by high protein diets (as uric acid is a product of protein breakdown). Diets that are high in protein can lead to the accumulation and build-up of uric acid. Uric acid may also be a sign of gout or chronic nephritis.
- Triple phosphate crystals: These are found in alkaline urine and are made-up of phosphate, magnesium and ammonia. High levels of this crystal can be a sign of cystitis or a hypertrophic prostate.
Some liver disease can also be detected through the presence of crystals in the urine, like tyrosine, leucine, billirubin, cystine, and ammonium biurate. Leucine crystals, for example, can be sign of cirrhosis or viral hepatitis, which require further testing to confirm.