Veterinary Guide to High Blood Sugar in Dogs 2025 ⚕️🐶

By Dr. Duncan Houston BVSc

🧬 What Is High Blood Sugar (Hyperglycemia)?

Hyperglycemia occurs when blood glucose rises above 200 mg/dL, exceeding the renal threshold (~180–200 mg/dL), leading to glucosuria and osmotic diuresis. Normal fasting glucose in dogs is about 80–120 mg/dL.

🚨 Common Causes of Hyperglycemia

• Diabetes mellitus: The most prevalent cause—insufficient insulin production or poor response.
• Pancreatitis: Inflammation of the pancreas affecting insulin‐producing cells.
• Hormonal disorders: Cushing’s, acromegaly, pheochromocytoma.
• Stress‑induced spikes: Vet visits, anxiety, and excitement can cause transient increases.
• Infections & illness: UTIs, dental disease, and sepsis elevate glucose through stress hormones.
• Medication side effects: Steroids, certain drugs may raise levels.

⚠️ Clinical Signs: The 3 P’s & Beyond

• Polyuria (frequent urination) and polydipsia (increased thirst): Due to osmotic diuresis.
• Polyphagia (increased appetite) paired with weight loss as fat & muscle breakdown.
• Lethargy & weakness: Glucose-starved cells lead to fatigue.
• Recurrent infections: Glucosuria fosters skin, urinary, and ear infections.
• Vision issues: Cataracts, rare retinal damage.
• GI upset: Vomiting, diarrhea—especially in severe cases or diabetic ketoacidosis (DKA).

🔍 Diagnosis: Tests That Confirm

1. Blood glucose: Fasting levels >200 mg/dL suggest hyperglycemia.
2. Fructosamine: Reflects average glucose over past 2–3 weeks—helps differentiate chronic from stress-related spikes.
3. Urinalysis: Glucosuria and/or ketonuria confirms diagnosis.
4. Blood panel: To evaluate kidneys, liver, electrolytes, and screen for complications.
5. Imaging/tests: Pancreas ultrasound, adrenal screening, infection testing per clinical signs.

💉 Treatment Strategies

Insulin Therapy

Dogs typically require twice-daily intermediate-acting insulin (e.g., Vetsulin®, NPH). Timing is crucial: inject 15–30 minutes before meals to match digestion. At-home glucose curves and spot checks guide dose adjustments.

Diet & Lifestyle

• High fiber, complex-carb diets with consistent calorie content.
• Maintain a stable meal schedule that aligns with insulin timing.
• Exercise: moderate, consistent activity; avoid peaks that cause hypoglycemia.

Addressing the Underlying Causes

• Treat pancreatitis, infections, and endocrine disorders as indicated.
• Review medications; switch if glucose.

Manage Complications

• For DKA: hospitalization, IV fluids, insulin, electrolyte correction.
• Monitor cataracts, neuropathy, and infection risks.

📊 Monitoring & Follow-Up

• Frequent glucose curves (every 1–2 hrs over a 12–24 hr period) during stabilization.
• Spot checks at home using a glucometer (AlphaTRAK2, FreeStyle Libre) for day-to-day management.
• Urine checks for glucosuria/ketones.
• Regular vet exams: every 3–6 months, once regulated.

🏡 At-Home Tips for Owners

• Keep a consistent meal, insulin, and activity schedule.
• Track appetite, water intake, urination, energy, and weight.
• Use non-skid mats and comfortable spaces if vision is affected.
• Have emergency glucose sources (dextrose gel, honey) ready.
• Avoid carb snacks—stick to vet-approved treats.
• Regular dental care to prevent infections.
• Consider pet insurance—diabetes is treatable, but long-term.

📱 Ask A Vet Integration

• Telehealth support: remote glucose reviews, insulin dose adjustments.
• Guidance on buying and using home monitoring devices.

📈 Prognosis

With stable insulin and lifestyle control, diabetic dogs live full lives similar in expectancy to their non-diabetic peers. Without treatment, chronic hyperglycemia leads to serious complications and the risk of death.

✅ Owner Checklist

1. Get vet-confirmed diagnosis via glucose & fructosamine tests.
2. Start insulin protocol with precise meal-injection timing.
3. Set weekly home glucose monitoring—track trends, not single values.
4. Use Ask A Vet for dietary, medical, and monitoring support.
5. Schedule biannual vet visits once stabilized.
6. Prepare for emergencies—hypo/hyper crises.

🎓 Case Highlight: “Charlie” the Diabetic Corgi

Charlie, a 9-year-old Corgi, presented with polyuria, weight loss, and cataracts. Fasting glucose was 350 mg/dL; fructosamine confirmed chronic hyperglycemia. With twice-daily insulin and a fiber‑rich diet guided by Ask A Vet’s  Charlie, 's blood sugar stabilized to ~120–180 mg/dL. Six months later, he's active, his coat is glossy, and his appetite is healthy. The owner reports he “feels like a puppy again”! 🐾

🔚 Final Thoughts

High blood sugar in dogs needs proactive care—early detection, consistent insulin, diet, and monitoring lead to an excellent long-term prognosis. Ask A Vet is here to partner with you and your pup every step of the way. With care, diabetic dogs thrive! ❤️

Dr Duncan Houston BVSc, Ask A Vet founder. Don’t forget to download the Ask A Vet app for expert diabetes guidance anytime—because your dog deserves paw-sitive care! 🐶