What is Fanconi syndrome?

Fanconi syndrome is a disorder caused by abnormal renal tubular function, commonly presenting with excessive thirst, frequent urination, weight loss, and electrolyte imbalance. Diagnosis requires blood and urine testing — consult your vet for a full evaluation.

How does the vet diagnose Fanconi syndrome?

The vet will perform blood chemistry, urinalysis, and urine specific gravity testing. Imaging and specialist tests may be added if needed to confirm renal tubular dysfunction and electrolyte status. Follow your vet's guidance for monitoring.

Can Fanconi syndrome be cured?

Outcomes depend on the underlying cause. Some cases can be stabilised with supportive care and dietary management, while others may require long-term management. Discuss the prognosis and follow-up plan with your vet.

What should I monitor and record at home?

Record your pet's weight, water intake, urination frequency, and any vomiting or appetite changes daily. Share these logs with your vet to help adjust treatment and track progress.

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

Fanconi Syndrome in Dogs & Cats: Symptoms, Diagnosis & Care Guide [2025]

Fanconi syndrome is a renal tubular reabsorption disorder that causes urinary loss of electrolytes and glucose. It is most common in Basenji dogs and typically requires lifelong electrolyte supplementation and dietary management.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap editorial team

Sources: IRIS, AVMA, National Taiwan University Veterinary Hospital

When to See a Vet

Immediate veterinary care needed (emergency)

•Persistent severe vomiting with inability to eat or obvious weakness
•Obvious dehydration, delayed skin tenting, and sunken eyes
•Sudden inability to stand or ongoing seizures

Schedule a clinic visit soon (within 24-72 hours)

•Persistent thirst with water intake clearly increased above normal
•Frequent urination or increased nighttime urination that disrupts sleep
•Ongoing weight loss without an obvious change in appetite

01What Symptoms Should I Watch For?

Fanconi syndrome in dogs and cats often presents with systemic and urinary-related changes. The following are symptoms commonly observed by pet owners.

Decreased energy and noticeably reduced activity
Gradual weight loss even without a clear drop in appetite
Significantly increased water intake (polydipsia) and frequent drinking
More frequent urination or increased nighttime urination
If any of the above changes occur, arrange a veterinary visit as soon as possible

Seek emergency care immediately if you notice the following symptoms:

⚠️ Persistent vomiting with inability to eat or marked weakness
⚠️ Obvious dehydration, poor skin turgor, and sunken eyes
⚠️ Sudden inability to stand or repeated seizures

02How to Monitor at Home: Key Observations and Emergency Guidelines

Recording key changes and collecting samples at home before your visit will help your vet assess the situation more quickly and plan appropriate tests.

Note when symptoms started and document any daily changes or worsening
Weigh your pet daily at the same time using the same scale and track the trend
Count daily urination episodes and estimate relative changes in urine volume each time
Track daily water intake volume and frequency (use a measuring cup)
Keep a detailed record of appetite changes, vomiting episodes, and diarrhea
If possible, record a video of urination or drinking behaviour and bring a fresh urine sample

03How Does the Vet Make a Diagnosis? Common Diagnostic Tests

At the clinic, the vet will begin with a physical examination and then combine blood, urine, and imaging tests to confirm the diagnosis and identify possible underlying causes.

Complete physical examination

assessing body condition, degree of dehydration, and vital signs

Blood chemistry panel

measuring electrolytes, kidney function, and blood glucose

Complete blood count (CBC)

checking for signs of anaemia or infection

Urinalysis and urine specific gravity

assessing renal tubular function and urine dilution

Imaging studies (X-ray, ultrasound, or CT if needed) to rule out other organ pathology

04Post-Diagnosis Treatment and Care: Medications, Diet, and Home Management

Treatment is tailored to test results and typically involves supportive care and dietary management, with regular monitoring of biochemical values and clinical signs.

Formulate a supportive or pharmacological treatment plan based on test findings
Implement a therapeutic diet and fluid management strategy
Weigh your pet daily at home and keep a log of water intake and urination to monitor trends
Attend scheduled follow-up appointments and monitor blood chemistry and urinalysis as directed
If the condition does not improve or a concurrent disease is suspected, a specialist referral is recommended

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

Prepare a timeline of when symptoms began, how they have changed, and daily records including weight

Bring a few days' worth of water intake and urination logs, plus any relevant videos

List all current medications, supplements, and their dosing schedule

Bring any recent blood work or imaging reports to the appointment

If possible, bring a small amount of fresh urine in a sealed container for on-site testing

Call ahead to book at a clinic equipped for imaging and comprehensive diagnostic testing

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.