What are the common causes of oliguria or anuria in pets?

Reduced or absent urine output can result from kidney dysfunction, urinary tract obstruction, or severe dehydration. Blood tests, urinalysis, and imaging are needed to identify the cause — seek veterinary care promptly.

What should I do if my pet has not urinated in 24 hours?

No urine in 24 hours is a medical emergency. Contact your nearest emergency or after-hours veterinary clinic immediately to prevent further deterioration.

What tests will the vet run at the appointment?

Common tests include a physical examination, blood biochemistry panel, urinalysis, X-rays, and abdominal ultrasound. Further imaging may be arranged if needed — follow your vet's recommendations.

How can I help prepare information for the vet visit?

You can help by recording when symptoms started, tracking daily water intake and urination volume, bringing a fresh urine sample if possible, and bringing a current medication list for the vet to review.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Oliguria & Anuria in Dogs & Cats: Symptoms, Diagnosis & Care [2025]

Oliguria (reduced urine output) or anuria (no urine) is a kidney emergency indicating severe renal impairment or urinary tract obstruction. Immediate veterinary attention is essential.

Take 1 minute to check the symptoms first

Last updated: 2026/01/06

Pethealthmap Editorial Team

Sources: AVMA, AAHA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek immediate veterinary care (emergency)

•No urine at all or extremely little output within 24 hours
•Repeated vomiting with persistently low spirits
•Dry mouth and gums or noticeably sunken eye sockets

Schedule a veterinary visit soon (within 24–72 hours)

•Markedly reduced frequency of urination persisting for several days
•Noticeably reduced appetite with refusal to eat for consecutive days
•Greatly reduced activity but still able to move

01What symptoms indicate a problem?

Oliguria (reduced urine output) or anuria (no urine) is often accompanied by changes in energy, appetite, or gastrointestinal signs. The following are common presentations and urgent warning signs to watch for.

Lethargy, dullness, or excessive sleepiness
Noticeably reduced appetite or complete refusal to eat for one or more days
Significantly reduced activity or reluctance to move
Decreased frequency of urination or almost no urination at all
Vomiting or diarrhoea, with possible signs of dehydration

Seek emergency care immediately if you notice the following symptoms:

⚠️ No urine produced at all within 24 hours, or extremely small amounts
⚠️ Repeated vomiting with sustained lethargy
⚠️ Dry or pale gums, sunken eyes, or other obvious signs of dehydration

02How can I tell if something is wrong? What to watch at home and when to go to the emergency vet

Keeping a home record of observations and measurements helps your vet assess the condition accurately and prioritise the next steps.

Note any changes in alertness and activity level compared to normal
Measure and record your pet's daily water intake
Count the number of urination attempts each day and estimate the volume produced
Weigh your pet regularly and track any weight changes over time
Take photos or video of urination attempts — or the absence of urination
If abnormalities persist, arrange a veterinary consultation as soon as possible

03How will the vet diagnose this? Common tests and procedures

Your vet will combine a physical examination with blood work and imaging to evaluate kidney function, electrolytes, and whether obstruction or structural abnormalities are present.

Full physical examination including abdominal and bladder palpation

Blood and biochemistry panel to assess kidney function and electrolyte balance

X-rays to evaluate kidney and urinary tract structure and screen for stones

Abdominal ultrasound to examine the kidneys, bladder, and ureters

CT scan for further advanced imaging if indicated

A clinic with ultrasound and X-ray capability is recommended for this presentation

04How is it treated and managed after diagnosis? Medications, diet, and home care guide

After treatment, ongoing monitoring of kidney function, urine output, and body weight is essential. Follow-up frequency and home care adjustments will be guided by your pet's progress.

Monitor the response to prescribed medications and fluid therapy as directed
Feed the renal prescription diet recommended by your vet and watch for any change in response
Attend regular follow-up appointments for blood tests to check kidney function and electrolytes
Record daily urine output and body weight — return to the clinic promptly if anything changes
Specialist referral or hospitalisation may be needed for further management
Home care focuses on maintaining hydration and providing a calm, quiet rest environment

05What should I prepare before the vet visit? Key information to help the vet assess your pet quickly

Record when symptoms began and how they have changed day by day

Note any changes in food intake and water consumption

Log the number of urination attempts and estimated urine volume each day

Bring a list of all current medications and supplements

Collect a fresh urine sample in a clean container and refrigerate it before the visit (if possible)

Bring videos of urination attempts and photos showing any changes

Book at a clinic that can perform ultrasound and X-ray imaging

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.