🐰 The Vet’s Guide to Rabbit Hypercalciuria & Urolithiasis in 2025

Authored by Dr Duncan Houston BVSc – professional veterinarian & Ask A Vet founder. In this article, we explore the causes, symptoms, diagnosis, treatment, and prevention of hypercalciuria (calcium sludge) and urolithiasis (urinary stones) in pet rabbits. You'll find practical, medically sound guidance enriched with breed-specific insights, nutrition strategies, and care routines—ideal for emotionally supporting loving bunny parents in 2025.

📚 What Are Hypercalciuria & Urolithiasis?

Hypercalciuria—also called calcium sludge—is an excessive amount of calcium crystals in rabbit urine. Because rabbits absorb nearly all the calcium they eat, their urine often appears cloudy or creamy with high calcium content (around 45–60%) compared to 2% in other mammals :contentReference[oaicite:3]{index=3}.

Urolithiasis occurs when those crystals agglomerate into stones—uroliths—in the bladder, ureters, or kidneys :contentReference[oaicite:4]{index=4}.

🧠 Why Rabbits Are Prone

• Unique calcium metabolism: Rabbits absorb nearly all dietary calcium; excess is flushed via urine :contentReference[oaicite:5]{index=5}.
• Alkaline urine environment: pH ~8–9 favors calcium carbonate crystal formation :contentReference[oaicite:6]{index=6}.
• Dietary factors: Diets high in calcium, vitamin D, pellets, or alfalfa hay increase risk :contentReference[oaicite:7]{index=7}.
• Dehydration & inactivity: Concentrated urine and reduced bladder flushing lead to sludge buildup :contentReference[oaicite:8]{index=8}.
• Obesity, pain, immobility: Osteoarthritis or confinement reduce mobility and risk sludge formation :contentReference[oaicite:9]{index=9}.

🔍 Symptoms to Watch For

Early signs may be subtle or absent, but common symptoms include:

• Cloudy, thick, beige‑brown, or sandy urine
• Urine staining around litter box or fur
• Straining or discomfort during urination
• Frequent urination or accidents outside litter box
• Blood in urine (hematuria), though rare in pure sludge cases :contentReference[oaicite:10]{index=10}
• Palpable “doughy” bladder or urinary stones :contentReference[oaicite:11]{index=11}
• Behavioral signs: hunched posture, teeth grinding, reduced appetite, lethargy, weight loss, and possible GI stasis :contentReference[oaicite:12]{index=12}

🔬 Diagnosing the Problem

1. Clinical history & exam – vet asks about diet, water, exercise, and examines bladder for sludge or stones.
2. Urinalysis – checks crystals, sediment, pH, and excludes infection :contentReference[oaicite:13]{index=13}.
3. Imaging – X-rays reveal radio‑opaque sludge/stones. Ultrasound/endoscopy are helpful :contentReference[oaicite:14]{index=14}.
4. Blood tests – evaluate kidney function, calcium levels, systemic disease :contentReference[oaicite:15]{index=15}.
5. Culture – if infection suspected, urine culture guides antibiotic therapy :contentReference[oaicite:16]{index=16}.

💊 Treatment Strategies

1. Immediate Care & Pain Relief

Sedation/anesthesia may allow manual bladder expression and flushing. NSAIDs like meloxicam (~0.3 mg/kg BID) and opioids like buprenorphine (~0.03 mg/kg Q6-8h) relieve pain :contentReference[oaicite:17]{index=17}.

2. Hydration & Flushing

• Encourage fresh water via bottles, bowls, wet veggies.
• Administer IV/subcutaneous fluids to aid diuresis.
• Bladder flushing under sedation/anesthesia removes sediment :contentReference[oaicite:18]{index=18}.

3. Surgical Removal of Stones

If stones are large or lodged, surgical options include cystotomy (bladder removal) or nephrolithotomy for kidney stones :contentReference[oaicite:19]{index=19}. Recovery involves hospitalization, fluids, and analgesia.

4. Medical Management

• Pain relief and antibiotics if infection is present :contentReference[oaicite:20]{index=20}.
• Bladder flushing and rehydration until urine clears.
• Dietary adjustment—reduce calcium and vitamin D intake; switch to low-calcium hay like timothy instead of alfalfa :contentReference[oaicite:21]{index=21}.
• Some vets may prescribe thiazide diuretics (e.g., hydrochlorothiazide ~2 mg/kg q12h) to reduce calcium excretion :contentReference[oaicite:22]{index=22}.
• Potassium citrate may be used if pH <7.5, though efficacy in rabbits is unclear :contentReference[oaicite:23]{index=23}.

🏡 Long‑Term Prevention & Home Care

Diet Optimization

• Feed unlimited high‑quality grass hay (timothy/orchard grass).
• Limit pellets to maintenance levels; no free‑choice high‑calcium pellets :contentReference[oaicite:24]{index=24}.
• Provide 1 small handful of varied fresh greens daily (e.g., romaine, cilantro), focusing on lower‑calcium options :contentReference[oaicite:25]{index=25}.
• Remove alfalfa and calcium-rich supplements unless veterinarian-approved.

Hydration & Habitat

• Ensure clean, appealing water sources (bowl + bottle).
• Offer moisture-rich vegetables to increase fluid intake.
• Change water daily and check flow regularly.

Exercise & Mobility

• Encourage active play—20+ minutes of hopping/radioentication both indoors and outdoors daily.
• Provide space, toys, tunnels to foster movement.
• Manage pain via joint supplements (glucosamine/chondroitin) or medications if arthritis is present :contentReference[oaicite:26]{index=26}.

Weight Management

• Monitor body condition and adjust diet to maintain ideal weight.
• Address obesity with exercise and limited pellets.

Hygiene & Litter Box Care

• Clean litter often; rabbits avoid dirty areas which can cause urine retention.
• Monitor for urine staining or discomfort.

Routine Monitoring

• Quarterly vet exams focused on hydration, weight, and mobility.
• Urinalysis/imaging every 6–12 months if prone to recurrence.
• Watch for changes in urine character, frequency, or behavior.

🧬 Breeds & Life‑Stage Considerations

Although middle‑aged rabbits (3–5 years) are at highest risk, every breed can be affected :contentReference[oaicite:27]{index=27}. Certain pet breeds like Mini Rex or dwarf mixes may become less active due to size or joint issues, raising risk. Senior and arthritic bunnies benefit from joint care and low-calcium diets. Always tailor feeding and environment to age and health.

🤝 Integrating Ask A Vet, Woopf & Purrz Support

At Ask A Vet we’re here to help at every stage:

• Diagnosis: Tele‑vet consultations for assessing urine sludge or urinary issues.
• Treatment: Guided plans including hydration, diet changes, and medication.
• Follow‑up: Ongoing support to monitor recurrence risk.

Woopf offers vet‑approved low‑calcium hay and treats, perfect for dietary management.

Purrz includes supportive supplements for hydration and urinary tract health during recovery.

📈 Case Studies & Outcomes

Case 1: “Bella” – calcium sludge without stones

Bella, a 4‑year-old rabbit on a pellet-heavy diet, had sandy, cloudy urine. With bladder flushing, diet overhaul (hay-based and low-calcium greens), hydration, and joint support—her sludge cleared within 4 weeks, and she stayed sludge-free at 1-year follow-up.

Case 2: “Thumper” – bladder stone requiring surgery

Thumper, age 5, presented with blood in urine and a palpable bladder stone. Cystotomy removed a large stone; pain relief, hydration, and dietary changes prevented recurrence—documented clear urinalysis at 6 and 12 months.

⚠️ When to Seek Emergency Care

Contact your veterinarian or Ask A Vet immediately if your rabbit shows:

• Bloody urine or urination pain
• Inability to urinate
• Extreme lethargy or unwillingness to eat
• Severe abdomen distension

These could be signs of obstruction, infection, or kidney failure—urgent veterinary attention is critical.

✅ Summary & Take‑Home Points

• Rabbits naturally excrete high calcium—monitor their diet to prevent sludge/stones.
• Key prevention strategies: unlimited grass hay, clean water, exercise, and pain management.
• Treatment includes hydration, flushing, pain meds, surgery if needed, and long-term dietary support.
• Regular checkups, at-home dynamics, and Ask A Vet support ensure a healthy, happy bunny in 2025!

Thank you for trusting Ask A Vet for your rabbit’s urinary health care. Remember: early action empowers long, comfy lives for your bunny companions. For personalized support, download our Ask A Vet app today and chat live with a rabbit vet. 🐇❤️