Crystals in urine - labsstudies

Crystals in urine

Crystals in Urine

Introduction to Crystals in urine

Crystals in urine form when there are too many minerals in your urine and not enough liquid. The tiny pieces accumulate and form masses.

These crystals may be discovered during urine tests (urinalysis). The presence of crystals in your urine is referred to as crystalluria.

Urine contains a wide range of chemicals. These chemicals may solidify into salt crystals in certain conditions. This is referred to as crystalluria.

Crystals have a distinct refractile appearance.

Testing for crystals in urine is frequently part of a urinalysis, which measures various substances in the urine.

Because normal urine contains many chemicals from which crystals can form, the discovery of most crystals is insignificant.

This means that crystals can be found in the urine of clinically healthy animals or animals that show no signs of urinary disease (such as obstruction and/or urolithiasis).

The pH (acidity) of your urine can affect the type of crystals that form.

Crystals in urine

Crystals Found in Urine include the Following :

Calcium phosphate crystals

Crystals in urine

Calcium phosphate crystals are common in urine and resemble large flat-shaped plates or wedge-shaped prisms. The prisms are frequently found in rosettes. Prisms are typically blunt on one end and pointed on the other. Although they are considered normal, they may be linked to kidney stone formation.

 

Uric acid crystals

Crystals in urine

Uric acid crystals form in acidic urine, which typically has a pH of 5.5. Uric acid dissolves in alkaline urine, preventing urate crystal precipitation.

Urinary alkalinization in patients at risk of acute uric acid nephropathy is justified by uric acid’s inability to crystallize at urine pH greater than 7.0. Uric acid crystalluria is not associated with hematuria, glycosuria, or proteinuria in significant amounts.

Uric acid crystals can vary in size and shape. They can have the appearance of barrels, rosettes, rhomboids, needles, or hexagonal plates. Regardless of the size or shape of the individual crystal, they are usually amber in color. However, urate crystals may take on the color of any pigments present in the urine (such as bilirubin or the medication pyridium).

Urate crystals can be seen in healthy people on occasion, but they are much more common in patients with urate nephrolithiasis or acute urate nephropathy

  Triple phosphate crystals

Crystals in urine

Also known as struvite, are described as having a “coffin-lid” shape. Above are several struvite crystals. Struvite is made up of magnesium ammonium phosphate crystals.

They are most commonly found in alkaline urine with a pH greater than 7.0. Triple phosphate crystals are frequently found in the urine of  patients with infected calculi and are seen in patients with urinary tract infections caused by urea-splitting bacteria such as Proteus mirabilis (struvite stones).

Microscopy in these patients with urinary tract infections may reveal significant leukocyturia (arrows, above right) and bacteriuria in addition to triple phosphate crystals.

  Calcium oxalate crystals

Crystals in urine

Acidic urine typically contains calcium oxalate crystals. They can be bihydrated or monohydrated calcium oxalate. Calcium oxalate bihydrate crystals appear in the form of colorless bipyramids of varying sizes (“envelope form”, above left).

Calcium oxalate monohydrate crystals are colorless and come in a variety of shapes such as ovoids, biconcave disks, rods, and dumbbells (above right, yellow arrows). They can be seen in healthy people who consume a lot of oxalate, in people who have nephrolithiasis, and in people who have acute renal failure due to ethylene glycol ingestion.

Also Read: Abnormalities Constituents of Urine

Amorphous crystals

Crystals in urine

At the light microscopic level, “amorphous” crystals appear as aggregates of finely granular material with no discernible shape. They can contain urates, phosphates, or xanthine.

They are typically small crystals that can only be seen under high magnification (unless there are a large number of them), i.e. they mimic bacteria.

 Calcium carbonate crystals

Crystals in urine

Calcium carbonate crystals come in a variety of sizes and frequently appear as large spheroids with radial striations. Smaller crystals with round to ovoid shapes can also be seen.

When present in large numbers, they are colorless to yellow-brown and can impart a brownish tinge to the urine. They are typically large crystals that can be seen at low magnification (however, confirmation of crystal identity should always be performed under high magnification and smaller variants of calcium carbonate may be missed if only low magnification is used).

These crystals are frequently found in the urine of healthy horses, rabbits, guinea pigs, and goats. They have not been found in either canine or feline urine.

Tyrosine crystals

They are yellow or dark in color and resemble needles clumped together. In ethanol, ether, and acetone, they are insoluble.

They are frequently found in acidic urine and can be caused by metabolic disorders such as liver disease or tyrosinemia.

 Bilirubin crystals

Crystals in urine

Bilirubin crystals are needle-like to granular yellow crystals formed from conjugated bilirubin (which is water soluble). They have a tendency to precipitate onto other formed elements in urine. Fine needle-like crystals have formed on an underlying cell in the top image. Bilirubin crystals most commonly appear in this form. In the lower two images, cylindrical bilirubin crystals have formed in association with fat droplets, giving the appearance of a “flashlight.” This is a less common variant. They are typically small crystals that can only be seen under high magnification (unless there are large aggregates of crystals). Bilirubin crystals are most commonly found in canine urine, particularly in highly concentrated samples. They are less common in other species’ urine.

Cholesterol crystal

crystals in Urine

Cholesterol crystals in urine are abnormal. They have the appearance of clear, flat plates with notched corners.

The presence of cholesterol is linked to the Nephrotic Syndrome.

Cholesterol crystals are accompanied by a positive protein biochemical test. They usually appear after the urine sample has been refrigerated and may be accompanied in the sediment by oval fat bodies, fatty casts, and free fat droplets.

 Ammonium Biurate crystals

Crystals in Urine

Crystals of ammonium biurate are commonly found in the shape of “thorn apples,” as shown here, or in polyhedral shapes. They range in color from dark yellow to brown. They can appear in clumps or clusters. This crystal can only be found in stale urine.

Cholesterol crystal

Crystals in Urine

Cholesterol crystals in urine are abnormal. They have the appearance of clear, flat plates with notched corners.

The presence of cholesterol is linked to the Nephrotic Syndrome.

Cholesterol crystals are accompanied by a positive protein biochemical test. They usually appear after the urine sample has been refrigerated and may be accompanied in the sediment by oval fat bodies, fatty casts, and free fat droplets.

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