Do crystals in my puppy’s urine indicate a UTI?

Disclaimer: This article, its content, and its related references do not constitute veterinary advice and should not be considered a substitute for veterinary care. If your pet is showing any symptoms that could indicate a medical emergency, please seek immediate emergency care.

Urinary crystals are very common in dogs of all ages, including puppies, and they don’t usually cause problems. The presence of crystals in the urine may or may not be related to a urinary tract infection (UTI) or other health concern. Read on to learn:

• What urinary crystals are
• Why a puppy may have crystals in their urine
• What to do if you’re concerned about your puppy’s urinary health

Crystals are common in completely healthy puppies and often an incidental finding in urine samples, meaning they’re unrelated to any problems the puppy may have. The presence of crystals doesn’t necessarily indicate that a puppy has a UTI or other medical problem that needs treatment.

Some puppies are genetically predisposed to producing certain types of crystals, and the type or amount of crystals present may also offer clues when a puppy has an underlying medical condition, such as bladder stones, a urinary tract infection, liver or kidney disease, or a toxin exposure.

Puppy owners may wonder about urinary crystals when they notice fine, grainy solids while cleaning up a spot of dried urine on the floor. Crystals that are large enough to see or feel commonly form as urine reaches room temperature and dries out. Their presence is unrelated to whether or not there are crystals actually present in your pet’s bladder and are not a sign of something going on in your puppy’s urinary tract, especially if your puppy is acting fine. Rather, it’s the crystals that can be seen when examining a fresh urine sample under a microscope that may be significant to your puppy’s health.

Crystalluria, or the presence of crystals in urine, occurs in both healthy and unhealthy puppies. It’s normal for undissolved solids to be excreted in the urine, and minerals may form crystals when the characteristics of the urine — pH, temperature, and concentration of minerals — don't allow the minerals to remain dissolved.

Urinary crystals are microscopic and can’t be seen with the naked eye unless they collect into larger clumps called urinary stones, or uroliths. The two most common types of crystals in dogs are struvite and calcium oxalate crystals. These are often incidental findings that do not cause any medical issues.

Several types of medical conditions are associated with changes in the type and/or quantity of crystals, such as urinary disorders and systemic diseases, like poisoning or liver disease. Sometimes crystals form due to altered urinary pH from a bacterial infection, but crystals do not directly cause UTIs.

Clinical signs of crystals in puppies

Urinary crystals usually do not produce clinical signs unless they congregate to form larger urinary stones that cause bloody urine or straining to urinate. In a puppy with abnormal crystalluria, any clinical signs are more likely to be due to the underlying medical condition.

Examples of clinical signs associated with a UTI include:

• Straining to urinate
• Frequent urination, often of small amounts
• Bloody urine
• House-soiling
• Abnormally dark urine
• Pain while urinating
• Excessively licking the genitals
• Wet or matted fur around the groin

If the abnormal crystalluria is due to liver disease, such as a portosystemic shunt (especially relevant for puppies), clinical signs may include:

• Poor/stunted growth
• Vomiting and diarrhea
• Seizures

If a puppy has abnormal urinary crystals from getting into a highly lethal toxin, like antifreeze, a sudden onset of additional and severe symptoms is expected, such as:

• Vomiting
• Diarrhea
• Collapse

A puppy may be born with a rare, inherited disorder called polycystic kidney disease that can cause abnormal urinary crystals. They may develop symptoms associated with renal failure later in life:

• Appetite loss
• Vomiting
• Lethargy

Some puppies may be born with a genetic predisposition for producing large numbers of certain types of crystals. Dalmatians, for example, so commonly produce large numbers of urate crystals that they’re considered normal in that breed. Calcium oxalate crystals may form in any breed of puppy, but miniature schnauzers, Lhasa apsos, Yorkshire terriers, bichon frises, shih tzus, and miniature poodles may be predisposed. Affected puppies typically do not show any clinical signs unless the crystals form into larger stones. Puppies with stones may show signs such as:

• Straining to urinate
• Bloody urine
• Passage of visible stones

“The significance of urinary crystals is variable,” states Dr. Jo Myers, a veterinarian on the Vetster platform. “They form as a normal part of the process of excreting minerals in urine.” Since crystalluria may or may not be normal, it must be considered within the context of everything else going on with the puppy.

Different factors can affect the type or number of crystals in the urine, contributing to abnormal crystalluria in puppies. These include:

• Urinary tract infection
• Liver disease, with portosystemic shunts being especially relevant for puppies
• Kidney disease
• Genetics
• Toxin ingestion, particularly antifreeze toxicosis (ethylene glycol)

Urinary crystals aren’t identified until a urinalysis is performed on a fresh sample, so typical next steps for a puppy with crystals usually focus on identifying the significance of the crystals and if they offer clues about something else that might be going on. If the urinalysis was performed because the puppy came in for something other than urinary symptoms, that issue is more likely to be the priority when determining next steps.

Though urinary crystals in puppies are often incidental, additional diagnostics may be recommended to look for underlying health problems contributing to abnormal crystal formation, such as:

• A UTI
• An anatomical defect that may contribute to incontinence and UTIs
• Kidney or liver disease.

In addition to a urinalysis, common diagnostics include:

• Thorough physical exam
• Blood work
• Diagnostic imaging
• Urine culture

Even if there’s no underlying cause for a puppy’s abnormal crystalluria other than a genetic predisposition, a vet may recommend monitoring or treatment out of concern for stone formation. Special diets can be used to reduce the formation of some types of crystals.

Are urinary crystals common in puppies?

Crystals are a normal part of urine, so they’re common in all dogs, including puppies. However, sometimes they congregate to form larger urinary stones, or crystalluria.

Bacterial UTIs are one of the most common causes of abnormal crystalluria, and they occur frequently in dogs of all ages, including puppies. Some breeds are predisposed to certain types of crystals, so those types may be commonly identified in urine samples from those (usually asymptomatic) puppies. Puppies and dogs of any age are susceptible to toxins that can cause abnormal crystalluria, such as antifreeze. Many other diseases associated with abnormal crystalluria usually affect older dogs, such as liver and kidney disease, but portosystemic shunt, while uncommon, is one example of a type of liver disease typically diagnosed in puppies.

Commonly, an owner will feel fine grains in their puppy’s urine when cleaning up after an accident on the floor. However, this is normal when urine reaches room temperature and starts to dry, so it’s unlikely to mean anything, especially if the puppy is acting fine.

If your puppy is showing urinary symptoms, such as frequent urination, bloody urine, or painful urination, a vet visit is warranted. Urinary symptoms are caused by a number of different medical conditions, including UTIs and urinary stones, so diagnostic tests are usually needed to determine the cause of the symptoms and to create an appropriate treatment plan.

Unproductive straining to urinate — when a puppy isn’t able to pass urine — is considered a medical emergency. This may be a sign of a urinary obstruction, which can quickly become life-threatening.

An online vet is a great tool for seeking advice if your puppy is showing urinary symptoms and you need help deciding what to do next, or if you need help while your puppy is recovering from a UTI or other urinary issue.

Do urinary crystals in dogs mean they have a UTI?

The presence of crystals in the urine does not necessarily mean a dog has a UTI or other urinary condition. Minerals are a normal component of urine, and they may not stay dissolved depending on their concentration in the urine and the urine’s pH and temperature. When conditions in the urine do not allow them to remain dissolved, they are visible as microscopic crystals. Different minerals can be identified by the shape of crystal they form. Urinary tract infections are diagnosed by identifying disease-causing bacteria in the urine, not crystals. Some UTIs change the pH of the urine enough to cause a high concentration of struvite crystals, but the presence of crystals alone does not necessarily mean a dog has a UTI.

Can UTIs cause urinary crystals in dogs?

Urinary tract infections can change the characteristics of a dog’s urine, allowing minerals to precipitate out of the urine instead of staying dissolved. The number of crystals usually decreases with successful treatment of the infection.

Why does my puppy have crystals in their urine?

Urinary crystals (crystalluria) form in a puppy’s urine based on the urine concentration, temperature, pH, and other factors. This is a normal part of how minerals are excreted in the urine. The presence of crystals in a puppy’s urine does not necessarily mean they have a UTI or other medical condition. Crystals are common in healthy dogs, including in puppies. There are a number of factors, such as urinary tract infections, liver disease, genetics, and ingestion of a toxin, that can influence the type and number of crystals in a puppy’s urine and cause abnormal crystalluria.