Disease Guide

Calcium Oxalate Urinary Stones in Dogs & Cats: Symptoms, Diagnosis & Treatment [2025]

Calcium oxalate stones cannot be dissolved and must be surgically removed; they are common in middle-aged to senior pets and require long-term dietary management to prevent recurrence

Last updated: 2026/01/06
Pethealthmap Editorial Team
Sources: WSAVA, AAHA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek immediate veterinary care (emergency)

  • Completely unable to urinate despite repeated straining
  • Large amounts of bright red urine or persistent blood clots
  • Lethargy, refusal to eat, or persistent vomiting

Arrange a clinic visit as soon as possible (within 24-72 hours)

  • Frequent urination but still passing urine, with signs of discomfort
  • Crying out or showing obvious pain while urinating
  • Persistent licking of the genital area or refusing to use the litter box/toilet

01What Symptoms Indicate a Problem?

Calcium oxalate urinary stones commonly cause blood in the urine and changes in urination habits; your pet may appear uncomfortable or make repeated attempts to urinate.

  • Urine is pink or bright red — visible blood in urine
  • Frequent squatting or repeated attempts to urinate in a short period
  • Signs of pain or vocalising during urination
  • Noticeable change in frequency or volume of urination
  • Persistent licking of the genital area or suddenly refusing to use the litter box

Seek emergency care immediately if you notice the following symptoms:

  • ⚠️ Completely unable to urinate despite repeated straining
  • ⚠️ Passing large amounts of bright red blood or persistent blood clots in urine
  • ⚠️ Lethargy, loss of appetite, or persistent vomiting

02How to Assess Abnormalities at Home: Key Observations and When to Seek Emergency Care

These are observations you can record at home that will help your vet understand the progression and prioritise treatment.

  • Note when symptoms first appeared and how they have changed over time
  • Record daily water intake and urination frequency, including any instances of no urination
  • Use your phone to photograph or video the urination process, urine colour, or any blood clots
  • Weigh your pet weekly and watch for short-term weight changes
  • If energy levels or appetite decline, arrange a clinic visit as soon as possible

03How Will the Vet Diagnose This? Common Diagnostic Tests

Common tests at the clinic include urinalysis, imaging, and blood work to confirm the presence of stones and check for complications.

Physical examination

palpation to assess abdominal and urinary tract pain

Urinalysis including urine sediment examination to confirm haematuria and crystal type

X-rays

to identify the location, size, and number of stones

CT scan

used for complex cases or precise localisation of stones

Blood biochemistry

to evaluate kidney function and markers of infection or inflammation

Referral to a specialist hospital with X-ray or CT capability is recommended for further evaluation

04Treatment and Home Care After Diagnosis: Medications, Diet, and Management

Treatment may include conservative management, surgery, or prescription diets; regular follow-up after treatment is essential to reduce the risk of recurrence.

  • Urinary obstruction typically requires emergency treatment and hospitalisation
  • Manage pain and address infection with medications as directed by your vet
  • Prescription diets to adjust urine pH and mineral content
  • Schedule regular follow-up visits for imaging and urinalysis after surgery or treatment
  • Encourage increased water intake at home and adjust feeding as directed by your vet
  • If symptoms recur or do not improve, arrange a specialist referral for further evaluation

05What to Prepare Before the Vet Visit: Key Information to Speed Up Diagnosis

1
List the onset time, frequency, and progression of symptoms
2
Bring a record of urination and water intake from the past 24 hours
3
Bring phone photos or videos of urine colour, blood clots, or the urination process
4
Prepare a list of current medications and supplements
5
Bring any previous imaging results or examination reports if available

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.

Frequently Asked Questions (FAQ)