고양이 다음다뇨(PU/PD) 자주 묻는 질문 Q&A — 보호자가 꼭 알아야 할 핵심

My Cat Is Drinking Too Much Water — Causes of PU/PD and When to Visit the Vet

KidneyQ&AMeongsiljang Veterinary Advisory Board

Feline polyuria and polydipsia (PU/PD), characterized by excessive drinking and frequent urination, can be an early sign of diabetes or kidney disease. It is important for pet owners to recognize these symptoms quickly and consult with a veterinarian.

What Is Feline Polyuria and Polydipsia (PU/PD)?

A scene of a cat drinking a lot of water

Feline polyuria and polydipsia (PU/PD) refers to excessive drinking and frequent urination, which can be early signs of kidney dysfunction or hormonal imbalances. - Increased water intake (polydipsia, PD): This occurs when a cat drinks more than 45 mL of water per kilogram of body weight per day. - Increased urine output (polyuria, PU): This is defined as producing more than 40 mL of urine per kilogram of body weight per day, characterized by more frequent litter box visits and larger urine volumes. This can signal various conditions, including diabetes mellitus, chronic kidney disease, and hyperadrenocorticism. Owners should carefully monitor and record any changes in symptoms and consult their veterinarian.

What Are the Main Causes of PU/PD?

Polyuria, or excessive urination, can stem from a variety of underlying conditions. - Diabetes mellitus: Insufficient insulin leads to elevated blood sugar levels, causing increased thirst and more frequent urination. - Chronic kidney disease: Symptoms arise as the kidneys’ ability to regulate water and electrolytes declines. - Hyperadrenocorticism (Cushing’s disease): Excess cortisol production results in increased urine output. - Electrolyte imbalances: Disruptions in sodium or potassium levels can also contribute. - Infections or medications: Urinary tract infections or certain medications may cause temporary symptoms. Blood and urine tests are essential to identify the exact cause.

An anatomical diagram explaining the main causes of feline diabetes mellitus

What Are the Main Symptoms of PU/PD?

The main symptoms of feline polyuria and polydipsia are frequent drinking and frequent litter box use. - Increased water intake: Drinking more than 45 mL per kilogram of body weight per day is considered polydipsia (excessive thirst). - Increased urine output: Urine volume exceeding 40 mL per kilogram of body weight per day may occur, often accompanied by a stronger odor and more frequent trips to the litter box. - Changes in elimination habits: More frequent urination can lead to a stronger smell, and some cats may start eliminating outside the litter box. - Changes in daily behavior: Fatigue, decreased appetite, and weight loss may also be present. These are not just behavioral changes but potential signs of disease, so prompt diagnosis is essential.

Your cat frequently using the litter box

Signs That Require Immediate Veterinary Care

If your cat drinks more than 45 mL/kg of water per day or experiences a sudden increase in urine output, seek veterinary care immediately. These symptoms could indicate diabetes or kidney dysfunction.

Comparison of PU/PD Symptoms by Severity and Management Strategies

Item	Mild	Moderate	Severe
Water intake	45 mL/kg/day or less (normal range)	Approaching 45 mL/kg/day	Exceeding 45 mL/kg/day (polydipsia criterion)
Urination frequency	2–3 times a day	4–6 times a day	7 or more times a day
Management	Observe and record	Consult a veterinarian	Immediate testing and treatment

In cats, water intake exceeding 45 mL/kg/day and urine output exceeding 40 mL/kg/day is considered polydipsia/polyuria (PU/PD) (normal urine output is 20–45 mL/kg/day). Water intake exceeding 45 mL/kg/day requires urgent veterinary care.

PU/PD Management Tips and Care Guidelines

The key to managing polyuria is accurately identifying the underlying cause. - Keep a log: Record your pet’s daily water intake and urine output as if keeping a diary. - Consult a veterinarian: If symptoms persist, seek veterinary care immediately. - Reduce stress: Avoid environmental changes and excessive stimulation, and provide a calm, stable space. - Dietary management: Use prescription diets as recommended by your veterinarian. - Ensure hydration: Change the water frequently and place multiple bowls around the home to improve accessibility. Early diagnosis and management are crucial to preventing disease progression.

A scene showing a pet owner recording their cat's water intake and urine output.

Precautions Related to PU/PD

Polyuria and polydipsia in cats are not merely a habit but may be an early sign of an underlying disease. - Do not self-diagnose: Using medications or supplements without veterinary guidance can worsen the condition. - Caution for senior cats: Older cats are at higher risk for diseases that cause polyuria and polydipsia, such as chronic kidney disease. - Importance of record-keeping: Carefully documenting changes in symptoms greatly assists in diagnosis. - Seek veterinary care early: If symptoms persist for more than 2–3 days, consult a veterinarian promptly. Early detection aids in effective treatment.

An elderly cat managing its health condition

Caution: Risk of Worsening Due to Improper Management

Ignoring excessive urination or attempting self-treatment without consulting a veterinarian can worsen diabetes or kidney disease. Accurate diagnosis and proper treatment are essential.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

Is it normal for a cat to drink a lot of water?

A daily water intake of 45 mL per kilogram of body weight or less is considered normal. Exceeding 45 mL/kg may indicate polydipsia (excessive drinking).

Is polydipsia related to a cat's age?

Yes, it can be more common in older cats. As cats age, their risk of developing related conditions such as chronic kidney disease increases.

What tests are needed to diagnose diabetes insipidus?

We start with basic blood tests, urinalysis, and imaging (ultrasound). If the cause isn’t clear, we may add hormone tests or a water restriction test to pinpoint the exact issue.

Can polydipsia-polyuria be treated?

Management depends on the underlying cause. For conditions like diabetes or kidney disease, it can be managed through medication and dietary adjustments.

What should I do at home if my pet develops polyuria?

Track your pet’s water intake and urination frequency for a few days, then discuss the records with your veterinarian. Also, try to minimize any sources of stress.